Figure 4.

HCM-causing R403Q myosin mutation destabilizes the myosin SRX state. Scatter plots showing the effect of R403Q mutation at 30-mM and 100-mM KCl concentrations for (A) A_slow, (B) k_fast, and (C) k_slow. PcSTF-WT and PcSTF-R403Q refer to porcine cardiac synthetic thick filaments made of WT and mutant R403Q myosin, respectively. All parameters are reported on an absolute scale (amplitudes in % and rates in s^-1). Statistical differences presented are based on two-way ANOVA and subsequent post hoc Tukey’s pair-wise comparisons (∗∗∗p < 0.001). Data are expressed as the mean ± SEM (n ≥ 8 for each). HCM, hypertrophic cardiomyopathy; NS, not significant; SRX, super-relaxed.