Rational Design of Orthogonal Receptor–Ligand Combinations

Abstract

A novel approach to understanding protein–ligand interactions is illustrated using the immunophilin receptor human cyclophilin A and its immunosuppressive ligand cyclosporin A. Synthetic chemistry is used to place “bumps” on the ligand, while site‐directed mutagenesis is used to create compensatory “holes” in the receptor. These novel receptor–ligand combinations can have an affinity even greater than that of the natural system, and are expected to facilitate the inducible dimerization of target proteins, and thus the activation of signaling proteins, in transgenic animals.