Short time investigation of the neurospora kinesin step

Abstract

Kinesin is a dimeric molecular motor, which processively moves along the microtubule in asequence of 8 nm steps. The stepping dynamics needs to be clarified: there are controversialreports about the existence of substructures in the mechanical step and the steptimescale. We present observations of the kinesin steps in the absence of externalforces, measured with subnanometre precision and microsecond time resolutionusing a technique which we have recently introduced and named travelling wavetracking. The data suggest that, at zero load, the 8 nm step occurs in less than30 µs and without any long mechanical substeps.