Fig. 2

Single mutation selectivity landscape of APPI-3M. The colors in the heatmaps indicate the enrichment ratio (defined as the frequency of a certain mutation in the sorted library divided by its frequency in the naive library) and represent the effect of a single-amino acid substitution on APPI-3M selectivity toward one serine protease (a: mesotrypsin, b: KLK6, c: cationic trypsin, and d: anionic trypsin) versus the other three. The different colors of the heatmaps correspond to the scale shown on the right of each panel and indicate log2 of the enrichment ratio [yellow and red: positive (increased selectivity); green: negative (decreased selectivity)]. The position of the substituted amino acid is shown on the X axis and the substituting amino acid is shown on the Y axis. Meso: mesotrypsin; Cationic: cationic trypsin; Anionic: anionic trypsin. See Supplementary Figure 3 for further details