The Effect of Removing Photosystem II Extrinsic Proteins on Dimer Formation and Recovery from Photodamage in Synechocystis sp. PCC 6803

Abstract

We have examined the level of photosystem II (PSII) dimers in Synechocystis sp. PCC 6803 strains lacking the individual extrinsic proteins PsbO, PsbU and PsbV. We have also compared the rate of recovery from photodamage in each of these mutants. Removal of PsbO resulted in a mutant with only monomeric PSII while the removal of PsbU created a strain with a similar ratio of dimers to monomers as detected in wild type. In the case of the ▵PsbV mutant a reduced amount of dimers was observed. All three mutants were rapidly photodamaged by high light and recovered to their initial PSII activity under low light. The rate of recovery of the ▵PsbU strain was rapid while that of ▵PsbV cells was slower. The ▵PsbO mutant exhibited an intermediate rate of recovery.