Spectral Properties of Bacterial Nitric-oxide Reductase. RESOLUTION OF pH-DEPENDENT FORMS OF THE ACTIVE SITE HEME b3

Field, S. J., Prior, Louise, Dolores Roldan, M, Cheesman, Myles, Thomson, Andrew J., Spiro, Stephen, Butt, Julea, Watmough, Nick and Richardson, David (2002) Spectral Properties of Bacterial Nitric-oxide Reductase. RESOLUTION OF pH-DEPENDENT FORMS OF THE ACTIVE SITE HEME b3. The Journal of Biological Chemistry, 277 (23). pp. 20146-20150. ISSN 1083-351X

Full text not available from this repository. (Request a copy)

Abstract

Bacterial nitric-oxide reductase catalyzes the two electron reduction of nitric oxide to nitrous oxide. In the oxidized form the active site non-heme FeB and high spin heme b 3 are µ-oxo bridged. The hemeb 3 has a ligand-to-metal charge transfer band centered at 595 nm, which is insensitive to pH over the range of 6.0–8.5. Partial reduction of nitric-oxide reductase yields a three electron-reduced state where only the hemeb 3 remains oxidized. This results in a shift of the heme b 3 charge transfer band ?max to longer wavelengths. At pH 6.0 the charge transfer band ?max is 605 nm, whereas at pH 8.5 it is 635 nm. At pH 6.5 and 7.5 the nitric-oxide reductase ferric hemeb 3 population is a mixture of both 605- and 635-nm forms. Magnetic circular dichroism spectroscopy suggests that at all pH values examined the proximal ligand to the ferric hemeb 3 in the three electron-reduced form is histidine. At pH 8.5 the distal ligand is hydroxide, whereas at pH 6.0, when the enzyme is most active, it is water.

Item Type: Article
Faculty \ School: Faculty of Science > School of Chemistry
Faculty of Science > School of Biological Sciences
University of East Anglia > Faculty of Science > Research Groups > Biophysical Chemistry
University of East Anglia > Faculty of Science > Research Groups > Molecular Microbiology
University of East Anglia > Faculty of Science > Research Groups > Organisms and the Environment
Related URLs:
Depositing User: Rachel Smith
Date Deposited: 15 Feb 2011 16:50
Last Modified: 25 Jul 2018 07:18
URI: https://ueaeprints.uea.ac.uk/id/eprint/21419
DOI: 10.1074/jbc.M112202200

Actions (login required)

View Item