Supplementary Fig. 6: Effect of amino acid addition on blockade current.
From: Electrical recognition of the twenty proteinogenic amino acids using an aerolysin nanopore
Histograms of Ib/I0 (left axis) and scatter plots of blockade duration versus Ib/I0 (right axis) obtained from nanopore experiments performed using an equimolar mixture (1 M) of VKR7, VHR7, VER7, VDR7, and VRR7 peptides (a, n = 18066 events) or an equimolar mixture (1 M) of KR7, HR7, ER7, DR7, or RR7 peptide species (b, n = 19641 events). In both cases, the addition of the mixture produces five distinct peaks matching the location of the peaks observed in the individual peptide species experiments. The addition of a V amino acid to each XR7 peptide leads to a shift of the population to lower Ib/I0 values. The mean Ib/I0 values are: 0.353 ± 0.003 (KR7) versus 0.314 ± 0.002 (VKR7); 0.362 ± 0.003 (HR7) versus 0.320 ± 0.002 (VHR7); 0.371 ± 0.004 (DR7) versus 0.336 ± 0.004 (VDR7); 0.332 ± 0.002 (RR7) versus 0.293 ± 0.001 (VRR7). The mean value (respectively uncertainty) of relative residual current of each peptide was obtained as the mean value (respectively standard deviation) of a gaussian fit of the corresponding Ib/I0 distribution; from single independent experiments. The data were acquired in 4 M KCl, 25 mM HEPES buffer, at 7.5 pH and 20.0 ± 0.5oC, and under a –50 mV bias applied to the trans compartment.
