Muscle contraction and free energy transduction in biological systems.
Muscle contraction occurs when the actin and myosin filaments in muscle are driven past each other by a cyclic interaction of adenosine triphosphate (ATP) and actin with cross-bridges that extend from myosin. Current biochemical studies suggest that, during each adenosine triphosphatase cycle, the myosin cross-bridge alternates between two main conformations, which differ markedly in their strength of binding to actin and in their overall structure. Binding of ATP to the cross-bridge induces the weak-binding conformation, whereas inorganic phosphate release returns the cross-bridge to the strong-binding conformation. This cross-bridge cycle is similar to the kinetic cycle that drives active transport and illustrates the general principles of free energy transduction by adenosine triphosphatase systems.
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D000199:Actins / Q000502:physiology; D000249:Adenosine Monophosphate / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000502:physiology; D000255:Adenosine Triphosphate / Q000378:metabolism; D001693:Biological Transport, Active; D004734:Energy Metabolism; D006801:Humans; D006868:Hydrolysis; D008954:Models, Biological; D009119:Muscle Contraction; D009132:Muscles / Q000378:metabolism / Q000502:physiology; D009218:Myosins / Q000502:physiology
D000199:Actins; D000249:Adenosine Monophosphate; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D009218:Myosins