Interacting-heads motif has been conserved as a mechanism of myosin II inhibition since before the origin of animals [Cell Biology]

Electron microscope studies have shown that the switched-off state of myosin II in muscle involves intramolecular interaction between the two heads of myosin and between one head and the tail. The interaction, seen in both myosin filaments and isolated molecules, inhibits activity by blocking actin-binding and ATPase sites on myosin....

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