Figure 7.

S4 histidine H328 is not required for sensitivity to extracellular pH in Kv12.1. (A–E) Normalized GV relations for Kv12.1 WT and S4 histidine mutants are shown at three bath pH values: pH 6, 7, and 8. Conductance was determined from isochronal tail currents recorded at −40 mV after 8-s steps to the indicated voltages. Data points show mean ± SEM, and curves represent single Boltzmann distribution fits; parameters and n are given in Table 1, and V₅₀ shifts from pH 8 to 6 are reported in Fig. 8.