Removal of both Ycf48 and Psb27 in Synechocystis sp PCC 6803 disrupts Photosystem II assembly and alters QA- oxidation in the mature complex

The Photosystem II (PS II) assembly factors Psb27 and Ycf48 are transiently associated with PS II during its biogenesis and repair pathways. We investigated the function of these proteins by constructing knockout mutants in Synechocystis sp. PCC 6803. In DYcf48 cells, PS II electron transfer and stable oxygen evolution were perturbed. Additionally, Psb27 was required for photoautotrophic growth of cells lacking Ycf48 and assembly beyond the RC47 assembly complex in Delta Ycf48: Delta Psb27 cells was impeded. Our results suggest the RC47 complex formed in DYcf48 cells is defective and that this deficiency is exacerbated if CP43 binds in the absence of Psb27. (C) 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.