Probing structural adaptivity at PPI interfaces with small molecules.

Area of Science:

• Chemical Biology
• Structural Biology
• Drug Discovery

Background:

• Protein-protein interactions (PPI) are crucial targets for therapeutic intervention.
• Fragment-based ligand discovery offers a powerful strategy for modulating PPI.
• Small molecules acting as drug leads or probes of protein function are of significant interest.

Purpose of the Study:

• To review the principles and applications of covalent disulfide trapping (Tethering) for fragment-based ligand discovery.
• To highlight Tethering's utility in investigating protein binding sites and allosteric modulation.
• To present examples demonstrating Tethering's success in expanding the understanding of PPI.

Main Methods:

• Fragment-based ligand discovery utilizing covalent disulfide trapping (Tethering).
• Employing native or engineered cysteine residues to select thiol-containing fragments.
• Site-directed analysis of protein binding sites and allosteric conformations.

Main Results:

• Tethering identified a binding site adjacent to the IL2/IL2-receptor and an allosterically coupled site.
• For kinase PDK1, Tethering discovered ligands modulating enzymatic activity via an allosteric site.
• The method successfully identified starting points for chemical biology and drug discovery.

Conclusions:

• Tethering is an effective fragment-based approach for discovering modulators of protein-protein interactions.
• The technique aids in characterizing protein druggability, identifying novel binding sites, and probing allosteric mechanisms.
• Successful fragment-discovery projects often integrate Tethering with complementary technologies.