DEPARTMENT OF BIOLOGY
Muscle Contraction Muscle contraction involves myosin thick filaments walking along actin thin filaments. Re-extension requires contraction of the opposing muscle, to pull the filaments back to their relaxed positions. Myosin Action Myosin undergoes a number of shape changes as ATP binds to it, is hydrolyzed, and then is released as separate phosphate and ADP molecules. Here, we illustrate the relationships of the several domains of the myosin protein during this cycle of activity. This is how each of the myosin molecules walks along actin filaments to achieve the contraction illustrated in the animation above.
last updated: Aug. 12, 2010