Article

Functional architecture of higher plant photosystem II supercomplexes.

Faculté des Sciences Luminy, Laboratoire de Génétique et Biophysique des Plantes, Université Aix Marseille, Marseille, France.
The EMBO Journal (impact factor: 9.2). 09/2009; 28(19):3052-63. DOI:10.1038/emboj.2009.232 pp.3052-63
Source: PubMed

ABSTRACT Photosystem II (PSII) is a large multiprotein complex, which catalyses water splitting and plastoquinone reduction necessary to transform sunlight into chemical energy. Detailed functional and structural studies of the complex from higher plants have been hampered by the impossibility to purify it to homogeneity. In this work, homogeneous preparations ranging from a newly identified particle composed by a monomeric core and antenna proteins to the largest C(2)S(2)M(2) supercomplex were isolated. Characterization by biochemical methods and single particle electron microscopy allowed to relate for the first time the supramolecular organization to the protein content. A projection map of C(2)S(2)M(2) at 12 A resolution was obtained, which allowed determining the location and the orientation of the antenna proteins. Comparison of the supercomplexes obtained from WT and Lhcb-deficient plants reveals the importance of the individual subunits for the supramolecular organization. The functional implications of these findings are discussed and allow redefining previous suggestions on PSII energy transfer, assembly, photoinhibition, state transition and non-photochemical quenching.

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Keywords

antenna proteins
 
biochemical methods
 
catalyses water splitting
 
chemical energy
 
Detailed functional
 
functional implications
 
homogeneity
 
large multiprotein complex
 
non-photochemical quenching
 
photoinhibition
 
Photosystem II
 
plastoquinone reduction necessary
 
protein content
 
PSII
 
PSII energy transfer
 
redefining previous suggestions
 
single particle electron microscopy
 
structural studies
 
supramolecular organization