title: Helical arrays of U-shaped ATP synthase dimers form tubular cristae in ciliate mitochondria.
abstract: F1Fo-ATP synthases are universal energy-converting membrane protein complexes that synthesize ATP from ADP and inorganic phosphate. In mitochondria of yeast and mammals, the ATP synthase forms V-shaped dimers, which assemble into rows along the highly curved ridges of lamellar cristae. Using electron cryotomography and subtomogram averaging, we have determined the in situ structure and organization of the mitochondrial ATP synthase dimer of the ciliate Paramecium tetraurelia. The ATP synthase forms U-shaped dimers with parallel monomers. Each complex has a prominent intracrista domain, which links the c-ring of one monomer to the peripheral stalk of the other. Close interaction of intracrista domains in adjacent dimers results in the formation of helical ATP synthase dimer arrays, which differ from the loose dimer rows in all other organisms observed so far. The parameters of the helical arrays match those of the cristae tubes, suggesting the unique features of the P. tetraurelia ATP synthase are directly responsible for generating the helical tubular cristae. We conclude that despite major structural differences between ATP synthase dimers of ciliates and other eukaryotes, the formation of ATP synthase dimer rows is a universal feature of mitochondria and a fundamental determinant of cristae morphology.
authors.affiliation: Department of Structural Biology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany;
authors.forename: Alexander W
authors.initials: AW
authors.lastname: Mühleip
authors.affiliation: Department of Structural Biology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany;
authors.forename: Friederike
authors.initials: F
authors.lastname: Joos
authors.affiliation: Buchmann Institute for Molecular Life Sciences, Goethe-University Frankfurt, 60438 Frankfurt am Main, Germany; Institute for Biophysics, Goethe-University Frankfurt, 60438 Frankfurt am Main, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Wigge
authors.affiliation: Buchmann Institute for Molecular Life Sciences, Goethe-University Frankfurt, 60438 Frankfurt am Main, Germany; Institute for Biophysics, Goethe-University Frankfurt, 60438 Frankfurt am Main, Germany.
authors.forename: Achilleas S
authors.initials: AS
authors.lastname: Frangakis
authors.affiliation: Department of Structural Biology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany; KMDavies@lbl.gov werner.kuehlbrandt@biophys.mpg.de.
authors.forename: Werner
authors.initials: W
authors.lastname: Kühlbrandt
authors.affiliation: Department of Structural Biology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany; KMDavies@lbl.gov werner.kuehlbrandt@biophys.mpg.de.
authors.forename: Karen M
authors.initials: KM
authors.lastname: Davies
mesh_terms: D000818:Animals; D008854:Microscopy, Electron; D008928:Mitochondria / Q000378:metabolism* / Q000648:ultrastructure; D051336:Mitochondrial Membranes / Q000378:metabolism* / Q000648:ultrastructure; D025261:Mitochondrial Proton-Translocating ATPases / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D016805:Paramecium tetraurelia / Q000201:enzymology / Q000378:metabolism / Q000648:ultrastructure; D011487:Protein Conformation; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D015800:Protozoan Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D015800:Protozoan Proteins; D025261:Mitochondrial Proton-Translocating ATPases
keywords: Paramecium; cryoelectron microscopy; macromolecular organization; serial block face imaging; subtomogram averaging