 Conformational selection

Conformational selection is a binding mechanism in which a ligand preferentially binds one of the conformations already sampled by an unbound protein. Binding shifts the conformational population toward that conformation. It differs from a pure induced-fit description, where the relevant structural rearrangement follows the initial encounter, although both contributions can occur in one system. Demonstrating a pre-existing state supports its availability; kinetic measurements are needed to determine how much binding flux actually follows that route. ^[ref]