The mechanism of coupling between electron transfer and proton translocation in respiratory complex I.

TitleThe mechanism of coupling between electron transfer and proton translocation in respiratory complex I.
Publication TypeJournal Article
Year of Publication2014
AuthorsSazanov, LA
JournalJ Bioenerg Biomembr
Volume46
Issue4
Pagination247-53
Date Published2014 Aug
ISSN1573-6881
KeywordsAnimals, Bacterial Proteins, Electron Transport, Electron Transport Complex I, Humans, Mitochondria, Mitochondrial Proteins, NAD, Proton-Motive Force, Thermus thermophilus
Abstract

NADH-ubiquinone oxidoreductase (complex I) is the first and largest enzyme in the respiratory chain of mitochondria and many bacteria. It couples the transfer of two electrons between NADH and ubiquinone to the translocation of four protons across the membrane. Complex I is an L-shaped assembly formed by the hydrophilic (peripheral) arm, containing all the redox centres performing electron transfer and the membrane arm, containing proton-translocating machinery. Mitochondrial complex I consists of 44 subunits of about 1 MDa in total, whilst the prokaryotic enzyme is simpler and generally consists of 14 conserved "core" subunits. Recently we have determined the first atomic structure of the entire complex I, using the enzyme from Thermus thermophilus (536 kDa, 16 subunits, 9 Fe-S clusters, 64 TM helices). Structure suggests a unique coupling mechanism, with redox energy of electron transfer driving proton translocation via long-range (up to ~200 Å) conformational changes. It resembles a steam engine, with coupling elements (akin to coupling rods) linking parts of this molecular machine.

DOI10.1007/s10863-014-9554-z
Alternate JournalJ. Bioenerg. Biomembr.
Citation Key10.1007/s10863-014-9554-z
PubMed ID24943718
Grant ListMC_U105674180 / / Medical Research Council / United Kingdom