Fourier transform infrared evidence for a ferric six-coordinate nitrosylheme b3 complex of cytochrome cbb3 oxidase from Pseudomonas stutzeri at ambient temperature

Stavros Stavrakis, Eftychia Pinakoulaki, Andrea Urbani, Constantinos Varotsis

Research output: Contribution to journalArticlepeer-review

Abstract

We report the first vibrational study of NO bound to an oxidized heme-copper oxidase. Cytochrome cbb3 oxidase from P. stutzeri reduces both O2 and NO to H2O and N2O, respectively. The ferric nitrosyl complex of cbb3 exhibits v(N-O) at 1903 cm-1. This frequency is very similar to v(NO) of nitric oxide reductase, the acidic form of Met Mb-NO, but 18 cm-1 lower than that of neutral Met Mb-NO. By monitoring the NO intensity, we estimate that NO dissociates from the heme b3 pocket, without binding to CuB, with k = 1.8 × 10-3 s-1. Therefore, NO binding occurs at the heme site and not at CuB, generating a nitrosonium CuB1+-NO+ species as proposed recently (Torres; J.; Cooper, C.E.; Wilson, M.T. J. Biol. Chem. 1998, 273, 8756-8766). The coordination of NO to cbb3 oxidase and to nitric oxide reductase and Mb is compared and discussed.

Original languageEnglish
Pages (from-to)12860-12862
Number of pages3
JournalJournal of Physical Chemistry B
Volume106
Issue number50
DOIs
Publication statusPublished - Dec 19 2002

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Fingerprint

Dive into the research topics of 'Fourier transform infrared evidence for a ferric six-coordinate nitrosylheme b3 complex of cytochrome cbb3 oxidase from Pseudomonas stutzeri at ambient temperature'. Together they form a unique fingerprint.

Cite this