Electrostatic interaction between myosin Loop-4 and tropomyosin pseudorepeat 3 during MD-based steering of myosin S1 from its pre-powerstroke to its target post-powerstroke configuration. The plot highlights the electrostatic interaction energy measured between Loop-4 residues Arg 369 and Glu 370 and tropomyosin during distinct phases of the steering protocol. The first 10-ns phase noted involved docking the pre-powerstroke S1 model to actin tropomyosin via its HLH motif (Dock HLH); the docked S1 was then allowed to equilibrate for 10 ns at its docked position (Hold HLH). Note the near-zero interaction energy as myosin S1 repels tropomyosin during the first two phases. During the next 20 ns, myosin S1 was steered to its target post-powerstroke position (steer cleft closure) driving myosin cleft closure in concert with CM loop binding to actin. Transient attractive interaction between myosin and tropomyosin occurs midway through this phase, reflected by a drop in interaction energy. As steered docking proceeds, electrostatic repulsion resumes and is maintained during the final steps of steering (complete cleft closure). Electrostatic energy was measured on each of the 3,000 frames during the simulation and plotted at the timepoints indicated.