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Cold-Adapted Protein Kinases and Thylakoid Remodeling Impact Energy Distribution in an Antarctic Psychrophile.
- Source :
-
Plant physiology [Plant Physiol] 2019 Jul; Vol. 180 (3), pp. 1291-1309. Date of Electronic Publication: 2019 Apr 24. - Publication Year :
- 2019
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Abstract
- The Antarctic psychrophile Chlamydomonas sp. UWO241 evolved in a permanently ice-covered lake whose aquatic environment is characterized not only by constant low temperature and high salt but also by low light during the austral summer coupled with 6 months of complete darkness during the austral winter. Since the UWO241 genome indicated the presence of Stt7 and Stl1 protein kinases, we examined protein phosphorylation and the state transition phenomenon in this psychrophile. Light-dependent [γ- <superscript>33</superscript> P]ATP labeling of thylakoid membranes from Chlamydomonas sp. UWO241 exhibited a distinct low temperature-dependent phosphorylation pattern compared to Chlamydomonas reinhardtii despite comparable levels of the Stt7 protein kinase. The sequence and structure of the UWO241 Stt7 kinase domain exhibits substantial alterations, which we suggest predisposes it to be more active at low temperature. Comparative purification of PSII and PSI combined with digitonin fractionation of thylakoid membranes indicated that UWO241 altered its thylakoid membrane architecture and reorganized the distribution of PSI and PSII units between granal and stromal lamellae. Although UWO241 grown at low salt and low temperature exhibited comparable thylakoid membrane appression to that of C. reinhardtii at its optimal growth condition, UWO241 grown under its natural condition of high salt resulted in swelling of the thylakoid lumen. This was associated with an upregulation of PSI cyclic electron flow by 50% compared to growth at low salt. Due to the unique 77K fluorescence emission spectra of intact UWO241 cells, deconvolution was necessary to detect enhancement in energy distribution between PSII and PSI, which was sensitive to the redox state of the plastoquinone pool and to the NaCl concentrations of the growth medium. We conclude that a reorganization of PSII and PSI in UWO241 results in a unique state transition phenomenon that is associated with altered protein phosphorylation and enhanced PSI cyclic electron flow. These data are discussed with respect to a possible PSII-PSI energy spillover mechanism that regulates photosystem energy partitioning and quenching.<br /> (© 2019 American Society of Plant Biologists. All Rights Reserved.)
- Subjects :
- Algal Proteins chemistry
Algal Proteins genetics
Amino Acid Sequence
Antarctic Regions
Chlamydomonas classification
Chlamydomonas genetics
Chlamydomonas metabolism
Chlamydomonas reinhardtii genetics
Chlamydomonas reinhardtii ultrastructure
Chlorophyll chemistry
Chlorophyll metabolism
Light
Microscopy, Electron, Transmission
Photosynthesis genetics
Photosynthesis radiation effects
Photosynthetic Reaction Center Complex Proteins genetics
Protein Domains
Protein Kinases chemistry
Protein Kinases genetics
Sequence Homology, Amino Acid
Species Specificity
Spectrometry, Fluorescence
Thylakoids genetics
Thylakoids ultrastructure
Algal Proteins metabolism
Chlamydomonas reinhardtii metabolism
Cold Temperature
Photosynthetic Reaction Center Complex Proteins metabolism
Protein Kinases metabolism
Thylakoids metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1532-2548
- Volume :
- 180
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Plant physiology
- Publication Type :
- Academic Journal
- Accession number :
- 31019005
- Full Text :
- https://doi.org/10.1104/pp.19.00411