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


Author(s): Sazanov, Leonid A
Article Title: The mechanism of coupling between electron transfer and proton translocation in respiratory complex I
Affiliation
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.
Keywords: NADH:ubiquinone oxidoreductase Complex I Membrane protein structure Proton pump Respiratory chain
Journal Title: Journal of Bioenergetics and Biomembranes
Volume: 46
Issue 4
ISSN: 1573-6881
Publisher: Springer  
Date Published: 2014-08-01
Start Page: 247
End Page: 253
DOI: 10.1007/s10863-014-9554-z
Open access: no