Fig. 1.

Sliding velocity as a function of lever arm length. The Dictyosteium discoideum myosin II gene was genetically engineered to produce four forms of S1 with different lever arm lengths (shown on the right), expressed in D. discoideum, and purified as described previously (Uyeda et al., 1996). The normal D. discoideum myosin S1 has two light chains. Constructs containing zero light chains and one light chain were expressed, as well as one containing three light chains. The latter was created by inserting an additional essential light chain (magenta) binding domain into the myosin II heavy chain. The fulcrum was inferred from the intercept of the straight line with the x-axis. v_o, unloaded sliding velocity; d, stroke size; t_s, strongly bound state time. Data are from Uyeda et al. (1996).