Force of single kinesin molecules measured with optical tweezers

Scot C. Kuo, Michael P. Sheetz

Research output: Contribution to journalArticlepeer-review

361 Scopus citations


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 ∼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.

Original languageEnglish (US)
Pages (from-to)232-234
Number of pages3
Issue number5105
StatePublished - 1993
Externally publishedYes

ASJC Scopus subject areas

  • General


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