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

Abstract

Cytochrome (Cyt) b559 is a key component of the photosystem II (PSII) complex for its assembly and proper function. Previous studies have suggested that Cytb559 has functional roles in early assembly of PSII and in secondary electron transfer pathways that protect PSII against photoinhibition. In addition, the Cytb559 in various PSII preparations exhibited multiple different redox potential forms. However, the precise functional roles of Cytb559 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 Cytb559. This mini-review gives an overview of new exciting results and their significance for understanding the structural and functional roles of Cytb559 in PSII.

The Ycf48 accessory factor occupies the site of the oxygen-evolving manganese cluster during photosystem II biogenesis

“…7a , Supplementary Table 1 ). Overall, the structures of the transmembrane regions of the PSII subunits in RCII were similar to that found in larger core complexes with only slight changes in the position of Cyt b-559 detected, which might alter the standard reduction potential of the heme 34 .…”

Unraveling the Mechanisms of Efficient Phosphorus Utilization in Popcorn (Zea mays L. var. everta): Insights from Proteomic and Metabolite Analysis

“…The antenna proteins CP43 and CP47 are a key part of the energy conversion process and are responsible for transferring the excitation energy to the reaction center proteins D1 and D2 in PSII. , The alpha subunit of cytochrome b559, in conjunction with the beta subunit, forms a crucial heme-binding heterodimer in the core of PSII. These subunits play a fundamental role in the assembly of PSII and probably participate in secondary electron transport mechanisms that protect PSII from light-induced damage. , The oxygen-evolving complex (OEC) oxidizes water to provide protons for use by PSI . In addition, chlorophyll a play a crucial role in the light-dependent reactions of photosynthesis, and chlorophyll b complements the action of chlorophyll a .…”

“…These subunits play a fundamental role in the assembly of PSII and probably participate in secondary electron transport mechanisms that protect PSII from light-induced damage. 42,43 The oxygenevolving complex (OEC) oxidizes water to provide protons for use by PSI. 44 In addition, chlorophyll a play a crucial role in the light-dependent reactions of photosynthesis, 45 and chlorophyll b complements the action of chlorophyll a.…”

Assembly and Repair of Photosystem II in Chlamydomonas reinhardtii

“…Protein biochemists study PSII to learn how membrane protein complexes assemble and function (see [ 7 , 8 ]). Bioinorganic chemists have been intrigued by the multiple metal cofactors in PSII including the OEC (see [ 9 ]), cytochrome(s) (see [ 10 ]) and a non-heme iron (see [ 11 ]). Biophysical chemists and biophysicists use PSII to study visible-to-chemical energy conversion and exciton and electron transfer reactions (see [ 12 ]).…”