Document Detail


Photoprotective energy dissipation involves the reorganization of photosystem II light-harvesting complexes in the grana membranes of spinach chloroplasts.
MedLine Citation:
PMID:  21498680     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Plants must regulate their use of absorbed light energy on a minute-by-minute basis to maximize the efficiency of photosynthesis and to protect photosystem II (PSII) reaction centers from photooxidative damage. The regulation of light harvesting involves the photoprotective dissipation of excess absorbed light energy in the light-harvesting antenna complexes (LHCs) as heat. Here, we report an investigation into the structural basis of light-harvesting regulation in intact spinach (Spinacia oleracea) chloroplasts using freeze-fracture electron microscopy, combined with laser confocal microscopy employing the fluorescence recovery after photobleaching technique. The results demonstrate that formation of the photoprotective state requires a structural reorganization of the photosynthetic membrane involving dissociation of LHCII from PSII and its aggregation. The structural changes are manifested by a reduced mobility of LHC antenna chlorophyll proteins. It is demonstrated that these changes occur rapidly and reversibly within 5 min of illumination and dark relaxation, are dependent on ΔpH, and are enhanced by the deepoxidation of violaxanthin to zeaxanthin.
Authors:
Matthew P Johnson; Tomasz K Goral; Christopher D P Duffy; Anthony P R Brain; Conrad W Mullineaux; Alexander V Ruban
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2011-04-15
Journal Detail:
Title:  The Plant cell     Volume:  23     ISSN:  1532-298X     ISO Abbreviation:  Plant Cell     Publication Date:  2011 Apr 
Date Detail:
Created Date:  2011-05-27     Completed Date:  2011-09-19     Revised Date:  2012-04-02    
Medline Journal Info:
Nlm Unique ID:  9208688     Medline TA:  Plant Cell     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1468-79     Citation Subset:  IM    
Affiliation:
School of Biological and Chemical Sciences, Queen Mary University of London, London E14NS, United Kingdom.
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MeSH Terms
Descriptor/Qualifier:
Chlorophyll / metabolism
Fluorescence Recovery After Photobleaching
Freeze Fracturing
Intracellular Membranes / metabolism*,  ultrastructure
Kinetics
Light-Harvesting Protein Complexes / metabolism*
Models, Molecular
Photochemical Processes*
Photosystem II Protein Complex / metabolism*
Plant Proteins / metabolism
Protein Transport
Spinacia oleracea / metabolism*,  ultrastructure
Thermodynamics
Thylakoids / metabolism*,  ultrastructure
Grant Support
ID/Acronym/Agency:
//Biotechnology and Biological Sciences Research Council; //Wellcome Trust
Chemical
Reg. No./Substance:
0/Light-Harvesting Protein Complexes; 0/Photosystem II Protein Complex; 0/Plant Proteins; 1406-65-1/Chlorophyll

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


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