title: Characterization of the [NiFe] hydrogenase from the sulfate reducer Desulfovibrio vulgaris Hildenborough.
abstract: The [NiFe] hydrogenase from Desulfovibrio vulgaris Hildenborough was isolated from the cytoplasmic membranes and characterized by EPR spectroscopy. It has a total molecular mass of 98.7 kDa (subunits of 66.4 and 32.3 kDa), and contains 1 nickel and 12 Fe atoms per heterodimer. The catalytic activities for hydrogen consumption and production were determined to be 174 and 89 mumol H2.min-1.mg-1, respectively. As isolated, under aerobic conditions, this hydrogenase exhibits EPR signals characteristic of the nickel centers in [NiFe] hydrogenases (Ni-A signal at gx,y,z = 2.32, 2.23 and approximately 2.0 and Ni-B signal at gx,y,z = 2.33, 2.16 and approximately 2.0) as well as an intense quasi-isotropic signal centered at g = 2.02 due to the oxidized [3Fe-4S] center. The redox profile under hydrogen atmosphere is remarkably similar to that of other [NiFe] hydrogenases. The signals observed for the oxidized state disappear, first being substituted by the Ni-C type signal (gx,y,z = 2.19, 2.14, approximately 2.01), which upon long incubation under hydrogen yields the split Ni-C signal due to interaction with the reduced [4Fe-4S] centers.
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
authors.forename: C V
authors.initials: CV
authors.lastname: Romão
authors.forename: I A
authors.initials: IA
authors.lastname: Pereira
authors.forename: A V
authors.initials: AV
authors.lastname: Xavier
authors.forename: J
authors.initials: J
authors.lastname: LeGall
authors.forename: M
authors.initials: M
authors.lastname: Teixeira
mesh_terms: D000595:Amino Acid Sequence; D016969:Desulfovibrio vulgaris / Q000201:enzymology* / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D006864:Hydrogenase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D007501:Iron; D008969:Molecular Sequence Data; D009532:Nickel; D010084:Oxidation-Reduction; D017386:Sequence Homology, Amino Acid; D013053:Spectrophotometry; D013431:Sulfates / Q000378:metabolism
chemical_list: D013431:Sulfates; D009532:Nickel; D007501:Iron; C043296:nickel-iron hydrogenase; D006864:Hydrogenase