Kinesin step without external force takes less than 70 microseconds

Giovanni Cappello
Institut Curie, France

A. Dornier, L. Busoni, J. Prost and G. Cappello



We study the motion of the kinesin molecular motor along microtubules using interference total internal reflection microscopy. This technique achieves nanometer scale resolution together with a fast time response.


We describe the first in vitro observation of kinesin stepping at high ATP concentration in the absence of an external load, where the 8-nm step can be clearly distinguished. We observe that, without external force, the kinesin 8-nanometer step occurs in less than 70 microseconds and the step has no internal structure at this time scale.


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