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Eur Biophys J. 2011 Sep;40(9):1071-9. doi: 10.1007/s00249-011-0724-1. Epub 2011 Jul 7.

Force-velocity relationship for multiple kinesin motors pulling a magnetic bead.

Author information

1
Department of Physics, Wake Forest University, PO Box 7507, Winston-Salem, NC 27109, USA.

Abstract

Although the velocity of single kinesin motors against an opposing force F of 0-10 pN is well known, the behavior of multiple kinesin motors working to overcome a larger load is still poorly understood. We have carried out gliding assays in which 3-7 Drosophila kinesin-1 motors moved a microtubule at 200-700 μm/s against a 0-31 pN load at saturating [ATP]. The load F was generated by applying a spatially uniform magnetic field gradient to a superparamagnetic bead attached to the (+) end of the microtubule. When F was scaled by the average number of motors [Symbol: see text]n[Symbol: see text], the force-velocity relationship for multiple motors was similar to the force-velocity relationship for a single motor, supporting a minimal load-sharing model. The velocity distribution at low load has a single mode consistent with rapid fluctuations of n. However, against a load of 2.5-4.7 pN/motor, additional modes appeared at lower velocity. These observations support the Klumpp-Lipowsky model of multimotor transport [Proc Natl Acad Sci USA 102. 17284-17289 (2005)].

PMID:
21735291
DOI:
10.1007/s00249-011-0724-1
[Indexed for MEDLINE]

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