TheF_1-ATP synthase is a factory for synthesizing ATP in virtually all cells. Its core machinery is the subcomplex F_1-motor (F_1-ATPase) and performs the reversible mechanochemical coupling. Isolated F_1-motor hydrolyzes ATP, which is accompanied by unidirectional rotation of its central \gamma-shaft. When a strong opposing torque is imposed, the \gamma-shaft rotates in the opposite direction and drives the F_1-motor to synthesize ATP. This mechanical-to-chemical } free-energy transduction at 100\% efficiency is not prohibited by thermodynamic laws. However, it is usually reached only at the quasi-static limit . Here, we evaluated the work exerted by the nanosized biological free-energy transducer F1-ATPase by single-molecule experiments on the basis of nonequilibrium theory . The results imply that the F1-ATPase achieves a nearly 100\% free-energy conversion efficiency even far from quasistatic process for both the mechanical-to-chemical and chemical-to-mechanical transductions. Such a high efficiency at a finite-time operation is not expected for macroscopic engines and highlights a remarkable property of the nanosized engines working in the energy scale of kBT .
F_\mathrm{oF_1-ATP synthase is a factory for synthesizing ATP in virtually all cells. Its core machinery is the subcomplex F_1-motor (F_1-ATPase) and performs the reversible mechanochemical coupling. Isolated F_1-motor hydrolyzes ATP, which is accompanied by unidirectional rotation of its central \gamma-shaft. When a strong opposing torque is imposed, the \gamma-shaft rotates in the opposite direction and drives the F_1-motor to synthesize ATP. This mechanical-to-chemical } free-energy transduction is the final and central step of the multistep cellular ATP-synthetic pathway . Here, we determined the amount of mechanical work exploited by the F_1-motor to synthesize an ATP molecule during forced rotations using methodology combining a nonequilibrium theory and single molecule measurements of responses to external torque. We found that the work exploited by the motor amounts only to that is thermodynamically required for the ATP synthesis. Specifically, F_1-motor converts mechanical work to chemical free energy at quite a high efficiency with negligible dissipation inside the motor even during rotations far from a quasistatic process .
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The
F_\mathrm{o
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transduction at 100\% efficiency is not prohibited by thermodynamic laws. However, it is usually reached only at the quasi-static limit
transduction is the final and central step of the multistep cellular ATP-synthetic pathway
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evaluated the work exerted by the nanosized biological free-energy transducer F1-ATPase by single-molecule experiments on the basis of nonequilibrium theory . The results imply that the F1-ATPase achieves a nearly 100\% free-energy conversion efficiency even far from quasistatic process for both the mechanical-to-chemical and chemical-to-mechanical transductions. Such
determined the amount of mechanical work exploited by the F_1-motor to synthesize an ATP molecule during forced rotations using methodology combining a nonequilibrium theory and single molecule measurements of responses to external torque. We found that the work exploited by the motor amounts only to that is thermodynamically required for the ATP synthesis. Specifically, F_1-motor converts mechanical work to chemical free energy at quite
R
at a finite-time operation is not expected for macroscopic engines and highlights a remarkable property of the nanosized engines working in the energy scale of kBT
with negligible dissipation inside the motor even during rotations far from a quasistatic process