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Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1992 Jan 1;89(1):339–343. doi: 10.1073/pnas.89.1.339

Dynamics of single-motor molecules: the thermal ratchet model.

N J Córdova 1, B Ermentrout 1, G F Oster 1
PMCID: PMC48232  PMID: 1530889

Abstract

We present a model for single-motor molecules--myosin, dynein, or kinesin--that is powered either by thermal fluctuations or by conformational change. In the thermally driven model, the cross-bridge fluctuates about its equilibrium position against an elastic restoring force. The attachment and detachment of the cross-bridge are determined by modeling the electrostatic attraction between the cross-bridge and the fiber binding sites, so that binding depends on the strain in the cross-bridge and its velocity with respect to the fiber. The model correctly predicts the empirical force-velocity characteristics for populations of motor molecules. For a single motor, the apparent cross-bridge step size per ATP hydrolysis depends nonlinearly on the load. When the elastic energy driving the cross-bridge is generated by a conformational change, the velocity and duty cycle are much larger than is observed experimentally for myosin.

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Selected References

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