Abstract: A method implemented in the form of a computer simulation code for evaluating the free energy of binding between polypeptide amino acid residues and one or more molecular fragment types is presented. The basis of the method is a novel weighted Metropolis Monte Carlo approach for sampling the grand canonical ensemble. By making use of the properties of the grand canonical ensemble, the affinity of fragments for binding in the vicinity of each protein residue can be efficiently computed. The binding volume associated to each fragment-residue pair is estimated on the basis of a simple proximity criteria, and a useful affinity mapping of the protein surface can be obtained in this way. The analysis of such data for various fragment types provides valuable information to help identify protein binding sites, as well as to identify key fragments used for building potential drug leads.

Abstract: A method implemented in the form of a computer simulation code for evaluating the free energy of binding between polypeptide amino acid residues and one or more molecular fragment types is presented. The basis of the method is a novel weighted Metropolis Monte Carlo approach for sampling the grand canonical ensemble. By making use of the properties of the grand canonical ensemble, the affinity of fragments for binding in the vicinity of each protein residue can be efficiently computed. The binding volume associated to each fragment-residue pair is estimated on the basis of a simple proximity criteria, and a useful affinity mapping of the protein surface can be obtained in this way. The analysis of such data for various fragment types provides valuable information to help identify protein binding sites, as well as to identify key fragments used for building potential drug leads.

Abstract: Methods and systems for determining the affinity between polypeptide amino acid residues and one or more molecular fragments, and for using the affinity values to aid in drug design including a computer simulation which calculates the interaction energy between a polypeptide and at least one molecular fragment. An affinity value is then assigned to at least one fragment and residue pair if the fragment is in the vicinity of the residue. Affinity values are used to rank fragments, build ligands and determine binding sites.

Abstract: A method, system, and computer program product are provided to develop a residue fingerprint for a molecular structure (such as a ligand). Based on the residues of a reference structure (such as a protein), a residue fingerprint defines a set of residues that interacts with the molecular structure. Residue fingerprints can be used to compare different poses of a molecular structure with a reference pose of the same molecular structure, poses of different molecular structures, and/or a different reference three-dimensional structure. Fingerprints are used to define the similarity of structures in terms of binding mode, identify molecules with similar binding modes, or select a subset of molecules that represent the full diversity of binding modes in a larger set. Fingerprints are computed by a van der Waals-based process, and expressed as a list of interacting residues or a binary string representation.