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.