pharmacophore

A pharmacophore is the essential three-dimensional pattern a molecule must present to be recognized by its target, like the precise arrangement of teeth on a key that lets it turn one particular lock. It is not the whole molecule, just the must-have features in their must-have positions.

Defined formally, it is the spatial arrangement of features essential for a molecule's recognition by its target. These features are described abstractly, for example 'a hydrogen-bond donor here, a positive charge there, an aromatic ring at this distance,' rather than as specific atoms.

Because the pharmacophore captures what matters rather than the exact atoms, chemists can build very different-looking molecules that all share it and still bind. This makes pharmacophore thinking a powerful guide for designing new compounds and for searching libraries for fresh starting points.