Dependency of the blocked pore currents on the ionic strength of cis and trans solutions for the αHL-2N pore at +160 mV. A) histograms of the blocked pore current levels for 4 poly(dC) oligonucleotides each containing either a single C, T, A, G nucleotide at position 14. The solution contained 1 M KCl in both cis and trans chambers (top), 0.2 M KCl in the cis chamber and 1 M in trans chamber (middle) or 0.2 M KCl in cis and trans chambers (bottom). B) the dependence of the open pore conductance (GO) and pore conductance in the presence of threaded poly(dC)40 oligonucleotide (GB) on the ionic strength of cis and trans solutions. C) the relationship of the open and blocked pore conductivities for a poly(dC)40 oligonucleotide on the ionic strength of the cis solution while keeping the ionic strength in the trans solution constant at 1 M KCl. D) Discrimination of the four DNA nucleotides in asymmetric salt conditions. The graph indicates the dependence of the differences in residual current between the oligonucleotides containing A, T, and G at position 14 and the a poly(dC)40 nucleotide (ΔIRESX-C = IRESX - IRESC) on the ionic strength of the cis solution. The trans solution was maintained at 1M KCl.