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Proton pumping by NADH:ubiquinone oxidoreductase. A redox driven conformational change mechanism?
Author(s) -
Brandt Ulrich,
Kerscher Stefan,
Dröse Stefan,
Zwicker Klaus,
Zickermann Volker
Publication year - 2003
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(03)00387-9
Subject(s) - oxidoreductase , redox , chemistry , conformational change , proton , chemiosmosis , proton pump , crystallography , stereochemistry , biophysics , atp synthase , biochemistry , enzyme , atpase , biology , inorganic chemistry , physics , quantum mechanics
The modular evolutionary origin of NADH:ubiquinone oxidoreductase (complex I) provides useful insights into its functional organization. Iron–sulfur cluster N2 and the PSST and 49 kDa subunits were identified as key players in ubiquinone reduction and proton pumping. Structural studies indicate that this ‘catalytic core’ region of complex I is clearly separated from the membrane. Complex I from Escherichia coli and Klebsiella pneumoniae was shown to pump sodium ions rather than protons. These new insights into structure and function of complex I strongly suggest that proton or sodium pumping in complex I is achieved by conformational energy transfer rather than by a directly linked redox pump.