Abstract
The dimeric motor protein kinesin-1 moves processively along microtubules against forces of up to 7 pN. However, the mechanism of force generation is still debated. Here, we point to the crucial importance of diffusion of the tethered motor domain for the stepping of kinesin-1: small crowders stop the motor at a viscosity of 5 —corresponding to a hydrodynamic load in the sub-fN () range—whereas large crowders have no impact even at viscosities above 100 . This indicates that the scale-dependent, effective viscosity experienced by the tethered motor domain is a key factor determining kinesin’s functionality. Our results emphasize the role of diffusion in the kinesin-1 stepping mechanism and the general importance of the viscosity scaling paradigm in nanomechanics.
- Received 7 February 2015
DOI:https://doi.org/10.1103/PhysRevLett.115.218102
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Published by the American Physical Society
Focus
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Published 20 November 2015
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