Titel
An electrogenic redox loop in sulfate reduction reveals a likely widespread mechanism of energy conservation
Autor*in
Américo G. Duarte
Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa
Teresa Catarino
Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa
Gaye F. White
Centre for Molecular and Structural Biochemistry, School of Biological Sciences and School of Chemistry, University of East Anglia
... show all
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 pocket. Our work provides evidence of how energy is conserved during dissimilatory sulfate reduction, and suggests mechanisms behind the functions of related bacterial respiratory complexes in other bioenergetic contexts.
Stichwort
BacteriologyBioenergetics, Biophysical methodsEnzyme mechanismsMetabolic pathways
Objekt-Typ
Sprache
Englisch [eng]
Persistent identifier
Erschienen in
Titel
Nature Communications
Band
9
Publication
Springer Science and Business Media LLC
Erscheinungsdatum
2018
Zugänglichkeit
Rechte
Rechteangabe
© The Author(s) 2018
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