Preparing train and test data sets. We downloaded the PDBbind data set v2019 (), and removed entries that contained cofactors, incomplete ligands, more than one ligand, incorrect valences, entries annotated as 'NMR', or entries for which the ligand was annotated as a peptide. This resulted in a data set containing 4,593 crystal structures from the 'refined' set, and 10,011 from the 'general' set. We split the data set into train (10,919) and test (5,206) sets by requiring that receptors share less than 70% or 50% sequence similarity between the sets ('seqsim70' and 'seqsim50' splits). For comparison, we also generated train and test sets identical in size to the seqsim70 and seqsim50 sets but split by enforcing that these sets do not share identical uniprot identifiers ('uniprot split').