Exchange of the carboxy termini downstream of helix A mostly inverts the differential P_o values and PIP₂-apparent affinities. The second chimera pair between Kv7.3 and Kv7.4 was created by exchange of the carboxy termini downstream of the end of helix A. Shown are single-channel patch-clamp recordings from the Kv7.3/7.4_C-2 (A) or Kv7.4/7.3_C-2 (B) chimeras obtained in the cell-attached (top) or excised inside-out (bottom) configurations at 0 mV. The indicated concentrations of diC8-PIP₂ were perfused over the inside-out patches. The insets above the current records show the topography and chimera junctions of the channel subunits. (C) Bars summarize the P_o at 0 mV in cell-attached patches for these chimeras. (D) Plotted are the summarized P_o values at 0 mV for the chimeras in inside-out configuration obtained over a range of diC8-PIP₂ concentrations. The data were fit by a Hill equation of the form and parameters given in the text.