New Structural and Mechanistic Insights Into Functional Roles of Cytochrome b559 in Photosystem II
Yi‐Fang Chiu, Hsiu‐An Chu
Abstract
Cytochrome (Cyt) b 559 is a key component of the photosystem II (PSII) complex for its assembly and proper function. Previous studies have suggested that Cyt b 559 has functional roles in early assembly of PSII and in secondary electron transfer pathways that protect PSII against photoinhibition. In addition, the Cyt b 559 in various PSII preparations exhibited multiple different redox potential forms. However, the precise functional roles of Cyt b 559 in PSII remain unclear. Recent site-directed mutagenesis studies combined with functional genomics and biochemical analysis, as well as high-resolution x-ray crystallography and cryo-electron microscopy studies on native, inactive, and assembly intermediates of PSII have provided important new structural and mechanistic insights into the functional roles of Cyt b 559 . This mini-review gives an overview of new exciting results and their significance for understanding the structural and functional roles of Cyt b 559 in PSII.