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".[1] 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.
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Typical pharmacophore features include hydrophobic centroids, aromatic rings, hydrogen bond acceptors or donor, cations, and anions. These pharmacophoric points may be located on the ligand its self or may be projected points in presumed to be located in the receptor.
The features need to match different chemical groups with similar properties, in order to identify novel ligands. Ligands receptor interactions are typically “polar positive”, “polar negative” or “hydrophobic”. A well-defined pharmacophore model includes both hydrophobic volumes and hydrogen bond vectors.
In modern computational chemistry, pharmacophores are used to define the essential features of one or more molecules with the same biological activity. A database of diverse chemical compounds can then be searched for more molecules which share the same features arranged in the same relative orientation.
Historically, pharmacophores were established by Lemont Kier, who first mentions the concept in 1967.[3] and uses the term in a publication in 1971.[4]
The development of the concept is often erroneously accredited to Paul Ehrlich. However neither the alleged source[5] nor any of his other works mention the term "pharmacophore" or make use of the concept.[6]
The following computer software packages enable the user to model the pharmacophore using a variety of computational chemistry methods:
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