title: Flexibility within the rotor and stators of the vacuolar H+-ATPase.
abstract: The V-ATPase is a membrane-bound protein complex which pumps protons across the membrane to generate a large proton motive force through the coupling of an ATP-driven 3-stroke rotary motor (V1) to a multistroke proton pump (Vo). This is done with near 100% efficiency, which is achieved in part by flexibility within the central rotor axle and stator connections, allowing the system to flex to minimise the free energy loss of conformational changes during catalysis. We have used electron microscopy to reveal distinctive bending along the V-ATPase complex, leading to angular displacement of the V1 domain relative to the Vo domain to a maximum of ~30°. This has been complemented by elastic network normal mode analysis that shows both flexing and twisting with the compliance being located in the rotor axle, stator filaments, or both. This study provides direct evidence of flexibility within the V-ATPase and by implication in related rotary ATPases, a feature predicted to be important for regulation and their high energetic efficiencies.
authors: Electron Microscopy Center, Hebei Medical University, Shijiazhuang, China.
authors: Chun Feng
authors: CF
authors: Song
authors: Kostas
authors: K
authors: Papachristos
authors: Shaun
authors: S
authors: Rawson
authors: Markus
authors: M
authors: Huss
authors: Helmut
authors: H
authors: Wieczorek
authors: Emanuele
authors: E
authors: Paci
authors: John
authors: J
authors: Trinick
authors: Michael A
authors: MA
authors: Harrison
authors: Stephen P
authors: SP
authors: Muench
mesh_terms: D000818:Animals; D020285:Cryoelectron Microscopy; D018402:Manduca / Q000201:enzymology; D012440:Saccharomyces / Q000201:enzymology; D025262:Vacuolar Proton-Translocating ATPases / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D025262:Vacuolar Proton-Translocating ATPases