title: Arrangement of electron transport chain components in bovine mitochondrial supercomplex I1III2IV1.
abstract: The respiratory chain in the inner mitochondrial membrane contains three large multi-enzyme complexes that together establish the proton gradient for ATP synthesis, and assemble into a supercomplex. A 19-Å 3D map of the 1.7-MDa amphipol-solubilized supercomplex I(1)III(2)IV(1) from bovine heart obtained by single-particle electron cryo-microscopy reveals an amphipol belt replacing the membrane lipid bilayer. A precise fit of the X-ray structures of complex I, the complex III dimer, and monomeric complex IV indicates distances of 13 nm between the ubiquinol-binding sites of complexes I and III, and of 10-11 nm between the cytochrome c binding sites of complexes III and IV. The arrangement of respiratory chain complexes suggests two possible pathways for efficient electron transfer through the supercomplex, of which the shorter branch through the complex III monomer proximal to complex I may be preferred.
authors: Abteilung Strukturbiologie, Max-Planck-Institut für Biophysik, Frankfurt, Germany.
authors: Thorsten
authors: T
authors: Althoff
authors: Deryck J
authors: DJ
authors: Mills
authors: Jean-Luc
authors: JL
authors: Popot
authors: Werner
authors: W
authors: Kühlbrandt
mesh_terms: D000818:Animals; D002417:Cattle; D018360:Crystallography, X-Ray; D004579:Electron Transport; D045222:Electron Transport Chain Complex Proteins / Q000378:metabolism*; D042967:Electron Transport Complex I / Q000737:chemistry / Q000378:metabolism; D014450:Electron Transport Complex III / Q000737:chemistry / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000737:chemistry / Q000378:metabolism; D008929:Mitochondria, Heart / Q000378:metabolism; D051336:Mitochondrial Membranes / Q000201:enzymology / Q000378:metabolism; D009097:Multienzyme Complexes / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D011487:Protein Conformation; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary
chemical_list: D045222:Electron Transport Chain Complex Proteins; D009097:Multienzyme Complexes; D003576:Electron Transport Complex IV; D042967:Electron Transport Complex I; D014450:Electron Transport Complex III