Piconewton Forces and Nanometre Steps: An Assessment of Experimental Results for Actomyosin Interaction using Huxley Kinetics

摘要

Laser trap measurements of piconewton forces and nanometre displacements of actomyosin interaction herald a new generation of powerful tools, both in their elegance and precision, with which the behaviour of individual molecular events can be investigated. Several laboratories have successfully used this technology to observe and score both forward and reverse displacements of molecular motors, together with the transduction of chemical energy into force and displacement. We propose a Langevin-type stochastic model, together with Huxley (1957) kinetics for myosin attachment and detachment, and use it to examine some experimental results for actomyosin interaction and force generation. Our model predictions indicate that in the absence of attachment the distribution of the ensuing displacements has approximately zero mean. Attachment events produced displacements with step sizes of approxi-mately 7 nm, which is in agreement with some recent optical tweezer experimental results.