Dwell time distributions for kinesin's mechanical steps

Max Planck Institute of Colloids and Interfaces, Department of Theory & Bio-Systems - 14424 Potsdam, Germany, EU

Corresponding author: valleriani@mpikg.mpg.de

Received: 14 January 2008
Accepted: 5 March 2008

Abstract

The mechanical steps of molecular motors that walk processively along filaments are governed by four distinct dwell time distributions corresponding to the four possible pairs of subsequent forward and backward steps. These distributions can be calculated from the master equation for the network of motor states if one extends this network by two absorbing states and determines the corresponding absorption times. This procedure is illustrated for the kinesin motor for which the four dwell time distributions are explicitly calculated. The tails of these distributions are governed by a single decay rate , which corresponds to the smallest nonzero eigenvalue of the master equation. For kinesin, this theoretical decay rate is found to be in good agreement with the experimental rate as deduced from recent measurements.