AUTHOR=Chu Hsiu-An , Chiu Yi-Fang 

TITLE=The Roles of Cytochrome b559 in Assembly and Photoprotection of Photosystem II Revealed by Site-Directed Mutagenesis Studies

JOURNAL=Frontiers in Plant Science

VOLUME=6

YEAR=2016

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2015.01261

DOI=10.3389/fpls.2015.01261

ISSN=1664-462X

ABSTRACT=<p>Cytochrome <italic>b</italic><sub>559</sub> (Cyt <italic>b</italic><sub>559</sub>) is one of the essential components of the Photosystem II reaction center (PSII). Despite recent accomplishments in understanding the structure and function of PSII, the exact physiological function of Cyt <italic>b</italic><sub>559</sub> remains unclear. Cyt <italic>b</italic><sub>559</sub> is not involved in the primary electron transfer pathway in PSII but may participate in secondary electron transfer pathways that protect PSII against photoinhibition. Site-directed mutagenesis studies combined with spectroscopic and functional analysis have been used to characterize Cyt <italic>b</italic><sub>559</sub> mutant strains and their mutant PSII complex in higher plants, green algae, and cyanobacteria. These integrated studies have provided important <italic>in vivo</italic> evidence for possible physiological roles of Cyt <italic>b</italic><sub>559</sub> in the assembly and stability of PSII, protecting PSII against photoinhibition, and modulating photosynthetic light harvesting. This mini-review presents an overview of recent important progress in site-directed mutagenesis studies of Cyt <italic>b</italic><sub>559</sub> and implications for revealing the physiological functions of Cyt <italic>b</italic><sub>559</sub> in PSII.</p>