question: List programs suitable for pharmacophore modelling
answer: A pharmacophore is an abstract description of molecular features which are necessary for molecular recognition of a ligand by a biological macromolecule. The IUPAC defines a pharmacophore to be "an ensemble of steric and electronic features that is necessary to ensure the optimal supramolecular interactions with a specific biological target and to trigger (or block) its biological response". A pharmacophore model explains how structurally diverse ligands can bind to a common receptor site. Furthermore pharmacophore models can be used to identify through denovo design or virtual screening novel ligands that will bind to the same receptor. Nowadays there are many programs suitable for pharmacophore modelling such as LigandScout, Discovery Studio, Catalyst, PharmaGist, Genetic Algorithm Similarity and Molecular Operating Environment.