Fig. 2.

Derivation of the STATIUM potential. The crystal structure of a Bcl-2 receptor bound to a BH3 peptide (here, PDB ID 3IO8) is used to identify interacting residue pairs (see Methods). The C^α–C^α and C^β–C^β distances for each interacting pair are measured, and pairs with similar distances are sought in a database of experimentally determined structures. The STATIUM score for amino acid i at position 1 and amino acid j at position 2 is the probability of that amino acid pair occurring in all pairs discovered, divided by the individual probabilities of finding i and j in the PDB. The total STATIUM score for a receptor–peptide interaction is the sum of all residue-pair scores.