Force of single kinesin molecules measured with optical tweezers.
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.
Kuo
S C
SC
Department of Cell Biology, Duke University Medical Center, Durham, NC 27710.
Sheetz
M P
MP
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D049832:Decapodiformes; D006160:Guanosine Triphosphate / Q000378:metabolism; D016547:Kinesins / Q000737:chemistry / Q000502:physiology*; D007834:Lasers; D008863:Microspheres; D008870:Microtubules / Q000502:physiology*
D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D016547:Kinesins