Qubisemiquinone radical in the bo-type ubiquinol oxidase studied by pulsed electron paramagnetic resonance and hyperfine sublevel correlation spectroscopy

Grimaldi, Stéphane, MacMillan, Fraser ORCID: https://orcid.org/0000-0002-2410-4790, Ostermann, Thomas, Ludwig, Bernd, Michel, Hartmut and Prisner, Thomas (2001) Qubisemiquinone radical in the bo-type ubiquinol oxidase studied by pulsed electron paramagnetic resonance and hyperfine sublevel correlation spectroscopy. Biochemistry, 40 (4). pp. 1037-1043. ISSN 0006-2960

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Abstract

The high-affinity Q ubiquinone-binding site in the bo ubiquinol oxidase from Escherichia coli has been characterized by an investigation of the native ubiquinone radical anion Q by pulsed electron paramagnetic resonance (EPR) spectroscopy. One- and two-dimensional electron spin-echo envelope modulation (ESEEM) spectra reveal strong interactions of the unpaired electron of Q with a nitrogen nucleus from the surrounding protein matrix. From analysis of the experimental data, the N nuclear quadrupolar parameters have been determined: κ = eqQ/4h = 0.93 MHz and η = 0.50. This assignment is confirmed by hyperfine sublevel correlation (HYSCORE) spectroscopy. On the basis of a comparison of these data with those obtained previously for other membrane-protein bound semiquinone radicals and model systems, this nucleus is assigned to a protein backbone nitrogen. This result is discussed with regard to the location and potential function of Q in the enzyme.

Item Type: Article
Faculty \ School: Faculty of Science > School of Chemistry
Related URLs:
Depositing User: Pure Connector
Date Deposited: 21 Jan 2015 11:44
Last Modified: 21 Oct 2022 00:28
URI: https://ueaeprints.uea.ac.uk/id/eprint/51849
DOI: 10.1021/bi001641+

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