Abstract
We investigated the role of a phospholipid, phosphatidylglycerol, in the PSI complex through characterization of a disruptant of Synechocystis sp. PCC6803 as to the cdsA gene responsible for the PG synthesis. The mutant showed decreased levels of PsaA and PsaB that construct the PSI core with a decrease in the PG content. Besides, the quantitative decrease in the PSI complex was shown to be caused by a drop of the population of the trimeric form, but not of the monomeric form. Thus, it was demonstrated that PG is responsible for the maintenance of the level of the PSI complex, and also for the trimeric form of the PSI complex.