The release of ADP and P from the myosin heads causes the myosin heads to change shape.
Yes...ATP causes myosin to detach from actin. Then, Hydrolysis of ATP, which results in ADP and P, causes conformational change in myosin head to swivel or pivot about its axis and then weakly bind to an actin filament. Once the myosin head binds, a conformational change in the myosin head will cause the P to leave (the ADP is still stuck on). The leaving of the P causes the power stroke or "the pulling of the actin filament/rowing stroke". ADP then leaves and the myosin is now back at its original state.
ATP, of course. When the myosin head extends towards the actin thin filament it has in it's active site ADP and P +. So, when the stroke is over the ADP and P+ fall out and are replaced by ATP, which immediately metabolizes to ADP and P +.
During the crossbridge cycle in muscle contraction, the key steps involve the binding of myosin to actin, the power stroke where the myosin head pivots and pulls the actin filament, the release of ADP and inorganic phosphate, and the resetting of the myosin head for the next cycle.
Molecules attached to the myosin head from the previous movement cycle are inorganic phosphate and ADP (adenosine diphosphate). These molecules are released when the myosin head binds to actin, leading to the power stroke of muscle contraction.
ATP not ADP binds to actin-myosin and is cleaved by to ADP.
The energy to swivel the head of myosin is provided by ATP (adenosine triphosphate) molecules. ATP is hydrolyzed to ADP (adenosine diphosphate) and inorganic phosphate during the power stroke of muscle contraction, releasing energy that causes the myosin head to swivel and slide along actin filaments.
Myosin heads are activated prior to contraction through the binding of calcium ions to troponin, which causes a conformational change in the tropomyosin complex. This shift exposes the binding sites on actin filaments, allowing myosin heads to attach. Additionally, ATP binds to the myosin head, hydrolyzing to ADP and inorganic phosphate, which energizes the myosin head and prepares it for the power stroke during muscle contraction.
Actin is the molecule that has a binding site for myosin heads. This interaction is crucial for muscle contraction as myosin binds to actin and generates force to cause muscle movement.
ATP (--> ADP+Pi) and actin
During the power stroke of muscle contraction, actin filaments slide past myosin filaments, resulting in the shortening of the muscle fiber. This process is initiated when myosin heads, which are bound to ADP and inorganic phosphate, attach to binding sites on actin, forming cross-bridges. The release of ADP and phosphate triggers the conformational change in the myosin head, pulling the actin filament inward. This sliding mechanism is a key component of the sarcomere's contraction, leading to muscle shortening and force generation.
Adenosine triphosphate (ATP) is the compound that binds to myosin and provides the energy needed for the power stroke in muscle contraction. Myosin hydrolyzes ATP to ADP and inorganic phosphate during the power stroke, releasing energy that enables the myosin head to move along the actin filament.
Myosin ATPase hydrolyze ATP into ADP+pi and yielding the energy required for muscle contraction.