Species: Pseudomonas stutzeri
Subunit composition of
nitric oxide reductase = [NorB][NorC]
nitric oxide reductase large subunit = NorB (summary available)
nitric-oxide reductase small subunit = NorC (summary available)
Nitric oxide reductase is an integral membrane component of the anaerobic respiratory chain of Pseudomonas stutzeri, which results in denitrification. The enzyme catalyzes the reduction of nitric oxide to nitrous oxide, a reaction that involves the formation of an N-N bond, in essence a reversal of nitrogen fixation. NO reduction is coupled to electron transport phosphorylation [Zumft94, Heiss89, Braun91, Kastrau94, Zumft97, Watmough99].
The enzyme consists of a cytochrome c and cytochrome b subunits [Kastrau94], encoded by the norC and norB, respectively. The two genes are contiguous and transcribed as a single 2.0-kb transcript [Zumft94].
The cytochrome b subunit is highly hydrophobic. Purified enzyme contained a cardiolipin, an L-1-phosphatidyl-glycerol, and an L-1-phosphatidylethanolamine, the latter being the major component. An activity of 60 μmol nitric oxide/min/mg protein was obtained after electrophoresis in the presence of laurylpropanediol-3-phosphorylcholine ether [Kastrau94]
The cytochrome c subunit is membrane-anchored, while the cytochrome b subunit has 12 transmembrane regions [Philippot02]. Spectroelectrochemical oxidoreductive titrations gave E'o (versus standard hydrogen electrode) of +322 mV for the cytochrome b and +280 mV for the cytochrome c components [Kastrau94].
Molecular Weight: 45.0 kD (experimental) [Kastrau94]
Enzymatic reaction of: nitric oxide reductase
Synonyms: NO reductase, nitrous oxide:(acceptor) oxidoreductase (NO-forming)
EC Number: 188.8.131.52
In Pathways: nitrate reduction I (denitrification)Inhibitors (Unknown Mechanism): free fatty acids [Kastrau94] Regulators of Unknown Type: an L-1-phosphatidyl-glycerol [Kastrau94], a cardiolipin [Kastrau94]
|Gene:||norB||Accession Number: G-253 (MetaCyc)|
Molecular Weight: 53.006 kD (from nucleotide sequence)
Molecular Weight: 38.0 kD (experimental) [Kastrau94]
Relationship Links: InterPro:IN-FAMILY:IPR000883, InterPro:IN-FAMILY:IPR023615, InterPro:IN-FAMILY:IPR023616, Panther:IN-FAMILY:PTHR10422, Pfam:IN-FAMILY:PF00115, Prosite:IN-FAMILY:PS00077, Prosite:IN-FAMILY:PS50855
This subunit binds a heme b-type cytochrome.
|Gene:||norC||Accession Number: G-254 (MetaCyc)|
Molecular Weight: 16.508 kD (from nucleotide sequence)
Molecular Weight: 17.0 kD (experimental) [Kastrau94]
This subunit binds a mono-heme c-type cytochrome.
Braun91: Braun C, Zumft WG (1991). "Marker exchange of the structural genes for nitric oxide reductase blocks the denitrification pathway of Pseudomonas stutzeri at nitric oxide." J Biol Chem 1991;266(34);22785-8. PMID: 1744072
Heiss89: Heiss B, Frunzke K, Zumft WG (1989). "Formation of the N-N bond from nitric oxide by a membrane-bound cytochrome bc complex of nitrate-respiring (denitrifying) Pseudomonas stutzeri." J Bacteriol 1989;171(6);3288-97. PMID: 2542222
Kastrau94: Kastrau DH, Heiss B, Kroneck PM, Zumft WG (1994). "Nitric oxide reductase from Pseudomonas stutzeri, a novel cytochrome bc complex. Phospholipid requirement, electron paramagnetic resonance and redox properties." Eur J Biochem 1994;222(2);293-303. PMID: 8020468
Watmough99: Watmough NJ, Butland G, Cheesman MR, Moir JW, Richardson DJ, Spiro S (1999). "Nitric oxide in bacteria: synthesis and consumption." Biochim Biophys Acta 1999;1411(2-3);456-74. PMID: 10320675
Zumft94: Zumft WG, Braun C, Cuypers H (1994). "Nitric oxide reductase from Pseudomonas stutzeri. Primary structure and gene organization of a novel bacterial cytochrome bc complex." Eur J Biochem 1994;219(1-2);481-90. PMID: 7508388
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