Fig. 3

Double mutation selectivity landscape of APPI-3M. Heatmaps demonstrating the effect of double-amino acid mutations in APPI-3M on the selectivity toward KLK6 versus the three other serine proteases. a The effect of different pairs of mutated residues on selectivity is illustrated by the colors of the heatmaps (red = increased selectivity, enrichment ratio >1; blue = decreased selectivity, enrichment ratio <1). The contribution of each double mutation to selectivity was summed and the maps demonstrate the overall effect. The X and Y axes indicate the position of the substituted amino acid residues. See Supplementary Figure 4 for further details. b The effect of different amino acid mutations at residues 11 and 17 of APPI-3M on its selectivity toward KLK6, illustrated by the colors in the heatmaps. The X axis indicates amino acids mutated at residue 17 and the Y axis indicates amino acids mutated at residue 11. c Crystal structure of APPI-3M (PDB ID: 5C67). Cartoon representation of APPI-3M illustrating the positions of correlated residues Thr-11 and Gly-17 (red) within the APPI binding loop (green, positions 11–18). The APPI scaffold is shown in gray