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Rotation scheme of V1-motor is different from that of F1-motor.

ABSTRACT: V(1), a water-soluble portion of vacuole-type ATPase (V-ATPase), is an ATP-driven rotary motor, similar to F(1)-ATPase. Hydrolysis of ATP is coupled to unidirectional rotation of the central rotor D and F subunits relative to the A(3)B(3) cylinder. In this study, we analyzed the rotation kinetics of V(1) in detail. At low ATP concentrations, the D subunit rotated stepwise, pausing every 120 degrees . The dwell time between steps revealed that V(1) consumes one ATP per 120 degrees step. V(1) generated torque of approximately 35 pN nm, slightly lower than the approximately 46 pN nm measured for F(1). Noticeably, the angles for both ATP cleavage and binding were apparently the same in V(1), in sharp contrast to F(1), which cleaves ATP at 80 degrees posterior to the binding of ATP. Thus, the mechanochemical cycle of V(1) has marked differences to that of F(1).

SUBMITTER: Imamura H

PROVIDER: S-EPMC1306795 | biostudies-literature | 2005 Dec

REPOSITORIES: biostudies-literature

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Rotation scheme of V1-motor is different from that of F1-motor.

Imamura Hiromi H Takeda Mizuho M Funamoto Saeko S Shimabukuro Katsuya K Yoshida Masasuke M Yokoyama Ken K

Proceedings of the National Academy of Sciences of the United States of America 20051205 50

V(1), a water-soluble portion of vacuole-type ATPase (V-ATPase), is an ATP-driven rotary motor, similar to F(1)-ATPase. Hydrolysis of ATP is coupled to unidirectional rotation of the central rotor D and F subunits relative to the A(3)B(3) cylinder. In this study, we analyzed the rotation kinetics of V(1) in detail. At low ATP concentrations, the D subunit rotated stepwise, pausing every 120 degrees . The dwell time between steps revealed that V(1) consumes one ATP per 120 degrees step. V(1) gene ...[more]

PMID: 16330761

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