AUTHOR=Chiu Yi-Fang , Chu Hsiu-An 

TITLE=New Structural and Mechanistic Insights Into Functional Roles of Cytochrome b559 in Photosystem II

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.914922

DOI=10.3389/fpls.2022.914922

ISSN=1664-462X

ABSTRACT=<p>Cytochrome (Cyt) <italic>b</italic><sub>559</sub> is a key component of the photosystem II (PSII) complex for its assembly and proper function. Previous studies have suggested that Cyt<italic>b</italic><sub>559</sub> has functional roles in early assembly of PSII and in secondary electron transfer pathways that protect PSII against photoinhibition. In addition, the Cyt<italic>b</italic><sub>559</sub> in various PSII preparations exhibited multiple different redox potential forms. However, the precise functional roles of Cyt<italic>b</italic><sub>559</sub> 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<italic>b</italic><sub>559</sub>. This mini-review gives an overview of new exciting results and their significance for understanding the structural and functional roles of Cyt<italic>b</italic><sub>559</sub> in PSII.</p>