Document Detail

Populations of photoinactivated photosystem II reaction centers characterized by chlorophyll a fluorescence lifetime in vivo.
MedLine Citation:
PMID:  15601775     Owner:  NLM     Status:  MEDLINE    
Photosystem (PS) II centers, which split water into oxygen, protons, and electrons during photosynthesis, require light but are paradoxically inactivated by it. Prolonged light exposure concomitantly decreased both the functional fraction of PSII reaction centers and the integral PSII chlorophyll (Chl) a fluorescence lifetime in leaf segments of Capsicum annuum L. Acceleration of photoinactivation of PSII by a pretreatment with the inhibitors/uncoupler lincomycin, DTT, or nigericin further reduced PSII Chl a fluorescence lifetimes. A global analysis of fluorescence lifetime distributions revealed the presence of at least two distinct populations of photoinactivated PSII centers, one at 1.25 ns, and the other at 0.58 ns. Light treatment first increased the 1.25-ns component, a weak quencher, at the expense of a component at 2.22 ns corresponding to functional PSII centers. The 0.58-ns component, a strong quencher, emerged later than the 1.25-ns component. The strongly quenching PSII reaction centers could serve to avoid further damage to themselves and protect their functional neighbors by acting as strong energy sinks.
Shizue Matsubara; Wah Soon Chow
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2004-12-15
Journal Detail:
Title:  Proceedings of the National Academy of Sciences of the United States of America     Volume:  101     ISSN:  0027-8424     ISO Abbreviation:  Proc. Natl. Acad. Sci. U.S.A.     Publication Date:  2004 Dec 
Date Detail:
Created Date:  2004-12-29     Completed Date:  2005-02-28     Revised Date:  2013-04-18    
Medline Journal Info:
Nlm Unique ID:  7505876     Medline TA:  Proc Natl Acad Sci U S A     Country:  United States    
Other Details:
Languages:  eng     Pagination:  18234-9     Citation Subset:  IM    
Photobioenergetics Group, Research School of Biological Sciences, Australian National University, G.P.O. Box 475, Canberra ACT 2601, Australia.
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MeSH Terms
Anti-Bacterial Agents / pharmacology
Capsicum / metabolism
Chlorophyll / chemistry*
Dithiothreitol / pharmacology
Light-Harvesting Protein Complexes / chemistry
Lincomycin / pharmacology
Microscopy, Fluorescence / methods
Models, Biological
Nigericin / pharmacology
Oxygen / metabolism
Photosynthetic Reaction Center Complex Proteins / chemistry
Photosystem II Protein Complex / chemistry*
Time Factors
Xanthophylls / metabolism
Reg. No./Substance:
0/Anti-Bacterial Agents; 0/Light-Harvesting Protein Complexes; 0/Photosynthetic Reaction Center Complex Proteins; 0/Photosystem II Protein Complex; 0/Protons; 0/Xanthophylls; 1406-65-1/Chlorophyll; 154-21-2/Lincomycin; 28380-24-7/Nigericin; 3483-12-3/Dithiothreitol; 7782-44-7/Oxygen; YF5Q9EJC8Y/chlorophyll a

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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