Direct observation of kinesin stepping by optical trapping interferometry

Nature. 1993 Oct 21;365(6448):721-7. doi: 10.1038/365721a0.


Do biological motors move with regular steps? To address this question, we constructed instrumentation with the spatial and temporal sensitivity to resolve movement on a molecular scale. We deposited silica beads carrying single molecules of the motor protein kinesin on microtubules using optical tweezers and analysed their motion under controlled loads by interferometry. We find that kinesin moves with 8-nm steps.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Triphosphate / physiology
  • Animals
  • Cattle
  • Decapodiformes
  • Interferometry
  • Kinesins / physiology*
  • Lasers
  • Light
  • Microspheres
  • Microtubules / physiology
  • Movement / physiology
  • Silicon Dioxide


  • Silicon Dioxide
  • Adenosine Triphosphate
  • Kinesins