TY  - JOUR
A1  - Zwicker, Klaus
A1  - Galkin, Alexander
A1  - Dröse, Stefan
A1  - Grgić, Ljuban
A1  - Kerscher, Stefan
A1  - Brandt, Ulrich
T1  - The Redox-Bohr group associated with iron-sulfur cluster N2 of complex I
T2  - Journal of biological chemistry
N2  - 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.
Y1  - 2021
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/76239
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-762399
SN  - 0021-9258
VL  - 281
IS  - 32
SP  - 23013
EP  - 23017
PB  - American Society for Biochemistry and Molecular Biology Publications
CY  - Bethesda, Md
ER  -