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

Grimaldi, S., Macmillan, F., Ostermann, T., Ludwig, B., Michel, H. and Prisner, T. (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 Dec 2018 15:30
URI: https://ueaeprints.uea.ac.uk/id/eprint/51849
DOI: 10.1021/bi001641+

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