123 results on '"Haik Chosrowjan"'
Search Results
2. Simultaneous analyses of the rates of photoinduced charge separation and recombination between the excited flavin and tryptophans in some flavoproteins: Molecular dynamics simulation
- Author
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Kiattisak Lugsanangarm, Haruhiko Tamaoki, Yasuzo Nishina, Masaya Kitamura, Nadtanet Nunthaboot, Fumio Tanaka, Seiji Taniguchi, and Haik Chosrowjan
- Subjects
Physics ,QC1-999 - Abstract
Ultrafast transient absorption (TA) spectroscopy has been one of the most powerful experimental tools to study the mechanism of photoinduced electron transfer (ET) as in photosynthetic and flavin photoreceptor systems in plants. However, no work has been reported on their quantitative mechanisms. Apparent rates of charge separation (CS) from tryptophans (Trps) to the excited isoalloxazine (Iso*) and charge recombination (CR) from the produced ion pairs to Trps and Iso in the ground states are reported to be 0.25 ps and 3.2 ps in medium-chain acyl-CoA dehydrogenase (MCAD), and 0.15 ps and 6.6 ps in flavin mononucleotide binding protein (FMN-bp), obtained by an ultrafast TA method. The decays of the CS and CR processes were for the first time simultaneously analyzed with an ET theory and structures obtained by molecular dynamics simulation. MCAD and FMN-bp form a tetramer and dimer, respectively. The CS and CR rates of an individual donor and various related physical quantities were numerically obtained. It was found that both CS and CR rates were fastest from Trp166 among four Trps in MCAD and those from Trp106 among two Trps in FMN-bp. Logarithmic CS rates in MCAD were dependent on the donor–acceptor distance (Rc) with parabolic functions, while those of CR rates linearly decreased with Rc. Reasons why CS rates were faster than CR rates in both MCAD and FMN-bp were elucidated in terms of pre-exponential factors in the theory. The present method could be useful to understand the precise mechanisms of initial steps of biological functions of photoreceptors in plants.
- Published
- 2020
- Full Text
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3. Mechanism of Photoinduced Electron Transfer from Tryptophanes to the Excited Isolloxazine in Animal-Like Cryptochrome from Chlamydomonas Reinhardtii Molecular Dynamics Simulation and Molecular Orbital Studies
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nadtanet nunthaboot, Arthit Nueangaudom, Fumio Tanaka, Seiji Taniguchi, and Haik Chosrowjan
- Published
- 2023
4. Possible Role of Essential Tyrosine on the Protonation of Isoalloxazine Ring in the Excited Singlet State and the Triplet State in Photolyase from Escherichia Coli. Molecular Orbital Study
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Arthit Nueangaudom, Nadtanet Nunthaboot, Fumio Tanaka, Seiji Taniguchi, and Haik Chosrowjan
- Published
- 2023
5. Equivalence between inverted regions of the energy gap law and inverted regions of donor–acceptor distances in photoinduced electron transfer processes in flavoproteins
- Author
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Haik Chosrowjan, Seiji Taniguchi, Fumio Tanaka, and Nadtanet Nunthaboot
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Physics ,Range (particle radiation) ,Work (thermodynamics) ,Logarithm ,Band gap ,General Chemical Engineering ,General Chemistry ,Photoinduced electron transfer ,Gibbs free energy ,symbols.namesake ,Molecular dynamics ,Law ,Excited state ,symbols - Abstract
In the present work, we discuss about the relationship between the energy gap law and extended Dutton law in flavoproteins. The extend Dutton law is defined herein as the dependence of logarithmic rates (ln Rate) of photoinduced electron transfer (ET) from aromatic amino acids to excited isoalloxazine (Iso*) on donor–acceptor distances (Rcs). Both functions of ln Rate vs. negative values of the standard free energy gap and ln Rate vs. Rc display a parabolic behavior, when the ET rates are ultrafast. The negative values of the standard free energy gap at peaks of ln Rate [Xm(ES)] were obtained for FMN-binding protein, wild-type pyranose 2-oxidase, T169S (Thr169 is replaced by Ser) pyranose 2-oxidase, and medium-chain acyl-CoA dehydrogenase. The values of Rc at peaks of ln Rate [Xm(Rc)] were also obtained for these flavoproteins. The negative values of the standard free energy gap decreased with approximate linear functions of Rc. The negative values of standard free energy gap [Xm(ESRc)] at Rc = Xm(Rc) were evaluated using the linear functions of the negative standard free energy gap with Rc. The values of Xm(ESRc) were mostly in very good agreement with the values of Xm(ES). This implies that the energy gap law and the extend Dutton law are equivalent. Xm(ES) values in ET donors displaying the linear extend Dutton law with Rc were obtained by energy gap law, and then Xm(Rc) values were evaluated with the negative standard free energy gap. Thus, the obtained Xm(Rc) values were much smaller than the Rc range obtained by the method of molecular dynamics simulation. This suggests that ET processes with linear profiles of the extend Dutton law could be parabolic when Rc becomes much shorter than the Rc range obtained by the method of molecular dynamics simulation.
- Published
- 2021
6. Development and Control of Fast Deformable Mirrors using the Influence Function Approach
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Haik Chosrowjan, Seiji Taniguchi, Masayuki Fujita, Tomohiro Tsukihana, Naoto Sakaki, Toshikazu Ebisuzaki, Masashi Iwashimizu, Takuya Noritake, Shingo Nishikata, and Hiroyuki Daigo
- Abstract
Development, characterization, and control of large diameter (10-cm) deformable mirrors for multi kW-class CW lasers, capable of operating at a 10-kHz sampling rate, have been described, and their operation has been verified experimentally.
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- 2022
7. Photoluminescence Upconversion Spectroscopy
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Seiji Taniguchi and Haik Chosrowjan
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Materials science ,Photoluminescence ,business.industry ,Optoelectronics ,business ,Spectroscopy ,Photon upconversion - Published
- 2020
8. Protein dynamics of five FMN binding protein isomers revealed by residue electrostatic energies between ionic residues: correlation coefficients
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Seiji Taniguchi, Somsak Pianwanit, Sirirat Kokpol, Fumio Tanaka, Arthit Nueangaudom, Kiattisak Lugsanangarm, Nadtanet Nunthaboot, and Haik Chosrowjan
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Residue (complex analysis) ,Chemistry ,General Chemical Engineering ,Protein dynamics ,Ionic bonding ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,Correlation ,Crystallography ,Protein structure ,FMN binding ,Significant positive correlation ,Materials Chemistry ,0210 nano-technology - Abstract
Dynamics of protein structures of five FMN binding isomers, WT, E13K, E13R, E13T and E13Q, were studied through time-dependent residue electrostatic energies (RESTs) of ionic residues and their correlation coefficients. The Arg86 and Glu119 have high positive correlation coefficients which are higher than 0.7 in most of FBP isomers. The Glu23 and FMN, Asp24 and FMN, and Asp61 and Arg63 pairs displayed relatively high negative coefficients. In these residues, the distributions of RESTs showed a few peaks. REST pairs have high positive coefficients when distribution of REST of one residue overlapped with that of REST of another residue, while the REST pairs displayed high negative coefficients when a peak distribution of REST of one residue overlapped with a minimum distribution of another residue. Correlations of REST pairs were not simple and displayed a few groups. Relationships were examined among the correlation coefficients, inter-residue distance (R) and signs of the charge. In the case of R ≤ 1 nm, the total number of the pairs with high negative coefficients in all FBP isomers was much greater when the pairs possess opposite signs of the charge, compared to that when the pairs possess same signs of the charge.
- Published
- 2020
9. Laser-fluence dependence of resonance-enhanced multiphoton reduction of trivalent europium
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Shohei Matsuda, Nobuaki Nakashima, Keiichi Yokoyama, Seiji Taniguchi, Haik Chosrowjan, Toshihiro Somekawa, and Tomoyuki Yatsuhashi
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General Physics and Astronomy ,Physical and Theoretical Chemistry - Published
- 2022
10. Comparative Study on the Mechanism of Photoinduced Electron Transfer from Tryptophan 168 to Excited Flavin in T169S and Wild-type Pyranose 2-Oxidase
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Kiattisak Lugsanangarm, Sirirat Kokpol, Haik Chosrowjan, Seiji Taniguchi, Arthit Nueangaudom, Fumio Tanaka, Somsak Pianwanit, and Nadtanet Nunthaboot
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Chemistry ,General Chemical Engineering ,Tryptophan ,Analytical chemistry ,General Chemistry ,Flavin group ,Fluorescence ,Photoinduced electron transfer ,lcsh:Chemistry ,Molecular dynamics ,Wavelength ,lcsh:QD1-999 ,Pyranose ,Excited state - Abstract
The rates of photoinduced electron transfer (ET) from Trp168 to the excited isoalloxazine (Iso*) in the pyranose 2-oxidase (P2O) with T169S mutation were studied using ET theory by fitting structural properties calculated from molecular dynamics simulation to the reported fluorescence lifetimes. The obtained ET rates and related physical quantities were compared to those reported for the wild-type (WT) P2O. Experimental fluorescence lifetimes of Iso in T169S have two components of 92–240 fs (depending on the emission wavelength) and 15 ps (independent of the emission wavelength). One of the four T169S subunits (Sub C) displayed a low rate, and the other three (Sub A, B, and D) had high rates. Mean ET rates of the fast components were ca. 10 ps–1 at 480 nm, 7 ps–1 at 500 nm, and 4.2 ps–1 at 530, 555, and 580 nm, which were lower than the reported rates in the WT P2O of ca. 17 ps–1 at 480 nm, 14 ps–1 at 500 nm, 9 ps–1 at 530 and 555 nm, and 11 ps–1 at 580 nm, while the rate for the slow component in T169S (...
- Published
- 2019
11. Experimental study for the development of remote sensing technology of hazardous substances by resonance Raman effect
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Dazhi Li, Seiji Taniguchi, Hiromi Kodama, Sachiyo Sugimoto, Yuji Ichikawa, Toshihiro Somekawa, Masakazu Ogita, Takayuku Higo, Ippei Asahi, Haik Chosrowjan, and Shuzo Eto
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symbols.namesake ,Materials science ,Hazardous waste ,symbols ,Resonance ,Nanotechnology ,Raman scattering - Published
- 2019
12. Ultrafast photoinduced electron transfer in o-aminobenzoate – d-Amino acid oxidase complex
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Haruhiko Tamaoki, Seiji Taniguchi, Arthit Nueangaudom, Fumio Tanaka, Haik Chosrowjan, and Yasuzo Nishina
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Absorption spectroscopy ,Band gap ,Chemistry ,General Chemical Engineering ,Excited state ,General Physics and Astronomy ,Physical chemistry ,Ionic bonding ,Molecular orbital ,General Chemistry ,Acceptor ,Photoinduced electron transfer ,Ion - Abstract
Absorption spectrum of ortho-amino benzoate (oAB) – D-amino acid oxidase complex (ODC) displays a charge transfer (CT) band around 570 nm. The fluorescence decays of the second lowest electronic state of ODC were measured using a fluorescence up-conversion technique. The lifetimes were 100 fs and 130 fs at 500 nm and 514 nm fluorescence emission wavelengths, respectively. These ultrafast lifetimes are ascribed to the photoinduced electron transfer (PET) from the oAB to the excited isoalloxazine (Iso*) in the ODC. The PET mechanism in ODC was studied with Marcus-Kakitani-Mataga (MKM) theory. The protein structures were obtained by molecular dynamics simulation (MDS). Mean distances between Iso and oAB over 12,500 MDS snapshots were 0.60 in subunit A (Sub A) and 0.58 nm in Sub B. The calculated lifetimes at 514 nm-emission were 97 and 179 fs in Sub A and Sub B, while at 500 nm there were 97 and 101 fs, respectively. Solvent reorganization energy was quite different between Sub A and Sub B, which is main reason for difference in the calculated lifetimes. Electrostatic (ES) energies between the photoproducts of donor -acceptor, and net ES energies between the photoproducts and ionic groups in the protein were calculated with MDS structures. These ES energies were evaluated with charge densities of neutral radical of oAB produced after PET and anion radical of Iso obtained by semi-empirical molecular orbital (MO) method. The logarithmic PET rate did not display any clear dependence on Rc, despite the ultrafast scale of the PET rates. Most of the logarithmic PET rates in Sub A displayed in the inverted region of the standard free energy gap in the energy gap law. The transition dynamics among local excited states of Iso, CT state and the ion-pair state were discussed.
- Published
- 2021
13. Effects of modification of protein nanospace structure and change of temperature on the femtosecond to picosecond fluorescence dynamics of photoactive yellow protein
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Noboru Mataga, Haik Chosrowjan, Yutaka Shibata, Yasushi Imamoto, and Funmio Tokunaga
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Chemistry, Physical and theoretical -- Research ,Fluorimetry -- Research ,Protein research -- Observations ,Chemicals, plastics and rubber industries - Abstract
Research is presented describing the study of photoactive yellow protein to determine the changes taking place after the protein nanospace structure has been altered using fluorescence dynamics.
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- 2000
14. Interactions between isoalloxazine and o-aminobenzoate in o-aminobenzoate−d-amino acid oxidase complex. Molecular dynamics and molecular orbital studies
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Seiji Taniguchi, Fumio Tanaka, Somsak Pianwanit, Yasuzo Nishina, Haruhiko Tamaoki, Arthit Nueangaudom, and Haik Chosrowjan
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Chemistry ,Hydrogen bond ,General Chemical Engineering ,Heteroatom ,General Physics and Astronomy ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Fluorescence ,0104 chemical sciences ,Crystallography ,Absorption band ,Excited state ,Molecule ,Molecular orbital ,0210 nano-technology ,Ground state - Abstract
Molecular interactions between o-aminobenzoate (oAB) and isoallxazine (Iso) in o-aminobenzoate - d -amino acid oxidase complex (ODC) were studied by means of molecular dynamics simulation (MDS) and molecular orbital (MO) method. The distances between oAB and Iso were 0.60 in subunit A (Sub A) and 0.58 nm in Sub B. Four of six heteroatoms of Iso ring formed hydrogen bonding (HB) with nearby amino acids. The oxygen atom and nitrogen atom of oAB also formed HB with amino acids. The ODC displays a broad absorption band around 570 nm, which is considered to be charge transfer (CT) band between oAB and Iso in the complex. The ODC displayed fluorescence at around 520 nm, which is different from that of DAAO (emission peak at 535 nm) without oAB. The emission is from a local excited state (LE) without CT interaction. The CT interaction was studied by a semi-empirical molecular orbital (MO) method, using the structures of oAB and Iso obtained by MDS. The CT state did not form in the ground state of Iso, but formed in the excited state of Iso (Iso*), when the both cannot move appreciably from the MDS structures. The CT states formed both in the oAB – Iso and oAB – Iso* (excited state of Iso) systems when the both molecules can move so as to attain the minimum energy state. It is concluded that a part of oAB could move to form CT complex with Iso in the ground state, which displays the CT absorption band, but others could not move in the protein without CT interaction, which displays the fluorescence.
- Published
- 2021
15. Dynamics of the protein structure of T169S pyranose 2-oxidase in solution: Molecular dynamics simulation
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Nadtanet Nunthaboot, Fumio Tanaka, Seiji Taniguchi, Sirirat Kokpol, Haik Chosrowjan, Somsak Pianwanit, Kiattisak Lugsanangarm, and Arthit Nueangaudom
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0301 basic medicine ,030102 biochemistry & molecular biology ,biology ,Hydrogen bond ,Chemistry ,Protein subunit ,Ionic bonding ,Biochemistry ,Cofactor ,Photoinduced electron transfer ,03 medical and health sciences ,Crystallography ,030104 developmental biology ,Protein structure ,Pyranose ,Tetramer ,Structural Biology ,biology.protein ,Molecular Biology - Abstract
Pyranose 2-oxidase (P2O) from Trametes multicolor contains FAD as cofactor, and forms a tetramer. The protein structure of a mutated P2O, T169S (Thr169 is replaced by Ser), in solution was studied by means of molecular dynamics simulation and analyses of photoinduced electron transfer (ET) from Trp168 to excited isoalloxazine (Iso*), and was compared with wild type (WT) P2O. Hydrogen bonding between Iso and nearby amino acids was very similar as between T169S and WT protein. Distances between Iso and Tyr456 were extremely heterogeneous among the subunits, 1.7 (1.5 in WT) in subunit A (Sub A), 0.97 (2.2 in WT) in Sub B, 1.3 (2.1 in WT) in Sub C, 1.3 nm (2.0 in WT) in Sub D. Mean values of root of mean square fluctuation over all residues were greater by four times than those in WT. This suggests that the protein structure of T169S is much more flexible than that of WT. Electrostatic (ES) energies between Iso anion in one subunit and ionic groups in the entire protein were evaluated. It was found that more than 50% of the total ES energy in each subunit is contributed from other subunits. Reported fluorescence decays were analyzed by a method as WT, previously reported. Electron affinities of Iso* in T169S were appreciably higher than those in WT. Static dielectric constants near Iso and Trp168 were also quite higher in T169S than those in WT. This article is protected by copyright. All rights reserved.
- Published
- 2017
16. Photoinduced electron transfer from aromatic amino acids to the excited isoalloxazine in single mutated flavin mononucleotide binding proteins: Effect of the dimer formation on the rate and the electrostatic energy inside the proteins
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Sirirat Kokpol, Somsak Pianwanit, Arthit Nueangaudom, Kiattisak Lugsanangarm, Fumio Tanaka, Masaya Kitamura, Nadtanet Nunthaboot, Seiji Taniguchi, Haik Chosrowjan, and Takeshi Nakanishi
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Chemistry ,Dimer ,Tryptophan ,Ionic bonding ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Photochemistry ,01 natural sciences ,Biochemistry ,Photoinduced electron transfer ,0104 chemical sciences ,Gibbs free energy ,Molecular dynamics ,chemistry.chemical_compound ,symbols.namesake ,Crystallography ,Excited state ,Aromatic amino acids ,symbols ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
Conformational changes in the single mutated flavin mononucleotide binding proteins (FBP), E13K (Glu13 of wild type FBP is replaced by Lys), E13R (Glu13 replaced by Arg), E13T (Glu13 replaced by Thr) and E13Q (Glu13 replaced by Gln) upon dimer formations were studied through the phenomena of photoinduced electron transfer (ET) from tryptophan 32 (Trp32) and tryptophan 106 (Trp106) to the excited isoalloxazine (Iso∗). The ET rates were obtained with atomic coordinates of the proteins determined by a method of molecular dynamics simulation (MDS) and an ET theory using the reported experimental fluorescence decays of the FBPs. The value of the net electrostatic energy (NetES) between the photo-products and ionic groups inside the proteins increased in magnitude upon the dimer formation in every mutated FBP. Dependencies in the logarithmic ET rate (ln Rate) on the donor-acceptor distances (Rc) could not be approximated with simple linear nor parabolic functions in most ET donors, which are ascribed to the relatively greater values of the NetES in the dimers compared to the energy terms of the standard free energy gap (SFEG), solvent reorganization energy (SROE) and the electrostatic energy between the photo-products (ESDA) in total free energy gap (GT) in the ET rates. The NetES vs Rc relations displayed two distinct groups in Trp32KB, Trp32QA and Trp32QB. The ln Rate vs Rc relations in these donors displayed different behaviors between the two groups.
- Published
- 2017
17. Zero-phonon line pumped Yb:YAG TRAM laser oscillator with direct jet impingement cooling
- Author
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Masayuki Fujita, Hiroshi Ikebuchi, Hiroyuki Daigo, Dazhi Li, Seiji Taniguchi, Haik Chosrowjan, Shingo Nishikata, Koichi Hamamoto, Shinji Motokoshi, Tomoya Morioka, Takeshi Kaneko, Yuichi Ohtani, and Yasukazu Izawa
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Materials science ,Phonon ,Zero (complex analysis) ,Laser oscillator ,Jet impingement ,Atomic physics ,Line (formation) - Published
- 2019
18. Comparative studies on picosecond-resolved fluorescence of d-amino acid oxidases from human with one from porcine kidney. Photoinduced electron transfer from aromatic amino acids to the excited flavin
- Author
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Kiattisak Lugsanangarm, Shoji Ito, Seiji Taniguchi, Sirirat Kokpol, Fumio Tanaka, Hiroshi Miyasaka, Arthit Nueangaudom, Haik Chosrowjan, Masumi Katane, and Hiroshi Homma
- Subjects
D-Amino-Acid Oxidase ,Swine ,Dimer ,Static Electricity ,Biophysics ,Flavin group ,Kidney ,Photoinduced electron transfer ,Electron Transport ,chemistry.chemical_compound ,Amino Acids, Aromatic ,Flavins ,Aromatic amino acids ,Animals ,Humans ,Radiology, Nuclear Medicine and imaging ,chemistry.chemical_classification ,Radiation ,Radiological and Ultrasound Technology ,Hydrogen Bonding ,Fluorescence ,Amino acid ,Crystallography ,Monomer ,Spectrometry, Fluorescence ,chemistry ,Electron affinity (data page) ,Dimerization - Abstract
Fluorescence dynamics of human d -amino acid oxidase (hDAAO) and its five inhibitors have been studied in the picoseconds time domain, and compared with one in d -amino acid oxidase from porcine kidney (pkDAAO) reported. The fluorescence lifetimes were identified as 47 ps in the dimer, 235 ps in the monomer, which are compared with those of pkDAAO (45 ps–185 ps). The fluorescence lifetimes of the hDAAO did not change upon the inhibitor bindings despite of modifications in the absorption spectra. This indicates that the lifetimes of the complexes are too short to detect with the picosecond lifetime instrument. Numbers of the aromatic amino acids are similar between the both DAAOs. The fluorescence lifetimes of hDAAO were analysed with an ET theory using the crystal structure. The difference in the lifetimes of the dimer and monomer was well described in terms of difference in the electron affinity of the excited isoalloxazine (Iso*) between the two forms of the protein, though it is not known whether the structure of the monomer is different from the dimer. Three fastest ET donors were Tyr314, Trp52 and Tyr224 in the dimer, while Tyr314, Tyr224 and Tyr55 in the monomer, which are compared to those in pkDAAO, Tyr314, Tyr224 and Tyr228 in the dimer, and Tyr224, Tyr314 and Tyr228 in the monomer. The ET rate from Trp55 in hDAAO dimer was much faster compared to the rate in pkDAAO dimer. A rise component with negative pre-exponential factor was not observed in hDAAO, which are found in pkDAAO.
- Published
- 2018
19. Effects of protein association on the rates of photoinduced electron transfer from tryptophan residues to excited flavin in medium-chain acyl-Co A dehydrogenase. Molecular dynamics simulation
- Author
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Kiattisak Lugsanangarm, Haik Chosrowjan, Nadtanet Nunthaboot, Sirirat Kokpol, Fumio Tanaka, and Seiji Taniguchi
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Flavin adenine dinucleotide ,General Chemical Engineering ,General Physics and Astronomy ,Dehydrogenase ,02 engineering and technology ,General Chemistry ,Flavin group ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Photoinduced electron transfer ,0104 chemical sciences ,Crystallography ,chemistry.chemical_compound ,Monomer ,chemistry ,Electron affinity (data page) ,Tetramer ,Excited state ,0210 nano-technology - Abstract
Rates of photoinduced electron transfer (ET) from tryptophan residues (Trps) to excited isoalloxazine (Iso*) of flavin adenine dinucleotide (FAD) in medium-chain acyl Co A dehydrogenase from porcine kidney (MCAD) have been studied using its entire tetrameric structures obtained by molecular dynamics simulation (MDS) and experimental ultrafast fluorescence decays reported. The ET rates were fastest from Trp166 to Iso* among the four Trps. The emission-wavelength dependent decays were elucidated by introducing emission-wavelength dependent electron affinity of Iso*. The ET rates in Sub C were much slower than those in other subunits, which was ascribed to non-equivalent electrostatic interactions among the subunits. Effect of the protein association on the ET rates and related physical quantities were examined comparing those in the tetramer and monomer reported. The donor-acceptor distances in the tetramer were shorter than those in the monomer. The ET rates from Trp166 in the tetramer were slower than that in the monomer. The ET rates and related physical quantities were examined at seven emission wavelengths. The values of standard free energy gap between the photo-products and reactants displayed to increase as the emission wavelength becomes longer at all subunits. The ET rates displayed to decrease in Sub A, Sub C and Sub D, as the emission wavelength becomes longer.
- Published
- 2021
20. Simultaneous analyses of the rates of photoinduced charge separation and recombination between the excited flavin and tryptophans in some flavoproteins: Molecular dynamics simulation
- Author
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Fumio Tanaka, Yasuzo Nishina, Masaya Kitamura, Kiattisak Lugsanangarm, Haruhiko Tamaoki, Haik Chosrowjan, Seiji Taniguchi, and Nadtanet Nunthaboot
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010302 applied physics ,animal structures ,biology ,Chemistry ,General Physics and Astronomy ,Flavoprotein ,02 engineering and technology ,Flavin group ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,lcsh:QC1-999 ,Photoinduced electron transfer ,Molecular dynamics ,Tetramer ,Photoinduced charge separation ,Excited state ,0103 physical sciences ,Ultrafast laser spectroscopy ,biology.protein ,0210 nano-technology ,lcsh:Physics - Abstract
Ultrafast transient absorption (TA) spectroscopy has been one of the most powerful experimental tools to study the mechanism of photoinduced electron transfer (ET) as in photosynthetic and flavin photoreceptor systems in plants. However, no work has been reported on their quantitative mechanisms. Apparent rates of charge separation (CS) from tryptophans (Trps) to the excited isoalloxazine (Iso*) and charge recombination (CR) from the produced ion pairs to Trps and Iso in the ground states are reported to be 0.25 ps and 3.2 ps in medium-chain acyl-CoA dehydrogenase (MCAD), and 0.15 ps and 6.6 ps in flavin mononucleotide binding protein (FMN-bp), obtained by an ultrafast TA method. The decays of the CS and CR processes were for the first time simultaneously analyzed with an ET theory and structures obtained by molecular dynamics simulation. MCAD and FMN-bp form a tetramer and dimer, respectively. The CS and CR rates of an individual donor and various related physical quantities were numerically obtained. It was found that both CS and CR rates were fastest from Trp166 among four Trps in MCAD and those from Trp106 among two Trps in FMN-bp. Logarithmic CS rates in MCAD were dependent on the donor–acceptor distance (Rc) with parabolic functions, while those of CR rates linearly decreased with Rc. Reasons why CS rates were faster than CR rates in both MCAD and FMN-bp were elucidated in terms of pre-exponential factors in the theory. The present method could be useful to understand the precise mechanisms of initial steps of biological functions of photoreceptors in plants.
- Published
- 2020
21. Photoinduced electron transfer from aromatic amino acids to the excited isoalloxazine in flavin mononucleotide binding protein. Is the rate in the inverted region of donor–acceptor distance not real?
- Author
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Arthit Nueangaudom, Takeshi Nakanishi, Kiattisak Lugsanangarm, Sirirat Kokpol, Somsak Pianwanit, Seiji Taniguchi, Fumio Tanaka, Haik Chosrowjan, Masaya Kitamura, and Nadtanet Nunthaboot
- Subjects
Range (particle radiation) ,General Chemical Engineering ,Dimer ,Solvation ,General Physics and Astronomy ,Ionic bonding ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Photoinduced electron transfer ,0104 chemical sciences ,Gibbs free energy ,Crystallography ,chemistry.chemical_compound ,symbols.namesake ,Molecular dynamics ,chemistry ,Excited state ,symbols ,0210 nano-technology - Abstract
Mechanisms of photoinduced electron transfer (ET) from tryptophanes 32 and 106 in subunits A and B (Trp32A, Trp32B, Trp106A and Trp106B) of wild type flavin mononucleotide binding protein (FBP) dimer were studied through relations of the logarithmic ET rate (ln Rate) vs the donor-acceptor distance (Rc). The sum (GT) of standard free energy gap (SFEG) between the products and reactants, electrostatic energy (ESDA) between the photo-products and solvation reorganization energy (SROE) and electrostatic energy (NetES) between the photo-products and ionic groups inside the protein were numerically determined for the all donors with atomic coordinates obtained by molecular dynamic simulation. The GT values of Trp32A and Trp32B displayed always negative in the entire Rc range, which predicts that ET rate becomes slower as the Rc shorter. The reason of negative GT values in Trp32A and Trp32B were numerically elucidated with the mean values of SFEG, ESDA, SROE, and NetES.
- Published
- 2016
22. Studies of melting ice using CO2 laser for ice drilling
- Author
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Okitsugu Watanabe, Toshimitsu Sakurai, Yasukazu Izawa, Toshihiro Somekawa, Hideaki Motoyama, Haik Chosrowjan, and Masayuki Fujita
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geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Ice crystals ,Mineralogy ,Drilling ,Geotechnical Engineering and Engineering Geology ,Laser ,01 natural sciences ,Ice wedge ,law.invention ,Sea ice growth processes ,law ,Pancake ice ,0103 physical sciences ,General Earth and Planetary Sciences ,Ice sheet ,010303 astronomy & astrophysics ,Geomorphology ,Geology ,0105 earth and related environmental sciences ,Laser drilling - Abstract
A CO 2 laser can be used to melt ice. Here we use a CO 2 laser at 10.6 μm, a wavelength at which ice strongly absorbs, to drill (via melting) through ice. The resulting drilling speed is measured at several irradiation intensities, ice-snow densities, and beam angles relative to the horizontal axis. The speed increases nearly in proportion to the laser intensity. For an intensity of about 50 W/cm 2 , for instance, the melting speed is 4 mm/s for snow of density 153 kg/m 3 and 0.8 mm/s for solid ice. Results also show that for downward beam angles, melt-water accumulates in the hole, reducing the drilling speed. Nevertheless, we also consider other laser mediums and argue that an optical-fiber-coupled laser drilling system could be used for drilling on glaciers and ice sheets.
- Published
- 2016
23. Corrigendum to 'Comparative studies on picosecond-resolved fluorescence of d- amino acid oxidases from human with one from porcine kidney. Photoinduced electron transfer from aromatic amino acids to the excited flavin' [Journal of Photochemistry & Photobiology, B: Biology, volume 198 (2019) 111546–111557/111546]
- Author
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Kiattisak Lugsanangarm, Masumi Katane, Fumio Tanaka, Shoji Ito, Sirirat Kokpol, Seiji Taniguchi, Hiroshi Miyasaka, Arthit Nueangaudom, Haik Chosrowjan, and Hiroshi Homma
- Subjects
Radiation ,Radiological and Ultrasound Technology ,Porcine kidney ,Biophysics ,Flavin group ,Photochemistry ,Fluorescence ,Photoinduced electron transfer ,chemistry.chemical_compound ,Photobiology ,chemistry ,Excited state ,Picosecond ,Aromatic amino acids ,Radiology, Nuclear Medicine and imaging - Published
- 2020
24. Heterogeneous subunit structures in the pyranose 2-oxidase homotetramer revealed by theoretical analysis of the rates of photoinduced electron transfer from a tryptophan to the excited flavin
- Author
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Sirirat Kokpol, Fumio Tanaka, Somsak Pianwanit, Nadtanet Nunthaboot, Seiji Taniguchi, Arthit Nueangaudom, Haik Chosrowjan, and Kiattisak Lugsanangarm
- Subjects
Flavin adenine dinucleotide ,General Chemical Engineering ,General Physics and Astronomy ,General Chemistry ,Flavin group ,Photochemistry ,Fluorescence ,Photoinduced electron transfer ,chemistry.chemical_compound ,Crystallography ,chemistry ,Electron affinity (data page) ,Pyranose ,Excited state ,Homotetramer - Abstract
Pyranose 2-oxidase (P2O) from Trametes multicolor forms a homotetramer in which each of the subunits contains flavin adenine dinucleotide (FAD). The fluorescence of P2O decays with two lifetime components; a slow (358 ps) and a fast (∼90 fs) decay. The lifetime of the fast component is emission-wavelength dependent and is ascribed to fast photoinduced electron transfer (ET) from Trp168 to the excited isoalloxazine (Iso*) in FAD. The donor–acceptor distances were ∼0.7 nm. The extraordinary heterogeneous decays were analyzed with atomic coordinates obtained by a molecular dynamics simulation and the ET rate by Kakitani and Mataga. The emission-wavelength dependent decays in the fast component were elucidated by introducing emission-wavelength dependent standard free energy related to electron affinity of Iso*. Examination of all possible combinations of the four subunits revealed that the slow component was from subunit A and the fast component was from the other three subunits. Agreements between the observed and calculated decays were all excellent. The large difference in the fast and slow fluorescent lifetimes is ascribed to the difference in the standard free energy gap related to electron affinity of Iso*. The dependence of the logarithmic ET rates on the center-to-center distance displayed approximate linear functions (Dutton rule) when the rate was relatively slow and parabolic functions when the rate was ultrafast. The Dutton rule originated from the exponential term of the ET rate, not from the electronic coupling term.
- Published
- 2015
25. Ultrafast fluorescence upconversion technique and its applications to proteins
- Author
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Haik Chosrowjan, Seiji Taniguchi, and Fumio Tanaka
- Subjects
Models, Molecular ,Flavoproteins ,Photoisomerization ,Chemistry ,Static Electricity ,Ionic bonding ,Cell Biology ,Chromophore ,Photoreceptors, Microbial ,Electrostatics ,Photochemistry ,Biochemistry ,Fluorescence ,Photon upconversion ,Electron Transport ,Crystal ,Electron transfer ,Spectrometry, Fluorescence ,Amino Acid Substitution ,Bacterial Proteins ,Microscopy, Fluorescence ,Point Mutation ,Crystallization ,Molecular Biology - Abstract
The basic principles and main characteristics of the ultrafast time-resolved fluorescence upconversion technique (conventional and space-resolved), including requirements for nonlinear crystals, mixing spectral bandwidth, acceptance angle, etc., are presented. Applications to flavoproteins [wild-type (WT) FMN-binding protein and its W32Y, W32A, E13R, E13K, E13Q and E13T mutants] and photoresponsive proteins [WT photoactive yellow protein and its R52Q mutant in solution and as single crystals] are demonstrated. For flavoproteins, investigations elucidating the effects of ionic charges on ultrafast electron transfer (ET) dynamics are summarized. It is shown that replacement of the ionic amino acid Glu13 and the resulting modification of the electrostatic charge distribution in the protein chromphore-binding pocket substantially alters the ultrafast fluorescence quenching dynamics and ET rate in FMN-binding protein. It is concluded that, together with donor-acceptor distances, electrostatic interactions between ionic photoproducts and other ionic groups in the proteins are important factors influencing the ET rates. In WT photoactive yellow protein and the R52Q mutant, ultrafast photoisomerization dynamics of the chromophore (deprotonated trans-p-coumaric acid) in liquid and crystal phases are investigated. It is shown that the primary dynamics in solution and single-crystal phases are quite similar; hence, the photocycle dynamics and structural differences observed at longer time scales arise mostly from the structural restraints imposed by the crystal lattice rigidity versus the flexibility in solution.
- Published
- 2015
26. New Aspects of the Structure of d-Amino Acid Oxidase from Porcine Kidney in Solution: Molecular Dynamics Simulation and Photoinduced Electron Transfer
- Author
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Kiattisak Lugsanangarm, Nadtanet Nunthaboot, Arthit Nueangaudom, Fumio Tanaka, Somsak Pianwanit, Haik Chosrowjan, Sirirat Kokpol, and Seiji Taniguchi
- Subjects
Molecular dynamics ,Chemistry ,Porcine kidney ,D-amino acid oxidase ,Photochemistry ,Photoinduced electron transfer - Published
- 2017
27. Dynamics of the protein structure of T169S pyranose 2-oxidase in solution: Molecular dynamics simulation
- Author
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Kiattisak, Lugsanangarm, Arthit, Nueangaudom, Somsak, Pianwanit, Sirirat, Kokpol, Nadtanet, Nunthaboot, Fumio, Tanaka, Seiji, Taniguchi, and Haik, Chosrowjan
- Subjects
Solutions ,Trametes ,Protein Conformation ,Carbohydrate Dehydrogenases ,Hydrogen Bonding ,Amino Acids ,Molecular Dynamics Simulation - Abstract
Pyranose 2-oxidase (P2O) from Trametes multicolor contains FAD as cofactor, and forms a tetramer. The protein structure of a mutated P2O, T169S (Thr169 is replaced by Ser), in solution was studied by means of molecular dynamics simulation and analyses of photoinduced electron transfer (ET) from Trp168 to excited isoalloxazine (Iso*), and was compared with wild type (WT) P2O. Hydrogen bonding between Iso and nearby amino acids was very similar as between T169S and WT protein. Distances between Iso and Tyr456 were extremely heterogeneous among the subunits, 1.7 (1.5 in WT) in subunit A (Sub A), 0.97 (2.2 in WT) in Sub B, 1.3 (2.1 in WT) in Sub C, 1.3 nm (2.0 in WT) in Sub D. Mean values of root of mean square fluctuation over all residues were greater by four times than those in WT. This suggests that the protein structure of T169S is much more flexible than that of WT. Electrostatic (ES) energies between Iso anion in one subunit and ionic groups in the entire protein were evaluated. It was found that more than 50% of the total ES energy in each subunit is contributed from other subunits. Reported fluorescence decays were analyzed by a method as WT, previously reported. Electron affinities of Iso* in T169S were appreciably higher than those in WT. Static dielectric constants near Iso and Trp168 were also quite higher in T169S than those in WT.
- Published
- 2017
28. Bell-shaped dependence of the rate of ultrafast photoinduced electron transfer from aromatic amino acids to the excited flavin on the donor–acceptor distance in FMN binding proteins
- Author
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Takeshi Nakanishi, Kiattisak Lugsanangarm, Haik Chosrowjan, Seiji Taniguchi, Sirirat Kokpol, Nadtanet Nunthaboot, Masaya Kitamura, Somsak Pianwanit, and Fumio Tanaka
- Subjects
biology ,Chemistry ,Tryptophan ,Flavin mononucleotide ,Flavin group ,Condensed Matter Physics ,biology.organism_classification ,Biochemistry ,Photoinduced electron transfer ,chemistry.chemical_compound ,Crystallography ,FMN binding ,Excited state ,Aromatic amino acids ,Physical and Theoretical Chemistry ,Desulfovibrio vulgaris - Abstract
Flavin mononucleotide (FMN)-binding proteins (FBP) from Desulfovibrio vulgaris , Miyazaki F, contain FMN as a cofactor. Upon photo-excitation of the FBP, photoinduced electron transfer (ET) takes place from tryptophan (Trp)32, tyrosine (Tyr)35 and Trp105 residues to the excited isoalloxazine ring (Iso ∗ ) of FMN. The ultrafast fluorescence dynamics of the wild type, and the E13K, E13R, E13T and E13Q substitution isoforms of FBP were simultaneously analyzed with molecular dynamics simulation structures and Kakitani-Mataga ET theory, to obtain the time-dependent ET rates. A bell-shaped behavior of the logarithmic ET rates (In k ET ) from Trp32 and Trp106 to Iso ∗ versus the centre-to-centre donor–acceptor distances ( Rc ) was obtained in the time domain of sub-ps to ps in all five FBP isoforms. The In k ET from Tyr35 to Iso ∗ linearly decreased with the Rc distance, which were much slower than those of Trp32 and Trp105. These findings suggest that the nuclear term in the ET theory is important in the ultrafast time domain, whereas the electronic coupling term may be dominant in slower ET rates.
- Published
- 2014
29. Theoretical analyses of the fluorescence lifetimes of the<scp>d</scp>-amino acid oxidase–benzoate complex dimer from porcine kidney: molecular dynamics simulation and photoinduced electron transfer
- Author
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Haik Chosrowjan, Seiji Taniguchi, Fumio Tanaka, Sirirat Kokpol, Arthit Nueangaudom, Nadtanet Nunthaboot, Kiattisak Lugsanangarm, and Somsak Pianwanit
- Subjects
General Chemical Engineering ,Dimer ,D-amino acid oxidase ,General Chemistry ,Photochemistry ,Fluorescence ,Photoinduced electron transfer ,chemistry.chemical_compound ,Crystallography ,Molecular dynamics ,Electron transfer ,Monomer ,chemistry ,Excited state - Abstract
The mechanism of photoinduced electron transfer (ET) from benzoate (Bz) and aromatic amino acids to the excited isoalloxazine (Iso*) in the D-amino acid oxidase–benzoate complex (DAOB) dimer from porcine kidney was studied using molecular dynamics simulation (MDS) and an electron transfer theory, and compared with that in the DAOB monomer. The DAOB dimer displayed two fluorescent lifetime components of 0.85 ps and 4.8 ps, as reported. The ET parameters contained in the Kakitani and Mataga (KM) model were determined so as to reproduce these lifetimes with MDS atomic coordinates. The Bz–isoalloxazine (Iso) distances were 0.66 nm in subunit A (Sub A), 0.68 nm in subunit B (Sub B) and 0.61 nm in the monomer. The fluorescent lifetimes of 4.8 ps and 0.85 ps were found to originate from Sub A and Sub B, respectively. In Sub A, Tyr228 was the fastest ET donor followed by Bz and Tyr55, while Bz was followed by Tyr228 and Tyr314 in Sub B. The ET rate from Bz was fastest in Sub B, followed by that in Sub A and the DAOB monomer. The static dielectric constants obtained near Iso were 2.4–2.6 in the DAOB dimer and monomer and 5.8–5.9 in holo D-amino oxidase (DAAO). The different dielectric constants could account for the experimental fluorescence peak observed for DAOB (524 nm) and DAAO (530 nm). Logarithmic ET rates decreased linearly with the donor–acceptor distance expressed by both center to center distance (Rc) and edge to edge distance (Re) in Sub A and Sub B of DAOB dimer and monomer, which reveals that the conventional Dutton rule holds in the ET processes in DAOB. The logarithmic ET rates were decomposed into the electronic coupling (EC), square root (SQ) and exponential (GTRAM) terms. It was found that both the EC term and the GTRAM term also decreased linearly with Rc. The sum of the slopes in the EC and GTRAM vs. Rc plots coincided with the slopes in the logarithmic ET rate vs. Rc functions, suggesting that the GTRAM term makes a significant contribution to the linear relations between logarithmic ET rate and Rc.
- Published
- 2014
30. Mechanism of photoinduced electron transfer from tyrosine to the excited flavin in the flavodoxin from Helicobacter pylori. A comparative study with the flavodoxin and flavin mononucleotide binding protein from Desulfovibrio vulgaris (Miyazaki F)
- Author
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Sirirat Kokpol, Kiattisak Lugsanangarm, Kumiko Ogino, Rikako Takagi, Nadtanet Nunthaboot, Haik Chosrowjan, Masaya Kitamura, Seiji Taniguchi, Fumio Tanaka, Takeshi Nakanishi, Arthit Nueangaudom, and Somsak Pianwanit
- Subjects
biology ,Flavodoxin ,Chemistry ,General Chemical Engineering ,Protein dynamics ,General Physics and Astronomy ,General Chemistry ,Flavin group ,Photochemistry ,biology.organism_classification ,Fluorescence ,Photoinduced electron transfer ,Crystallography ,Electron transfer ,Excited state ,biology.protein ,Desulfovibrio vulgaris - Abstract
Photoinduced electron transfer in the Helicobacter pylori flavodoxin (HPFD) was investigated using both experimental and theoretical techniques. Recombinant (r)HPFD was prepared by expression in Escherichia coli and the ultrafast fluorescence dynamics of the purified rHPFD was measured by means of fluorescence up-conversion. The fluorescence was found to decay with a lifetime of 173 fs (amplitude, 0.963) and 2.08 ps (0.037). These data were used in the Kakitani and Mataga theory to calculate the electron transfer (ET) rate inside the native HPFD. Molecular dynamics simulations of HPFD were performed over a 50 ns period to enable an inclusion of the protein dynamics effect on the ET process. The ET rate from Tyr91 to an excited isoalloxazine (Iso*) ranged from 6 to 23 ps −1 , depending on the analysis method used, while the ET rates from Trp63 and Tyr120 to Iso* were negligibly slow. The logarithmic ET rate and net electrostatic (ES) energy between the photo-products and ionic groups inside HPFD both displayed a parabolic relationship with the total free energy gap, indicating that the net ES energy is one of the most influential factors upon the ultrafast ET rate. Although the logarithmic ET rate should theoretically be decreased with increasing center-to-center distances according to Dutton's law, this relationship was not observed in this system. One possible reason for this was elucidated by comparing our results with those from the flavin mononucleotide binding protein.
- Published
- 2013
31. A Key Factor for Ultrafast Rates of Photoinduced Electron Transfer among Five Flavin Mononucleotide Binding Proteins: Effect of Negative, Positive, and Neutral Charges at Residue 13 on the Rate
- Author
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Takeshi Nakanishi, Shuta Sato, Haik Chosrowjan, Fumio Tanaka, Seiji Taniguchi, Yoshihiro Haruyama, and Masaya Kitamura
- Subjects
Residue (chemistry) ,chemistry.chemical_compound ,chemistry ,Stereochemistry ,Negative charge ,mental disorders ,Flavin mononucleotide binding ,Wild type ,Flavin mononucleotide ,General Chemistry ,Crystal structure ,psychological phenomena and processes ,Photoinduced electron transfer - Abstract
Crystal structures of E13K [Glu13 with negative charge in wild type (WT) was replaced by Lys with positive charge] and E13R (Glu13 was replaced by Arg with positive charge) of flavin mononucleotide...
- Published
- 2013
32. Photochemistry of fac-[Re(bpy)(CO)3Cl]
- Author
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Ken Onda, Naoto Fukazawa, Seiji Taniguchi, Yukihide Ishibashi, Shin-ya Koshihara, Hiroshi Miyasaka, Magnus Falkenström, Tetsuro Katayama, Noboru Mataga, Yasuo Matubara, Osamu Ishitani, Haik Chosrowjan, Kazuhide Koike, and Shunsuke Sato
- Subjects
Ligand field theory ,photochemistry ,Chemistry ,Organic Chemistry ,Infrared spectroscopy ,General Chemistry ,Associative substitution ,rhenium ,Full Papers ,Photochemistry ,Catalysis ,isomerization ,Intersystem crossing ,Excited state ,Singlet state ,ligand substitution ,Triplet state ,Isomerization ,photophysics - Abstract
The photochemistry of fac-[Re(bpy)(CO)(3)Cl] (1 a; bpy=2,2'-bipyridine) initiated by irradiation using330 nm light has been investigated. Isomerization proceeded in THF to give the corresponding mer-isomer 1 b. However, in the presence of a small amount of MeCN, the main product was the CO-ligand-substituted complex (OC-6-24)-[Re(bpy)(CO)(2) Cl(MeCN)] (2 c; bpy=2,2'-bipyridine). In MeCN, two isomers, 2 c and its (OC-6-34) form (2 a), were produced. Only 2 c thermally isomerized to produce the (OC-6-44) form 2 b. A detailed investigation led to the conclusion that both 1 b and 2 c are produced by a dissociative mechanism, whereas 2 a forms by an associative mechanism. A comparison of the ultrafast transient UV-visible absorption, emission, and IR spectra of 1 a acquired by excitation using higher-energy light (e.g., 270 nm) and lower-energy light (e.g., 400 nm) gave detailed information about the excited states, intermediates, and kinetics of the photochemical reactions and photophysical processes of 1 a. Irradiation of 1 a using the higher-energy light resulted in the generation of the higher singlet excited state with τ≤25 fs, from which intersystem crossing proceeded to give the higher triplet state ((3)HES(1)). In THF, (3)HES(1) was competitively converted to both the triplet ligand field ((3)LF) and metal-to-ligand charge transfer ((3)MLCT) with lifetimes of 200 fs, in which the former is a reactive state that converts to [Re(bpy)(CO)(2)Cl(thf)](+) (1 c) within 10 ps by means of a dissociative mechanism. Re-coordination of CO to 1 c gives both 1 a and 1 b. In MeCN, irradiation of 1 a by using high-energy light gives the coordinatively unsaturated complex, which rapidly converted to 2 c. A seven-coordinate complex is also produced within several hundred femtoseconds, which is converted to 2 a within several hundred picoseconds.
- Published
- 2012
33. Ultrafast fluorescence dynamics of flavin adenine dinucleotide in pyranose 2-oxidases variants and their complexes with acetate: Conformational heterogeneity with different dielectric constants
- Author
-
Jeerus Sucharitakul, Fumio Tanaka, Pimchai Chaiyen, Seiji Taniguchi, Thanyaporn Wongnate, and Haik Chosrowjan
- Subjects
Flavin adenine dinucleotide ,biology ,General Chemical Engineering ,General Physics and Astronomy ,Flavoprotein ,General Chemistry ,Flavin group ,Photochemistry ,Fluorescence ,Photoinduced electron transfer ,Crystallography ,chemistry.chemical_compound ,Pyranose ,chemistry ,Excited state ,biology.protein ,Conformational isomerism - Abstract
Pyranose 2-oxidase from Trametes multicolor (P2O) catalyzes oxidations of aldopyranoses by using molecular oxygen. The enzyme is composed of four identical subunits with a native molecular weight of 270 kDa and each of which contains flavin adenine dinucleotide (FAD) as a cofactor. P2O contains the Trp168 residue near the flavin isoalloxazine ring (Iso), which can potentially act as an electron donor to the excited Iso (Iso*). Iso is covalently linked to His167 in WT P2O, but not in H167A (His167 replaced by Ala). Ultrafast fluorescence dynamics of H167A, T169S (Thr169 replaced by Ser) and acetate complexes with WT and T169S were studied by the fluorescence up-conversion method. The fluorescence decays were well described with two-exponential functions. The shorter fluorescence lifetimes ( τ 1 ) were 87–184 fs depending on an emission wavelength, and the longer lifetimes ( τ 2 ) was 120 ps without the emission wavelength-dependence in H167A. The shorter lifetimes of T169S were 92–240 fs, and the longer lifetime 15 ps. In WT P2O–acetate complex τ 1 was 110 fs and τ 2 50 ps, and in T169S P2O–acetate complex τ 1 was 250 fs and τ 2 300 ps at 530 nm. The ratio of the lifetime ( τ 2 / τ 1 ) was extraordinary high compared to the other flavoproteins. This result was interpreted as two conformers of P2O, Conformers 1 and 2 (Conf 1 and Conf 2), in which each was associated with τ 1 and τ 2 , respectively. The ultra-short lifetimes were ascribed to photoinduced electron transfer (ET) mainly from Trp168 to the excited Iso (Iso*). ET rates of Confs 1 and 2 were calculated based on structural parameters reported. According to the crystal structures, distances between Iso and Trp168 were not different among the four subunits. It was found that static dielectric constants of the Conf 1 with τ 1 ( ɛ 1 = 3.51) was different from that of the Conf 2 with τ 2 ( ɛ 2 = 5.95). Fluorescence spectra with τ 1 and τ 2 were constructed based on the emission-wavelength dependent-decay functions. Emission peak with τ 1 was time-dependent from the wavelengths shorter than 480 to 540 nm within 1 ps after excitation, whereas that with τ 2 was steady at around 530 nm.
- Published
- 2012
34. Conformational heterogeneity in pyranose 2-oxidase from Trametes multicolor revealed by ultrafast fluorescence dynamics
- Author
-
Seiji Taniguchi, Jeerus Sucharitakul, Pimchai Chaiyen, Fumio Tanaka, Thanyaporn Wongnate, and Haik Chosrowjan
- Subjects
Flavin adenine dinucleotide ,Quenching (fluorescence) ,biology ,General Chemical Engineering ,General Physics and Astronomy ,Flavoprotein ,General Chemistry ,Photochemistry ,Fluorescence ,Photoinduced electron transfer ,chemistry.chemical_compound ,Pyranose ,chemistry ,Excited state ,biology.protein ,Conformational isomerism - Abstract
Ultrafast fluorescence dynamics of flavin adenine dinucleotide (FAD) in wild type pyranose 2-oxidase (P2O) has been investigated in solution by means of fluorescence up-conversion method. Fluorescence decays were well described by two-exponential model function. Fluorescence lifetimes were τ1 ∼ 110 fs and τ2 ∼ 360 ps, respectively. The (τ2/τ1) ratio (∼3200) was extraordinary high compared to other flavoproteins without subunit structure. The heterogeneous distribution of emission lifetimes were elucidated in terms of two different conformers of P2O; conformer 1 with τ1 and conformer 2 with τ2. Emission peaks of conformer 1 and conformer 2 were determined to be at ∼540 nm and 510 nm, respectively, using transient spectral reconstruction procedure. Using dynamics analysis by Kakitani and Mataga (KM) theory, both quenching processes were ascribed to photoinduced electron transfer (ET) reactions mainly from Trp168 to the excited isoalloxazine (Iso*) in different protein tetramers having different static dielectric constants (ɛ1 ∼ 3.25 for conformer 1 and ɛ2 ∼ 5.93 for conformer 2). The quaternary structure seems to be responsible for the observed conformational heterogeneity.
- Published
- 2012
35. Quantum mechanical study of photoinduced charge transfer in FMN binding protein
- Author
-
Nadtanet Nunthaboot, Fumio Tanaka, Sirirat Kokpol, Haik Chosrowjan, Seiji Taniguchi, and Noboru Mataga
- Subjects
Charge transfer -- Analysis ,Flavin mononucleotide -- Chemical properties ,Flavin mononucleotide -- Structure ,Protein binding -- Analysis ,Quantum theory -- Usage ,Chemicals, plastics and rubber industries - Published
- 2008
36. Theoretical analyses of photoinduced electron transfer in medium chain acyl-CoA dehydrogenase: Electron transfer in the normal region
- Author
-
Sirirat Kokpol, Kiattisak Lugsanangarm, Seiji Taniguchi, Somsak Pianwanit, Nadtanet Nunthaboot, Haik Chosrowjan, and Fumio Tanaka
- Subjects
chemistry.chemical_classification ,Flavin adenine dinucleotide ,biology ,Stereochemistry ,General Chemical Engineering ,General Physics and Astronomy ,Fatty acid ,Flavoprotein ,General Chemistry ,Photochemistry ,Photoinduced electron transfer ,Cofactor ,Amino acid ,Electron transfer ,chemistry.chemical_compound ,chemistry ,biology.protein ,Aromatic amino acids - Abstract
Medium chain acyl-CoA dehydrogenase (MCAD) binds flavin adenine dinucleotide (FAD) as cofactor, and catalyze α,β-dehydrogenation of fatty acid acyl-CoA conjugates as the first step of β-oxidation of fatty acids in mitochondria. The dynamic properties of geometrical factors as distances between isoalloxazine (Iso) and the aromatic amino acids of Trp and Tyr were studied by molecular dynamic (MD) simulation. The center-to-center distances ( R c ) between Iso and aromatic amino acids were shortest in Tyr365 (0.99 nm) and then in Trp156 (1.00 nm), Tyr123 (1.29 nm), Tyr362 (1.42 nm). The Iso moiety was buried inside the protein, and surrounded by rigid and hydrophobic amino acids. The motions of the aromatic amino acids were suggested to be cooperative and synchronized with each other at some places in the protein. H-bonds were formed between Iso and Tyr123, Val125, Thr126 and Thr158. Photoinduced electron transfer (ET) from aromatic amino acids to the excited Iso (Iso*) was analysed from the reported ultrafast fluorescence dynamics of MCAD with Kakitani and Mataga (KM) theory. The ET rate was fastest from Trp156, and then from Tyr365, Trp47, Tyr302 and Trp165 in this order. Physical constants contained in KM theory were determined by a best-fit procedure between the observed and calculated fluorescence decays. Most of those quantities were similar to those derived from other flavoproteins. The free energy related to electron affinity of Iso* ( G Iso 0 ) and dielectric constant ( ɛ 0 ) were, however, quite low compared to their mean values among four other flavoproteins, which was elucidated by the low polarity around Iso. The energy gap law of ET was examined and revealed that ET in MCAD takes place in the normal region.
- Published
- 2011
37. Photoinduced electron transfer in wild type and mutated flavodoxin from Desulfovibrio vulgaris, strain Miyazaki F.: Energy gap law
- Author
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Fumio Tanaka, Noboru Mataga, Seiji Taniguchi, Somsak Pianwanit, Kiattisak Lugsanangarm, Haik Chosrowjan, and Sirirat Kokpol
- Subjects
biology ,Flavodoxin ,Band gap ,Chemistry ,General Chemical Engineering ,General Physics and Astronomy ,General Chemistry ,biology.organism_classification ,Photoinduced electron transfer ,Gibbs free energy ,symbols.namesake ,Electron transfer ,Crystallography ,Molecular dynamics ,Excited state ,biology.protein ,symbols ,Atomic physics ,Desulfovibrio vulgaris - Abstract
Time–dependent changes in the geometrical factors near the isoalloxazine (Iso) residue of FMN in three mutant isoforms [Y97F, W59F and W59F–Y97F (DM, double mutation)] of the flavodoxin (FD) from Desulfovibrio vulgaris, strain Miyazaki F., were obtained by molecular dynamic (MD) simulation. The center to center distances from Iso to Trp59 in Y97F and to Tyr97 in W59F were 0.78 nm and 0.55 nm, respectively. The remarkable fluorescence quenching in these proteins has been explained in terms of photoinduced electron transfer (ET) from the Trp59 and/or Tyr97 residues to the excited isoalloxazine (Iso*). The ultrafast fluorescence dynamics of the wild type (WT) and the Y97F, W59F and DM variant FDs reported by Mataga et al. (J. Phys. Chem. B 106 (2002) 8917–8920), were simultaneously analyzed by the electron transfer theory of Kakitani and Mataga (KM theory) and the atomic coordinates determined by MD, according to a non-linear least squares method. Agreements between the observed and calculated decays were all very good. The obtained physical constants contained in the KM theory were, for Trp and Tyr, respectively, a frequency factor (ν0) of 3.09 × 103 ps−1 and 2.46 × 103 ps−1, an ET process coefficient (β) of 55.6 nm−1 and 9.64 nm−1, a critical transfer distance (R0) of 0.772 nm and 0.676 nm, plus a free energy related to the electron affinity of Iso* ( G Iso 0 ) of 7.67 eV. These constants were common to all three mutant FD systems. In contrast, the static dielectric constant depended on the FD systems, being 4.78, 4.04 and 2.28 in the Y97F, W59F and DM variant FDs, respectively. The mean ET rate to Iso* was fastest from Trp59 in Y97F among the three systems. The total free energy gap in the FD systems was obtained as a sum of the net electrostatic (ES) energy between ion pairs and the standard free energy gap. A plot of ln kET/λS vs. − Δ G T 0 / λ S in all ET donors, where kET is ET rate, λS is the reorganization energy and Δ G T 0 is the total free energy gap, revealed that ln kET/λS can be expressed by a parabolic function of − Δ G T 0 / λ S and the ET process in FD took place mostly in the normal region.
- Published
- 2011
38. Fluorescence Dynamics of Photoactive Protein Micro-Crystals Using Femtosecond Time-Resolved Fluorescence Microscope
- Author
-
Seiji Taniguchi and Haik Chosrowjan
- Subjects
Microscope ,Materials science ,Micro crystals ,law ,business.industry ,Dynamics (mechanics) ,Femtosecond ,Optoelectronics ,Time-resolved spectroscopy ,business ,Fluorescence ,law.invention - Published
- 2011
39. Ultrafast Photodissociation Dynamics of a Hexaarylbiimidazole Derivative with Pyrenyl Groups: Dispersive Reaction from Femtosecond to 10 ns Time Regions
- Author
-
Yukihide Ishibashi, Syoji Ito, Hiroshi Miyasaka, Haik Chosrowjan, Seiji Taniguchi, Azusa Kikuchi, Yusuke Satoh, Jiro Abe, Noboru Mataga, Daisuke Kato, and Yutaka Nagasawa
- Subjects
Photodissociation ,General Chemistry ,Photochemistry ,Biochemistry ,Fluorescence ,Catalysis ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,chemistry ,Hexaarylbiimidazole ,Excited state ,Ultrafast laser spectroscopy ,Moiety ,Spectroscopy ,Ground state - Abstract
The photodissociation dynamics of a hexaarylbiimidazole (HABI) derivative with two pyrenyl groups was investigated by time-resolved transient absorption spectroscopy and fluorescence measurements. Transient absorption spectroscopy revealed that photodissociation took place in the wide time region of
- Published
- 2009
40. Structural Effects on the Ultrafast Photoisomerization of Photoactive Yellow Protein. Transient Absorption Spectroscopy of Two Point Mutants
- Author
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Seiji Taniguchi, Haik Chosrowjan, Mikio Kataoka, M.M. Martin, Noboru Mataga, Pascale Changenet-Barret, Pascal Plaza, Yasushi Imamoto, Processus d'Activation Sélective par Transfert d'Energie Uni-électronique ou Radiatif (UMR 8640) (PASTEUR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Département de Chimie - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institute for Laser Technology (ILT), Institute for Laser Technology, Department of Biophysics, Kyoto University [Kyoto], Graduate School of Materials Science, Nara Institute of Science and Technology, and ANR-05-BLAN-0188,Femtomobile,Etude de microactionneurs photobiologiques à l'échelle moléculaire :Photodéclenchement ultrarapide de la motilité cellulaire(2005)
- Subjects
chemistry.chemical_classification ,0303 health sciences ,biology ,Photoisomerization ,Mutant ,Active site ,Chromophore ,010402 general chemistry ,Thioester ,Photochemistry ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Amino acid ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,03 medical and health sciences ,General Energy ,chemistry ,Ultrafast laser spectroscopy ,biology.protein ,Physical and Theoretical Chemistry ,Spectroscopy ,030304 developmental biology - Abstract
International audience; Subpicosecond transient absorption spectroscopy was used to address the role of the local environment on the photoisomerization process of the p-coumaric thioester chromophore in Photoactive Yellow Protein (PYP) by studying two point mutants, T50V and E46Q. These mutations introduce alterations of the hydrogen-bond network involving the amino acids of the active site close to the chromophore and the chromophore phenolate group, respectively. Transient-absorption spectra of T50V and E46Q are found to be qualitatively similar to those of the wild-type PYP (WT) and R52Q, suggesting that the earliest steps of the photoinduced processes in all three mutants remain similar to those of the WT. Target analyses of the transient spectra of T50V, E46Q, R52Q and WT, were successfully performed by using a model based on the one previously published by Larsen et al. (Biophys. J. 2004, 87, 1858), which involves heterogeneous excited-state populations undergoing deactivation along two competitive relaxation pathways. A so-called reactive pathway leads to the sequential formation of the well-characterized cis intermediates, I0 and I1, of the photocycle. The second pathway is non reactive and produces a transient species that restores the initial trans ground state in 3-6 ps. This transient is tentatively attributed to a distorted vibrationally-hot trans ground state. The most prominent effect of mutation is observed for T50V and R52Q which exhibit significantly slower excited-state deactivations, whereas E46Q behaves like the WT protein. This difference is analyzed in terms of a significant decrease, in T50V and R52Q, of the fraction of heterogeneous excited-state population that undergoes isomerization. The quantum yield of isomerization deduced from the target analyses was found to be 0.31 ± 0.08 for WT, 0.22 ± 0.06 for T50V, 0.29 ± 0.08 for E46Q and 0.19 ± 0.05 for R52Q. The decrease of isomerization yield observed in T50V and R52Q is mainly attributed to the loss of rigidity of the protein active site, induced by these mutations, rather than to the deletion of the positive charge of Arg52 in R52Q.
- Published
- 2009
41. Simulation of ultrafast non-exponential fluorescence decay induced by electron transfer in FMN binding protein
- Author
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Sirirat Kokpol, Haik Chosrowjan, Fumio Tanaka, Nadtanet Nunthaboot, Noboru Mataga, and Seiji Taniguchi
- Subjects
chemistry.chemical_classification ,Quantitative Biology::Biomolecules ,Chemistry ,General Chemical Engineering ,General Physics and Astronomy ,Ionic bonding ,General Chemistry ,Flavin group ,Electron acceptor ,Fluorescence ,Marcus theory ,Electron transfer ,FMN binding ,Excited state ,Physics::Chemical Physics ,Atomic physics - Abstract
The ultrafast non-exponential fluorescence decay of FMN binding protein (FBP) was analyzed with three electron transfer (ET) theories, Marcus theory, Bixon and Jortner theory and Kakitani and Mataga theory. Center to center distances between electron acceptor, the excited isoalloxazine, and donors, Trp-32, Tyr-35 and Trp-106, in FBP were determined by molecular dynamic simulation. Electron transfer parameters containing in these theories were determined so as to fit the calculated decay with the observed decay, according to a non-linear least squares method. Introduction of electrostatic energies between isoalloxazine anion and other ionic groups and between the donor cations and other ionic groups in the protein into any ET theories improved the fitting. The non-exponential behavior in the fluorescence decay is considered to be ascribed to a fluctuation of the protein structure with long period.
- Published
- 2009
42. Quantum Mechanical Study of Photoinduced Charge Transfer in FMN Binding Protein
- Author
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Sirirat Kokpol, Haik Chosrowjan, Noboru Mataga, Nadtanet Nunthaboot, Fumio Tanaka, and Seiji Taniguchi
- Subjects
Models, Molecular ,Binding Sites ,Flavoproteins ,Electrons ,Charge (physics) ,Interaction energy ,Crystal structure ,Electron ,Crystallography, X-Ray ,Photochemical Processes ,Protein Structure, Tertiary ,Surfaces, Coatings and Films ,Crystal ,chemistry.chemical_compound ,Crystallography ,FMN binding ,Bacterial Proteins ,chemistry ,Materials Chemistry ,Aromatic amino acids ,Quantum Theory ,Computer Simulation ,Lumiflavin ,Physical and Theoretical Chemistry ,Nuclear Magnetic Resonance, Biomolecular - Abstract
CT interactions between Iso* and nearby aromatic amino acids in FBP were investigated by a semiempirical MO method. Atomic coordinates of lumiflavin as Iso, 3-methylindole as Trp, and 4-methylphenol as Tyr, used for MO calculations, were obtained from crystal, 20 NMR structures and 40 MD structures (20 ps time intervals). Geometries of Iso-Trp32, Iso-Trp106 and Iso-Tyr35 systems were optimized by the PM3 method. The interaction energies (kcal/mol) of crystal structure were -16.9 in the Iso-Trp32 system, -7.4 in the Iso-Trp106 system and 1.4 in the Iso-Tyr35 system. The interaction energies (kcal/mol) of NMR structures were -16.5 +/- 0.28 in the Iso-Trp32 system, -10.6 +/- 0.14 in the Iso-Trp106 system, and 0.97 +/- 0.09 in the Iso-Tyr35 system. The interaction energies (kcal/mol) of MD structures were -24.3 +/- 0.19 in the Iso-Trp32 system, -10.2 +/- 0.49 in the Iso-Trp106 system, and 0.285 +/- 0.037 in the Iso-Tyr35 system. CT interaction from the aromatic amino acids to Iso* was judged from negative charge at Iso*. The charge in the Iso-Trp32 system was -0.490 in crystals, -0.439 +/- -0.099 in NMR structures, -0.454 +/- 0.048 in MD structures. The charge in the Iso and Trp106 system was -0.011 +/- 0.004 in MD structures, but negligible in other structures. CT interactions in Iso-Tyr35 system were also negligible. The ET rate obtained with Kakitani and Mataga theory and MD decreased as the magnitude of the interaction energy decreased. Correlation between the ET rate and CT interaction in FBP was examined. The interaction energy (Y) was approximated with ln(ET rate) (X) by a function, Y = 0.0036X(3) + 0.0306X(2) - 1.7822X - 21.177.
- Published
- 2008
43. Simultaneous Analysis of Ultrafast Fluorescence Decays of FMN Binding Protein and Its Mutated Proteins by Molecular Dynamic Simulation and Electron Transfer Theory
- Author
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Sirirat Kokpol, Fumio Tanaka, Seiji Taniguchi, Nadtanet Nunthaboot, Noboru Mataga, and Haik Chosrowjan
- Subjects
Time Factors ,Flavin Mononucleotide ,Ionic bonding ,Fluorescence ,Ion ,Electron Transport ,Molecular dynamics ,Electron transfer ,FMN binding ,Bacterial Proteins ,Materials Chemistry ,Computer Simulation ,Desulfovibrio vulgaris ,Physical and Theoretical Chemistry ,Flavoproteins ,biology ,Chemistry ,biology.organism_classification ,Protein Structure, Tertiary ,Surfaces, Coatings and Films ,Crystallography ,Amino Acid Substitution ,Models, Chemical ,Electron affinity (data page) ,Excited state ,Thermodynamics ,Algorithms - Abstract
Ultrafast fluorescence decays of FMN binding proteins (FBP) from Desulfovibrio vulgaris (Miyazaki F) were analyzed with an electron transfer (ET) theory by Kakitani and Mataga (KM theory). Time-dependent distances among isoalloxazine (Iso) and Trp-32, Tyr-35, and Trp-106 in wild-type FBP (WT), among Iso and Tyr-32, Tyr-35, and Trp-106 in W32Y (Trp-32 was replaced by Tyr-32), and among Iso and Tyr-35 and Trp-106 in W32A (Trp-32 was replaced by Ala-32) were determined by molecular dynamic simulation (MD). Electrostatic energies between Iso anion and all other ionic groups, between Trp-32 cation and all other ionic groups, and between Tyr-32 cation and all other ionic groups were calculated in WT, W32Y, and W32A, from the MD coordinates. ET parameters contained in KM theory, such as frequency (nu 0), a coefficient of the ET process (beta), a critical distance of the ET process ( R 0), standard free energy related to the electron affinity of the excited Iso ( G Iso (0)), and the static dielectric constant in FBP species (epsilon 0), were determined with and without inclusion of the electrostatic energy, so as to fit the calculated fluorescence decays with the observed decays of all FBP species, by a nonlinear least-squares method according to the Marquardt algorithm. In the analyses the parameters, nu 0, beta, and R 0 were determined separately between Trp residues and Tyr residues among all FBP species. Calculated fluorescence intensities with the inclusion of the electrostatic energy fit quite well with the observed ones of all WT, W32Y, and W32A.
- Published
- 2008
44. Ultrafast fluorescence dynamics of FMN-binding protein from Desulfovibrio vulgaris (Miyazaki F) and its site-directed mutated proteins
- Author
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Daisuke Todoroki, Noboru Mataga, Seiji Taniguchi, Masaya Kitamura, Haik Chosrowjan, and Fumio Tanaka
- Subjects
FMN binding ,biology ,Chemistry ,Ionization ,Dynamics (mechanics) ,General Physics and Astronomy ,Physical and Theoretical Chemistry ,Photochemistry ,Desulfovibrio vulgaris ,biology.organism_classification ,Ultrashort pulse ,Fluorescence - Abstract
Ultrafast fluorescence dynamics of FMN in FMN-binding protein (FMN-bp), and its mutated proteins, W32Y and W32A, were investigated by the fluorescence up-conversion method. Fluorescence lifetimes were 167 fs (96%) and 1.5 ps (4%) in wild-type FMN-bp (WT), and 3.4 ps (23%), 18.2 ps (74%), and 96 ps (3%) at 530 nm in W32Y, and 30.1 ps in W32A. The fluorescence lifetime of W32A, in which Trp-32 was absent, was about 140 times longer than that of WT. Tyr-32 in W32Y was not so effective quencher as Trp-32 in WT. This was explained in terms of different ionization potentials of quenchers and average donor–acceptor distances in the protein.
- Published
- 2008
45. Analyses of donor–acceptor distance-dependent rates of photo-induced electron transfer in flavoproteins with three kinds of electron transfer theories
- Author
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Haik Chosrowjan, Fumio Tanaka, Seiji Taniguchi, Noboru Mataga, and Rong Rujkorakarn
- Subjects
Electron transfer ,biology ,Chemistry ,Excited state ,Tryptophan ,biology.protein ,General Physics and Astronomy ,Flavoprotein ,Physical and Theoretical Chemistry ,Donor acceptor ,Photochemistry - Abstract
Reported donor–acceptor distance-dependent rates of photo-induced electron transfer from tryptophan (Trp), tyrosine (Tyr), and benzoate (Bz) to the excited isoalloxazine in ten flavoprotein systems were analyzed with three kinds of electron transfer theories by Marcus, by Bixon and Jortner, and also by Kakitani, Yoshimori, and Mataga. Average donor–acceptor distances that were obtained from X-ray structures of flavoproteins were used for the analysis, rather than the edge-to-edge distance. The observed photo-induced electron transfer rates were best reproduced by the Kakitani, Yoshimori, and Mataga theory.
- Published
- 2008
46. Ultrafast laser photolysis study on photodissociation dynamics of a hexaarylbiimidazole derivative
- Author
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Yusuke Satoh, Azusa Kikuchi, Noboru Mataga, Jiro Abe, Seiji Taniguchi, Syoji Ito, Daisuke Kato, Yukihide Ishibashi, Yutaka Nagasawa, Hiroshi Miyasaka, and Haik Chosrowjan
- Subjects
chemistry.chemical_compound ,chemistry ,Hexaarylbiimidazole ,Radical ,Photodissociation ,Ultrafast laser spectroscopy ,Time evolution ,General Physics and Astronomy ,Physical and Theoretical Chemistry ,Photochemistry ,Spectroscopy ,Derivative (chemistry) ,Excitation - Abstract
Dynamics of the photodissociation process of a hexaarylbiimidazole derivative, 2,2′-di(ortho-chlorophenyl)-4,4′,5,5′-tetraphenylbiimidazole (o-Cl-HABI), in benzene solution was investigated by means of the femtosecond–nanosecond laser spectroscopy. The time evolution of the transient absorption of the lophyl radical, the product of the photodissociation, was biphasic with the faster and the slower time constants of 80 fs and 1.9 ps, respectively. The faster time constant was ascribable to the formation of the lophyl radical through the bond fission after the excitation, and the slower time constant may be attributed to the conformational change and/or vibrational cooling of nascent radicals.
- Published
- 2007
47. Donor−Acceptor Distance-Dependence of Photoinduced Electron-Transfer Rate in Flavoproteins
- Author
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Noboru Mataga, Haik Chosrowjan, Kyosuke Sato, Yasuzo Nishina, Fumio Tanaka, Seiji Taniguchi, and Kiyoshi Shiga
- Subjects
Models, Molecular ,Photochemistry ,Protein Conformation ,Flavodoxin ,Analytical chemistry ,Flavoprotein ,Flavin group ,Acyl-CoA Dehydrogenase ,Photoinduced electron transfer ,Electron Transport ,Glucose Oxidase ,Flavins ,Materials Chemistry ,Physical and Theoretical Chemistry ,biology ,Chemistry ,Tryptophan ,Membrane Transport Proteins ,Fluorescence ,Electron transport chain ,Surfaces, Coatings and Films ,Marcus theory ,biology.protein ,Tyrosine - Abstract
Ultrafast fluorescence quenching of flavin in flavodoxin from Megasphaera elsdenii was investigated by means of a fluorescence up-conversion method. Fluorescence lifetimes of flavodoxin from M. elsdenii were estimated to be tau(1) approximately 165 fs (0.97%) and tau(2) approximately 10 ps (0.03%). Correlation of photoinduced electron-transfer rates (k(ET)) with averaged distances (D(av)) between isoalloxazine and nearby tryptophan or tyrosine was examined and obtained an empirical equation of ln k(ET) vs D(av) by means of a nonlinear least-squares method using reported data together with flavodoxin from M. elsdenii. The values of D(av) were calculated from X-ray structures of the flavoproteins. The ln k(ET) was approximately linear at D(av) shorter than 7 A. The model free empirical equation was expressed as ln k(ET) = 29.7 + (-0.327 D(av) + 2.84 x 10(-5))/(0.698 - D(av)(2)). We also analyzed the observed values of ln k(ET) with Marcus theory, but could not obtain reasonable results. Our analysis suggests that the average distance, rather than the shortest (edge to edge) distance or interplanar angles between the aromatics rings, is the key factor in the process of the photoinduced electron transfer in these flavoproteins.
- Published
- 2007
48. Role of arginine 52 on the primary photoinduced events in the PYP photocycle
- Author
-
Haik Chosrowjan, Seiji Taniguchi, Yasushi Imamoto, Mikio Kataoka, Pascal Plaza, Pascale Changenet-Barret, Noboru Mataga, Monique M. Martin, Processus d'Activation Sélective par Transfert d'Energie Uni-électronique ou Radiatif (UMR 8640) (PASTEUR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Département de Chimie - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institute for Laser Technology (ILT), Institute for Laser Technology, Graduate School of Materials Science, and Nara Institute of Science and Technology
- Subjects
0303 health sciences ,Aqueous solution ,Arginine ,Chemistry ,General Physics and Astronomy ,Chromophore ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Fluorescence ,0104 chemical sciences ,[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry ,03 medical and health sciences ,Residue (chemistry) ,Ultrafast laser spectroscopy ,Physical and Theoretical Chemistry ,Spectroscopy ,Cis–trans isomerism ,030304 developmental biology - Abstract
International audience; We investigated the earliest steps of the photocycle of photoactive yellow protein (PYP) and its R52Q mutant in aqueous solution, by subpicosecond transient absorption spectroscopy. Our aim was to address the role of the positively charged Arg52 residue. We found that the relaxation mechanism of R52Q is similar to that of wt-PYP and discarded that Arg52 plays a key role in the chromophore photoreactivity. The excited-state decay of R52Q is however slower, confirming previous fluorescence up-conversion data. The experiments also reveal a slower stabilization of the cis isomer product. The loosening of the protein pocket and structural heterogeneities are discussed.
- Published
- 2007
49. Classification of the mechanisms of photoinduced electron transfer from aromatic amino acids to the excited flavins in flavoproteins
- Author
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Kiattisak Lugsanangarm, Haik Chosrowjan, Sirirat Kokpol, Nadtanet Nunthaboot, Fumio Tanaka, Seiji Taniguchi, Arthit Nueangaudom, and Somsak Pianwanit
- Subjects
biology ,Flavoproteins ,Flavodoxin ,Tryptophan ,General Physics and Astronomy ,Ionic bonding ,Flavin group ,Photochemistry ,Photochemical Processes ,Photoinduced electron transfer ,Fluorescence ,Ion ,Electron Transport ,chemistry.chemical_compound ,Amino Acids, Aromatic ,chemistry ,Excited state ,Flavins ,Aromatic amino acids ,biology.protein ,Physical and Theoretical Chemistry - Abstract
In many flavoproteins photoinduced electron transfer (ET) efficiently takes place from aromatic amino acids such as tryptophan or tyrosine to the excited isoalloxazine, so that the fluorescence lifetimes of isoalloxazine in some flavoproteins become ultrashort. The mechanism of ET in the flavoproteins was classified into four classes from the relationship between logarithmic ET rates (ln Rate) and the donor-acceptor distances (Rc), using reported data. The physical quantity, GT, is defined as the sum of solvent reorganization energy, electrostatic energy between a donor cation and an Iso anion, the standard free energy gap between the photoproducts and reactants, and net electrostatic energy between the photoproducts and other ionic groups in the flavoproteins (NetES). When GT fluctuates around zero with Rc, the ET rate becomes fastest (faster than 1 ps(-1)) in Kakitani and Mataga rates. In the ultrafast ET processes, the ln Rate becomes a parabolic function (category 1) of Rc as in FMN binding proteins and pyranose 2-oxidase at the shorter emission wavelengths, when NetES is negligible compared to the other quantities in the GT function. In the ultrafast ET processes, the ln Rate does not display any clear function of Rc (category 2) when NetES is dominant in the GT function, because of no direct relation between NetES and Rc. ET in flavodoxin from Helicobacter pylori may be classified into category 2. When GT linearly varies with Rc around a certain positive value, the ET rates become much slower (1 ps(-1)). In this case the ln Rate linearly decreases with Rc (category 3), as Tyr224 in d-amino acid oxidase dimers. It is also conceivable that the ln Rate decreases with much scattered function of Rc (category 4), when NetES is dominant in the GT function, as Tyr314 in d-amino acid oxidase dimers. In ET processes of category 1, ET rates decrease as Rc becomes shorter than the distance at the maximum values of ln Rates, where GT is negative. Conditions and physical meanings were discussed for the GT-negative region.
- Published
- 2015
50. kW-class Zig-Zag Active-Mirror Laser Amplifier with Jet Impingement Cooling
- Author
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Tomoya Morioka, Junnosuke Nakatani, Naoki Inoue, Seiji Taniguchi, Koichi Hamamoto, Yasukazu Izawa, Shingo Nishikata, and Haik Chosrowjan
- Subjects
Distributed feedback laser ,Materials science ,business.industry ,Far-infrared laser ,Laser pumping ,Injection seeder ,Laser ,law.invention ,Vertical-cavity surface-emitting laser ,Optics ,law ,Diode-pumped solid-state laser ,Optoelectronics ,Laser power scaling ,business - Abstract
We developed a Yb:YAG Zig-Zag Active-Mirror laser amplifier with jet impingement cooling system for high average power laser systems. The output power of laser was beyond 1kW which was stable nearly 30 minutes.
- Published
- 2015
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