title: Nitric oxide-reductase homologue that contains a copper atom and has cytochrome c-oxidase activity from an aerobic phototrophic bacterium Roseobacter denitrificans.
abstract: A cytochrome cb-type enzyme with cytochrome c-oxidase activity was purified from an aerobic phototrophic bacterium Roseobacter denitrificans. The enzyme was solubilized with sucrose monodecanoate from the membranes of R. denitrificans grown aerobically under light conditions, and purified to electrophoretic homogeneity. Absorption spectra of the purified enzyme showed peaks at 410 nm and 530 nm in the oxidized state, and peaks at 420, 522, and 551 nm and a shoulder at around 560 nm in the reduced state. The enzyme is composed of two subunits with apparent molecular weights on SDS-PAGE of 37,000 and 18,000, the latter positive to heme staining. The protein contains heme c, heme b, and copper in a 1:2:1 stoichiometry. The spectral properties indicated that the heme c and one heme b are in low-spin states, while the other heme b is in a high-spin state. The base sequences of the genes and the deduced amino acid sequences are similar to those of known NorB and NorC subunits of nitric oxide reductases from other bacterial species. The enzyme is similar to nitric oxide reductase, but differs in that it contains copper. Virtually no nitric oxide reductase activity was detected in the purified enzyme.
authors.affiliation: Department of Biology, Graduate School of Sciences, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Matsuda
authors.forename: Kei-ichiro
authors.initials: K
authors.lastname: Inamori
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Osaki
authors.forename: Akane
authors.initials: A
authors.lastname: Eguchi
authors.forename: Azusa
authors.initials: A
authors.lastname: Watanabe
authors.forename: Shun-ichiro
authors.initials: S
authors.lastname: Kawabata
authors.forename: Koh
authors.initials: K
authors.lastname: Iba
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Arata
mesh_terms: D000332:Aerobiosis; D020561:Alphaproteobacteria / Q000201:enzymology* / Q000235:genetics; D000595:Amino Acid Sequence; D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D003486:Cyanides / Q000494:pharmacology; D003576:Electron Transport Complex IV / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013057:Spectrum Analysis
chemical_list: D003486:Cyanides; D004791:Enzyme Inhibitors; D003300:Copper; D010088:Oxidoreductases; C034747:nitric-oxide reductase; D003576:Electron Transport Complex IV