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Fourier transform infrared spectroscopic study on the conformational reorganization in Escherichia coli complex I due to redox‐driven proton translocation
Author(s) -
Hellwig Petra,
Stolpe Stefan,
Friedrich Thorsten
Publication year - 2004
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.20046
Subject(s) - chemistry , infrared , fourier transform infrared spectroscopy , fourier transform , redox , proton , escherichia coli , conformational change , chromosomal translocation , photochemistry , stereochemistry , biochemistry , inorganic chemistry , physics , optics , gene , quantum mechanics
The proton‐pumping NADH:ubiquinone oxidoreductase (complex I) couples the transfer of electrons from NADH to ubiquinone with the translocation of protons across the membrane. Electron transfer is accomplished by flavin mononucleotide (FMN) and a series of iron–sulfur (Fe/S) clusters. A novel mechanism has been proposed wherein the electron transfer reaction induces conformational changes that subsequently lead to the translocation of protons. Redox‐induced Fourier transform infrared difference spectra have been obtained, showing strong conformational changes in the amide I region. The amplitude of the signal is pH dependent, as expected for an energy coupling step in the enzymes reaction. Furthermore, pH‐dependent protonation events and quinone binding were detected. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004