Intermediates are part of the translocation pathway. Plot of fraction of events with subconductance state(s) (oscillating events), against voltage (mV), in (a) WT PA channel in the presence of L-Trp (black square), D-Trp (red circle), and D,L-Trp (blue triangle) peptides; and (b) PA R178A channel in the presence of L-Trp (black square), D-Trp (red circle), and D,L-Trp (blue triangle) peptides. (c) Plot showing the correlation of voltages obtained from midpoint of sigmoid plots from single-channel measurements, and voltages at which maximum binding occurs in ensemble measurements. Adjusted R2 value is 0.95.