title: Characterization of the cytochrome system of a nitrogen-fixing strain of a sulfate-reducing bacterium: Desulfovibrio desulfuricans strain Berre-Eau.
abstract: Two c-type cytochromes were purified and characterized by electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopic techniques, from the sulfate-reducer nitrogen-fixing organism, Desulfovibrio desulfuricans strain Berre-Eau (NCIB 8387). The purification procedures included several chromatographic steps on alumina, carboxymethylcellulose and gel filtration. A tetrahaem and a monohaem cytochrome were identified. The multihaem cytochrome has visible, EPR and NMR spectra with general properties similar to other low-potential bis-histidinyl axially bound haem proteins, belonging to the class of tetrahaem cytochrome c3 isolated from other Desulfovibrio species. The monohaem cytochrome c553 is ascorbate-reducible and its EPR and NMR data are characteristic of a cytochrome with methionine-histidine ligation. Their properties are compared with other homologous proteins isolated from sulfate-reducing bacteria.
mesh_terms: D003574:Cytochrome c Group / Q000032:analysis*; D003901:Desulfovibrio / Q000201:enzymology*; D004578:Electron Spin Resonance Spectroscopy; D006418:Heme / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D009586:Nitrogen Fixation; D010084:Oxidation-Reduction; D013053:Spectrophotometry; D013431:Sulfates / Q000378:metabolism; D013696:Temperature
chemical_list: D003574:Cytochrome c Group; D013431:Sulfates; D006418:Heme