Figure 7.

Paxilline sensitivity is restored in constructs with a Slo3 S6 by a glycine at position S300. (A) Paxilline blocks MC10-S300G. 50 nM paxilline markedly inhibits MC10-S300G currents activated at +150 mV with 0 Ca²⁺. (B) G-V curves are plotted for MC10-S300G with and without 50 nM paxilline (n = 4 patches). Red lines are a fit of Eq. 2 with K_b = 13.1 ± 0.6 nM and no voltage dependence. (C) Paxilline more weakly blocks MC13-S300G. Traces show MC13-S300G currents activated at pH 8.5 at +200 mV. Inhibition occurs with high concentrations of paxilline. (D) G-V curves are plotted for MC13-S300G with and without paxilline (n = 3 patches). Red lines are a fit of Eq. 2 with K_b = 170.2 ± 7.2 nM and no voltage dependence.