Figure 2.

3-D view of myosin (thick) filaments in vertebrate striated muscle. (A) Myosin filaments extend from the central M-band toward Z-discs with cross-bridges arranged in a three-stranded helical arrays with helical pitches of 3 × 42.9 nm, i.e., three myosin molecules (crowns) are located at 14.3-nm intervals. Inspired by 3-D lattice figure from Williams et al. (2013). (B) The crowns, consisting of three myosin molecules, are shifted 40° azimuthally axially for 14.3 nm and repeating every fourth crown displaced axially for 42.9 nm. Further away, myosin molecules are shown in lighter colors. Inspired by projection of myosin filament in the lattice cross section from figure in Squire (1997).