Considerations on muscle contraction.
The independent force generator and the power-stroke cross-bridge model have dominated the thinking on mechanisms of muscular contraction for nearly the past five decades. Here, we review the evolution of the cross-bridge theory from its origins as a two-state model to the current thinking of a multi-state mechanical model that is tightly coupled with the hydrolysis of ATP. Finally, we emphasize the role of skeletal muscle myosin II as a molecular motor whose actions are greatly influenced by Brownian motion. We briefly consider the conceptual idea of myosin II working as a ratchet rather than a power stroke model, an idea that is explored in detail in the companion paper.
Herzog
W
W
Faculty of Kinesiology, University of Calgary, 2500 University Dr. N.W., AB, Canada. walter@kin.ucalgary.ca
Ait-Haddou
R
R
D000199:Actins / Q000502:physiology; D004734:Energy Metabolism; D006801:Humans; D008954:Models, Biological; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D009218:Myosins / Q000502:physiology
D000199:Actins; D009218:Myosins