Geng, Yi-Zhao; Liu, Shu-Xia; Ji, Qing; Yan, Shiwei
Mechanical amplification mechanism of kinesin's beta-domain
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS, 543:10-14, FEB 1 2014

Conventional kinesin's force generation process always takes place on the leading head and the generated force is transmitted to the trailing head through two neck linkers. To guarantee a strong force to be transmitted to the trailing head so that it can be detached from microtubule surface, the neck linker of the leading head must have a large enough forward displacement, which is proposed to be achieved by the amplifying function of the beta-domain. However, the experimental result shows that the forward displacement of the beta-domain itself appears too small. To elucidate the function of the beta-domain, we make a detailed analysis of the mechanical relationship between the two motor heads and, based on the results of molecular dynamics simulation and mechanical analysis, we calculate the forward displacement of the neck linker of the leading head during the ATP binding induced motor head rotation. We show that beta-domain achieves its amplifying function together with fib, so that neck linker can have a forward displacement during motor head rotation. This displacement of neck linker is large enough to cause detachment of the trailing head. Based on these results, a possible initiation mechanism of neck linker docking is proposed. (C) 2013 Elsevier Inc. All rights reserved.

DOI:10.1016/j.abb.2013.12.017

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