Figure 3.

X-ray diffraction pattern recorded from an intact trabecula in diastole with the detector at 1.6 m from the preparation. The horizontal axis, perpendicular to the long axis of the trabecula, shows the low-angle equatorial reflections (1,0 and 1,1) from the lattice planes formed by the thick and thin filaments. The vertical axis, parallel to the trabecula axis, shows the meridional reflections from the axial periodicity of the proteins along the filaments up to the sixth order of the meridional myosin-based reflections (M1, M2, M3, M5, and M6; M4 is visible but not used in the x-ray analysis because of its complexity). The ML1 extends in the radial direction in correspondence to the M1 axial spacing. SL, 2.11 µm; total exposure time, 30 ms. The pattern has been quadrant folded to increase the signal-to-noise ratio.