Force of single kinesin molecules measured with optical tweezers

Science. 1993 Apr 9;260(5105):232-4. doi: 10.1126/science.8469975.

Abstract

Isometric forces generated by single molecules of the mechanochemical enzyme kinesin were measured with a laser-induced, single-beam optical gradient trap, also known as optical tweezers. For the microspheres used in this study, the optical tweezers was spring-like for a radius of 100 nanometers and had a maximum force region at a radius of approximately 150 nanometers. With the use of biotinylated microtubules and special streptavidin-coated latex microspheres as handles, microtubule translocation by single squid kinesin molecules was reversibly stalled. The stalled microtubules escaped optical trapping forces of 1.9 +/- 0.4 piconewtons. The ability to measure force parameters of single macromolecules now allows direct testing of molecular models for contractility.

Publication types

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

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Animals
  • Decapodiformes
  • Guanosine Triphosphate / metabolism
  • Kinesins / chemistry
  • Kinesins / physiology*
  • Lasers
  • Microspheres
  • Microtubules / physiology*

Substances

  • Guanosine Triphosphate
  • Adenosine Triphosphate
  • Kinesins