An electrogenic redox loop in sulfate reduction reveals a likely widespread mechanism of energy conservation.

ABSTRACT: The bioenergetics of anaerobic metabolism frequently relies on redox loops performed by membrane complexes with substrate- and quinone-binding sites on opposite sides of the membrane. However, in sulfate respiration (a key process in the biogeochemical sulfur cycle), the substrate- and quinone-binding sites of the QrcABCD complex are periplasmic, and their role in energy conservation has not been elucidated. Here we show that the QrcABCD complex of Desulfovibrio vulgaris is electrogenic, as protons and electrons required for quinone reduction are extracted from opposite sides of the membrane, with a H⁺/e^- ratio of 1. Although the complex does not act as a H⁺-pump, QrcD may include a conserved proton channel leading from the N-side to the P-side menaquinone

SUBMITTER: Duarte AG 

PROVIDER: S-EPMC6303296 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature