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- Title
Cooperative three-step motions in catalytic subunits of F<sub>1</sub>-ATPase correlate with 80° and 40° substep rotations.
- Authors
Masaike, Tomoko; Koyama-Horibe, Fumie; Oiwa, Kazuhiro; Yoshida, Masasuke; Nishizaka, Takayuki
- Abstract
Rotation of the central shaft γ subunit in a molecular motor F1-ATPase is assumed to correlate with and probably be driven by domain motions of the three catalytic β subunits. Here we observe directly these β motions through an attached fluorophore, concomitantly with 80° and 40° substep rotations of γ in the same single molecules. We show the sequence of conformations that each β subunit undergoes in three-step bending, a ∼40° counterclockwise turn followed by two ∼20° clockwise turns, occurring in synchronization with two substep rotations of γ. The results indicate that most previous crystal structures mimic the conformational set of three β subunits in the catalytic dwells. Moreover, a previously undescribed set of β conformations, open, closed and partially closed, is revealed in the ATP-waiting dwells. The present study thus bridges the gap between the chemical and mechanical steps in F1-ATPase.
- Subjects
ADENOSINE triphosphatase; CATALYSTS; CHEMICAL systems; SYNCHRONIZATION; DYNAMICS
- Publication
Nature Structural & Molecular Biology, 2008, Vol 15, Issue 12, p1326
- ISSN
1545-9993
- Publication type
Article
- DOI
10.1038/nsmb.1510