title: Acceleration of the ATP-binding rate of F1-ATPase by forcible forward rotation.
abstract: F1-ATPase (F1) is a reversible ATP-driven rotary motor protein. When its rotary shaft is reversely rotated, F1 produces ATP against the chemical potential of ATP hydrolysis, suggesting that F1 modulates the rate constants and equilibriums of catalytic reaction steps depending on the rotary angle of the shaft. Although the chemomechanical coupling scheme of F1 has been determined, it is unclear how individual catalytic reaction steps depend on its rotary angle. Here, we report direct evidence that the ATP-binding rate of F1 increases upon the forward rotation of the rotor, and its binding affinity to ATP is enhanced by rotation.
authors.affiliation: Institute of Scientific and Industrial Science, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Iko
authors.forename: Kazuhito V
authors.initials: KV
authors.lastname: Tabata
authors.forename: Shouichi
authors.initials: S
authors.lastname: Sakakihara
authors.forename: Takako
authors.initials: T
authors.lastname: Nakashima
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Noji
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry*; D007700:Kinetics; D006180:Proton-Translocating ATPases / Q000737:chemistry*; D012399:Rotation
chemical_list: D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases