Concentration dependencies for high- and low-affinity Zn²⁺-induced gating effects. (A) Comparison of best-fit logK_Zn values and confidence limits for the indicated gating changes obtained in recordings with 4 mM Ca²⁺ at pH 7.4. Note that some of the values shown on the right were obtained by globally fitting the high-affinity shift and slowing (high-affinity I) or the low affinity shift (low-affinity II) with shared K_Zn values as described in the text. (B) Concentration–response curves, reconstructed from best-fit values obtained by globally fitting the changes in channel voltage dependence (ΔV_0.5act, ΔV_0.5inact) and kinetics (Ratio τ_act) under the indicated conditions with a single, shared K_Zn for the high-affinity component and all other values fixed to the values shown in Table S4. For comparison, the extrapolated E_max values were normalized by the E_max values observed with 4 mM Ca²⁺ at pH 7.4 (black line). (C–E) Concentration–response curves reconstructed from best-fit values for the changes in activation slope factor (Ratio k_act; C), the low-affinity changes in activation kinetics (Ratio τ_act; D), and the low-affinity changes in channel voltage dependence (E). For comparison, the extrapolated E_max values were normalized as in B.