Myosin regulation domain

Class II myosins have a fundamental role in muscle contraction and in a variety of cellular motilities. The regulatory domain (RD) acts as a lever arm during force generation, and it is the site of regulation in regulated conventional myosins. The class II myosin of Physarum polycephalum is uniquely inhibited by direct binding of Ca²⁺. In our structure of the regulatory domain, the regulatory Ca²⁺ is bound by the ELC. The Ca²⁺-binding first EF-hand unusually possesses "closed" conformation. In scallop myosin the activating Ca²⁺ is bound to the first EF-hand of the ELC that is also in a closed state, but it is coordinated by different residues. In the case of Physarum myosin II the change in dynamics of the molecule upon Ca²⁺-binding plays an important role in Ca²⁺-inhibition.

Structure of the myosin regulatory domain

Cooperation

Motor Proteins: Structural Biology Research Group of the Department of Biochemistry, Eötvös Loránd University, Budapest

Structures determined

2BL0