The comparison of activation and inactivation thresholds for WT MscS, soft A98S, and stiff L111S mutants. (A) A series of traces obtained in response to step pulse protocol shows that the soft A98S MscS mutant does not inactivate. (B) The stiff L111S mutant partially inactivates silently without opening, as illustrated by trace 3 (arrows). (C) Positions of activation curves for A98S (γ_0.5 = 5.8 mN/m), WT (γ_0.5 = 7.8 mN/m), and L111S (γ_0.5 = 13.4 mN/m), and the tension dependence of the inactivation rate of WT MscS (data from Fig. 3 E) on the tension scale.