For each of those three protein targets, the set of ligands active against a given target was split by their activity levels (as measured by EC50, IC50 or Ki values reported in ChEMBL) into two subsets, one with the bottom 95% least active molecules, and the other with the top 5% most active molecules. Molecules from the first (weakly and moderately active ligands) were inputted into the corresponding target-agnostic transformer model. Then, the Tanimoto similarity score (on ECFP4, Morgan fingerprints with the radius of 2, computed with AllChem.GetMorganFingerprint from RDKit) was calculated between each generated molecule and each of the top 5% most active ligands from ChEMBL for the same protein target. The Tanimoto similarity score is a standard metric of a structural similarity of two organic molecules. Then, for each of those most active molecules from ChEMBL (that is, experimentally known to be active), a closest generated molecule was identified (as the molecule with the highest Tanimoto similarity). The scatter plots for the corresponding Tanimoto similarities vs. the corresponding experimental potencies were drawn for each of the protein targets (Fig. ).