Malone LA, Proctor MS, Hitchcock A, Hunter CN, Johnson MP. Cytochrome b
6f - Orchestrator of photosynthetic electron transfer.
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021;
1862:148380. [PMID:
33460588 DOI:
10.1016/j.bbabio.2021.148380]
[Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 01/06/2021] [Accepted: 01/09/2021] [Indexed: 11/18/2022]
Abstract
Cytochrome b6f (cytb6f) lies at the heart of the light-dependent reactions of oxygenic photosynthesis, where it serves as a link between photosystem II (PSII) and photosystem I (PSI) through the oxidation and reduction of the electron carriers plastoquinol (PQH2) and plastocyanin (Pc). A mechanism of electron bifurcation, known as the Q-cycle, couples electron transfer to the generation of a transmembrane proton gradient for ATP synthesis. Cytb6f catalyses the rate-limiting step in linear electron transfer (LET), is pivotal for cyclic electron transfer (CET) and plays a key role as a redox-sensing hub involved in the regulation of light-harvesting, electron transfer and photosynthetic gene expression. Together, these characteristics make cytb6f a judicious target for genetic manipulation to enhance photosynthetic yield, a strategy which already shows promise. In this review we will outline the structure and function of cytb6f with a particular focus on new insights provided by the recent high-resolution map of the complex from Spinach.
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