Figure 3.

Atomic structure of a myosin molecule A ribbon representation of the head portion myosin (S1). The heavy chain is colored in blue, gray, green, and red, denoting different regions of the protein. The light chains are colored in yellow (Essential) and pink (Regulatory). The upper portion of the motor domain is separated by a large cleft (actin-binding cleft), the opening and closing of which modulates actin affinity. Subtle changes in the nucleotide-binding site are amplified in the converter region resulting in a large rotation of the lever arm. Figure from Geeves and Holmes (2005), reprinted with permission from the publisher.