title: Haloarcula marismortui cytochrome b-561 is encoded by the narC gene in the dissimilatory nitrate reductase operon.
abstract: The composition of membrane-bound electron-transferring proteins from denitrifying cells of Haloarcula marismortui was compared with that from the aerobic cells. Accompanying nitrate reductase catalytic NarGH subcomplex, cytochrome b-561, cytochrome b-552, and halocyanin-like blue copper protein were induced under denitrifying conditions. Cytochrome b-561 was purified to homogeneity and was shown to be composed of a polypeptide with a molecular mass of 40 kDa. The cytochrome was autooxidizable and its redox potential was -27 mV. The N-terminal sequence of the cytochrome was identical to the deduced amino acid sequence of the narC gene product encoded in the third ORF of the nitrate reductase operon with a unique arrangement of ORFs. The sequence of the cytochrome was homologous with that of the cytochrome b subunit of respiratory cytochrome bc. A possibility that the cytochrome bc and the NarGH constructed a supercomplex was discussed.
authors.affiliation: Department of Biological Science, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Yoshimatsu
authors.forename: Osamu
authors.initials: O
authors.lastname: Araya
authors.forename: Taketomo
authors.initials: T
authors.lastname: Fujiwara
mesh_terms: D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D003573:Cytochrome b Group / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014450:Electron Transport Complex III / Q000378:metabolism; D019848:Gene Expression Regulation, Archaeal; D019614:Haloarcula marismortui / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009565:Nitrate Reductases / Q000235:genetics / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D016366:Open Reading Frames; D009876:Operon; D010084:Oxidation-Reduction
chemical_list: D019843:Archaeal Proteins; D002352:Carrier Proteins; D003573:Cytochrome b Group; C023548:copper-binding protein; C023646:cytochrome b561; C048756:cytochrome b 555; D009565:Nitrate Reductases; D014450:Electron Transport Complex III; D009584:Nitrogen