Figure 4.

The intensities of A1, A2, A6, and A7 actin layer lines calculated at different positions of the tropomyosin strand in the overlap zone of thin filament and with different fractions of myosin heads bound to actin. Solid, dashed, and dotted lines correspond to 40%, 20%, and 0% of myosin heads strongly bound to actin in the “open” (O-state) and “closed” (C-state) positions of Tpm, the color code is shown on the left. The O-state is the original structural model (17) while the C-state was obtained by azimuthal movement of the Tpm strand around the thin filament axis by 10°. To see this figure in color, go online.