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First published online October 9, 2003; 10.1104/pp.103.026955 Plant Physiology 133:1376-1384 (2003) © 2003 American Society of Plant Biologists Requirement of Phosphatidylglycerol for Maintenance of Photosynthetic Machinery1Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Tokyo 1538902, Japan (I.S., H.W.); Department of Biology, Graduate School of Sciences, Ropponmatsu, Kyushu University, Fukuoka 8108560, Japan (M.H.); Institute of Plant Biology, Biological Research Center of the Hungarian Academy of Sciences, P.O. Box 521, H6701 Szeged, Hungary (Z.G.); Department of Biology, University of Turku, FIN20014 Turku, Finland (T.T., V.P., E.-M.A.)
Phosphatidylglycerol (PG) is a ubiquitous component of thylakoid membranes. Experiments with the pgsA mutant of the cyanobacterium Synechocystis sp. PCC6803 defective in biosynthesis of PG have demonstrated an indispensable role of PG in photosynthesis. In the present study, we have investigated the light susceptibility of the pgsA mutant with regard to the maintenance of the photosynthetic machinery. Growth of the mutant cells without PG increased the light susceptibility of the cells and resulted in severe photoinhibition of photosynthesis upon a high-light treatment, whereas the growth in the presence of PG was protected against photoinhibition. Photoinhibition induced by PG deprivation was mainly caused by an impairment of the restoration process. The primary target of the light-induced damage in thylakoid membranes, the D1 protein of photosystem (PS) II was, however, synthesized and degraded with similar rates irrespective of whether the mutant cells were incubated with PG or not. Intriguingly, it was found that instead of the synthesis of the D1 protein, the dimerization of the PSII core monomers was impaired in the PG-deprived mutant cells. Addition of PG to photoinhibited cells restored the dimerization capacity of PSII core monomers. These results suggest that PG plays an important role in the maintenance of the photosynthetic machinery through the dimerization and reactivation of the PSII core complex.
Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.103.026955. 1 This work was supported by a Grant-in-Aid from the Japan Society for the Promotion of Science, by the Program for Promotion of Basic Research Activities for Innovative Biosciences, and by the Academy of Finland. * Corresponding author; e-mail hwada{at}bio.c.u-tokyo.ac.jp; fax 81354546656. Received May 17, 2003; returned for revision June 10, 2003; accepted August 17, 2003. This article has been cited by other articles:
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