Shoichi Toyabe, Eiro Muneyuki
The free-energy transduction at 100% efficiency is not prohibited by thermodynamic laws. However, it is usually reached only at the quasi-static limit such as the macroscopic piston pulled or pushed at the infinitely slow velocity. If we operate the piston quickly, turbulence is inevitable and irreversible heat dissipates through the microscopic degrees of freedom. Here, we evaluated the work performed by the nano-sized biological free-energy transducer F1-ATPase by single-molecule experiments on the basis of nonequilibrium theory. We show 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 nano-sized engines working in the energy scale of k_{B}T. Some of the microscopic degrees of freedom may not be hidden but accessible to the F1-ATPase. Hence, the F1-ATPase possibly utilizes the thermal fluctuation and rectifies the microscopic energy flow to maximize their efficiency.
View original:
http://arxiv.org/abs/1210.4017
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