Background: Allosteric drugs, taking an action-at-a-distance mechanism to achieve regulations on the protein functions, have several advantages over conventional orthosteric drugs, including diverse regulation types and fewer side effects.The rational design of allosteric ligands, however, remains challenging, especially for the step of allosteric site identification.As allosteric ligand binding may work by inducing changes in the pattern of residue-residue interactions, we calculated the residue-residue interaction energies within the allosteric site based on the molecular mechanics generalized Born surface area (MM/GBSA) energy decomposition scheme.