title: A change in the radius of rotation of F1-ATPase indicates a tilting motion of the central shaft.
abstract: F(1)-ATPase is a water-soluble portion of F(o)F(1)-ATP synthase and rotary molecular motor that exhibits reversibility in chemical reactions. The rotational motion of the shaft subunit γ has been carefully scrutinized in previous studies, but a tilting motion of the shaft has never been explicitly postulated. Here we found a change in the radius of rotation of the probe attached to the shaft subunit γ between two different intermediate states in ATP hydrolysis: one waiting for ATP binding, and the other waiting for ATP hydrolysis and/or subsequent product release. Analysis of this radial difference indicates a ~4° outward tilting of the γ-subunit induced by ATP binding. The tilt angle is a new parameter, to our knowledge, representing the motion of the γ-subunit and provides a new constraint condition of the ATP-waiting conformation of F(1)-ATPase, which has not been determined as an atomic structure from x-ray crystallography.
authors: Department of Physics, Gakushuin University, Tokyo, Japan.
authors: Mitsuhiro
authors: M
authors: Sugawa
authors: Kaoru A
authors: KA
authors: Okada
authors: Tomoko
authors: T
authors: Masaike
authors: Takayuki
authors: T
authors: Nishizaka
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D001407:Bacillus / Q000187:drug effects / Q000201:enzymology*; D008958:Models, Molecular; D050505:Mutant Proteins / Q000737:chemistry; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors / Q000737:chemistry*; D012399:Rotation
chemical_list: D050505:Mutant Proteins; D000244:Adenosine Diphosphate; C444660:gamma subunit, F(1) ATPase; D006180:Proton-Translocating ATPases