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Biophys J. 2013 May 7;104(9):1969-78. doi: 10.1016/j.bpj.2013.03.051.

Modular aspects of kinesin force generation machinery.

Author information

1
Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.

Abstract

The motor head of kinesin carries out microtubule binding, ATP hydrolysis, and force generation. Despite a high level of sequence and structural conservation, subtle variations in subdomains of the motor head determine family-specific properties. In particular, both Kinesin-1 (Kin-1) and Kinesin-5 (Kin-5) walk processively to the microtubule plus-end, yet show distinct motility characteristics suitable for their functions. We studied chimeric Kin-1/Kin-5 constructs with a combination of single molecule motility assays and molecular dynamics simulations to demonstrate that Kin-5 possesses a force-generating element similar to Kin-1, i.e., the cover-neck bundle. Furthermore, the Kin-5 neck linker makes additional contacts with the core of the motor head via loop L13, which putatively compensates for the shorter cover-neck bundle of Kin-5. Our results indicate that Kin-1 is mechanically optimized for individual cargo transport, whereas Kin-5 does not necessarily maximize its mechanical performance. Its biochemical rates and enhanced force sensitivity may instead be beneficial for operation in a group of motors. Such variations in subdomains would be a strategy for achieving diversity in motility with the conserved motor head.

PMID:
23663840
PMCID:
PMC3647194
DOI:
10.1016/j.bpj.2013.03.051
[Indexed for MEDLINE]
Free PMC Article

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