Li, M, Jørgensen, SK, McMillan, DGG et al. (8 more authors) (2015) Single Enzyme Experiments Reveal a Long-Lifetime Proton Leak State in a Heme-Copper Oxidase. Journal of the American Chemical Society, 137 (51). pp. 16055-16063. ISSN 0002-7863
Abstract
Heme-copper oxidases (HCOs) are key enzymes in prokaryotes and eukaryotes for energy production during aerobic respiration. They catalyze the reduction of the terminal electron acceptor, oxygen, and utilize the Gibbs free energy to transport protons across a membrane to generate a proton (ΔpH) and electrochemical gradient termed proton motive force (PMF), which provides the driving force for the adenosine triphosphate (ATP) synthesis. Excessive PMF is known to limit the turnover of HCOs, but the molecular mechanism of this regulatory feedback remains relatively unexplored. Here we present a single-enzyme study that reveals that cytochrome bo₃ from Escherichia coli, an HCO closely homologous to Complex IV in human mitochondria, can enter a rare, long-lifetime leak state during which proton flow is reversed. The probability of entering the leak state is increased at higher ΔpH. By rapidly dissipating the PMF, we propose that this leak state may enable cytochrome bo₃, and possibly other HCOs, to maintain a suitable ΔpH under extreme redox conditions.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2015 American Chemical Society. This is an open access article published under a Creative Commons Attribution (CC-BY) License, which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Biomedical Sciences (Leeds) The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Molecular and Cellular Biology (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 07 Jan 2016 09:23 |
Last Modified: | 20 Jul 2018 10:33 |
Status: | Published |
Publisher: | American Chemical Society |
Identification Number: | 10.1021/jacs.5b08798 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:93255 |