title: Stator structure and subunit composition of the V(1)/V(0) Na(+)-ATPase of the thermophilic bacterium Caloramator fervidus.
abstract: The V-type Na(+)-ATPase of the thermophilic, anaerobic bacterium Caloramator fervidus was purified to homogeneity. The subunit compositions of the catalytic V(1) and membrane-embedded V(0) parts were determined and the structure of the enzyme complex was studied by electron microscopy. The V(1) headpiece consists of seven subunits present in one to three copies, and the V(0) part of two subunits in a ratio of 5:2. An analysis of over 7500 single particle images obtained by electron microscopy of the purified V(1)V(0) enzyme complex revealed that the stalk region, connecting the V(1) and V(0) parts, contains two peripheral stalks in addition to a central stalk. One of the two is connected to the V(0) part, while the other is connected to the first via a bar-like structure that is positioned just above V(0), parallel with the plane of the membrane. In projection, this bar seems to contact the central stalk. The data show that the stator structure that prevents rotation of the static part of V(0) relative to V(1) in the rotary catalysis mechanism of energy coupling in ATPases/ATPsynthases is more complex than previously thought.
authors.affiliation: Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, Kerklaan, 9751 NN Haren, The Netherlands.
authors.forename: T
authors.initials: T
authors.lastname: Ubbink-Kok
authors.forename: E J
authors.initials: EJ
authors.lastname: Boekema
authors.forename: J F
authors.initials: JF
authors.lastname: van Breemen
authors.forename: A
authors.initials: A
authors.lastname: Brisson
authors.forename: W N
authors.initials: WN
authors.lastname: Konings
authors.forename: J S
authors.initials: JS
authors.lastname: Lolkema
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism / Q000648:ultrastructure*; D000255:Adenosine Triphosphate / Q000378:metabolism; D001406:Bacillaceae / Q000201:enzymology*; D020134:Catalytic Domain; D027682:Cation Transport Proteins; D004795:Enzyme Stability; D008565:Membrane Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism / Q000648:ultrastructure; D008854:Microscopy, Electron; D008958:Models, Molecular; D008970:Molecular Weight; D011489:Protein Denaturation; D020836:Protein Structure, Quaternary; D012399:Rotation; D012964:Sodium / Q000378:metabolism; D013696:Temperature
chemical_list: D027682:Cation Transport Proteins; D008565:Membrane Proteins; D000255:Adenosine Triphosphate; D012964:Sodium; D000251:Adenosine Triphosphatases; C021838:sodium-translocating ATPase