Residual current histogram of nucleotide binding events within the TBMΔ6/M113F•am7βCD pore. Data were acquired in 1 M KCl, 25 mM Tris.HCl, pH 7.5, at +120 mV in the presence of 40 μM am7βCD (trans). (A) dNMP results corresponding to the experiment shown in Figure 4B. (B) rNMP results from a typical experiment in the presence of 10 μM rGMP, 10 μM rAMP, 10 μM rCMP and 10 μM rUMP (all cis). (C) koff values for each NMP detected with the TBMΔ6•am7βCD, TBMΔ6/M113F•am7βCD and TBMΔ6 M113N•am7βCD pores. Values of koff were determined by using koff = 1/τoff, where τoff is the mean dwell time for each rNMP in the pore. Each experiment was conducted at least three times.