Figure 6.

(a) Single-channel currents elicited by 100 μM ACh from WT and the triple-Leu-substituted AChR at a bandwidth 10 kHz. (b) Histogram of cluster mean open probability (P_open) shows a broad distribution for the triple mutant (gray bars), indicating heterogeneous kinetics, but the distribution is narrow for the WT AChR (black bars). (c) Single-channel currents elicited by 1 mM ACh from the triple-Val-substituted AChR. Clusters could not be identified even at a concentration of 1 mM ACh. (d) Open and closed time histograms were fitted by sums of exponentials using the program TAC.