From induced fit to conformational selection: a continuum of binding mechanism controlled by the timescale of conformational transitions.

In receptor-ligand binding, a question that generated considerable interest is whether the mechanism is induced fit or conformational selection. This question is addressed here by a solvable model, in which a receptor undergoes transitions between active and inactive forms. The inactive form is favored while unbound but the active form is favored while a ligand is loosely bound. As the active-inactive transition rates increase, the binding mechanism gradually shifts from conformational selection to induced fit. The timescale of conformational transitions thus plays a crucial role in controlling binding mechanisms. Copyright 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.