Regulation of acto-myosin interactions: Understanding the molecular mechanism of regulation of binding of myosin molecules to actin is important in understanding the mechanisms of muscle contraction and genetic diseases. There are two basic models for regulation in muscles: the ?steric blocking? model and the ?allosteric? model. In the ?steric blocking? model, binding of regulatory ligands (Ca++ or proteins) to actin uncovers binding sites for myosin binding and increases the acto-myosin interaction. In the ?allosteric? model, the regulated actin is assumed to exist in two or more states with different cooperativities and acto-myosin interactions. The binding of regulatory ligands shifts the equilibrium between the states and therefore the total acto-myosin interactions of the muscle. In collaboration with Dr. Chalovich at East Carolina University Medical School where all the experiments were carried out, the applicability of the models to the regulation by [Ca++], ionic strength, drugs, and other protein molecules (such as ATP-free myosins, caldesmon, etc) in skeletal and smooth muscles is assessed.
