Selective one-electron reduction of Nitrosomonas europaea hydroxylamine oxidoreductase with nitric oxide.
Hydroxylamine oxidoreductase (HAO) from the autotrophic bacterium Nitrosomonas europaea catalyzes the 4-e- oxidation of NH2-OH to NO2-. The e- are transferred from NH2OH to an unusual 5-coordinate heme known as P460, which is the active site of HAO, and from there to an array of seven c-type hemes. NO., generated by laser flash photolysis of N,N'-bis(carboxymethyl)-N,N'-dinitroso-1,4-phenylenediamine, is found to act as a 1-e- donor to HAO. Most likely NO. binds P460 to yield a [Fe(NO)]6 moiety, which then hydrolyzes to give the reduced enzyme and NO2-. The [Fe(NO)]6 moiety is also a plausible final intermediate in the oxidation of NH2OH.
Cabail
Maria Zulema
MZ
Department of Chemistry, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53211, USA.
Pacheco
A Andrew
AA
D002384:Catalysis; D004579:Electron Transport; D006418:Heme / Q000378:metabolism*; D006868:Hydrolysis; D019811:Hydroxylamine / Q000737:chemistry / Q000378:metabolism; D015394:Molecular Structure; D009569:Nitric Oxide / Q000737:chemistry / Q000378:metabolism; D009585:Nitrogen Dioxide / Q000737:chemistry / Q000378:metabolism; D009606:Nitrosomonas / Q000201:enzymology*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism*
D019811:Hydroxylamine; D009569:Nitric Oxide; D006418:Heme; D010088:Oxidoreductases; C021401:hydroxylamine dehydrogenase; D009585:Nitrogen Dioxide