Two CO molecules can bind concomitantly at the diiron site of NO reductase from Bacillus azotoformans

Shen Lu, Suharti, Simon De Vries, Pierre Moënne-Loccoz

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24 Scopus citations

Abstract

CO complexes formed in reduced nitric oxide reductase from Bacillus azotoformans were investigated with resonance Raman and FTIR techniques. These experiments shows the presence of two ν(C-O) bands, one at 1970 cm-1 assigned to the heme-CO complex, and one at 2070 cm-1 from the non-heme iron, FeBCO. At cryogenic temperatures, the heme-CO complex adopts a semi-bridging configuration with FeB which decreases its stretching frequency to 1910 cm-1 and decreases the ν(C-O) of FeBCO by 20 cm-1. The concomitant binding of two CO molecules, one per iron(II) at the active site, is consistent with the formation of a [{FeNO}7]2 iron-nitrosyl dimer during substrate turnover. This study strongly supports the notion that this family of enzymes utilizes a reaction mechanism based on catalysis by proximity, where the formation of two iron-nitrosyl groups promotes N-N bond formation.

Original languageEnglish (US)
Pages (from-to)15332-15333
Number of pages2
JournalJournal of the American Chemical Society
Volume126
Issue number47
StatePublished - Dec 1 2004

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ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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