Figure 3. αN217 gating.

A, low time-resolution view of single-channel currents. The clusters of openings (down) are gating events and the long gaps between clusters are desensitization. Top, with 20 mm choline (WT background); bottom, constitutively-active background (DYS). B, higher-resolution views of clusters for αN217 mutants, with and without agonist. In both conditions, K and T mutations increase cluster P_O. C, for all mutations, the change in the C vs. O free energy difference (ΔG_n) was the same regardless of whether or not agonists were present (n = 2 or 0). D, REFERs. In the α subunit the linear slope (φ, given below) is the same either with (filled circles) or without (open circles) agonists. For mutations in non-α subunits the change in gating equilibrium constant was too small to allow φ estimation.