Azimuthal weight factors Cβ and Cα of myosin binding in 3-D sarcomere lattice. (A) When myosin heads in Crown 1 are directly aligned with three actin filaments, then Cα = 1 and Cβ weights the azimuthal departure of a myosin-binding site on actin filament from the plane passing through myosin and actin longitudinal axes. The angle β is a function of the axial departure from perfect matching, ξ, resembles the preference for myosin heads to bind to favorably oriented sites on the actin filament similar to the observed distributions of bound level in single molecule studies (Simmons, R.M., et al., 2001. Biophysical Society 45th Annual Meeting. Abstr. 80a; Steffen et al., 2001). (B) When myosin heads are not directly aligned with the surrounding actin filaments, such as with Crowns 2 and 3, the weight factor Cα takes into account the departure by the angle α from perfect alignment between the heads on the crown and the reachable actin filaments.
