title: Macromolecular organization of ATP synthase and complex I in whole mitochondria.
abstract: We used electron cryotomography to study the molecular arrangement of large respiratory chain complexes in mitochondria from bovine heart, potato, and three types of fungi. Long rows of ATP synthase dimers were observed in intact mitochondria and cristae membrane fragments of all species that were examined. The dimer rows were found exclusively on tightly curved cristae edges. The distance between dimers along the rows varied, but within the dimer the distance between F(1) heads was constant. The angle between monomers in the dimer was 70° or above. Complex I appeared as L-shaped densities in tomograms of reconstituted proteoliposomes. Similar densities were observed in flat membrane regions of mitochondrial membranes from all species except Saccharomyces cerevisiae and identified as complex I by quantum-dot labeling. The arrangement of respiratory chain proton pumps on flat cristae membranes and ATP synthase dimer rows along cristae edges was conserved in all species investigated. We propose that the supramolecular organization of respiratory chain complexes as proton sources and ATP synthase rows as proton sinks in the mitochondrial cristae ensures optimal conditions for efficient ATP synthesis.
authors.affiliation: Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue Strasse 3, 60438 Frankfurt am Main, Germany.
authors.forename: Karen M
authors.initials: KM
authors.lastname: Davies
authors.forename: Mike
authors.initials: M
authors.lastname: Strauss
authors.forename: Bertram
authors.initials: B
authors.lastname: Daum
authors.forename: Jan H
authors.initials: JH
authors.lastname: Kief
authors.forename: Heinz D
authors.initials: HD
authors.lastname: Osiewacz
authors.forename: Adriana
authors.initials: A
authors.lastname: Rycovska
authors.forename: Volker
authors.initials: V
authors.lastname: Zickermann
authors.forename: Werner
authors.initials: W
authors.lastname: Kühlbrandt
mesh_terms: D000818:Animals; D002417:Cattle; D042967:Electron Transport Complex I / Q000378:metabolism* / Q000648:ultrastructure; D005658:Fungi / Q000201:enzymology; D046911:Macromolecular Substances / Q000378:metabolism*; D008928:Mitochondria / Q000201:enzymology* / Q000648:ultrastructure; D051336:Mitochondrial Membranes / Q000201:enzymology / Q000648:ultrastructure; D025261:Mitochondrial Proton-Translocating ATPases / Q000378:metabolism* / Q000648:ultrastructure; D055503:Protein Multimerization; D011198:Solanum tuberosum / Q000201:enzymology; D014054:Tomography
chemical_list: D046911:Macromolecular Substances; D025261:Mitochondrial Proton-Translocating ATPases; D042967:Electron Transport Complex I