MD-based steering of the 7G myosin mutant from its pre-powerstroke to its post-powerstroke configuration fails to fully separate tropomyosin from S1. The minimum distance between Cα atoms of tropomyosin residues 87–108 and myosin Loop-4 residues 361–371 was measured during successive phases of steered MD for simulations involving the WT-S1 (green) and for the 7G-mutant S1 (dark green). Measurements on each of 3,000 frames during the simulations are plotted at time points indicated. Note the difference in tropomyosin–Loop-4 separation following cleft closure.