Drug-target interactions that involve the replacement or displacement of magnesium ions

Metal ions play important roles in protein and RNA structure and function and the construction of ligands frequently focuses on the exploitation of functionality designed to engage a metal. However, there are circumstances where functionality can be incorporated into a ligand to emulate the metal ion, allowing target engagement by displacing or replacing the metal and directly interacting with the metal-binding elements in the target. In this Digest, we illustrate protein and RNA modulators that exploit this design principle, with all of the examples based on the displacement or replacement of a magnesium ion, and which can confer a potency advantage. Moreover, this approach relies upon an inversion of the physical chemical properties of a more conventional metal-binding ligand.