EXPERIMENTAL FIGURE 17-27 The length of the myosin II neck domain determines the rate of movement. To test the lever-arm model of myosin movement, investigators used recombinant DNA techniques to make myosin heads attached to neck domains of different lengths. The rate at which these myosins moved on actin filaments was determined. The longer the lever arm, the faster the myosin moved, supporting the proposed mechanism.

[Data from K. A. Ruppel and J. A. Spudich, 1996, Ann. Rev. Cell Dev. Biol. 12:543–573.]