Short time investigation of the neurospora kinesin step

Kinesin is a dimeric molecular motor, which processively moves along the microtubule in a sequence of 8 nm steps. The stepping dynamics needs to be clarified: there are controversial reports about the existence of substructures in the mechanical step and the step timescale. We present observations of the kinesin steps in the absence of external forces, measured with subnanometre precision and microsecond time resolution using a technique which we have recently introduced and named travelling wave tracking . The data suggest that, at zero load, the 8 nm step occurs in less than 30 µs and without any long mechanical substeps.