Figure 9. Predicted relationships between the intensity of the M3 reflection (I_M3) and the displacement Δz of the shared S1–S2 junction of the two myosin heads relative to the CD.

Here Δz = 0 corresponds to the conformation of the two heads in low force rigor as described in the text and in Fig. 6. The grey dot indicates the starting point (Δz = 0.8 nm) for the length oscillations imposed on a steady force of 0.5T₀. Δz is positive for the stretch corresponding to a movement of the CD towards the Z-line relative to the S1–S2 junction.