title: Molecular architecture of the N-type ATPase rotor ring fromBurkholderia pseudomallei.
abstract: The genome of the highly infectious bacteriumBurkholderia pseudomalleiharbors anatpoperon that encodes an N-type rotary ATPase, in addition to an operon for a regular F-type rotary ATPase. The molecular architecture of N-type ATPases is unknown and their biochemical properties and cellular functions are largely unexplored. We studied theB. pseudomalleiN1No-type ATPase and investigated the structure and ion specificity of its membrane-embedded c-ring rotor by single-particle electron cryo-microscopy. Of several amphiphilic compounds tested for solubilizing the complex, the choice of the low-density, low-CMC detergent LDAO was optimal in terms of map quality and resolution. The cryoEM map of the c-ring at 6.1 Å resolution reveals a heptadecameric oligomer with a molecular mass of ~141 kDa. Biochemical measurements indicate that the c17ring is H+specific, demonstrating that the ATPase is proton-coupled. The c17ring stoichiometry results in a very high ion-to-ATP ratio of 5.7. We propose that this N-ATPase is a highly efficient proton pump that helps these melioidosis-causing bacteria to survive in the hostile, acidic environment of phagosomes.
authors.affiliation: Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: Schulz
authors.affiliation: Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Wilkes
authors.affiliation: Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
authors.forename: Deryck J
authors.initials: DJ
authors.lastname: Mills
authors.affiliation: Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
authors.forename: Werner
authors.identifier: 0000-0002-2013-4810
authors.initials: W
authors.lastname: Kühlbrandt
authors.affiliation: Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany t.meier@imperial.ac.uk.
authors.forename: Thomas
authors.identifier: 0000-0003-3364-3320
authors.initials: T
authors.lastname: Meier
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D019943:Amino Acid Substitution; D001665:Binding Sites; D016957:Burkholderia pseudomallei / Q000201:enzymology* / Q000235:genetics; D023061:Gene Order; D007477:Ions / Q000737:chemistry / Q000378:metabolism; D008954:Models, Biological; D008958:Models, Molecular; D009876:Operon; D011485:Protein Binding; D011487:Protein Conformation; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013329:Structure-Activity Relationship
chemical_list: D007477:Ions; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; D000251:Adenosine Triphosphatases
keywords: 
  Burkholderia pseudomallei
  ; N‐type rotary ATPase; cryoEM; c‐ring stoichiometry; proton homeostasis