The Molecular Tweezer CLR01 Stabilizes a Disordered Protein-Protein Interface

Area of Science:

• Biochemistry
• Structural Biology
• Molecular Pharmacology

Background:

• Protein-protein interactions (PPIs) often involve intrinsically disordered regions.
• The 14-3-3 adapter proteins bind partner proteins via recognition motifs that transition from disordered to ordered states.
• Controlling these disorder-to-order transitions with stabilizing agents is desirable.

Purpose of the Study:

• To investigate how the molecular tweezer CLR01 modulates the 14-3-3/Cdc25CpS216 protein-protein interaction.
• To provide structural and functional evidence for a supramolecular ligand targeting a PPI interface.

Main Methods:

• Protein crystallography
• Biophysical affinity determination
• Biomolecular simulations

Main Results:

• A supramolecular 'Janus' ligand (CLR01) binds simultaneously to a flexible PPI motif and a structured adapter protein.
• CLR01 fills the protein-protein interface gap, stabilizing the disordered Cdc25C protein partner.
• The ligand enhances the apparent affinity of the 14-3-3/Cdc25CpS216 interaction.

Conclusions:

• This is the first demonstration of a supramolecular ligand stabilizing the binding of an intrinsically disordered motif to a rigid partner protein.
• CLR01 acts as a molecular bridge, freezing a specific conformation and enhancing PPI affinity.