resting stage, no contraction. ADP + PI are bound to ATpase of mysosin. Myosin binding site of acti is covered by tropomyosin.
ca2+ binds to troponin, pulls troponin-tropomyosin complex off the myosin binding site of actin. Actin binds to myosin.
adp + pi are released from myosin atpase, acusing a change in the conformation of the myosin head. the thin filament is pulled toward the center of the sarcomere.
ATP is hydrolized into DP + PI and energy is released. This energy is used to swivel the myosin head back to its original conformation. myosin is now ready to form a new crossbridge with another actin protein if ca2+ and ATP are still available
are formed when ca2+ binds to troponin, troponin-tropomyosin complex is pulled off the binding site of actin. actin binds to myosin formin crossbridge
roles of atp and ca2+
ca2+ binds o troponin, which changes formation of tropomyosin, revealing binding site of actin. ATP binds to atpase and breaks crossbridge