Electronic Similarity among Protein-Ligand Complexes: Development of the Interaction-Energy Projection Method

A numerical model, called the interaction energy projection method (IEPM), is suggested to evaluate electronic similarity among protein-ligand complexes. Herein we apply the method by referring to the "inter-fragment interaction energy (IFIE)," calculated using the fragment molecular orbital (FMO) method, in two human estrogen receptor complexes.