Figure 2.

X-ray diffraction pattern from resting (left) and activated (right) mouse soleus muscle. The 1,0 and 1,1 equatorial reflections are indicated. The M3 reflection on the meridian arises from the 14.3 nm myosin axial displacement. The M6 reflection at 7.15 nm arises primarily from structures within the thick-filament backbone. The meridional reflection at 2.86 nm is the 15th order of the myosin repeat. The M4 layer line is derived from the helical arrangement of myosin heads around the thick-filament backbone. The reflection on the second actin layer line, arising from tropomyosin, is indicated as TM. See text for additional details.