An independent role of cytochrome c-550 in cyanobacterial photosystem II as revealed by double-deletion mutagenesis of the psbO and psbV genes in Synechocystis sp. PCC 6803

Cytochrome (cyt) c-550 is an extrinsic protein, analogous to the 33 kDa protein, which independently supports oxygen evolution in cynobacterial photosystem II and maintains photoautotrophic development. A double-deletion mutant devoid of both c-550 and the 33 kDa protein by simultaneous inactivation of the psbO and psbV genes in Synechocystis sp. PCC 6803 reveals inhibited oxygen-producing ability.