Abstract: A system and method of identifying a target molecule that bind to the bioactive site of a protein or protein complex is described. The system and method includes the steps of calculating the information signature of a first molecule that is known to bind to the bioactive site of a protein or protein complex, wherein the information signature is a string of numerical values based on the average distance and physico-chemical properties of each atom of a plurality of atoms in the first molecule, calculating the information signature of each target molecule in a library of target molecules, comparing the information signature of the first molecule to the information signatures of the target molecules, and selecting the target molecules having an information signature that is similar to the information signature of the first molecule.