pharmacophore point

Think of what a target really demands from a drug as a short checklist: a hand to grab here, a hook to catch there, a greasy patch to nestle against. A pharmacophore point is a single item on that checklist — one abstract feature, in one place in space, that a molecule must provide to bind well.

Formally, a pharmacophore point is a defined feature type located at a particular three-dimensional position, the kind of feature being something like a hydrogen-bond donor, a hydrogen-bond acceptor, a positively or negatively ionizable center, an aromatic ring, or a hydrophobic group. Several such points together, arranged with specific distances and angles, make up a pharmacophore — the abstract pattern of interactions responsible for activity, independent of any particular chemical skeleton that displays it.

Pharmacophore points are useful precisely because they describe function, not atoms: two chemically very different molecules can hit the same set of points and so share activity. The caveat is that a pharmacophore is a hypothesis built from known actives; assigning the wrong points, or too many, produces a model that retrieves false hits and misses genuine new chemistry.