Kinesins are processive motor proteins that move along microtubules in a stepwise manner, and the motion is powered by the hydrolysis of ATP. Recent experiments investigated the coupling between individual forward and backward steps of single kinesin molecules and ATP hydrolysis. A theoretical study of mechanochemical coupling in kinesins is presented, which extends the approach used successfully to describe the dynamics of conventional kinesins and myosins. Using the method of first-passage times, experimental data on mechanochemical coupling in kinesins are fully described. It is shown that the dwell times for kinesin moves forward or backward are the same, although the probabilities of forward and backward steps are different. We conclude that, most probably, only the forward motion of the motor protein is coupled to ATP hydrolysis.
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