Actin myosin binding animation. (a) The myosin-V dimer model (red) is shown bound to the actin filament model (green). The actin polarity runs from right (− or “pointed”) to left (+ or “barbed”) so the myosin “walks” from left to right. Secondary structure elements (SSEs) are depicted as cylinders (with large/small diameters for α/β) connected by fine lines. The translucent spheres show the higher level groupings of SSEs into domains. (b) Annotates part (a), with the myosin leading leg bound tightly to the actin in prepowerstroke conformation. The myosin trailing leg has just detached from the actin filament (solid line) and is now free to pivot about the hip-joint between the two legs. The height (H) of the free myosin above the filament determines when it is recaptured, initially into a loose-binding mode. Parts (c) and (d) capture the myosin in a similar conformation showing the circuit of 104 actin molecules (52 dimers with 8 half repeats) over which the myosin can move.
