title: Requirement for the proton-pumping NADH dehydrogenase I of Escherichia coli in respiration of NADH to fumarate and its bioenergetic implications.
abstract: In Escherichia coli the expression of the nuo genes encoding the proton pumping NADH dehydrogenase I is stimulated by the presence of fumarate during anaerobic respiration. The regulatory sites required for the induction by fumarate, nitrate and O2 are located at positions around -309, -277, and downstream of -231 bp, respectively, relative to the transcriptional-start site. The fumarate regulator has to be different from the O2 and nitrate regulators ArcA and NarL. For growth by fumarate respiration, the presence of NADH dehydrogenase I was essential, in contrast to aerobic or nitrate respiration which used preferentially NADH dehydrogenase II. The electron transport from NADH to fumarate strongly decreased in a mutant lacking NADH dehydrogenase I. The mutant used acetyl-CoA instead of fumarate to an increased extent as an electron acceptor for NADH, and excreted ethanol. Therefore, NADH dehydrogenase I is essential for NADH-->fumarate respiration, and is able to use menaquinone as an electron acceptor. NADH-->dimethylsulfoxide respiration is also dependent on NADH dehydrogenase I. The consequences for energy conservation by anaerobic respiration with NADH as a donor are discussed.
authors.affiliation: Institut für Mikrobiologie und Weinforschung, Universität Mainz, Germany.
authors.forename: Q H
authors.initials: QH
authors.lastname: Tran
authors.forename: J
authors.initials: J
authors.lastname: Bongaerts
authors.forename: D
authors.initials: D
authors.lastname: Vlad
authors.forename: G
authors.initials: G
authors.lastname: Unden
mesh_terms: D000085:Acetates / Q000378:metabolism; D000693:Anaerobiosis; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004579:Electron Transport; D042967:Electron Transport Complex I; D004734:Energy Metabolism / Q000187:drug effects; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism; D005650:Fumarates / Q000378:metabolism* / Q000494:pharmacology; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D009243:NAD / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D017494:Proton Pumps / Q000378:metabolism*
chemical_list: D000085:Acetates; D005650:Fumarates; D017494:Proton Pumps; D009243:NAD; D000431:Ethanol; D009247:NADH, NADPH Oxidoreductases; D042967:Electron Transport Complex I; D004121:Dimethyl Sulfoxide