Claude E. Hatchikian

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BACKGROUND Many microorganisms have the ability to either oxidize molecular hydrogen to generate reducing power or to produce hydrogen in order to remove low-potential electrons. These reactions are catalyzed by two unrelated enzymes: the Ni-Fe hydrogenases and the Fe-only hydrogenases. RESULTS We report here the structure of the heterodimeric Fe-only(More)
The metabolism of Desulfovibrio vulgaris Hildenborough grown on medium containing lactate or pyruvate plus a high concentration of sulfate (36 mM) was studied. Molecular growth yields were 6.7 +/- 1.3 and 10.1 +/- 1.7 g/mol for lactate and pyruvate, respectively. Under conditions in which the energy source was the sole growth-limiting factor, we observed(More)
We performed a comparative study of the growth energetics of some species of Desulfovibrio by measuring microcalorimetric and molar growth yield values. Lactate and pyruvate were used as energy sources for sulfate reduction. On lactate-sulfate media Desulfovibrio desulfuricans Norway, Desulfovibrio gigas, and Desulfovibrio africanus exhibited molar growth(More)
Fe-hydrogenase is a 54-kDa iron-sulfur enzyme essential for hydrogen cycling in sulfate-reducing bacteria. The x-ray structure of Desulfovibrio desulfuricans Fe-hydrogenase has recently been solved, but structural information on the recognition of its redox partners is essential to understand the structure-function relationships of the enzyme. In the(More)
Interspecies hydrogen transfer was studied in Desulfovibrio vulgaris-Methanosarcina barkeri mixed cultures. Experiments were performed under batch and continuous growth culture conditions. Lactate or pyruvate was used as an energy source. In batch culture and after 30 days of simultaneous incubation, these organisms were found to yield 1.5 mol of methane(More)
Hydrogenases are proteins which metabolize the most simple of chemical compounds, molecular hydrogen, according to the reaction H2<-->2H+ + 2e-. These enzymes are found in many microorganisms of great biotechnological interest such as methanogenic, acetogenic, nitrogen fixing, photosynthetic or sulfate-reducing bacteria. The X-ray structure of a dimeric(More)
Different electron carriers of the non-desulfoviridin-containing, sulfate-reducing bacterium Desulfovibrio desulfuricans (Norway strain) have been studied. Two nonheme iron proteins, ferredoxin and rubredoxin, have been purified. This ferredoxin contains four atoms of non-heme iron and acid-labile sulfur and six residues of cysteine per molecule. Its amino(More)
The periplasmic hydrogenase from Desulfovibrio fructosovorans grown on fructose/sulfate medium was purified to homogeneity. It exhibits a molecular mass of 88 kDa and is composed of two different subunits of 60 kDa and 28.5 kDa. The absorption spectrum of the enzyme is characteristic of an iron-sulfur protein and its absorption coefficients at 400 and 280(More)
The maintenance energy coefficient of Desulfovibrio vulgaris was studied by using a chemostat, with Methanosarcina barkeri or sulfate as the electron acceptor; lithium lactate or sodium pyruvate served as the electron donor. The experiments showed that the growth energetics of D. vulgaris or M. barkeri were greatly affected by maintenance energy(More)
The binding of carbon monoxide, a competitive inhibitor of many hydrogenases, to the active site of Desulfovibrio fructosovorans hydrogenase has been studied by infrared spectroscopy in a spectroelectrochemical cell. Direct evidence has been obtained of which redox states of the enzyme can bind extrinsic CO. Redox states A, B and SU do not bind extrinsic(More)