Fig. 3.

Mapping the sensing spots of aerolysin by abasic site scanning of dA₁₄. a Schematic representation of dA₁₄X1 oligonucleotide; the red sphere of X represented the single-nucleobase deletion. b Comparison between the percentage of increase in residual current for each abasic oligonucleotide (red circle with error bar) and the pore diameter (blue line) calculated by the PoreWalker server. Data were obtained in 1.0 M KCl, 10 mM Tris, and 1.0 mM EDTA, pH=8.0, 24 ± 2 °C at the bias potential of +140 mV. The errors of the data were based on at least three separate measurements. c Selected MD snapshot of dA₁₄ fully inserted in the pore, showing the two main constriction points (R220 and K238, in blue van der Waals representation) and the DNA in red, with bases at positions 11 and 4 in yellow van der Waal representation