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Budiman, K., Kannt, A., Lyubenova, S., Richter, O. M. H., Ludwig, B., Michel, H. and Macmillan, F. 
ORCID: https://orcid.org/0000-0002-2410-4790
(2004)
Tyrosine 167: The origin of the radical species observed in the reaction of cytochrome c oxidase with hydrogen peroxide in Paracoccus denitrificans.
Biochemistry, 43 (37).
pp. 11709-11716.
ISSN 0006-2960
Abstract
Determination of the three-dimensional structure of cytochrome c oxidase, the terminal enzyme of the respiratory chain, from Paracoccus denitrificans offers the possibility of site-directed mutagenesis studies to investigate the relationship between the structure and the catalytic function of the enzyme. The mechanism of electron-coupled proton transfer is still, however, poorly understood. The P-M intermediate of the catalytic cycle Is an oxoferryl state the generation of which requires one additional electron, which cannot be provided by the two metal centers. It is suggested that the missing electron is donated to this binuclear site by a tyrosine residue that forms a radical species, which can then be detected in both the P-M and F-. intermediates of the catalytic cycle. One possibility to produce P-M and F-. intermediates artificially in cytochrome c oxidase is the addition of hydrogen peroxide to the fully oxidized enzyme. Using electron paramagnetic resonance (EPR) spectroscopy, we assign a radical species detected in this reaction to a tyrosine residue. To address the question, which tyrosine residue is the origin of the radical species, several tyrosine variants of subunit I are investigated. These variants are characterized by their turnover rates, as well as using EPR and optical spectroscopy. From these experiments, it is concluded that the origin of the radical species appearing in P-M and F-. intermediates produced with hydrogen peroxide is tyrosine 167. The significance of this finding for the catalytic function of the enzyme is discussed.
| Item Type: | Article |
|---|---|
| Faculty \ School: | Faculty of Science > School of Chemistry (former - to 2024) |
| UEA Research Groups: | Faculty of Science > Research Groups > Biophysical Chemistry (former - to 2017) Faculty of Science > Research Groups > Chemistry of Life Processes Faculty of Science > Research Centres > Centre for Molecular and Structural Biochemistry Faculty of Science > Research Groups > Chemistry of Light and Energy |
| Depositing User: | Rachel Smith |
| Date Deposited: | 18 Jul 2011 15:56 |
| Last Modified: | 24 Sep 2024 10:03 |
| URI: | https://ueaeprints.uea.ac.uk/id/eprint/33889 |
| DOI: | 10.1021/bi048898i |
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