Dynamic origin of the force driving kinesin to move hand-over-hand along microtubule
Kiwing To1, Yi-Feng Hsiao2, Ya-chang Chou2*
1Institute of Physics, Academia Sinica, Taipei, Taiwan
2Department of Physics, National Tsing-Hua University, Hsinchu, Taiwan
* presenting author:Ya-chang Chou, email:ycchou@phys.nthu.edu.tw
A new mechanism for the motility of kinesin, including stochastic-force generation and step formation is proposed. According to recent AFM results, both head domains bind to a protofilament of the microtubule (MT) and the stalk domain lies sideward to the protofilament. The force generated by the random motion of the long-chain stalk produces greater tension on the trailing head than on the leading head, and stochastically triggers the trailing head to flip over the leading head. So kinesin progresses along the protofilament in a non-conventional hand-over-hand fashion. We demonstrate the applicability of the new mechanism in a simulation system with (a) ratchet structures similar to the outer surface of MT, (b) a bead chain connected to two heads, similarly to the kinesin motor, and (c) the interaction between them. Most of the dynamical and statistical features of the motility of kinesin are established. And the inchworm-type of the motion of kinesin on MT is also possible under the influence of the stochastic force.

Keywords: microtubule, molecular motor, kinesin, motility, stochastic force