Figure 7.

Influence of mutating Ser42 in the pore helix anchoring the selectivity filter (Fig. 1B) on O‐M gating at negative voltages. (A,B) Comparison of the amplitude histogram at −140 mV of Kcv_NH S42V S77G (A) with that of Kcv_NH S77G (B). Representative histograms in 0.1 m KCl, pH 7 (gray) and the best fit with the model in Fig. 2A (black). (C,D) Comparison of the voltage dependence of k _OM (C) and k _MO (D) of Kcv_NH S42V S77G (blue open circles) with that of Kcv_NH S77G (blue filled circles) and Kcv_NTS (black circles). Inset in D: Gating factor gf [Eqn (5)] for Kcv_NH S77G and Kcv_NH S42V S77G, symbols are the same as in (C) and (D). Recordings in symmetrical 0.1 m KCl from three different bilayers for each Kcv_NH mutant and six for Kcv_NTS, respectively.