The force exerted by a molecular motor.
The stochastic driving force exerted by a single molecular motor (e. g., a kinesin, or myosin) moving on a periodic molecular track (microtubule, actin filament, etc.) is discussed from a general viewpoint open to experimental test. An elementary "barometric" relation for the driving force is introduced that (i) applies to a range of kinetic and stochastic models, (ii) is consistent with more elaborate expressions entailing explicit representations of externally applied loads, and (iii) sufficiently close to thermal equlibrium, satisfies an Einstein-type relation in terms of the velocity and diffusion coefficient of the (load-free) motor. Even in the simplest two-state models, the velocity-vs.-load plots exhibit a variety of contrasting shapes (including nonmonotonic behavior). Previously suggested bounds on the driving force are shown to be inapplicable in general by analyzing discrete jump models with waiting time distributions.
Fisher
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ME
Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA.
Kolomeisky
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D000818:Animals; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry; D004398:Dyneins / Q000737:chemistry; D006801:Humans; D006868:Hydrolysis; D016547:Kinesins / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000737:chemistry*; D009218:Myosins / Q000737:chemistry*
D020409:Molecular Motor Proteins; D012321:DNA-Directed RNA Polymerases; D009218:Myosins; D004398:Dyneins; D016547:Kinesins