Intracellular localization of the hydrogenase in Desulfotomaculum orientis

Cypionka, H

doi:10.1016/0378-1097(86)90322-8

Cited by 11 publications

(13 citation statements)

References 10 publications

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“…Copper inhibition studies with suspensions of whole cells of S. wolfei and S. buswellii indicate that at least part of the hydrogenase activity of both strains is membraneassociated, and that it faces the outer side of the cytoplasmic membrane (Cypionka and Dilling 1986 buswellii/M, hungatei cocultures formed similar amounts of hydrogen from benzoate. Inhibition of this hydrogen formation by low amounts of CCCP or DCCD indicates 141 that butyrate and benzoate conversion to acetate and hydrogen depends on an intact proton potential that is maintained by ATP hydrolysis.…”

Section: Localization Of Enzyme Activitiesmentioning

confidence: 97%

Evidence of reversed electron transport in syntrophic butyrate or benzoate oxidation by Syntrophomonas wolfei and Syntrophus buswellii

Wallrabenstein

Schink

1994

Arch. Microbiol.

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Evidence of reversed electron transport in syntrophic butyrateor benzoate oxidation by Syntrophomonas wolfei and Syntrophus buswellii Received: 2 March 1994 / Accepted: 20 April 1994 Abstract Syntrophomonas wolfei and Syntrophus buswellii were grown with butyrate or benzoate in a defined binary coculture with Methanospirillum hungatei. Both strains also grew independent of the partner bacteria with crotonate as substrate. Localization of enzymes involved in butyrate oxidation by S. wolfei revealed that ATP synthase, hydrogenase, and butyryl-CoA dehydrogenase were at least partially membrane-associated whereas 3-hydroxybutyryl-CoA dehydrogenase and crotonase were entirely cytoplasmic. Inhibition experiments with copper chloride indicated that hydrogenase faced the outer surface of the cytoplasmic membrane. Suspensions of butyrate-or benzoate-grown cells of either strain accumulated hydrogen during oxidation of butyrate or benzoate to a low concentration that was thermodynamically in equilibrium with calculated reaction energetics. The protonophore carbonylcyanide m-chlorophenyl-hydrazone (CCCP) and the proton-translocating ATPase inhibitor N,N'dicyclohexylcarbodiimide (DCCD) both specifically inhibited hydrogen formation from butyrate or benzoate at low concentrations, whereas hydrogen formation from crotonate was not affected. A menaquinone was extracted from cells of S. wolfei and S. buswellii grown syntrophically in a binary methanogenic culture. The results indicate that a proton-potential-driven process is involved in hydrogen release from butyrate or benzoate oxidation. Degradation of both compounds becomes feasible only at low hydrogen partial pressure (10-4-10 -5 atm; Schink 1992), which can be maintained by hydrogen-oxidizing anaerobes such as methanogenic bacteria (Zehnder 1978;Dolfing 1988). The pathways of butyrate and benzoate degradation in these bacteria have been at least tentatively elucidated (see Schink 1992). The energetically most difficult electron transfer steps are the oxidations of the saturated acid esters butyryl-CoA or glutaryl-CoA to the respective unsaturated compounds. The electrons released in the butyryl-CoA dehydrogenase reaction (E 0, = -125 mV; Gustafson et al. 1986) and glutaryl-CoA dehydrogenase, for which a similar redox potential is assumed, are used to reduce protons to molecular hydrogen (E 0" = -414 mV). Even at 10 .4 atm hydrogen, the redox potential of the couple 2 H+/H2 is still -295 mV and is much lower than that of the electron donor. It has been hypothesized, therefore, that part of the ATP gained by substrate level phosphorylation during butyrate oxidation has to be spent in a reversed electron transport step to shift these electrons to a lower redox potential (Thauer and Morris 1984). Similar problems arise with oxidation of saturated intermediates in syntrophic benzoate degradation, and involvement of reversed electron transport in this oxidation also has been postulated (Schink 1992). However, experimental evidence of such energy-driven processes in syntrophic ...

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Section: Localization Of Enzyme Activitiesmentioning

confidence: 97%

Evidence of reversed electron transport in syntrophic butyrate or benzoate oxidation by Syntrophomonas wolfei and Syntrophus buswellii

Wallrabenstein

Schink

1994

Arch. Microbiol.

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“…The absorption spectra showed bands typical for cytochrome c 3 as already described by Badziong and Thauer (1980). Addition of 150 µM CuCl 2 as a hydrogenase inhibitor (Cypionka and Dilling 1986;Fitz and Cypionka 1991) led to complete inhibition of oxygen uptake with hydrogen ( Fig. 1) and of the hydrogenase activity measured with methyl viologen.…”

Section: Oxygen Reduction With Hydrogen and Hydrogenase Activitymentioning

confidence: 86%

Periplasmic oxygen reduction by Desulfovibrio species

Baumgarten

Redenius

Kranczoch

et al. 2001

Archives of Microbiology

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Washed cells of Desulfovibrio vulgaris strain Marburg (DSM 2119) reduced oxygen to water with H(2) as electron donor at a mean rate of 253 nmol O(2) min(-1) (mg protein)(-1). After separating the periplasm from the cells, more than 60% of the cytochrome c activity and 90% of the oxygen-reducing activity were found in the periplasmic fraction. Oxygen reduction and the reduction of cytochrome c with H(2) were inhibited by CuCl(2). After further separation of the periplasm by ultrafiltration (exclusion sizes 30, 50, and 100 kDa), oxygen reduction with H(2) occurred with the retentates only. Ascorbate plus tetramethyl-p-phenylenediamine (TMPD), however, were also oxidized by the filtrates. The stoichiometry of 1 mol O(2) reduced per 2 mol ascorbate oxidized indicated the formation of water. Our experiments present evidence that in D. vulgaris periplasmic hydrogenase and cytochrome c play a major role in oxygen reduction. Preliminary studies with other Desulfovibrio species indicated a similar function of periplasmic c-type cytochromes in D. desulfuricans CSN and D. termitidis KH1.

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“…1). Membranes have been shown to be impermeable to methyl viologen; therefore, activity in whole cells is often used as supportive evidence for extracytoplasmic hydrogenases (Cypionka and Dilling 1986;Jones and Garland 1977;Schink and Friedrich 1994). When Triton X-100 was added to cells, hydrogenase activity increased approximately threefold (Fig.…”

Section: Extracytoplasmic Hydrogenase Activity Can Be Detectedmentioning

confidence: 97%

Membrane-associated redox activities in Thermotoga neapolitana

Käslin

Childers

Noll

1998

Archives of Microbiology

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Elemental sulfur reduction by the hyperthermophilic bacterium Thermotoga neapolitana provides an alternative to hydrogen evolution during fermentation. Electrons are transferred from reduced cofactors (ferredoxin and NADH) to sulfur by a series of unknown steps. One enzyme that may be involved is an NADH:methyl viologen oxidoreductase (NMOR), an activity that in other fermenting organisms is associated with NADH:ferredoxin oxidoreductase. We found that 83% of NMOR activity was contained in the pellet fraction of cell extracts subjected to ultracentrifugation. This pellet fraction, presumably containing cell membranes, was required for electron transfer to NAD+ from ferredoxin-dependent pyruvate oxidation. However, the NMOR activity in this fraction used neither Thermotoga nor clostridial ferredoxins as substrates. NMOR activity was also detected in aerobically prepared vesicles. By comparison with ATPase activities, NMOR was found primarily on the cytoplasmic face of these vesicles. During these studies, an extracytoplasmic hydrogenase activity was discovered. In contrast to the soluble hydrogenase, this hydrogenase activity was completely inhibited when intact cells were treated with cupric chloride and was present on the extracytoplasmic face of vescides. In contrast to a soluble hydrogenase reported in Thermotoga maritima, this activity was air-stable and was inhibited by low concentrations of nitrite.

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Intracellular localization of the hydrogenase in Desulfotomaculum orientis

Cited by 11 publications

References 10 publications

Evidence of reversed electron transport in syntrophic butyrate or benzoate oxidation by Syntrophomonas wolfei and Syntrophus buswellii

Evidence of reversed electron transport in syntrophic butyrate or benzoate oxidation by Syntrophomonas wolfei and Syntrophus buswellii

Periplasmic oxygen reduction by Desulfovibrio species

Membrane-associated redox activities in Thermotoga neapolitana

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