The PsbW protein stabilizes the supramolecular organization of photosystem II in higher plants.
PsbW, a 6.1-kDa low-molecular-weight protein, is exclusive to photosynthetic eukaryotes, and associates with the photosystem II (PSII) protein complex. In vivo and in vitro comparison of Arabidopsis thaliana wild-type plants with T-DNA insertion knock-out mutants completely lacking the PsbW protein, or with antisense inhibition plants exhibiting decreased levels of PsbW, demonstrated that the loss of PsbW destabilizes the supramolecular organization of PSII. No PSII-LHCII supercomplexes could be detected or isolated in the absence of the PsbW protein. These changes in macro-organization were accompanied by a minor decrease in the chlorophyll fluorescence parameter F(V) /F(M) , a strongly decreased PSII core protein phosphorylation and a modification of the redox state of the plastoquinone (PQ) pool in dark-adapted leaves. In addition, the absence of PsbW protein led to faster redox changes in the PQ pool, i.e. transitions from state 1 to state 2, as measured by changes in stationary fluorescence (F(S) ) kinetics, compared with the wild type. Despite these dramatic effects on macromolecular structure, the transgenic plants exhibited no significant phenotype under normal growth conditions. We suggest that the PsbW protein is located close to the minor antenna of the PSII complex, and is important for the contact and stability between several PSII-LHCII supercomplexes.
Department of Chemistry, Umeå Plant Science Centre (UPSC), Umeå University, SE-901 87 Umeå, Sweden.
José G
JG
García-Cerdán
Laszlo
L
Kovács
Tünde
T
Tóth
Sami
S
Kereïche
Elena
E
Aseeva
Egbert J
EJ
Boekema
Fikret
F
Mamedov
Christiane
C
Funk
Wolfgang P
WP
Schröder
D017360:Arabidopsis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000378:metabolism*; D004269:DNA, Bacterial; D004735:Energy Transfer / Q000502:physiology; D055786:Gene Knockout Techniques; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010641:Phenotype; D010766:Phosphorylation; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018515:Plant Leaves / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D030821:Plants, Genetically Modified / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D020836:Protein Structure, Quaternary; D016372:RNA, Antisense; D013312:Stress, Physiological; D020524:Thylakoids / Q000737:chemistry* / Q000648:ultrastructure
D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D045342:Light-Harvesting Protein Complexes; D008565:Membrane Proteins; D045332:Photosystem II Protein Complex; C571003:PsbW protein, Arabidopsis; D016372:RNA, Antisense; C036483:T-DNA