The globular head of myosin contains

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Myosins (500,000 Da) are a family of motor proteins present in the muscles cell. They help in muscle contraction. Among different classes of myosin proteins, Myosin II is the major class of myosin that is present in muscle cells.

Structurally, the myosin protein has three domains. They are the head domain, the neck domain, and the tail domain. The myosin II consists of six polypeptide chains. They are two heavy chains (200,000 Da) and four light chains (15,000-20,000 Da). The N terminal domain of the heavy chain is globular in structure. It forms the head domain. The C terminal domain of the heavy chain forms a coiled structure that holds the two heavy chains together.

The head domain of each myosin consists of an ATPase enzyme. The ATPase activity of the head breaks down the ATP into ADP and pi. The hydrolysis of ATP helps in the movement of the myosin head during muscle contraction.