A model of stepping kinetics for rotary enzymes. Application to the F1-ATPase

The load dependence of the physical properties of a molecular motor

The physical properties of a molecular motor with load changing in a wide range will be discussed in this study, in particular the mean velocity, output power and energy efficiency. The main difficulty of this study is that both the states of the molecular motor and the energy barriers between them change with the loading force. Moreover, with the change of load, the number of motor states may also change, so different models should be used to calculate the corresponding physical quantities in different ranges of load. The results show that, in contrast to the usual intuition, the mean velocity and output power of the molecular motor do not change continuously with load.