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Generation of a proton gradient in Desulfovibrio vulgaris

Generation of a proton gradient in Desulfovibrio vulgaris 203 155 155 5 5 Robert M. Fitz Heribert Cypionka Fakultät für Biologie Universität Konstanz W-7750 Konstanz Germany Abstract Washed cells of Desulfovibrio vulgaris strain Marburg oxidized H 2 , formate, lactate or pyruvate with sulfate, sulfite, trithionate, thiosulfate or oxygen as electron acceptor. CuCl 2 as an inhibitor of periplasmic hydrogenase inhibited H 2 and formate oxidation with sulfur compounds, and lactate oxidation in H 2 -grown, but not in lactate-grown cells. H 2 oxidation was sensitive to O 2 concentrations above 2% saturation. Carbon monoxide inhibited the oxidation of all substrates tested. Additions of micromolar H 2 pulses to cells incubated in KCl in the presence of various sulfur compounds ( reductant pulse method ) resulted in a reversible acidification. This proton release was stimulated by thiocyanate, methyl triphenylphosphonium (MTPP + ) or valinomycin plus EDTA, and completely inhibited by the uncoupler carbonylcyanide m -chlorophenylhydrazone (CCCP), CuCl 2 or carbon monoxide. The extrapolated H + /H 2 ratios obtained with sulfate, sulfite, trithionate or thiosulfate varied from 1.0 to 1.7. Micromolar additions of O 2 to cells incubated in the presence of excess of electron donor ( oxidant pulse method ) caused proton translocation with extrapolated H + /H 2 ratios of 3.9 with H 2 , 1.6 with lactate and 2.4 with pyruvate. Since a periplasmic hydrogenase can release at maximum 2 H + /H 2 , it is concluded that D. vulgaris is able to generate a proton gradient by vectorial proton translocation across the cytoplasmic membrane and by extracellular proton release by a periplasmic hydrogenase. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Archives of Microbiology Springer Journals

Generation of a proton gradient in Desulfovibrio vulgaris

Fitz, Robert; Cypionka, Heribert
Archives of Microbiology , Volume 155 (5) – Apr 1, 1991
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References (24)

Publisher
Springer Journals
Copyright
Copyright © 1991 by Springer-Verlag
Subject
Life Sciences; Biotechnology; Biochemistry, general; Cell Biology; Ecology; Microbial Ecology; Microbiology
ISSN
0302-8933
eISSN
1432-072X
DOI
10.1007/BF00244959
Publisher site
See Article on Publisher Site

Abstract

203 155 155 5 5 Robert M. Fitz Heribert Cypionka Fakultät für Biologie Universität Konstanz W-7750 Konstanz Germany Abstract Washed cells of Desulfovibrio vulgaris strain Marburg oxidized H 2 , formate, lactate or pyruvate with sulfate, sulfite, trithionate, thiosulfate or oxygen as electron acceptor. CuCl 2 as an inhibitor of periplasmic hydrogenase inhibited H 2 and formate oxidation with sulfur compounds, and lactate oxidation in H 2 -grown, but not in lactate-grown cells. H 2 oxidation was sensitive to O 2 concentrations above 2% saturation. Carbon monoxide inhibited the oxidation of all substrates tested. Additions of micromolar H 2 pulses to cells incubated in KCl in the presence of various sulfur compounds ( reductant pulse method ) resulted in a reversible acidification. This proton release was stimulated by thiocyanate, methyl triphenylphosphonium (MTPP + ) or valinomycin plus EDTA, and completely inhibited by the uncoupler carbonylcyanide m -chlorophenylhydrazone (CCCP), CuCl 2 or carbon monoxide. The extrapolated H + /H 2 ratios obtained with sulfate, sulfite, trithionate or thiosulfate varied from 1.0 to 1.7. Micromolar additions of O 2 to cells incubated in the presence of excess of electron donor ( oxidant pulse method ) caused proton translocation with extrapolated H + /H 2 ratios of 3.9 with H 2 , 1.6 with lactate and 2.4 with pyruvate. Since a periplasmic hydrogenase can release at maximum 2 H + /H 2 , it is concluded that D. vulgaris is able to generate a proton gradient by vectorial proton translocation across the cytoplasmic membrane and by extracellular proton release by a periplasmic hydrogenase.

Journal

Archives of Microbiology – Springer Journals

Published: Apr 1, 1991

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