Functional characterization of mutant strains of the cyanobacterium Synechocystis sp. PCC 6803 lacking short domains within the large, lumen-exposed loop of the chlorophyll protein CP47 in photosystem II

A study of autotrophic mutant strains of Synechocystis sp. PCC 6803 carrying short deletions or a single-site mutation within the large, lumen-exposed loop of the chlorophyll a-binding photosystem II core protein, CP47, through measurement of thermoluminescence, oxygen yield and fluorescence quantum yield, reveals that deletion of charged and conserved amino acids between residues 370 and 390 decreases the binding affinity of the extrinsic PS II-O protein to photosystem II. Marked differences with PS II-O deletion mutants, with respect to Ca2+ requirement and flash-induced pattern of oxygen evolution, exist.