Scandium, Interactions with Myosin Subfragment 1
This entry refers to the features of myosin subfragment 1 (S1) and its interactions with scandium. S1 is the globular head region of the myosin produced by proteolytic cleavage of the intact myosin molecule. It contains one heavy chain compactly folded into a motor domain and an extended regulatory or light chain domain wrapped by two light chains. S1 contains the ATPase and actin binding sites. The energy for muscle contraction is derived from the cyclic attachment and detachment of S1 to the actin filament with the concomitant hydrolysis of MgATP. The series of events occurred during the contractile cycle is: MgATP rapidly releases myosin from actin by binding to the ATPase site of myosin; then, myosin hydrolyzes ATP to form a relatively stable intermediate myosin-ADP·Pi; and finally, actin recombines with this complex and dissociates the products, thereby forming the original actin-myosin complex.
Gopal and Burke (1995) found that the existence of scandium (presumably ScF