Energy economy in the actomyosin interaction: lessons from simple models.
The energy economy of the actomyosin interaction in skeletal muscle is both scientifically fascinating and practically important. This chapter demonstrates how simple cross-bridge models have guided research regarding the energy economy of skeletal muscle. Parameter variation on a very simple two-state strain-dependent model shows that early events in the actomyosin interaction strongly influence energy efficiency, and late events determine maximum shortening velocity. Addition of a weakly-bound state preceding force production allows weak coupling of cross-bridge mechanics and ATP turnover, so that a simple three-state model can simulate the velocity-dependence of ATP turnover. Consideration of the limitations of this model leads to a review of recent evidence regarding the relationship between ligand binding states, conformational states, and macromolecular structures of myosin cross-bridges. Investigation of the fine structure of the actomyosin interaction during the working stroke continues to inform fundamental research regarding the energy economy of striated muscle.
Lehman
Steven L
SL
Department of Integrative Biology, University of California Berkeley, Berkeley, CA, 94720, USA. slehman@berkeley.edu
D000205:Actomyosin / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000328:Adult; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology; D006801:Humans; D007700:Kinetics; D008954:Models, Biological; D018482:Muscle, Skeletal / Q000502:physiology*; D012146:Rest / Q000502:physiology
D000255:Adenosine Triphosphate; D000205:Actomyosin