The kinetics of double-headed myosin motors bound to regulated cTFs. (a and b) Representative time course of binomial binding (a) and heads displacements (b) calculated for the individual HMM molecules (M1–M4) at the given time for upper and lower heads of each HMM molecule in the presence of 0.5 μM ATP and high Ca²⁺ concentrations. (c) The backward and forward myosin displacements in the cTFs–HMM complex (5,911 events, ∼35 HMM molecules); data sets were fitted by sum of two Gaussians (r² = 0.99). The two peaks for backward displacement were −1.7 ± 0.27 and −4.2 ± 1.2 nm; the two peaks for forward displacement were 1.7 ± 0.29 and 3.9 ± 0.64 nm.