Met246 and Asn250 in the D2 protein are essential for the operation of the quinone-Fe-acceptor complex of Photosystem II.

ABSTRACT: The chemical properties of the primary (QA) and secondary (QB) plastoquinone electron acceptors of Photosystem II (PS II) depend on their protein environments. The DE loop of the D2 protein (residues 222-262) contributes to the QA-binding site while the DE loop of the D1 protein (residues 233-266) contributes to the QB-binding environment. The roles of the invariant D2-Met246 and D2-Asn250 residues in the vicinity of the QA-binding site have been investigated in the cyanobacterium Synechocystis sp. PCC 6803 using mutants targeting both residues. The M246F strain was phenotypically similar to control cells; however, the M246A, N250A, and N250H strains had slowed photoautotrophic growth and were sensitive to high light and the addition of formate. In addition, the M246K and N250N strains wer

SUBMITTER: Zhong V 

PROVIDER: S-EPMC12661319 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature