Using the model for the processive movement of a dimeric kinesin we proposed before, we study the dynamics of a number of mutant homodimeric and heterodimeric kinesins that were constructed by Kaseda et al. (Kaseda, K., Higuchi, H. and Hirose, K. PNAS 99, 16058 (2002)). The theoretical results of ATPase rate per head, moving velocity, and stall force of the motors show good agreement with the experimental results by Kaseda et al.: The puzzling dynamic behaviors of heterodimeric kinesin that consists of two distinct heads compared with its parent homodimers can be easily explained by using independent ATPase rates of the two heads in our model. We also study the collective kinetic behaviors of kinesins in MT-gliding motility. The results explains well that the average MT-gliding velocity is independent of the number of bound motors and is equal to the moving velocity of a single kinesin relative to MT.

18 pages, 5 figures