Small Crowders Slow Down Kinesin-1 Stepping by Hindering Motor Domain Diffusion

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 t...

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Bibliographic Details
Published in:Physical review letters 2015-11, Vol.115 (21), p.218102-218102, Article 218102
Main Authors: Sozański, Krzysztof, Ruhnow, Felix, Wiśniewska, Agnieszka, Tabaka, Marcin, Diez, Stefan, Hołyst, Robert
Format: Article
Language:English
Subjects:
Diffusion
Fluid dynamics
Fluid flow
Kinesin - chemistry
Loads (forces)
Models, Chemical
Models, Molecular
Motors
Nanostructure
Plugs
Viscosity
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Summary: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 mPa·s-corresponding to a hydrodynamic load in the sub-fN (~10^{-4} pN) range-whereas large crowders have no impact even at viscosities above 100 mPa·s. 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.
ISSN:0031-9007
1079-7114
DOI:10.1103/physrevlett.115.218102