pharmacophore

thumb|right|300px|An example of a pharmacophore model In medicinal chemistry and molecular biology, a pharmacophore is an abstract description of molecular features that are necessary for molecular recognition of a ligand by a biological macromolecule. 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 de novo design or virtual screening novel ligands that will bind to the same receptor.

== Features == thumb|right|300px|alt=Superposition of the chemical structures of a benzodiazepine and nonbenzodiazepine ligand and their interactions with binding sites within the receptor.|An example of a pharmacophore model of the benzodiazepine binding site on the GABAA receptor. White sticks represent the carbon atoms of the benzodiazepine [[diazepam, while green represents carbon atoms of the nonbenzodiazepine CGS-9896. Red and blue sticks are oxygen and nitrogen atoms that are present in both structures. The red spheres labeled H1 and H2/A3 are, respectively, hydrogen bond donating and accepting sites in the receptor, while L1, L2, and L3 denote lipophilic binding sites.]]