127 results on '"Chlorophyll f"'
Search Results
2. Optically detected magnetic resonance and mutational analysis reveal significant differences in the photochemistry and structure of chlorophyll f synthase and photosystem II.
- Author
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Agostini A, Shen G, Bryant DA, Golbeck JH, van der Est A, and Carbonera D
- Subjects
- Chlorophyll A, Carotenoids chemistry, Nitric Oxide Synthase, Magnetic Resonance Spectroscopy, Photosystem II Protein Complex metabolism, Chlorophyll metabolism
- Abstract
In cyanobacteria that undergo far red light photoacclimation (FaRLiP), chlorophyll (Chl) f is produced by the ChlF synthase enzyme, probably by photo-oxidation of Chl a. The enzyme forms homodimeric complexes and the primary amino acid sequence of ChlF shows a high degree of homology with the D1 subunit of photosystem II (PSII). However, few details of the photochemistry of ChlF are known. The results of a mutational analysis and optically detected magnetic resonance (ODMR) data from ChlF are presented. Both sets of data show that there are significant differences in the photochemistry of ChlF and PSII. Mutation of residues that would disrupt the donor side primary electron transfer pathway in PSII do not inhibit the production of Chl f, while alteration of the putative Chl
Z , P680 and QA binding sites rendered ChlF non-functional. Together with previously published transient EPR and flash photolysis data, the ODMR data show that in untreated ChlF samples, the triplet state of P680 formed by intersystem crossing is the primary species generated by light excitation. This is in contrast to PSII, in which3 P680 is only formed by charge recombination when the quinone acceptors are removed or chemically reduced. The triplet states of a carotenoid (3 Car) and a small amount of3 Chl f are also observed by ODMR. The polarization pattern of3 Car is consistent with its formation by triplet energy transfer from ChlZ if the carotenoid molecule is rotated by 15° about its long axis compared to the orientation in PSII. It is proposed that the singlet oxygen formed by the interaction between molecular oxygen and3 P680 might be involved in the oxidation of Chl a to Chl f., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.) more...- Published
- 2023
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3. Chlorophyll f production in two new subaerial cyanobacteria of the family Oculatellaceae.
- Author
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Shen LQ, Zhang ZC, Huang L, Zhang LD, Yu G, Chen M, Li R, and Qiu BS
- Subjects
- Phylogeny, RNA, Ribosomal, 16S genetics, Light, Chlorophyll metabolism, Cyanobacteria chemistry
- Abstract
Chlorophyll (Chl) f was recently identified in a few cyanobacteria as the fifth chlorophyll of oxygenic organisms. In this study, two Leptolyngbya-like strains of CCNU0012 and CCNU0013 were isolated from a dry ditch in Chongqing city and a brick wall in Mount Emei Scenic Area in China, respectively. These two strains were described as new species: Elainella chongqingensis sp. nov. (Oculatellaceae, Synechococcales) and Pegethrix sichuanica sp. nov. (Oculatellaceae, Synechococcales) by the polyphasic approach based on morphological features, phylogenetic analysis of 16S rRNA gene and secondary structure comparison of 16S-23S internal transcribed spacer domains. Both strains produced Chl a under white light (WL) but additionally induced Chl f synthesis under far-red light (FRL). Unexpectedly, the content of Chl f in P. sichuanica was nearly half that in most Chl f-producing cyanobacteria. Red-shifted phycobiliproteins were also induced in both strains under FRL conditions. Subsequently, additional absorption peak beyond 700 nm in the FRL spectral region appeared in these two strains. This is the first report of Chl f production induced by FRL in the family Oculatellaceae. This study not only extended the diversity of Chl f-producing cyanobacteria but also provided precious samples to elucidate the essential binding sites of Chl f within cyanobacterial photosystems., (© 2023 Phycological Society of America.) more...
- Published
- 2023
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4. Structure of a monomeric photosystem II core complex from a cyanobacterium acclimated to far-red light reveals the functions of chlorophylls d and f.
- Author
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Gisriel CJ, Shen G, Ho MY, Kurashov V, Flesher DA, Wang J, Armstrong WH, Golbeck JH, Gunner MR, Vinyard DJ, Debus RJ, Brudvig GW, and Bryant DA
- Subjects
- Light, Photosynthesis, Photosystem I Protein Complex metabolism, Water metabolism, Chlorophyll metabolism, Photosystem II Protein Complex metabolism, Synechococcus metabolism
- Abstract
Far-red light (FRL) photoacclimation in cyanobacteria provides a selective growth advantage for some terrestrial cyanobacteria by expanding the range of photosynthetically active radiation to include far-red/near-infrared light (700-800 nm). During this photoacclimation process, photosystem II (PSII), the water:plastoquinone photooxidoreductase involved in oxygenic photosynthesis, is modified. The resulting FRL-PSII is comprised of FRL-specific core subunits and binds chlorophyll (Chl) d and Chl f molecules in place of several of the Chl a molecules found when cells are grown in visible light. These new Chls effectively lower the energy canonically thought to define the "red limit" for light required to drive photochemical catalysis of water oxidation. Changes to the architecture of FRL-PSII were previously unknown, and the positions of Chl d and Chl f molecules had only been proposed from indirect evidence. Here, we describe the 2.25 Å resolution cryo-EM structure of a monomeric FRL-PSII core complex from Synechococcus sp. PCC 7335 cells that were acclimated to FRL. We identify one Chl d molecule in the Chl
D1 position of the electron transfer chain and four Chl f molecules in the core antenna. We also make observations that enhance our understanding of PSII biogenesis, especially on the acceptor side of the complex where a bicarbonate molecule is replaced by a glutamate side chain in the absence of the assembly factor Psb28. In conclusion, these results provide a structural basis for the lower energy limit required to drive water oxidation, which is the gateway for most solar energy utilization on earth., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.) more...- Published
- 2022
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5. Phthalocyanine as a Bioinspired Model for Chlorophyll f-Containing Photosystem II Drives Photosynthesis into the Far-Red Region.
- Author
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Follana-Berná J, Farran R, Leibl W, Quaranta A, Sastre-Santos Á, and Aukauloo A
- Subjects
- Chlorophyll chemistry, Isoindoles, Models, Molecular, Oxidation-Reduction, Photosynthesis radiation effects, Photosystem II Protein Complex chemistry, Spectroscopy, Fourier Transform Infrared, Zinc Compounds, Chlorophyll analogs & derivatives, Indoles chemistry, Light, Organometallic Compounds chemistry, Photosystem II Protein Complex metabolism
- Abstract
The textbook explanation that P
680 pigments are the red limit to drive oxygenic photosynthesis must be reconsidered by the recent discovery that chlorophyll f (Chlf)-containing Photosystem II (PSII) absorbing at 727 nm can drive water oxidation. Two different families of unsymmetrically substituted Zn phthalocyanines (Pc) absorbing in the 700-800 nm spectral window and containing a fused imidazole-phenyl substituent or a fused imidazole-hydroxyphenyl group have been synthetized and characterized as a bioinspired model of the Chlf/TyrosineZ /Histidine190 cofactors of PSII. Transient absorption studies in the presence of an electron acceptor and irradiating in the far-red region evidenced an intramolecular electron transfer process. Visible and FT-IR signatures indicate the formation of a hydrogen-bonded phenoxyl radical in ZnPc II-OH. This study sets the foundation for the utilization of a broader spectral window for multi-electronic catalytic processes with one of the most robust and efficient dyes., (© 2021 Wiley-VCH GmbH.) more...- Published
- 2021
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6. Evidence that chlorophyll f functions solely as an antenna pigment in far-red-light photosystem I from Fischerella thermalis PCC 7521.
- Author
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Cherepanov DA, Shelaev IV, Gostev FE, Aybush AV, Mamedov MD, Shen G, Nadtochenko VA, Bryant DA, Semenov AY, and Golbeck JH
- Subjects
- Chlorophyll metabolism, Spectrometry, Fluorescence, Chlorophyll analogs & derivatives, Cyanobacteria metabolism, Cyanobacteria radiation effects, Light, Light-Harvesting Protein Complexes metabolism, Photosystem I Protein Complex metabolism
- Abstract
The Photosystem I (PSI) reaction center in cyanobacteria is comprised of ~96 chlorophyll (Chl) molecules, including six specialized Chl molecules denoted Chl1A/Chl1B (P
700 ), Chl2A/Chl2B, and Chl3A/Chl3B that are arranged in two branches and function in primary charge separation. It has recently been proposed that PSI from Chroococcidiopsis thermalis (Nürnberg et al. (2018) Science 360, 1210-1213) and Fischerella thermalis PCC 7521 (Hastings et al. (2019) Biochim. Biophys. Acta 1860, 452-460) contain Chl f in the positions Chl2A/Chl2B. We tested this proposal by exciting RCs from white-light grown (WL-PSI) and far-red light grown (FRL-PSI) F. thermalis PCC 7521 with femtosecond pulses and analyzing the optical dynamics. If Chl f were in the position Chl2A/Chl2B in FRL-PSI, excitation at 740 nm should have produced the charge-separated state P700 + A0 - followed by electron transfer to A1 with a τ of ≤25 ps. Instead, it takes ~230 ps for the charge-separated state to develop because the excitation migrates uphill from Chl f in the antenna to the trapping center. Further, we observe a strong electrochromic shift at 685 nm in the final P700 + A1 - spectrum that can only be explained if Chl a is in the positions Chl2A/Chl2B. Similar arguments rule out the presence of Chl f in the positions Chl3A/Chl3B; hence, Chl f is likely to function solely as an antenna pigment in FRL-PSI. We additionally report the presence of an excitonically coupled homo- or heterodimer of Chl f absorbing around 790 nm that is kinetically independent of the Chl f population that absorbs around 740 nm., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.) more...- Published
- 2020
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7. Substantial near-infrared radiation-driven photosynthesis of chlorophyll f -containing cyanobacteria in a natural habitat.
- Author
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Kühl M, Trampe E, Mosshammer M, Johnson M, Larkum AW, Frigaard NU, and Koren K
- Subjects
- Cells, Cultured, Chlorophyll chemistry, Chlorophyll metabolism, Ecosystem, Geologic Sediments microbiology, Oxygen metabolism, Seawater microbiology, Chlorophyll analogs & derivatives, Cyanobacteria chemistry, Cyanobacteria metabolism, Cyanobacteria radiation effects, Infrared Rays, Photosynthesis physiology, Photosynthesis radiation effects
- Abstract
Far-red absorbing chlorophylls are constitutively present as chlorophyll (Chl) d in the cyanobacterium Acaryochloris marina , or dynamically expressed by synthesis of Chl f , red-shifted phycobiliproteins and minor amounts of Chl d via far-red light photoacclimation in a range of cyanobacteria, which enables them to use near-infrared-radiation (NIR) for oxygenic photosynthesis. While the biochemistry and molecular physiology of Chl f -containing cyanobacteria has been unraveled in culture studies, their ecological significance remains unexplored and no data on their in situ activity exist. With a novel combination of hyperspectral imaging, confocal laser scanning microscopy, and nanoparticle-based O
2 imaging, we demonstrate substantial NIR-driven oxygenic photosynthesis by endolithic, Chl f -containing cyanobacteria within natural beachrock biofilms that are widespread on (sub)tropical coastlines. This indicates an important role of NIR-driven oxygenic photosynthesis in primary production of endolithic and other shaded habitats., Competing Interests: MK, ET, MM, MJ, AL, NF, KK No competing interests declared, (© 2020, Kühl et al.) more...- Published
- 2020
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8. Far-red light acclimation in diverse oxygenic photosynthetic organisms.
- Author
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Wolf BM and Blankenship RE
- Subjects
- Acclimatization, Chlorophyll metabolism, Chlorophyll A metabolism, Light, Light-Harvesting Protein Complexes metabolism, Photosystem II Protein Complex metabolism, Chlorophyll analogs & derivatives, Cyanobacteria physiology, Photosynthesis, Plant Physiological Phenomena
- Abstract
Oxygenic photosynthesis has historically been considered limited to be driven by the wavelengths of visible light. However, in the last few decades, various adaptations have been discovered that allow algae, cyanobacteria, and even plants to utilize longer wavelength light in the far-red spectral range. These adaptations provide distinct advantages to the species possessing them, allowing the effective utilization of shade light under highly filtered light environments. In prokaryotes, these adaptations include the production of far-red-absorbing chlorophylls d and f and the remodeling of phycobilisome antennas and reaction centers. Eukaryotes express specialized light-harvesting pigment-protein complexes that use interactions between pigments and their protein environment to spectrally tune the absorption of chlorophyll a. If these adaptations could be applied to crop plants, a potentially significant increase in photon utilization in lower shaded leaves could be realized, improving crop yields. more...
- Published
- 2019
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9. Fourier transform visible and infrared difference spectroscopy for the study of P700 in photosystem I from Fischerella thermalis PCC 7521 cells grown under white light and far-red light: Evidence that the A -1 cofactor is chlorophyll f.
- Author
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Hastings G, Makita H, Agarwala N, Rohani L, Shen G, and Bryant DA
- Subjects
- Bacterial Proteins metabolism, Chlorophyll chemistry, Chlorophyll metabolism, Cyanobacteria metabolism, Hydrogen Bonding, Models, Molecular, Molecular Structure, Photosynthesis, Photosystem I Protein Complex metabolism, Spectrophotometry, Bacterial Proteins chemistry, Bacterial Proteins radiation effects, Chlorophyll analogs & derivatives, Cyanobacteria chemistry, Light, Photosystem I Protein Complex chemistry
- Abstract
(P700
+ - P700) Fourier transform visible and infrared difference spectra (DS) have been obtained using photosystem I (PSI) complexes isolated from cells of Fischerella thermalis PCC 7521 grown under white light (WL) or far-red light (FRL). PSI from cells grown under FRL (FRL-PSI) contain ~8 chlorophyll f (Chl f) molecules (Shen et al., Photosynth. Res. Jan. 2019). Both the visible and infrared DS indicate that neither the PA or PB pigments of P700 are Chl f molecules, but do support the conclusion that at least one of the A-1 cofactors is a Chl f molecule. The FTIR DS indicate that the hydrogen bond to the 131 -keto CO group of the PA pigment of P700 is weakened in FRL-PSI, as might be expected given that the proteins that bind the P700 pigments are substantially different in FRL-PSI (Gan et al., Science 345, 1312-1317, 2014). The FTIR DS obtained using FRL-PSI display a band at 1664 cm-1 that is assigned (based on density functional theory calculations) to the 21 -formyl CO group of Chl f, that upshifts 5 cm-1 upon P700+ formation. This is much less than expected for a cation-induced upshift, indicating that the Chl f molecule is not one of the pigments of P700. In WL-PSI the A-1 cofactor is a Chl a molecule with 131 -keto and 133 -methylester CO mode vibrations at 1696 and 1750 cm-1 , respectively. In FRL-PSI the A-1 cofactor is a Chl f molecule with 131 -keto and 133 -methylester CO mode vibrations at 1702 and 1754 cm-1 , respectively., (Copyright © 2019 Elsevier B.V. All rights reserved.) more...- Published
- 2019
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10. Excited State Frequencies of Chlorophyll f and Chlorophyll a and Evaluation of Displacement through Franck-Condon Progression Calculations.
- Author
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Zamzam N and van Thor JJ
- Subjects
- Algorithms, Chlorophyll chemistry, Models, Molecular, Spectrum Analysis, Chlorophyll analogs & derivatives, Chlorophyll A chemistry, Models, Chemical
- Abstract
We present ground and excited state frequency calculations of the recently discovered extremely red-shifted chlorophyll f. We discuss the experimentally available vibrational mode assignments of chlorophyll f and chlorophyll a which are characterised by particularly large downshifts of 13¹-keto mode in the excited state. The accuracy of excited state frequencies and their displacements are evaluated by the construction of Franck-Condon (FC) and Herzberg-Teller (HT) progressions at the CAM-B3LYP/6-31G(d) level. Results show that while CAM-B3LYP results are improved relative to B3LYP calculations, the displacements and downshifts of high-frequency modes are underestimated still, and that the progressions calculated for low temperature are dominated by low-frequency modes rather than fingerprint modes that are Resonant Raman active. more...
- Published
- 2019
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11. Spectral signatures of five hydroxymethyl chlorophyll a derivatives chemically derived from chlorophyll b or chlorophyll f.
- Author
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Sawicki A, Willows RD, and Chen M
- Subjects
- Borohydrides chemistry, Chlorophyll analogs & derivatives, Chlorophyll isolation & purification, Chlorophyll A chemistry, Chlorophyll A isolation & purification, Mercaptoethanol chemistry, Oxidation-Reduction, Photosynthesis, Plant Leaves chemistry, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Chlorophyll chemistry, Spinacia oleracea chemistry
- Abstract
Chlorophylls (Chls) are pigments involved in light capture and light reactions in photosynthesis. Chl a, Chl b, Chl d, and Chl f are characterized by unique absorbance maxima in the blue (Soret) and red (Q
y ) regions with Chl b, Chl d, and Chl f each possessing a single formyl group at a unique position. Relative to Chl a the Qy absorbance maximum of Chl b is blue-shifted while Chl d and Chl f are red-shifted with the shifts attributable to the relative positions of the formyl substitutions. Reduction of a formyl group of Chl b to form 7-hydroxymethyl Chl a, or oxidation of the vinyl group of Chl a into a formyl group to form Chl d was achieved using sodium borohydride (NaBH4 ) or β-mercaptoethanol (BME/O2 ), respectively. During the consecutive reactions of Chl b and Chl f using a three-step procedure (1. NaBH4 , 2. BME/O2 , and 3. NaBH4 ) two new 7-hydroxymethyl Chl a species were prepared possessing the 3-formyl or 3-hydroxymethyl groups and three new 2-hydroxymethyl Chl a species possessing the 3-vinyl, 3-formyl, or 3-hydroxymethyl groups, respectively. Identification of the spectral properties of 2-hydroxymethyl Chl a may be biologically significant for deducing the latter stages of Chl f biosynthesis if the mechanism parallels Chl b biosynthesis. The spectral features and chromatographic properties of these modified Chls are important for identifying potential intermediates in the biosynthesis of Chls such as Chl f and Chl d and for identification of any new Chls in nature. more...- Published
- 2019
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12. Photosynthesis supported by a chlorophyll f-dependent, entropy-driven uphill energy transfer in Halomicronema hongdechloris cells adapted to far-red light.
- Author
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Schmitt FJ, Campbell ZY, Bui MV, Hüls A, Tomo T, Chen M, Maksimov EG, Allakhverdiev SI, and Friedrich T
- Subjects
- Chlorophyll metabolism, Entropy, Photosynthesis genetics, Photosystem II Protein Complex metabolism, Chlorophyll analogs & derivatives, Light, Photosynthesis physiology
- Abstract
The phototrophic cyanobacterium Halomicronema hongdechloris shows far-red light-induced accumulation of chlorophyll (Chl) f, but the involvement of the pigment in photosynthetic energy harvesting by photosystem (PS) II is controversially discussed. While H. hongdechloris contains negligible amounts of Chl f in white-light culture conditions, the ratio of Chl f to Chl a is reversibly changed up to 1:8 under illumination with far-red light (720-730 nm). We performed UV-Vis absorption spectroscopy, time-integrated and time-resolved fluorescence spectroscopy for the calculation of decay-associated spectra (DAS) to determine excitation energy transfer (EET) processes between photosynthetic pigments in intact H. hongdechloris filaments. In cells grown under white light, highly efficient EET occurs from phycobilisomes (PBSs) to Chl a with an apparent time constant of about 100 ps. Charge separation occurs with a typical apparent time constant of 200-300 ps from Chl a. After 3-4 days of growth under far-red light, robust Chl f content was observed in H. hongdechloris and EET from PBSs reached Chl f efficiently within 200 ps. It is proposed based on mathematical modeling by rate equation systems for EET between the PBSs and PSII and subsequent electron transfer (ET) that charge separation occurs from Chl a and excitation energy is funneled from Chl f to Chl a via an energetically uphill EET driven by entropy, which is effective because the number of Chl a molecules coupled to Chl f is at least eight- to tenfold larger than the corresponding number of Chl f molecules. The long lifetime of Chl f molecules in contact to a tenfold larger pool of Chl a molecules allows Chl f to act as an intermediate energy storage level, from which the Gibbs free energy difference between Chl f and Chl a can be overcome by taking advantage from the favorable ratio of degeneracy coefficients, which formally represents a significant entropy gain in the Eyring formulation of the Arrhenius law. Direct evidence for energetically uphill EET and charge separation in PSII upon excitation of Chl f via anti-Stokes fluorescence in far-red light-adapted H. hongdechloris cells was obtained: Excitation by 720 nm laser light resulted in robust Chl a fluorescence at 680 nm that was distinctly temperature-dependent and, notably, increased upon DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) treatment in far-red light-adapted cells. Thus, rather than serving as an excitation energy trap, Chl f in far-red light-adapted H. hongdechloris cells is directly contributing to oxygenic photosynthesis at PSII. more...
- Published
- 2019
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13. The C2 1 -formyl group in chlorophyll f originates from molecular oxygen.
- Author
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Garg H, Loughlin PC, Willows RD, and Chen M
- Subjects
- Chlorophyll isolation & purification, Chlorophyll metabolism, Isotope Labeling, Kinetics, Light, Photosynthesis, Chlorophyll analogs & derivatives, Cyanobacteria metabolism, Oxygen metabolism
- Abstract
Chlorophylls (Chls) are the most important cofactors for capturing solar energy to drive photosynthetic reactions. Five spectral types of Chls have been identified to date, with Chl f having the most red-shifted absorption maximum because of a C2
1 -formyl group substitution of Chl f However, the biochemical provenance of this formyl group is unknown. Here, we used a stable isotope labeling technique (18 O and2 H) to determine the origin of the C21 -formyl group of Chl f and to verify whether Chl f is synthesized from Chl a in the cyanobacterial species Halomicronema hongdechloris. In the presence of either H2 18 O or18 O2 , the origin of oxygen atoms in the newly synthesized chlorophylls was investigated. The pigments were isolated with HPLC, followed by MS analysis. We found that the oxygen atom of the C21 -formyl group originates from molecular oxygen and not from H2 O. Moreover, we examined the kinetics of the labeling of Chl a and Chl f from H. hongdechloris grown in 50% D2 O-seawater medium under different light conditions. When cells were shifted from white light D2 O-seawater medium to far-red light H2 O-seawater medium, the observed deuteration in Chl f indicated that Chl(ide) a is the precursor of Chl f Taken together, our results advance our understanding of the biosynthesis pathway of the chlorophylls and the formation of the formyl group in Chl f ., (© 2017 by The American Society for Biochemistry and Molecular Biology, Inc.) more...- Published
- 2017
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14. Subcellular pigment distribution is altered under far-red light acclimation in cyanobacteria that contain chlorophyll f.
- Author
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Majumder EL, Wolf BM, Liu H, Berg RH, Timlin JA, Chen M, and Blankenship RE
- Subjects
- Acclimatization physiology, Chlorophyll metabolism, Cyanobacteria radiation effects, Cyanobacteria ultrastructure, Microscopy, Electron, Transmission, Photosynthesis physiology, Acclimatization radiation effects, Chlorophyll analogs & derivatives, Cyanobacteria physiology, Light, Phycobilisomes metabolism
- Abstract
Far-Red Light (FRL) acclimation is a process that has been observed in cyanobacteria and algae that can grow solely on light above 700 nm. The acclimation to FRL results in rearrangement and synthesis of new pigments and pigment-protein complexes. In this study, cyanobacteria containing chlorophyll f, Synechococcus sp. PCC 7335 and Halomicronema hongdechloris, were imaged as live cells with confocal microscopy. H. hongdechloris was further studied with hyperspectral confocal fluorescence microscopy (HCFM) and freeze-substituted thin-section transmission electron microscopy (TEM). Under FRL, phycocyanin-containing complexes and chlorophyll-containing complexes were determined to be physically separated and the synthesis of red-form phycobilisome and Chl f was increased. The timing of these responses was observed. The heterogeneity and eco-physiological response of the cells was noted. Additionally, a gliding motility for H. hongdechloris is reported. more...
- Published
- 2017
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15. Harvesting Far-Red Light by Chlorophyll f in Photosystems I and II of Unicellular Cyanobacterium strain KC1.
- Author
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Itoh S, Ohno T, Noji T, Yamakawa H, Komatsu H, Wada K, Kobayashi M, and Miyashita H
- Subjects
- Chlorophyll metabolism, Chlorophyll analogs & derivatives, Cyanobacteria metabolism, Photosystem I Protein Complex metabolism, Photosystem II Protein Complex metabolism
- Abstract
Cells of a unicellular cyanobacterium strain KC1, which were collected from Japanese fresh water Lake Biwa, formed chlorophyll (Chl) f at 6.7%, Chl a' at 2.0% and pheophytin a at 0.96% with respect to Chl a after growth under 740 nm light. The far-red-acclimated cells (Fr cells) formed extra absorption bands of Chl f at 715 nm in addition to the major Chl a band. Fluorescence lifetimes were measured. The 405-nm laser flash, which excites mainly Chl a in photosystem I (PSI), induced a fast energy transfer to multiple fluorescence bands at 720-760 and 805 nm of Chl f at 77 K in Fr cells with almost no PSI-red-Chl a band. The 630-nm laser flash, which mainly excited photosystem II (PSII) through phycocyanin, revealed fast energy transfer to another set of Chl f bands at 720-770 and 810 nm as well as to the 694-nm Chl a fluorescence band. The 694-nm band did not transfer excitation energy to Chl f. Therefore, Chl a in PSI, and phycocyanin in PSII of Fr cells transferred excitation energy to different sets of Chl f molecules. Multiple Chl f forms, thus, seem to work as the far-red antenna both in PSI and PSII. A variety of cyanobacterial species, phylogenically distant from each other, seems to use a Chl f antenna in far-red environments, such as under dense biomats, in colonies, or under far-red LED light., (© The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.) more...
- Published
- 2015
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16. Energy transfer processes in chlorophyll f-containing cyanobacteria using time-resolved fluorescence spectroscopy on intact cells.
- Author
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Tomo T, Shinoda T, Chen M, Allakhverdiev SI, and Akimoto S
- Subjects
- Chlorophyll chemistry, Energy Transfer, Chlorophyll analogs & derivatives, Cyanobacteria metabolism, Spectrometry, Fluorescence methods
- Abstract
We examined energy transfer dynamics in the unique chlorophyll (Chl) f-containing cyanobacterium Halomicronema hongdechloris. The absorption band of Chl f appeared during cultivation of this organism under far-red light. The absorption maximum of Chl f in organic solvents occurs at a wavelength of approximately 40 nm longer than that of Chl a. In vivo, the cells display a new absorption band at approximately 730 nm at 298 K, which is at a significantly longer wavelength than that of Chl a. We primarily assigned this band to a long wavelength form of Chl a. The function of Chl f is currently unknown. We measured the fluorescence of cells using time-resolved fluorescence spectroscopy in the picosecond-to-nanosecond time range and found clear differences in fluorescence properties between the cells that contained Chl f and the cells that did not. After excitation, the fluorescence peaks of photosystem I and photosystem II appeared quickly but diminished immediately. A unique fluorescence peak located at 748 nm subsequently appeared in cells containing Chl f. This finding strongly suggests that the Chl f in this alga exists in photosystem I and II complexes and is located close to each molecule of Chl a. This article is part of a special issue entitled: photosynthesis research for sustainability: keys to produce clean energy., (Copyright © 2014 Elsevier B.V. All rights reserved.) more...
- Published
- 2014
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17. On the Edge of the Rainbow: Red-Shifted Chlorophylls and Far-Red Light Photoadaptation in Cyanobacteria.
- Author
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Pinevich, A. V. and Averina, S. G.
- Subjects
- *
CHLOROPHYLL , *CYANOBACTERIA , *PHOTOSYNTHETIC pigments , *BACTERIAL diversity , *RAINBOWS , *PHOTOSYNTHETIC bacteria - Abstract
The phenomenon of photosynthetic adaptation of cyanobacteria to far-red light (FRL; 700−750 nm) is closely related to such basic themes as: phototrophy, microbial ecology, and diversity of bacteria. In applied terms, this bioenergetic strategy is essential for biotechnology, with a perspective to possess additional photosynthetic energy. The majority of cyanobacteria is known to use 400−700 nm light, excited state being channeled from light-harvesting complex to reaction centers of two photosystems containing chlorophyll (Chl) a showing red maxima at ~700 nm. After the isolation of first strains producing Chls d and f it became clear that cyanobacteria can also use FRL. Large amount of data has been obtained on cyanobacteria which constitutively produce Chl d as well as on those strains which produce Chl f or Chl f/Chl d during FRL photoacclimation (FaRLiP). Inclusion of these pigments in photosynthetic apparatus, particularly using FaRLiP mechanisms, augments the adaptive potential of cyanobacteria and expands their distribution range. The review provides evidence on such aspects as: photosynthetic apparatus containing Chl d or Chld/Chl f; the FaRLiP gene cluster; phylogeny of cyanobacteria which constitutively or inducibly produce red-shifted chlorophylls; the use of chlorophylls in chemotaxonomy of cyanobacteria, and application of this character in nomenclature. [ABSTRACT FROM AUTHOR] more...
- Published
- 2022
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18. Recent structural discoveries of photosystems I and II acclimated to absorb far-red light.
- Author
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Gisriel, Christopher J.
- Subjects
- *
PHOTOSYSTEMS , *LIGHT absorbance , *ENGINEERING tolerances , *VISIBLE spectra , *PHOTOSYNTHESIS , *CHLOROPHYLL - Abstract
Photosystems I and II are the photooxidoreductases central to oxygenic photosynthesis and canonically absorb visible light (400–700 nm). Recent investigations have revealed that certain cyanobacteria can acclimate to environments enriched in far-red light (700–800 nm), yet can still perform oxygenic photosynthesis in a process called far-red light photoacclimation, or FaRLiP. During this process, the photosystem subunits and pigment compositions are altered. Here, the current structural understanding of the photosystems expressed during FaRLiP is described. The design principles may be useful for guiding efforts to engineer shade tolerance in organisms that typically cannot utilize far-red light. • Some cyanobacteria acclimate to environments enriched in far-red light. • During this process, the photosystems are altered to absorb far-red light. • Cryo-EM has revealed the structures of the far-red light-absorbing photosystems. • Identifying sites that bind red-shifted chlorophylls required novel approaches. • The structures provide design principles to confer far-red light absorbance. [ABSTRACT FROM AUTHOR] more...
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- 2024
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19. Kovacikia minuta sp. nov. (Leptolyngbyaceae, Cyanobacteria), a new freshwater chlorophyll f‐producing cyanobacterium.
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Shen, Li‐Qin, Zhang, Zhong‐Chun, Shang, Jin‐Long, Li, Zheng‐Ke, Chen, Min, Li, Renhui, Qiu, Bao‐Sheng, and Lane, C.
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- *
CHLOROPHYLL , *CYANOBACTERIA , *FRESH water , *OPERONS , *CHROMOSOMES , *SYNECHOCOCCUS - Abstract
A few groups of cyanobacteria have been characterized as having far‐red light photoacclimation (FaRLiP) that results from chlorophyll f (Chl f) production. In this study, using a polyphasic approach, we taxonomically transferred the Cf. Leptolyngbya sp. CCNUW1 isolated from a shaded freshwater pond, which produces Chl f under far‐red light, to the genus Kovacikia and named this taxon Kovacikia minuta sp. nov. This strain was morphologically similar to Leptolyngbya‐like strains. The thin filaments were purplish‐brown under white light but became grass green under far‐red light. The 31‐gene phylogeny grouped K. minuta CCNU0001 into order Synechococcales and family Leptolyngbyaceae. Phylogenetic analysis based on 16S rRNA gene sequences further showed that K. minuta CCNU0001 was clustered into Kovacikia with similarities of 97.2–97.4% to the recently reported type species of Kovacikia muscicola HA7619‐LM3. Additionally, the internal transcribed spacer region between 16S–23S rRNA genes had a unique sequence and secondary structure compared with other Kovacikia strains and phylogenetically related taxa. Draft genome sequences of K. minuta CCNU0001 (8,564,336 bp) were assembled into one circular chromosome and two circular plasmids. A FaRLiP 20‐gene cluster comprised two operons with the unique organization. In sum, K. minuta was established as a new species, and it is the first species reported to produce Chl f and for which a draft genome was produced in genus Kovacikia. This study expanded our knowledge regarding the diversity of Chl f‐producing cyanobacteria in far‐red light‐enriched environments and provides important foundational information for future investigations of FaRLiP evolution in cyanobacteria. [ABSTRACT FROM AUTHOR] more...
- Published
- 2022
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20. Phthalocyanine as a Bioinspired Model for Chlorophyll f‐Containing Photosystem II Drives Photosynthesis into the Far‐Red Region.
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Follana‐Berná, Jorge, Farran, Rajaa, Leibl, Winfried, Quaranta, Annamaria, Sastre‐Santos, Ángela, and Aukauloo, Ally
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PHOTOSYSTEMS ,CHLOROPHYLL ,PHOTOSYNTHESIS ,PHTHALOCYANINE derivatives ,CHARGE exchange ,OXIDATION of water - Abstract
The textbook explanation that P680 pigments are the red limit to drive oxygenic photosynthesis must be reconsidered by the recent discovery that chlorophyll f (Chlf)‐containing Photosystem II (PSII) absorbing at 727 nm can drive water oxidation. Two different families of unsymmetrically substituted Zn phthalocyanines (Pc) absorbing in the 700–800 nm spectral window and containing a fused imidazole‐phenyl substituent or a fused imidazole‐hydroxyphenyl group have been synthetized and characterized as a bioinspired model of the Chlf/TyrosineZ/Histidine190 cofactors of PSII. Transient absorption studies in the presence of an electron acceptor and irradiating in the far‐red region evidenced an intramolecular electron transfer process. Visible and FT‐IR signatures indicate the formation of a hydrogen‐bonded phenoxyl radical in ZnPc II‐OH. This study sets the foundation for the utilization of a broader spectral window for multi‐electronic catalytic processes with one of the most robust and efficient dyes. [ABSTRACT FROM AUTHOR] more...
- Published
- 2021
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21. Chapter Four - Chlorophylls d and f: Synthesis, occurrence, light-harvesting, and pigment organization in chlorophyll-binding protein complexes.
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Min Chen
- Subjects
- *
CHLOROPHYLL , *ECOLOGICAL niche , *PIGMENTS , *PROTEINS , *LIGHT intensity , *CYANOBACTERIAL toxins , *BIOSYNTHESIS - Abstract
Now is a very exciting time for those people who are interested in understanding oxygenic photosynthesis driven by longer wavelength radiation. The past two decades have seen the determination of molecular mechanisms of photosynthesis driven by long wavelengths. Apart from the characterization of additional potential of longer wavelength absorption from chlorophyll a, the two chlorophyll variants chlorophyll d and chlorophyll f were introduced with red-shifted absorption features compared to chlorophyll a and chlorophyll b, which are attributable to the position of the formyl substitutions. The maximal absorption of chlorophyll d is 697 nm, 32 nm red-shifted compared with that of chlorophyll a at 665 nm in 100% methanol; while the maximal absorption of chlorophyll f is 707 nm in methanol, red-shifted 42 nm compared with that of chlorophyll a. Chlorophyll d was reported to be widely distributed in the ecological niches with lower light intensities, but enriched by far-red wavelength light, but so far has been found only in one species of cyanobacteria, Acaryochloris marina. Chlorophyll f is co-occurring with chlorophyll a and its biosynthesis is regulated by far-red light conditions. It has been reported from various genera of cyanobacteria. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
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22. Phototrophic Bacteria.
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Blankenship, Robert, Blankenship, Robert, and Sattley, Matthew
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Biology, life sciences ,Microbiology (non-medical) ,Research & information: general ,AAP ,Acaryochloris ,AerR photoreceptor ,Alphaproteobacteria ,Chloroflexus aurantiacus ,DNA binding ,Ectothiorhodospiraceae ,FNR ,Halorhodospira abdelmalekii ,Halorhodospira halochloris ,Halorhodospiraceae ,Heliobacteria ,Heliophilum fasciatum ,HiPIP ,Ignavibacteria ,Lake Winnipeg ,Moss Beach ,NDH ,NDH-1 ,Nostoc sp ,Photosystem II ,PpsR ortholog ,RNase ,RegA ,Rhodobacter ,Rhodocyclus ,Rhodovulum sulfidophilum ,Rhodovulum tesquicola ,Rhodovulum visakhapatnamense ,Synechococcus sp. PCC 7335 ,Synechocystis ,Yellowstone ,absorbance spectra ,aerobic ,aerobic anoxygenic phototrophic bacteria ,aerobic anoxygenic phototrophs ,alkaliphiles ,alternative complex III ,ancestral sequence reconstruction ,anoxygenic phototrophs ,bacterial community ,bacteriochlorophyll ,bacteriochlorophyll b ,bacteriochlorophyll g ,bacterioplankton ,carotenoid ,chelatase ,chlIDH ,chlorophototroph ,chlorophyll ,chlorophyll d ,chlorophyll f ,chlorosome ,chromatic acclimation ,class Chlorobia and the families Chlorobiaceae and Chloroherpetonaceae ,cobNST ,cobalamin ,comparative genome analysis ,comparative genomics ,conserved signature indels (CSIs) ,copper ion ,cryo-electron microscopy ,cyanobacteria ,cyanobacterial photoreceptors ,cyanophage ,cyclic GMP ,cyclic electron flow ,diazotroph ,disulfide bond ,electron transport ,energy metabolism ,evolution ,extremophile ,far-red light photoacclimation ,far-red photosynthesis ,ferredoxin-NADP reductase ,food web dynamics ,frameshifting ,gene expression ,gene regulation ,gene transfer ,genome sequence ,genomic phylogeny ,genomics ,gracilis ,halophiles ,heliobacteria ,high light ,horizontal gene transfer ,hot spring ,hydrogen ,label-free quantitative proteomics ,light regulation ,light-harvesting ,light-harvesting 1 reaction center ,linker proteins ,microbial ecology of lakes ,molecular signatures ,near infrared ,new family and genus ,nitrogen fixation ,oxygenic photosynthesis ,persulfide ,photoheterotrophic growth ,photosynthesis ,photosynthesis gene regulators ,photosynthetic pigments ,photosynthetic reaction center ,photosystem I ,photosystem II ,phototrophic bacteria ,phototrophic extracellular electron uptake ,phycobiliproteins ,phycobilisome ,phylogenetic comparison ,phylogenomic and comparative genomic analyses ,picoplankton ,plasmid ,promoters ,proteomic analysis ,proton motive force ,purple nonsulfur bacteria ,purple phototrophic bacteria ,purple sulfur bacteria ,purpureus ,redox signaling ,reduction-oxidation ,reporters ,respiration ,salt- and pH-dependence ,scytonemin ,shark bay ,stromatolite ,substance metabolism ,taxonomy ,tenuis ,thermal stability ,thermophile ,thylakoid ,transcriptional regulation ,transcriptomics ,two-component system ,ultraviolet radiation ,uncultured species/strains related to Chlorobia/Ignavibacteria ,vitamin B12 ,whole genome sequencing ,xanthorhodopsin ,zeta-carotene isomerase (Z-ISO) - Abstract
Summary: Microorganisms is pleased to publish this book, which reprints papers that appeared in a Special Issue on "Phototrophic Bacteria", with Guest Editors Robert Blankenship and Matthew Sattley. This Special Issue included research on all types of phototrophic bacteria, including both anoxygenic and oxygenic forms. Research on these bacterial organisms has greatly advanced our understanding of the basic principles that underlie the energy storage that takes place in all types of photosynthetic organisms, including both bacterial and eukaryotic forms. Topics of interest include: microbial physiology, microbial ecology, microbial genetics, evolutionary microbiology, systems microbiology, agricultural microbiology, microbial biotechnology, and environmental microbiology, as all are related to phototrophic bacteria. more...
23. Far-red absorption and light-use efficiency trade-offs in chlorophyll f photosynthesis
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Vincenzo Mascoli, Luca Bersanini, Roberta Croce, Biophysics Photosynthesis/Energy, and LaserLaB - Energy
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0106 biological sciences ,0301 basic medicine ,Chlorophyll ,Chlorophyll a ,Photosystem II ,Light ,Photosystem I Protein Complex ,Chlorophyll f ,Photosystem II Protein Complex ,Far-red ,Plant Science ,Photosynthesis ,Photosystem I ,Cyanobacteria ,01 natural sciences ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,chemistry ,Biophysics ,010606 plant biology & botany ,Photosystem - Abstract
Plants and cyanobacteria use the chlorophylls embedded in their photosystems to absorb photons and perform charge separation, the first step of converting solar energy to chemical energy. While oxygenic photosynthesis is primarily based on chlorophyll a photochemistry, which is powered by red light, a few cyanobacterial species can harness less energetic photons when growing in far-red light. Acclimatization to far-red light involves the incorporation of a small number of molecules of red-shifted chlorophyll f in the photosystems, whereas the most abundant pigment remains chlorophyll a. Due to its different energetics, chlorophyll f is expected to alter the excited-state dynamics of the photosynthetic units and, ultimately, their performances. Here we combined time-resolved fluorescence measurements on intact cells and isolated complexes to show that chlorophyll f insertion slows down the overall energy trapping in both photosystems. While this marginally affects the efficiency of photosystem I, it substantially decreases that of photosystem II. Nevertheless, we show that despite the lower energy output, the insertion of red-shifted chlorophylls in the photosystems remains advantageous in environments that are enriched in far-red light and therefore represents a viable strategy for extending the photosynthetically active spectrum in other organisms, including plants. However, careful design of the new photosynthetic units will be required to preserve their efficiency. more...
- Published
- 2020
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24. Harvesting far-red light
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Luca Bersanini, Roberta Croce, Martijn Tros, Gaozhong Shen, Donald A. Bryant, Ming Yang Ho, Ivo H. M. van Stokkum, Biophysics Photosynthesis/Energy, and LaserLaB - Energy
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0106 biological sciences ,0301 basic medicine ,Photosynthetic reaction centre ,Chlorophyll ,Pigments ,Light ,Chlorophyll f ,Biophysics ,Photosynthesis ,Photosystem I ,01 natural sciences ,Biochemistry ,03 medical and health sciences ,chemistry.chemical_compound ,Excitation energy transfer ,SDG 7 - Affordable and Clean Energy ,Synechococcus ,biology ,Photosystem I Protein Complex ,Far-red ,Time-resolved fluorescence ,Cell Biology ,biology.organism_classification ,Light harvesting ,030104 developmental biology ,chemistry ,Energy Transfer ,Photosynthetically active radiation ,010606 plant biology & botany ,Protein Binding - Abstract
The heterologous expression of the far-red absorbing chlorophyll (Chl) f in organisms that do not synthesize this pigment has been suggested as a viable solution to expand the solar spectrum that drives oxygenic photosynthesis. In this study, we investigate the functional binding of Chl f to the Photosystem I (PSI) of the cyanobacterium Synechococcus 7002, which has been engineered to express the Chl f synthase gene. By optimizing growth light conditions, one-to-four Chl f pigments were found in the complexes. By using a range of spectroscopic techniques, isolated PSI trimeric complexes were investigated to determine how the insertion of Chl f affects excitation energy transfer and trapping efficiency. The results show that the Chls f are functionally connected to the reaction center of the PSI complex and their presence does not change the overall pigment organization of the complex. Chl f substitutes Chl a (but not the Chl a red forms) while maintaining efficient energy transfer within the PSI complex. At the same time, the introduction of Chl f extends the photosynthetically active radiation of the new hybrid PSI complexes up to 750 nm, which is advantageous in far-red light enriched environments. These conclusions provide insights to engineer the photosynthetic machinery of crops to include Chl f and therefore increase the light-harvesting capability of photosynthesis. more...
- Published
- 2020
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25. Structure of a monomeric photosystem II core complex from a cyanobacterium acclimated to far-red light reveals the functions of chlorophylls d and f
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Vasily Kurashov, Gary W. Brudvig, Marilyn R. Gunner, Donald A. Bryant, Gaozhong Shen, Jimin Wang, William H. Armstrong, Richard J. Debus, Christopher J. Gisriel, Ming Yang Ho, David J. Vinyard, David A. Flesher, and John H. Golbeck more...
- Subjects
Chlorophyll ,Photosystem II ,Light ,Oxygen-evolving complex ,Photochemistry ,Biochemistry ,cyanobacteria ,CTF, contrast transfer function ,chemistry.chemical_compound ,PBS, phycobilisome ,Photosynthesis ,PSII, photosystem II ,Synechococcus ,Chemistry ,OEC, oxygen-evolving complex ,electron transfer ,Chl, chlorophyll ,FRL-AP, FRL-specific allophycocyanin ,XRD, X-ray diffraction ,Research Article ,FRL-BC, far-red light bicylindrical core antenna complex(es) ,NH-Fe, non-heme Fe(II) ,Chlorophyll f ,FaRLiP, far-red light photoacclimation ,chlorophyll d ,Chlorophyll d ,Plastoquinone ,FRL-PBS, far-red light phycobilisom(es) ,bicarbonate ,ETC, electron transfer chain ,chlorophyll f ,Photosystem I ,β-DM, n-dodecyl-β-d-maltoside ,PDB, Protein Data Bank ,Molecular Biology ,energy transfer ,FRL, far-red light ,Photosystem I Protein Complex ,ESP, electrostatic potential ,PIB, photosystem isolation buffer ,Photosystem II Protein Complex ,Water ,photosystem II ,WL, white light ,Far-red ,far-red light photoacclimation ,FRL-PSII, far-red light–acclimated photosystem II ,Cell Biology ,PSI, photosystem I ,cryo-EM - Abstract
Far-red light (FRL) photoacclimation (FaRLiP) in cyanobacteria provides a selective growth advantage for some terrestrial cyanobacteria by expanding the range of photosynthetically active radiation to include far-red/near-infrared light (700 to 800 nm). During this photoacclimation process, photosystem II (PSII), the water:plastoquinone photooxidoreductase involved in oxygenic photosynthesis, is modified. The resulting FRL-PSII is comprised of FRL-specific core subunits and binds chlorophyll (Chl) d and Chl f molecules in place of several of the Chl a molecules found when cells are grown in visible light. These new Chls effectively lower the energy canonically thought to define the “red limit” for light required to drive photochemical catalysis of water oxidation. Changes to the architecture of FRL-PSII were previously unknown, and the positions of Chl d and Chl f molecules had only been proposed from indirect evidence. Here, we describe the 2.25-A resolution cryo-EM structure of a monomeric FRL-PSII core complex from Synechococcus sp. PCC 7335 cells that were acclimated to FRL. We identify one Chl d molecule in the ChlD1 position of the electron transfer chain, and four Chl f molecules in the core antenna. We also make observations that enhance our understanding of PSII biogenesis, especially on the acceptor side of the complex where a bicarbonate molecule is replaced by a glutamate sidechain in the absence of the assembly factor Psb28. In conclusion, these results provide a structural basis for the lower energy limit required to drive water oxidation, which is the gateway for most solar energy utilization on Earth. more...
- Published
- 2021
26. Chlorophylls d and f and their role in primary photosynthetic processes of cyanobacteria.
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Allakhverdiev, S., Kreslavski, V., Zharmukhamedov, S., Voloshin, R., Korol'kova, D., Tomo, T., and Shen, J.-R.
- Subjects
- *
CHLOROPHYLL , *PHOTOSYNTHESIS , *CYANOBACTERIA , *ANTENNAE (Biology) , *ELECTRON transport - Abstract
The finding of unique Chl d- and Chl f-containing cyanobacteria in the last decade was a discovery in the area of biology of oxygenic photosynthetic organisms. Chl b, Chl c, and Chl f are considered to be accessory pigments found in antennae systems of photosynthetic organisms. They absorb energy and transfer it to the photosynthetic reaction center (RC), but do not participate in electron transport by the photosynthetic electron transport chain. However, Chl d as well as Chl a can operate not only in the light-harvesting complex, but also in the photosynthetic RC. The long-wavelength (Q) Chl d and Chl f absorption band is shifted to longer wavelength (to 750 nm) compared to Chl a, which suggests the possibility for oxygenic photosynthesis in this spectral range. Such expansion of the photosynthetically active light range is important for the survival of cyanobacteria when the intensity of light not exceeding 700 nm is attenuated due to absorption by Chl a and other pigments. At the same time, energy storage efficiency in photosystem 2 for cyanobacteria containing Chl d and Chl f is not lower than that of cyanobacteria containing Chl a. Despite great interest in these unique chlorophylls, many questions related to functioning of such pigments in primary photosynthetic processes are still not elucidated. This review describes the latest advances in the field of Chl d and Chl f research and their role in primary photosynthetic processes of cyanobacteria. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
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27. The specificity of the bilin lyase CpcS for chromophore attachment to allophycocyanin in the chlorophyll f-containing cyanobacterium Halomicronima hongdechloris
- Author
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Yaqiong Li and Min Chen
- Subjects
Cyanobacteria ,Chlorophyll ,Allophycocyanin ,biology ,Chlorophyll f ,Phycobiliprotein ,Phycocyanin ,Lyases ,Cell Biology ,Plant Science ,General Medicine ,Lyase ,biology.organism_classification ,Biochemistry ,chemistry.chemical_compound ,chemistry ,Gene cluster ,Phycobilisomes ,Phycobilisome ,Bile Pigments ,Bilin - Abstract
Phycobilisomes are light-harvesting antenna complexes of cyanobacteria and red algae that are comprised of chromoproteins called phycobiliproteins. PBS core structures are made up of allophycocyanin subunits. Halomicronema hongdechloris (H. hongdechloris) is one of the cyanobacteria that produce chlorophyll f (Chl f) under far-red light and is regulated by the Far-Red Light Photoacclimation gene cluster. There are five genes encoding APC in this specific gene cluster, and they are responsible for assembling the red-shifted PBS in H. hongdechloris grown under far-red light. In this study, the five apc genes located in the FaRLiP gene cluster were heterologously expressed in an Escherichia coli reconstitution system. The canonical APC-encoding genes were also constructed in the same system for comparison. Additionally, five annotated phycobiliprotein lyase-encoding genes (cpcS) from the H. hongdechloris genome were phylogenetically classified and experimentally tested for their catalytic properties including their contribution to the shifted absorption of PBS. Through analysis of recombinant proteins, we determined that the heterodimer of CpcS-I and CpcU are able to ligate a chromophore to the APC-α/APC-β subunits. We discuss some hypotheses towards understanding the roles of the specialised APC and contributions of PBP lyases. more...
- Published
- 2021
28. Spectral Properties of Chlorophyll f in the B800 Cavity of Light-harvesting Complex 2 from the Purple Photosynthetic Bacterium Rhodoblastus acidophilus
- Author
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Toshiyuki Shinoda, Yukihiro Kimura, Aiko Tanaka, Madoka Yamashita, Tatsuya Tomo, and Yoshitaka Saga
- Subjects
Chlorophyll ,Bacteria ,Chlorophyll f ,Resonance Raman spectroscopy ,Light-Harvesting Protein Complexes ,General Medicine ,Photosynthesis ,Photochemistry ,Biochemistry ,Light-harvesting complex ,chemistry.chemical_compound ,Pigment ,chemistry ,Bacterial Proteins ,Beijerinckiaceae ,visual_art ,visual_art.visual_art_medium ,Bacteriochlorophyll ,Photosynthetic bacteria ,Physical and Theoretical Chemistry ,Bacteriochlorophylls - Abstract
The interactions of chlorophyll (Chl) and bacteriochlorophyll (BChl) pigments with the polypeptides in photosynthetic light-harvesting proteins are responsible for controlling the absorption energy of (B)Chls in protein matrixes. The binding pocket of B800 BChl a in LH2 proteins, which are peripheral light-harvesting proteins in purple photosynthetic bacteria, is useful for studying such structure-property relationships. We report the reconstitution of Chl f, which has the formyl group at the 2-position, in the B800 cavity of LH2 from the purple bacterium Rhodoblastus acidophilus. The Qy absorption band of Chl f in the B800 cavity was shifted by 14 nm to longer wavelength compared to that of the corresponding five-coordinated monomer in acetone. This redshift was larger than that of Chl a and Chl b. Resonance Raman spectroscopy indicated hydrogen bonding between the 2-formyl group of Chl f and the LH2 polypeptide. These results suggest that this hydrogen bonding contributes to the Qy redshift of Chl f. Furthermore, the Qy redshift of Chl f in the B800 cavity was smaller than that of Chl d. This may have arisen from the different patterns of hydrogen bonding between Chl f and Chl d and/or from the steric hindrance of the 3-vinyl group in Chl f. more...
- Published
- 2021
29. Spectral signatures of five hydroxymethyl chlorophyll a derivatives chemically derived from chlorophyll b or chlorophyll f
- Author
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Artur Sawicki, Min Chen, and Robert D. Willows
- Subjects
Chlorophyll ,0106 biological sciences ,0301 basic medicine ,Chlorophyll b ,Chlorophyll a ,Chlorophyll f ,Stereochemistry ,Borohydrides ,Plant Science ,Photosynthesis ,01 natural sciences ,Biochemistry ,Absorbance ,03 medical and health sciences ,chemistry.chemical_compound ,Pigment ,Spinacia oleracea ,Hydroxymethyl ,Mercaptoethanol ,Chemistry ,Chlorophyll A ,Cell Biology ,General Medicine ,Plant Leaves ,030104 developmental biology ,Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ,visual_art ,visual_art.visual_art_medium ,Oxidation-Reduction ,010606 plant biology & botany - Abstract
Chlorophylls (Chls) are pigments involved in light capture and light reactions in photosynthesis. Chl a, Chl b, Chl d, and Chl f are characterized by unique absorbance maxima in the blue (Soret) and red (Qy) regions with Chl b, Chl d, and Chl f each possessing a single formyl group at a unique position. Relative to Chl a the Qy absorbance maximum of Chl b is blue-shifted while Chl d and Chl f are red-shifted with the shifts attributable to the relative positions of the formyl substitutions. Reduction of a formyl group of Chl b to form 7-hydroxymethyl Chl a, or oxidation of the vinyl group of Chl a into a formyl group to form Chl d was achieved using sodium borohydride (NaBH4) or β-mercaptoethanol (BME/O2), respectively. During the consecutive reactions of Chl b and Chl f using a three-step procedure (1. NaBH4, 2. BME/O2, and 3. NaBH4) two new 7-hydroxymethyl Chl a species were prepared possessing the 3-formyl or 3-hydroxymethyl groups and three new 2-hydroxymethyl Chl a species possessing the 3-vinyl, 3-formyl, or 3-hydroxymethyl groups, respectively. Identification of the spectral properties of 2-hydroxymethyl Chl a may be biologically significant for deducing the latter stages of Chl f biosynthesis if the mechanism parallels Chl b biosynthesis. The spectral features and chromatographic properties of these modified Chls are important for identifying potential intermediates in the biosynthesis of Chls such as Chl f and Chl d and for identification of any new Chls in nature. more...
- Published
- 2019
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30. Femtosecond infrared spectroscopy of chlorophyll f-containing photosystem I
- Author
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Noura Zamzam, Jasper J. van Thor, Marius Kaucikas, Dennis J. Nürnberg, A. William Rutherford, and The Leverhulme Trust
- Subjects
DYNAMICS ,Chlorophyll ,Chlorophyll a ,Spectrophotometry, Infrared ,Photosystem II ,Infrared Rays ,Chlorophyll f ,Analytical chemistry ,General Physics and Astronomy ,02 engineering and technology ,Physics, Atomic, Molecular & Chemical ,Cyanobacteria ,010402 general chemistry ,Photosystem I ,PRIMARY ELECTRON-TRANSFER ,01 natural sciences ,CHLAMYDOMONAS-REINHARDTII ,chemistry.chemical_compound ,EXCITATION ,PUMP-PROBE ,REACTION CENTERS ,Physical and Theoretical Chemistry ,ULTRAFAST TRANSIENT ABSORPTION ,Synechococcus ,Science & Technology ,02 Physical Sciences ,Chemical Physics ,P700 ,Photosystem I Protein Complex ,Chemistry, Physical ,Physics ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Chemistry ,Kinetics ,Energy Transfer ,chemistry ,Absorption band ,Excited state ,Physical Sciences ,CORE ANTENNA ,ENERGY-TRANSFER ,03 Chemical Sciences ,0210 nano-technology ,CHARGE SEPARATION - Abstract
The recent discovery of extremely red-shifted chlorophyll f pigments in both photosystem I (PSI) and photosystem II has led to the conclusion that chlorophyll f plays a role not only in the energy transfer, but also in the charge separation processes [Nürnberg et al., Science, 2018, 360, 1210–1213]. We have employed ultrafast transient infrared absorption spectroscopy to study the contribution of far-red light absorbing chlorophyll f to energy transfer and charge separation processes in far-red light-grown PSI (FRL-PSI) from the cyanobacterium Chroococcidiopsis thermalis PCC 7203. We compare the kinetics and spectra of FRL-grown PSI excited at 670 nm and 740 nm wavelengths to those of white light-grown PSI (WL-PSI) obtained at 675 nm excitation. We report a fast decay of excited state features of chlorophyll a and complete energy transfer from chlorophyll a to chlorophyll f in FRL-PSI upon 670 nm excitation, as indicated by a frequency shift in a carbonyl absorption band occurring within a 1 ps timescale. While the WL-PSI measurements support the assignment of initial charge separation to A−1+˙A0−˙ [Di Donato et al., Biochemistry, 2011, 50, 480–490] from the kinetics of a distinct cation feature at 1710 cm−1, in the case of FRL-PSI, small features at 1715 cm−1 from the chlorophyll cation are present from sub-ps delays instead, supporting the replacement of the A−1 pigment with chlorophyll f. Comparisons of nanosecond spectra show that charge separation proceeds with 740 nm excitation, which selectively excites chlorophyll f, and modifications in specific carbonyl absorption bands assigned to P700+˙ minus P700 and A1−˙ minus A1 indicate dielectric differences of FRL-PSI compared to WL-PSI in one or both of the two electron transfer branches of FRL-PSI. more...
- Published
- 2019
- Full Text
- View/download PDF
31. Quantitative assessment of chlorophyll types in cryo-EM maps of photosystem I acclimated to far-red light
- Author
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Gary W. Brudvig, Victor S. Batista, Donald A. Bryant, Jimin Wang, Hao-Li Huang, Christopher J. Gisriel, David A. Flesher, and Krystle Reiss
- Subjects
Chlorophyll ,Photosystem I ,Cyanobacteria ,biology ,Chlorophyll f ,Cryo-electron microscopy ,Biophysics ,Far-red light ,Far-red ,QD415-436 ,macromolecular substances ,QH426-470 ,biology.organism_classification ,Photosynthesis ,Biochemistry ,chemistry.chemical_compound ,chemistry ,Genetics ,Cryo-EM ,Photosystem ,Research Article - Abstract
Chlorophyll cofactors are vital for the metabolism of photosynthetic organisms. Cryo-electron microscopy (cryo-EM) has been used to elucidate molecular structures of pigment-protein complexes, but the minor structural differences between multiple types of chlorophylls make them difficult to distinguish in cryo-EM maps. This is exemplified by inconsistencies in the assignments of chlorophyll f molecules in structures of photosystem I acclimated to far-red light (FRL-PSI). A quantitative assessment of chlorophyll substituents in cryo-EM maps was used to identify chlorophyll f-binding sites in structures of FRL-PSI from two cyanobacteria. The two cryo-EM maps provide direct evidence for chlorophyll f-binding at two and three binding sites, respectively, and three more sites in each structure exhibit strong indirect evidence for chlorophyll f-binding. Common themes in chlorophyll f-binding are described that clarify the current understanding of the molecular basis for FRL photoacclimation in photosystems. more...
- Published
- 2021
32. RfpA, RfpB, and RfpC are the Master Control Elements of Far-Red Light Photoacclimation (FaRLiP).
- Author
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Chi Zhao, Fei Gan, Gaozhong Shen, Bryant, Donald A., Min Chen, and Garcia-Pichel, Ferran
- Subjects
PHOTOSYNTHESIS ,PHYCOBILISOMES ,CHLOROPHYLL - Abstract
Terrestrial cyanobacteria often occur in niches that are strongly enriched in far-red light (FRL; λ > 700 nm). Some cyanobacteria exhibit a complex and extensive photoacclimation response, known as FRL photoacclimation (FaRLiP). During the FaRLiP response, specialized paralogous proteins replace 17 core subunits of the three major photosynthetic complexes: Photosystem (PS) I, PS II, and the phycobilisome. Additionally, the cells synthesize both chlorophyll (Chl) f and Chl d. Using biparental mating from Escherichia coli, we constructed null mutants of three genes, rfpA, rfpB, and rfpC, in the cyanobacteria Chlorogloeopsis fritschii PCC 9212 and Chroococcidiopsis thermalis PCC 7203. The resulting mutants were no longer able to modify their photosynthetic apparatus to absorb FRL, were no longer able to synthesize Chl f, inappropriately synthesized Chl d in white light, and were unable to transcribe genes of the FaRLiP gene cluster. We conclude that RfpA, RfpB, and RfpC constitute a FRL-activated signal transduction cascade that is the master control switch for the FaRLiP response. FRL is proposed to activate (or inactivate) the histidine kinase activity of RfpA, which leads to formation of the active state of RfpB, the key response regulator and transcription activator. RfpC may act as a phosphate shuttle between RfpA and RfpB. Our results show that reverse genetics via conjugation will be a powerful approach in detailed studies of the FaRLiP response. [ABSTRACT FROM AUTHOR] more...
- Published
- 2015
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33. Harvesting Far-Red Light by Chlorophyllfin Photosystems I and II of Unicellular Cyanobacterium strain KC1.
- Author
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Shigeru Itoh, Tomoki Ohno, Tomoyasu Noji, Hisanori Yamakawa, Hirohisa Komatsu, Katsuhiro Wada, Masami Kobayashi, and Hideaki Miyashita
- Subjects
- *
CHLOROPHYLL , *CYANOBACTERIA , *PHEOPHYTIN , *ENERGY transfer - Abstract
Cells of a unicellular cyanobacterium strain KC1, which were collected from Japanese fresh water Lake Biwa, formed chlorophyll (Chl) f at 6.7%, Chl a' at 2.0% and pheophytin a at 0.96% with respect to Chl a after growth under 740 nm light. The far-red-acclimated cells (Fr cells) formed extra absorption bands of Chl f at 715nm in addition to the major Chl a band. Fluorescence lifetimes were measured. The 405-nm laser flash, which excites mainly Chl a in photo-system I (PSI), induced a fast energy transfer to multiple fluorescence bands at 720-760 and 805 nm of Chl f at 77 K in Fr cells with almost no PSI-red-Chl a band. The 630-nm laser flash, which mainly excited photosystem II (PSII) through phycocyanin, revealed fast energy transfer to another set of Chl f bands at 720-770 and 810 nm as well as to the 694-nm Chl a fluorescence band. The 694-nm band did not transfer excitation energy to Chl f. Therefore, Chl a in PSI, and phycocyanin in PSII of Fr cells transferred excitation energy to different sets of Chlfmolecules. Multiple Chlf forms, thus, seem to work as the far-red antenna both in PSI and PSII. A variety of cyanobacterial species, phylogenically distant from each other, seems to use a Chl fantenna in far-red environments, such as under dense biomats, in colonies, or under far-red LED light. [ABSTRACT FROM AUTHOR] more...
- Published
- 2015
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34. Novel chlorophylls and new directions in photosynthesis research.
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Li, Yaqiong and Chen, Min
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- *
PHOTOSYNTHESIS , *CARBON fixation , *EFFECT of light on plants , *CHLOROPHYLL , *CHLOROPLAST pigments - Abstract
Chlorophyll d and chlorophyll f are red-shifted chlorophylls, because their Qy absorption bands are significantly red-shifted compared with chlorophyll a. The red-shifted chlorophylls broaden the light absorption region further into far red light. The presence of red-shifted chlorophylls in photosynthetic systems has opened up new possibilities of research on photosystem energetics and challenged the unique status of chlorophyll a in oxygenic photosynthesis. In this review, we report on the chemistry and function of red-shifted chlorophylls in photosynthesis and summarise the unique adaptations that have allowed the proliferation of chlorophyll d- and chlorophyll f-containing organisms in diverse ecological niches around the world. [ABSTRACT FROM AUTHOR] more...
- Published
- 2015
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35. Chlorophyll f and chlorophyll d are produced in the cyanobacterium Chlorogloeopsis fritschii when cultured under natural light and near-infrared radiation.
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Airs, R.L., Temperton, B., Sambles, C., Farnham, G., Skill, S.C., and Llewellyn, C.A.
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- *
CHLOROPHYLL , *CYANOBACTERIA , *NEAR infrared radiation , *BACTERIAL cultures , *BUBBLE column reactors , *PHOTOBIOREACTORS , *PHOTOSYNTHESIS - Abstract
We report production of chlorophyll f and chlorophyll d in the cyanobacterium Chlorogloeopsis fritschii cultured under near-infrared and natural light conditions. C. fritschii produced chlorophyll f and chlorophyll d when cultured under natural light to a high culture density in a 20 L bubble column photobioreactor. In the laboratory, the ratio of chlorophyll f to chlorophyll a changed from 1:15 under near-infrared, to an undetectable level of chlorophyll f under artificial white light. The results provide support that chlorophylls f and d are both red-light inducible chlorophylls in C. fritschii . [ABSTRACT FROM AUTHOR] more...
- Published
- 2014
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36. Life in the dark:far-red absorbing cyanobacteria extend photic zones deep into terrestrial caves
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Jen Nguyen, Alex Nyarko, Olivia S. Hershey, Ali Dhinojwala, Nadia B. Nord, Lars Behrendt, Danijela Lonco, Michael Kühl, Erik Trampe, and Hazel A. Barton
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Chlorophyll ,Cyanobacteria ,BIOFILMS ,Infrared Rays ,CHLOROPHYLL F ,ANTENNA COMPLEX ,Forests ,Photosynthesis ,Microbiology ,03 medical and health sciences ,chemistry.chemical_compound ,Cave ,Photic zone ,Ecosystem ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,0303 health sciences ,geography ,geography.geographical_feature_category ,biology ,030306 microbiology ,Aquatic ecosystem ,PHOTOSYNTHESIS ,Far-red ,DRIVEN ,biology.organism_classification ,CONTAINS ,Caves ,Oceanography ,Habitat ,chemistry ,COMMUNITIES - Abstract
Chlorophyll (Chl) f and d are the most recently discovered chlorophylls, enabling cyanobacteria to harvest near-infrared radiation (NIR) at 700-780 nm for oxygenic photosynthesis. Little is known about the occurrence of these pigments in terrestrial habitats. Here, we provide first details on spectral photon irradiance within the photic zones of four terrestrial cave systems in concert with a detailed investigation of photopigmentation, light reflectance and microbial community composition. We frequently found Chl f and d along the photic zones of caves characterized by low light enriched in NIR and inhabited by cyanobacteria producing NIR-absorbing pigments. Surprisingly, deeper parts of caves still contained NIR, an effect likely attributable to the reflectance of specific wavelengths by the surface materials of cave walls. We argue that the stratification of microbial communities across the photic zones of cave entrances resembles the light-driven species distributions in forests and aquatic environments. more...
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- 2020
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37. Chlorophyll f synthesis by a super-rogue photosystem II complex
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Jianfeng Yu, Shengxi Shao, Martina Bečková, Joko P Trinugroho, Ziyu Zhao, Roman Sobotka, Josef Komenda, Peter J. Nixon, James W. Murray, and Biotechnology and Biological Sciences Research Council (BBSRC) more...
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Chlorophyll ,0106 biological sciences ,0301 basic medicine ,Cyanobacteria ,Photosystem II ,Chlorophyll f ,Stereochemistry ,Protein subunit ,Plant Science ,Photosynthesis ,01 natural sciences ,Cofactor ,03 medical and health sciences ,chemistry.chemical_compound ,Sequence Analysis, Protein ,ATP synthase ,biology ,Synechocystis ,Photosystem II Protein Complex ,biology.organism_classification ,030104 developmental biology ,chemistry ,biology.protein ,Microorganisms, Genetically-Modified ,010606 plant biology & botany - Abstract
Certain cyanobacteria synthesize chlorophyll molecules (Chl d and Chl f) that absorb in the far-red region of the solar spectrum, thereby extending the spectral range of photosynthetically active radiation1,2. The synthesis and introduction of these far-red chlorophylls into the photosynthetic apparatus of plants might improve the efficiency of oxygenic photosynthesis, especially in far-red enriched environments, such as in the lower regions of the canopy3. Production of Chl f requires the ChlF subunit, also known as PsbA4 (ref. 4) or super-rogue D1 (ref. 5), a paralogue of the D1 subunit of photosystem II (PSII) which, together with D2, bind cofactors involved in the light-driven oxidation of water. Current ideas suggest that ChlF oxidizes Chl a to Chl f in a homodimeric ChlF reaction centre (RC) complex and represents a missing link in the evolution of the heterodimeric D1/D2 RC of PSII (refs. 4,6). However, unambiguous biochemical support for this proposal is lacking. Here, we show that ChlF can substitute for D1 to form modified PSII complexes capable of producing Chl f. Remarkably, mutation of just two residues in D1 converts oxygen-evolving PSII into a Chl f synthase. Overall, we have identified a new class of PSII complex, which we term 'super-rogue' PSII, with an unexpected role in pigment biosynthesis rather than water oxidation. more...
- Published
- 2020
38. Molecular Mechanism of Photosynthesis Driven by Red-Shifted Chlorophylls
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Artur Sawicki and Min Chen
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Chlorophyll b ,chemistry.chemical_compound ,Chlorophyll a ,chemistry ,biology ,Chlorophyll f ,Chlorophyll ,Acaryochloris marina ,Chlorophyll d ,Botany ,Photosynthetic bacteria ,biology.organism_classification ,Photosynthesis - Abstract
Photosynthesis is the process of light-driven production of organic molecules needed as starting components for whole cellular processes and as the energy source. It is carried out by primary producers including land plants, algae, and oxygenic/anoxygenic photosynthetic bacteria. Oxygenic photosynthesis involves two stages: light-dependent reactions generating NADPH and ATP molecules with oxygen as a by-product and light-independent reactions involving utilization of NADPH and ATP as the energy source to convert carbon dioxide into organic molecules. Light-dependent processes require light-absorbing pigments categorized as carotenoids, bilins, and chlorophylls. Chlorophylls and carotenoids are ubiquitous to all photosynthetic organisms, while bilins in phycobiliprotein complexes are specific to cyanobacteria, rhodophytes, glaucophytes, and cryptophytes. Each pigment has several variations, and a particular type of organism has a specific set optimized for light-capture and photosynthetic efficiency in the given environment. The common chlorophyll to each oxygenic photosynthetic organism is chlorophyll a, with chlorophyll b, c, d, or f synthesized depending on the organism. Chlorophyll d (3-formyl-chlorophyll a) and chlorophyll f (2-formyl-chlorophyll a) have far-red long-wavelength absorption features, namely, red-shifted chlorophylls. These chlorophyll molecules enable some cyanobacterial species to grow in shaded environments and establish unique habitats. Acaryochloris marina is predominantly a chlorophyll d-containing cyanobacterium with minor (≤ 5%) amounts of chlorophyll a under all culture conditions, while all chlorophyll f-producing cyanobacteria constitute chlorophyll f as a minor chlorophyll ~2–15% of the total chlorophyll pool and only produced under far-red light conditions. This chapter will focus on summarizing the current knowledge of the light-dependent processes with particular attention on structures and functions of far-red absorbing pigments and pigment-binding protein complexes. more...
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- 2020
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39. Substantial near-infrared radiation-driven photosynthesis of chlorophyll f-containing cyanobacteria in a natural habitat
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Michael Kühl, Michael Johnson, Klaus Koren, Anthony W. D. Larkum, Niels-Ulrik Frigaard, Maria Mosshammer, and Erik Trampe
- Subjects
0301 basic medicine ,Cyanobacteria ,In situ ,Chlorophyll ,Geologic Sediments ,Chlorophyll f ,Infrared Rays ,QH301-705.5 ,Acaryochloris marina ,Science ,Short Report ,02 engineering and technology ,chlorophyll f ,Photosynthesis ,confocal microscopy ,cyanobacteria ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,chemistry.chemical_compound ,Botany ,Seawater ,Biology (General) ,Cells, Cultured ,Ecosystem ,Beachrock ,photosynthesis ,General Immunology and Microbiology ,biology ,Ecology ,Chemistry ,General Neuroscience ,Phycobiliprotein ,imaging ,General Medicine ,021001 nanoscience & nanotechnology ,biology.organism_classification ,microenvironment ,Oxygen ,030104 developmental biology ,Medicine ,Other ,ecology ,0210 nano-technology - Abstract
Far-red absorbing chlorophylls are constitutively present as chlorophyll (Chl) d in the cyanobacterium Acaryochloris marina, or dynamically expressed by synthesis of Chl f, red-shifted phycobiliproteins and minor amounts of Chl d via far-red light photoacclimation in a range of cyanobacteria, which enables them to use near-infrared-radiation (NIR) for oxygenic photosynthesis. While the biochemistry and molecular physiology of Chl f-containing cyanobacteria has been unraveled in culture studies, their ecological significance remains unexplored and no data on their in situ activity exist. With a novel combination of hyperspectral imaging, confocal laser scanning microscopy, and nanoparticle-based O2 imaging, we demonstrate substantial NIR-driven oxygenic photosynthesis by endolithic, Chl f-containing cyanobacteria within natural beachrock biofilms that are widespread on (sub)tropical coastlines. This indicates an important role of NIR-driven oxygenic photosynthesis in primary production of endolithic and other shaded habitats. more...
- Published
- 2020
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40. Global distribution of a chlorophyll f cyanobacterial marker
- Author
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Tanai Cardona, Laura A. Antonaru, Dennis J. Nürnberg, Anthony W. D. Larkum, Leverhulme Trust, and Biotechnology and Biological Sciences Research Council (BBSRC)
- Subjects
Cyanobacteria ,Chlorophyll ,Light ,05 Environmental Sciences ,DIVERSITY ,Microbial ecology ,chemistry.chemical_compound ,10 Technology ,Microbial mat ,Photosynthesis ,Phylogeny ,Photosystem ,SEQUENCE ALIGNMENT ,0303 health sciences ,biology ,Ecology ,Environmental microbiology ,Arctic Regions ,500 Naturwissenschaften und Mathematik::530 Physik::530 Physik ,Horizontal gene transfer ,ACCURATE ,Life Sciences & Biomedicine ,FAR-RED LIGHT ,Chlorophyll f ,OCEANS ,Antarctic Regions ,Environmental Sciences & Ecology ,CHLOROPHYLL F ,Microbiology ,Article ,03 medical and health sciences ,Botany ,CYANOBACTERIUM ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,Science & Technology ,030306 microbiology ,Chlorophyll A ,06 Biological Sciences ,biology.organism_classification ,chemistry ,Phycobilisome ,COMMUNITIES ,500 Naturwissenschaften und Mathematik::570 Biowissenschaften ,Biologie::577 Ökologie ,PHOTOACCLIMATION FARLIP - Abstract
Some cyanobacteria use light outside the visible spectrum for oxygenic photosynthesis. The far-red light (FRL) region is made accessible through a complex acclimation process that involves the formation of new phycobilisomes and photosystems containing chlorophyll f. Diverse cyanobacteria ranging from unicellular to branched-filamentous forms show this response. These organisms have been isolated from shaded environments such as microbial mats, soil, rock, and stromatolites. However, the full spread of chlorophyll f-containing species in nature is still unknown. Currently, discovering new chlorophyll f cyanobacteria involves lengthy incubation times under selective far-red light. We have used a marker gene to detect chlorophyll f organisms in environmental samples and metagenomic data. This marker, apcE2, encodes a phycobilisome linker associated with FRL-photosynthesis. By focusing on a far-red motif within the sequence, degenerate PCR and BLAST searches can effectively discriminate against the normal chlorophyll a-associated apcE. Even short recovered sequences carry enough information for phylogenetic placement. Markers of chlorophyll f photosynthesis were found in metagenomic datasets from diverse environments around the globe, including cyanobacterial symbionts, hypersaline lakes, corals, and the Arctic/Antarctic regions. This additional information enabled higher phylogenetic resolution supporting the hypothesis that vertical descent, as opposed to horizontal gene transfer, is largely responsible for this phenotype’s distribution. more...
- Published
- 2020
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41. Structure of a photosystem I-ferredoxin complex from a marine cyanobacterium provides insights into far-red light photoacclimation
- Author
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Donald A. Bryant, Jimin Wang, Gary W. Brudvig, Ming Yang Ho, David A. Flesher, Gaozhong Shen, and Christopher J. Gisriel
- Subjects
Chlorophyll ,Cyanobacteria ,photosystem I ,Light ,FaRLiP, far-red light photoacclimation ,Chlorophyll f ,PsaF ,Fischerella 7521, Fischerella thermalis PCC 7521 ,macromolecular substances ,chlorophyll f ,PG, phosphatidylglycerol ,Photosystem I ,Photosynthesis ,PsaJ ,cyanobacteria ,CTF, contrast transfer function ,Biochemistry ,Synechococcus 7335, Synechococcus sp. PCC 7335 ,chemistry.chemical_compound ,β-DM, n-dodecyl-β-D-maltoside ,PDB, Protein Data Bank ,polycyclic compounds ,Molecular Biology ,Ferredoxin ,Synechococcus ,FRL, far-red light ,FRL-PSI, far-red light-acclimated PSI ,Photosystem I Protein Complex ,biology ,ESP, electrostatic potential ,Fd, ferredoxin ,PIB, photosystem isolation buffer ,food and beverages ,WL, white light ,far-red light photoacclimation ,Far-red ,Cell Biology ,ferredoxin ,biology.organism_classification ,Chl, chlorophyll ,chemistry ,PSI, photosystem I ,Biophysics ,Ferredoxins ,Ferredoxin—NADP(+) reductase ,Research Article - Abstract
Far-red light photoacclimation (FaRLiP) exhibited by some cyanobacteria allows these organisms to use light of the far-red region of the solar spectrum (700 to 800 nm) for photosynthesis. Part of this process includes the replacement of six photosystem I (PSI) subunits with isoforms that confer the binding of chlorophyll (Chl) f molecules that are synthesized by chlorophyll f synthase and that absorb far-red light. However, the exact sites at which Chl f molecules are bound are still challenging to determine. To aid in the identification of Chl f-binding sites, we solved the cryo-EM structure of PSI from far-red light-acclimated cells (FRL-PSI) of the cyanobacterium Synechococcus sp. PCC 7335. We identified six sites that bind Chl f with high specificity, and three additional sites that are likely to bind Chl f at lower specificity. All of these binding sites are in the core antenna regions of PSI, and Chl f was not observed among the electron transport cofactors. This structural analysis also reveals both conserved and non-conserved Chl f-binding sites, the latter of which exemplify the diversity in FRL-PSI among species. We found that the FRL-PSI structure also contains a bound soluble ferredoxin, PetF1, at low occupancy, which suggests that ferredoxin binds less transiently than expected according to the canonical view of ferredoxin-binding to facilitate electron transfer. We suggest that this may result from structural changes in FRL-PSI that occur specifically during FaRLiP. more...
- Published
- 2022
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42. Characterization of isolated photosystem I from Halomicronema hongdechloris, a chlorophyll f-producing cyanobacterium
- Author
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Yaqiong Li, N. Vella, and Min Chen
- Subjects
0301 basic medicine ,Photosynthetic reaction centre ,P700 ,Physiology ,Chemistry ,Chlorophyll f ,Analytical chemistry ,Plant Science ,Photosystem I ,Photosynthesis ,Fluorescence ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,Chlorophyll ,Density gradient ultracentrifugation - Abstract
Halomicronema hongdechloris is a chlorophyll (Chl) f-producing cyanobacterium. Chl f biosynthesis is induced under far-red light, extending its photosynthetically active radiation range to 760 nm. In this study, PSI complexes were isolated and purified from H. hongdechloris, grown under white light (WL) and far-red light (FR), by a combination of density gradient ultracentrifugation and chromatographic separation. WL-PSI showed similar pigment composition as that of Synechocystis 6803, using Chl a in the reaction center. Both Chl a and f were detected in the FR-PSI, although Chl f was a minor component (~8% of total Chl). The FR-PSI showed a maximal fluorescence emission peak of 750 nm at 77 K, which is red-shifted ~20 nm compared to the 730 nm recorded from the WL-PSI. The absorption peaks of P700 for WLPSI and FR-PSI were 699 nm and 702 nm, respectively. The function of Chl f in FR-PSI is discussed. more...
- Published
- 2018
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43. A cyanobacterium that contains chlorophyll f – a red-absorbing photopigment
- Author
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Chen, Min, Li, Yaqiong, Birch, Debra, and Willows, Robert D
- Subjects
- *
CYANOBACTERIA , *CHLOROPHYLL , *STROMATOLITES , *PHYLOGENY , *PHYCOBILIPROTEINS , *FLUORESCENCE , *TRANSMISSION electron microscopy , *PHOTOSYSTEMS - Abstract
Abstract: A Chl f-containing filamentous cyanobacterium was purified from stromatolites and named as Halomicronema hongdechloris gen., sp. nov. after its phylogenetic classification and the morphological characteristics. Hongdechloris contains four main carotenoids and two chlorophylls, a and f. The ratio of Chl f to Chl a is reversibly changed from 1:8 under red light to an undetectable level of Chl f under white-light culture conditions. Phycobiliproteins were induced under white light growth conditions. A fluorescence emission peak of 748nm was identified as due to Chl f. The results suggest that Chl f is a red-light inducible chlorophyll. [Copyright &y& Elsevier] more...
- Published
- 2012
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44. Extinction coefficient for red-shifted chlorophylls: Chlorophyll d and chlorophyll f
- Author
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Li, Yaqiong, Scales, Nicholas, Blankenship, Robert E., Willows, Robert D., and Chen, Min
- Subjects
- *
CHLOROPHYLL , *REDSHIFT , *PHOTOSYNTHESIS , *CHEMICAL reactions , *PHOTOCHEMISTRY , *ATOMIC absorption spectroscopy , *INDUCTIVELY coupled plasma mass spectrometry - Abstract
Abstract: Both chlorophyll f and chlorophyll d are red-shifted chlorophylls in oxygenic photosynthetic organisms, which extend photon absorbance into the near infrared region. This expands the range of light that can be used to drive photosynthesis. Quantitative determination of chlorophylls is a crucial step in the investigation of chlorophyll-photosynthetic reactions in the field of photobiology and photochemistry. No methods have yet been worked out for the quantitative determination of chlorophyll f. There is also no method available for the precise quantitative determination of chlorophyll d although it was discovered in 1943. In order to obtain the extinction coefficients (ε) of chlorophyll f and chlorophyll d, the concentrations of chlorophylls were determined by Inductive Coupled Plasma Mass Spectrometry according to the fact that each chlorophyll molecule contains one magnesium (Mg) atom. Molar extinction coefficient εchl f is 71.11×103 Lmol−1 A707nm cm−1 and εchl d is 63.68×103 Lmol−1 A697nm cm−1 in 100% methanol. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial. [Copyright &y& Elsevier] more...
- Published
- 2012
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45. Chlorophylls - Natural Solar Cells.
- Author
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Jäntschi, Lorentz, Bolboacă, Sorana D., Bţlan, Mugur C., and Sestraş, Radu E.
- Subjects
CHLOROPHYLL ,SOLAR spectra ,MOLECULAR models ,MAGNESIUM ,MOLECULAR orbitals ,PLANT diversity - Abstract
A molecular modeling study was conducted on a series of six natural occurring chiorophylls. Quantum chemistry calculated orbital energies were used to estimate frequency of transitions between occupied molecular orbital and unoccupied molecular orbital energy levels of chlorophyll molecules in vivo conditions in standard (ASTMG 173) environmental conditions. Obtained results are in good agreement with energies necessary to fix the Magnesium atom by chlorophyll molecules and with occurrence of chlorophylls in living vegetal organisms. [ABSTRACT FROM AUTHOR] more...
- Published
- 2011
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46. The C21-formyl group in chlorophyll f originates from molecular oxygen
- Author
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Patrick C. Loughlin, Robert D. Willows, Min Chen, and Harsh Garg
- Subjects
0106 biological sciences ,0301 basic medicine ,Cyanobacteria ,Chlorophyll f ,Photosynthetic pigment ,Photosynthesis ,Photochemistry ,01 natural sciences ,7. Clean energy ,Biochemistry ,Cofactor ,03 medical and health sciences ,chemistry.chemical_compound ,Pigment ,Biosynthesis ,Molecular Biology ,biology ,Cell Biology ,biology.organism_classification ,030104 developmental biology ,chemistry ,visual_art ,Chlorophyll ,biology.protein ,visual_art.visual_art_medium ,010606 plant biology & botany - Abstract
Chlorophylls (Chls) are the most important cofactors for capturing solar energy to drive photosynthetic reactions. Five spectral types of Chls have been identified to date, with Chl f having the most red-shifted absorption maximum because of a C21-formyl group substitution of Chl f. However, the biochemical provenance of this formyl group is unknown. Here, we used a stable isotope labeling technique (18O and 2H) to determine the origin of the C21-formyl group of Chl f and to verify whether Chl f is synthesized from Chl a in the cyanobacterial species Halomicronema hongdechloris. In the presence of either H218O or 18O2, the origin of oxygen atoms in the newly synthesized chlorophylls was investigated. The pigments were isolated with HPLC, followed by MS analysis. We found that the oxygen atom of the C21-formyl group originates from molecular oxygen and not from H2O. Moreover, we examined the kinetics of the labeling of Chl a and Chl f from H. hongdechloris grown in 50% D2O-seawater medium under different light conditions. When cells were shifted from white light D2O-seawater medium to far-red light H2O-seawater medium, the observed deuteration in Chl f indicated that Chl(ide) a is the precursor of Chl f. Taken together, our results advance our understanding of the biosynthesis pathway of the chlorophylls and the formation of the formyl group in Chl f. more...
- Published
- 2017
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47. Subcellular pigment distribution is altered under far-red light acclimation in cyanobacteria that contain chlorophyll f
- Author
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Robert E. Blankenship, R. Howard Berg, Haijun Liu, Erica L.-W. Majumder, Min Chen, Benjamin M. Wolf, and Jerilyn A. Timlin
- Subjects
Chlorophyll ,0106 biological sciences ,0301 basic medicine ,Cyanobacteria ,Light ,Chlorophyll f ,Acclimatization ,Plant Science ,Photosynthesis ,01 natural sciences ,Biochemistry ,03 medical and health sciences ,chemistry.chemical_compound ,Microscopy, Electron, Transmission ,Algae ,Botany ,Phycobilisomes ,Fluorescence microscope ,biology ,Far-red ,Cell Biology ,General Medicine ,biology.organism_classification ,030104 developmental biology ,chemistry ,Biophysics ,Phycobilisome ,010606 plant biology & botany - Abstract
Far-Red Light (FRL) acclimation is a process that has been observed in cyanobacteria and algae that can grow solely on light above 700 nm. The acclimation to FRL results in rearrangement and synthesis of new pigments and pigment-protein complexes. In this study, cyanobacteria containing chlorophyll f, Synechococcus sp. PCC 7335 and Halomicronema hongdechloris, were imaged as live cells with confocal microscopy. H. hongdechloris was further studied with hyperspectral confocal fluorescence microscopy (HCFM) and freeze-substituted thin-section transmission electron microscopy (TEM). Under FRL, phycocyanin-containing complexes and chlorophyll-containing complexes were determined to be physically separated and the synthesis of red-form phycobilisome and Chl f was increased. The timing of these responses was observed. The heterogeneity and eco-physiological response of the cells was noted. Additionally, a gliding motility for H. hongdechloris is reported. more...
- Published
- 2017
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48. A niche for cyanobacteria producing chlorophyll f within a microbial mat
- Author
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Hideaki Miyashita and Satoshi Ohkubo
- Subjects
Chlorophyll ,0301 basic medicine ,Cyanobacteria ,Light ,Chlorophyll f ,030106 microbiology ,Photosynthesis ,Microbiology ,Hot Springs ,03 medical and health sciences ,chemistry.chemical_compound ,Japan ,Botany ,Microbial mat ,Ecosystem ,Ecology, Evolution, Behavior and Systematics ,biology ,Ecotype ,Ecology ,Synechococcus ,biology.organism_classification ,chemistry ,Photosynthetically active radiation ,Original Article - Abstract
Acquisition of additional photosynthetic pigments enables photosynthetic organisms to survive in particular niches. To reveal the ecological significance of chlorophyll (Chl) f, we investigated the distribution of Chl and cyanobacteria within two microbial mats. In a 7-mm-thick microbial mat beneath the running water of the Nakabusa hot spring, Japan, Chl f was only distributed 4.0–6.5 mm below the surface, where the intensity of far-red light (FR) was higher than that of photosynthetically active radiation (PAR). In the same mat, two ecotypes of Synechococcus and two ecotypes of Chl f-producing Leptolyngbya were detected in the upper and deeper layers, respectively. Only the Leptolyngbya strains could grow when FR was the sole light source. These results suggest that the deeper layer of the microbial mat was a habitat for Chl f-producing cyanobacteria, and Chl f enabled them to survive in a habitat with little PAR. more...
- Published
- 2017
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49. Evidence that chlorophyll f functions solely as an antenna pigment in far-red-light photosystem I from Fischerella thermalis PCC 7521
- Author
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Dmitry A. Cherepanov, John H. Golbeck, Victor A. Nadtochenko, Fedor E. Gostev, Donald A. Bryant, Gaozhong Shen, Alexey Yu. Semenov, Arseniy V. Aybush, Ivan V. Shelaev, and Mahir D. Mamedov
- Subjects
0301 basic medicine ,Photosynthetic reaction centre ,Chlorophyll ,Light ,Chlorophyll f ,Population ,Biophysics ,Analytical chemistry ,Light-Harvesting Protein Complexes ,Primary charge separation ,010402 general chemistry ,Photosystem I ,Cyanobacteria ,01 natural sciences ,Biochemistry ,03 medical and health sciences ,chemistry.chemical_compound ,education ,education.field_of_study ,P700 ,Photosystem I Protein Complex ,Far-red ,Cell Biology ,0104 chemical sciences ,030104 developmental biology ,Spectrometry, Fluorescence ,chemistry - Abstract
The Photosystem I (PSI) reaction center in cyanobacteria is comprised of ~96 chlorophyll (Chl) molecules, including six specialized Chl molecules denoted Chl1A/Chl1B (P700), Chl2A/Chl2B, and Chl3A/Chl3B that are arranged in two branches and function in primary charge separation. It has recently been proposed that PSI from Chroococcidiopsis thermalis (Nurnberg et al. (2018) Science 360, 1210–1213) and Fischerella thermalis PCC 7521 (Hastings et al. (2019) Biochim. Biophys. Acta 1860, 452–460) contain Chl f in the positions Chl2A/Chl2B. We tested this proposal by exciting RCs from white-light grown (WL-PSI) and far-red light grown (FRL-PSI) F. thermalis PCC 7521 with femtosecond pulses and analyzing the optical dynamics. If Chl f were in the position Chl2A/Chl2B in FRL-PSI, excitation at 740 nm should have produced the charge-separated state P700+A0− followed by electron transfer to A1 with a τ of ≤25 ps. Instead, it takes ~230 ps for the charge-separated state to develop because the excitation migrates uphill from Chl f in the antenna to the trapping center. Further, we observe a strong electrochromic shift at 685 nm in the final P700+A1− spectrum that can only be explained if Chl a is in the positions Chl2A/Chl2B. Similar arguments rule out the presence of Chl f in the positions Chl3A/Chl3B; hence, Chl f is likely to function solely as an antenna pigment in FRL-PSI. We additionally report the presence of an excitonically coupled homo- or heterodimer of Chl f absorbing around 790 nm that is kinetically independent of the Chl f population that absorbs around 740 nm. more...
- Published
- 2019
50. Excited State Frequencies of Chlorophyll f and Chlorophyll a and Evaluation of Displacement through Franck-Condon Progression Calculations
- Author
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Noura Zamzam, Jasper J. van Thor, and The Leverhulme Trust
- Subjects
INFRARED-SPECTRA ,Chlorophyll ,Models, Molecular ,Chemistry, Multidisciplinary ,CAM-B3LYP ,Pharmaceutical Science ,RESONANCE RAMAN-SPECTRA ,010501 environmental sciences ,01 natural sciences ,0305 Organic Chemistry ,Displacement (vector) ,Analytical Chemistry ,chemistry.chemical_compound ,Drug Discovery ,excited state ,Physics ,Physics::Biological Physics ,Chemistry ,Chemistry (miscellaneous) ,Excited state ,Physical Sciences ,symbols ,Molecular Medicine ,Density functional theory ,VIBRATIONAL PROPERTIES ,Atomic physics ,Life Sciences & Biomedicine ,Algorithms ,Chlorophyll a ,Biochemistry & Molecular Biology ,B3LYP ,Chlorophyll f ,II REACTION-CENTER ,chlorophyll a ,RHODOBACTER-SPHAEROIDES ,chlorophyll f ,010402 general chemistry ,vibrational frequencies ,Article ,ABSORPTION-SPECTRA ,lcsh:QD241-441 ,symbols.namesake ,Franck-Condon ,lcsh:Organic chemistry ,FLUORESCENCE-SPECTRA ,0307 Theoretical and Computational Chemistry ,Physical and Theoretical Chemistry ,density functional theory ,0105 earth and related environmental sciences ,Science & Technology ,PHOTOSYNTHETIC REACTION CENTERS ,0304 Medicinal and Biomolecular Chemistry ,Spectrum Analysis ,Organic Chemistry ,0104 chemical sciences ,Franck–Condon ,chemistry ,Models, Chemical ,PHOTOSYSTEM-I ,PRIMARY ELECTRON-DONOR ,Raman spectroscopy - Abstract
We present ground and excited state frequency calculations of the recently discovered extremely red-shifted chlorophyll f. We discuss the experimentally available vibrational mode assignments of chlorophyll f and chlorophyll a which are characterised by particularly large downshifts of 131-keto mode in the excited state. The accuracy of excited state frequencies and their displacements are evaluated by the construction of Franck&ndash, Condon (FC) and Herzberg&ndash, Teller (HT) progressions at the CAM-B3LYP/6-31G(d) level. Results show that while CAM-B3LYP results are improved relative to B3LYP calculations, the displacements and downshifts of high-frequency modes are underestimated still, and that the progressions calculated for low temperature are dominated by low-frequency modes rather than fingerprint modes that are Resonant Raman active. more...
- Published
- 2019
- Full Text
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