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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 ? 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 ? 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 ?-subunit induced by ATP binding. The tilt angle is a new parameter, to our knowledge, representing the motion of the ?-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.

SUBMITTER: Sugawa M

PROVIDER: S-EPMC3207153 | biostudies-literature | 2011 Nov

REPOSITORIES: biostudies-literature

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A change in the radius of rotation of F1-ATPase indicates a tilting motion of the central shaft.

Sugawa Mitsuhiro M Okada Kaoru A KA Masaike Tomoko T Nishizaka Takayuki T

Biophysical journal 20111101 9

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 t ...[more]

PMID: 22067159

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