Rectified Brownian motion and kinesin motion along microtubules - art. no.051901

The mechanism of rectified Brownian movement is used to analyze measured da ta for kinesin motion along microtubules. A key component of the mechanism is the diffusive movement of the microtubule binding heads of kinesin durin g the adenosine triphosphate (ATP) cycle. The first-passage time distributi on for this step is analyzed in detail and is shown to be responsible for o bserved load-velocity profiles. The ATPase activity of the kinesin heads is that of a nucleotide switch and not that of a direct chemomechanical energ y converter. Experimental data acquisition, rate constants, and alternative explanations are discussed. The mechanism described in this paper is funda mental to the nanobiology of intracellular processes.