Current traces in response to deactivation voltage protocols. The patch was held at 0 mV, stepped to +100 mV to activate the channels, and then down to voltage levels of −190 to 0 mV to deactivate the channels, with 10-mV increments between sweeps. Current traces of the first 35 ms of the deactivation period are shown. (A; 1) Experiments were done for M314H, 0 Ca²⁺, pH 5, in low ionic strength, with 14 mM K⁺ in the intracellular solution. (2) Experiments were done for M314H, 0 Ca²⁺, pH 5, in high ionic strength, with 284 mM K⁺ in the intracellular solution. (3) τ_app–V relations of M314H in pH 5 and 0 Ca²⁺, with various ionic strength. (B; 1) Experiments were done for M314E, 0 Ca²⁺, pH 9, in low ionic strength, with 14 mM K⁺ in the intracellular solution. (2) Experiments were done for M314E, 0 Ca²⁺, pH 9, in high ionic strength, with 284 mM K⁺ in the intracellular solution. (3) τ_app–V relations of M314E in pH 9 and 0 Ca²⁺, with various ionic strength. Each point was calculated from a dataset with n ≥ 3.