The Redox-Bohr group associated with iron-sulfur cluster N2 of complex I
- Proton pumping respiratory complex I (NADH:ubiquinone oxidoreductase) is a major component of the oxidative phosphorylation system in mitochondria and many bacteria. In mammalian cells it provides 40% of the proton motive force needed to make ATP. Defects in this giant and most complicated membrane-bound enzyme cause numerous human disorders. Yet the mechanism of complex I is still elusive. A group exhibiting redox-linked protonation that is associated with iron-sulfur cluster N2 of complex I has been proposed to act as a central component of the proton pumping machinery. Here we show that a histidine in the 49-kDa subunit that resides near iron-sulfur cluster N2 confers this redox-Bohr effect. Mutating this residue to methionine in complex I from Yarrowia lipolytica resulted in a marked shift of the redox midpoint potential of iron-sulfur cluster N2 to the negative and abolished the redox-Bohr effect. However, the mutation did not significantly affect the catalytic activity of complex I and protons were pumped with an unchanged stoichiometry of 4 H+/2e−. This finding has significant implications on the discussion about possible proton pumping mechanism for complex I.
Author: | Klaus ZwickerORCiD, Alexander GalkinORCiD, Stefan DröseORCiDGND, Ljuban GrgićGND, Stefan Kerscher, Ulrich BrandtORCiDGND |
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URN: | urn:nbn:de:hebis:30:3-762399 |
DOI: | https://doi.org/10.1074/jbc.M603442200 |
ISSN: | 0021-9258 |
Pubmed Id: | https://pubmed.ncbi.nlm.nih.gov/16760472 |
Parent Title (English): | Journal of biological chemistry |
Publisher: | American Society for Biochemistry and Molecular Biology Publications |
Place of publication: | Bethesda, Md |
Document Type: | Article |
Language: | English |
Date of Publication (online): | 2021/01/04 |
Year of first Publication: | 2006 |
Publishing Institution: | Universitätsbibliothek Johann Christian Senckenberg |
Release Date: | 2023/09/20 |
Volume: | 281 |
Issue: | 32 |
Page Number: | 5 |
First Page: | 23013 |
Last Page: | 23017 |
HeBIS-PPN: | 513168974 |
Institutes: | Medizin |
Dewey Decimal Classification: | 5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie |
Sammlungen: | Universitätspublikationen |
Licence (German): | ![]() |