Thermodynamics and Mechanics of Molecular Motors

Abstract

Thermodynamics and mechanics of molecular motors are studied base on kinetic theory and mechanical modeling. The 2nd law of thermodynamics sets a finite energy price for directional motion in an isothermal environment. In the thermodynamic study, the least energy price for microscopic direction is derived and proved by experimental data of bio-motors kinesin-1 and F1-ATPase. Based on the least energy price, the efficiency limit of molecular motors is formulated and a quantity called directionality is identified as the key parameter to access the limit. The concepts of energy efficiency and corresponding output power are generalized and found to characterize the performance of kinesin-1 and F1-ATPase. In the mechanical study, a molecular `fishing? mechanism is proposed to explain the working of bio-motor Kar3/Vik1. An artificial nano-motor is designed to implement the fishing mechanism. Predictions of mechanical modeling and thermodynamic optimization of this motor are consistent with the thermodynamic study above.