title: An intermediate step in the evolution of ATPases: a hybrid F(0)-V(0) rotor in a bacterial Na(+) F(1)F(0) ATP synthase.
abstract: The Na(+) F(1)F(0) ATP synthase operon of the anaerobic, acetogenic bacterium Acetobacterium woodii is unique because it encodes two types of c subunits, two identical 8 kDa bacterial F(0)-like c subunits (c(2) and c(3)), with two transmembrane helices, and a 18 kDa eukaryal V(0)-like (c(1)) c subunit, with four transmembrane helices but only one binding site. To determine whether both types of rotor subunits are present in the same c ring, we have isolated and studied the composition of the c ring. High-resolution atomic force microscopy of 2D crystals revealed 11 domains, each corresponding to two transmembrane helices. A projection map derived from electron micrographs, calculated to 5 A resolution, revealed that each c ring contains two concentric, slightly staggered, packed rings, each composed of 11 densities, representing 22 transmembrane helices. The inner and outer diameters of the rings, measured at the density borders, are approximately 17 and 50 A. Mass determination by laser-induced liquid beam ion desorption provided evidence that the c rings contain both types of c subunits. The stoichiometry for c(2)/c(3) : c(1) was 9 : 1. Furthermore, this stoichiometry was independent of the carbon source of the growth medium. These analyses clearly demonstrate, for the first time, an F(0)-V(0) hybrid motor in an ATP synthase.
authors: Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt/Main, Germany.
authors: Michael
authors: M
authors: Fritz
authors: Adriana L
authors: AL
authors: Klyszejko
authors: Nina
authors: N
authors: Morgner
authors: Janet
authors: J
authors: Vonck
authors: Bernd
authors: B
authors: Brutschy
authors: Daniel J
authors: DJ
authors: Muller
authors: Thomas
authors: T
authors: Meier
authors: Volker
authors: V
authors: Müller
mesh_terms: D045855:Acetobacterium / Q000201:enzymology*; D025243:Bacterial Proton-Translocating ATPases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism / Q000648:ultrastructure; D001665:Binding Sites; D019143:Evolution, Molecular; D018625:Microscopy, Atomic Force; D008854:Microscopy, Electron; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D009876:Operon; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry
chemical_list: D020409:Molecular Motor Proteins; D021122:Protein Subunits; D025243:Bacterial Proton-Translocating ATPases