Mechanical measurements of single actomyosin motor force.
- 1 April 1995
- journal article
- Vol. 68, 286S-290S
Abstract
To elucidate the mechanism of force generation by actomyosin motor, a measuring system was constructed, in which an in vitro motility assay was combined with an optical trapping technique. An actin filament of several micron long was attached to a gelsolin-coated polystyrene bead, and was allowed to interact with a small number (approximately 1/1 micron actin filament) of rabbit skeletal heavy meromyosin (an active subfragment of myosin) molecules bound to a nitrocellulose-coated coverglass. The bead position was determined at 33-ms intervals. We measured the force generation event at relatively low (100-400 nM) ATP concentration so that the occurrence of individual force generation events could be detected with our time resolution. The actin-bound bead held in the optical trap moved in a stepwise manner in the direction of the actin filament only in the presence of ATP. At the trap strength of 0.3 pN/nm, the maximum size of the step was 11 nm, and the maximum force associated with the movement was 3.3 pN.This publication has 11 references indexed in Scilit:
- Evidence for alternating head catalysis by kinesin during microtubule-stimulated ATP hydrolysis.Proceedings of the National Academy of Sciences, 1994
- Force and velocity measured for single kinesin moleculesCell, 1994
- Single-Molecule Analysis of the Actomyosin Motor Using Nano-ManipulationBiochemical and Biophysical Research Communications, 1994
- Single myosin molecule mechanics: piconewton forces and nanometre stepsNature, 1994
- Structure of the actin-myosin complex and its implications for muscle contractionScience, 1993
- Scanning electron microscopy of negatively stained catalase on a silicon waferMicroscopy Research and Technique, 1992
- Quantized velocities at low myosin densities in an in vitro motilityNature, 1991
- [33] Assays for actin sliding movement over myosin-coated surfacesPublished by Elsevier ,1991
- Kinetics of the Actomyosin ATPase in Muscle FibersAnnual Review of Physiology, 1987