Related Experiment Video
Updated: Jul 13, 2026

Dissecting Mechanoenzymatic Properties of Processive Myosins with Ultrafast Force-Clamp Spectroscopy
Published on: July 1, 2021
Single myosin molecule mechanics: piconewton forces and nanometre steps
J T Finer1, R M Simmons, J A Spudich
1Department of Biochemistry, Beckman Center, Stanford University School of Medicine, California 94305.
Abstract:
A new in vitro assay using a feedback enhanced laser trap system allows direct measurement of force and displacement that results from the interaction of a single myosin molecule with a single suspended actin filament. Discrete stepwise movements averaging 11 nm were seen under conditions of low load, and single force transients averaging 3-4 pN were measured under isometric conditions. The magnitudes of the single forces and displacements are consistent with predictions of the conventional swinging-crossbridge model of muscle contraction.
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