DNA-Encoded Macrocyclic Peptide Libraries Enable the Discovery of a Neutral MDM2–p53 Inhibitor

Macrocyclic peptides are an emerging molecular class for targeting intracellular protein–protein interactions (PPIs) and for providing an oral modality for drug targets. Herein, we use DNA-encoded cyclic peptide libraries to discover a neutral nonapeptide, UNP-6457, that inhibits MDM2–p53 interaction with an IC50 of 8.9 nM. These studies showcase how tailored DEL libraries can directly yield macrocyclic peptides benefiting from low MW, TPSA, and HBD/HBA counts that are capable of potently inhibiting therapeutically relevant protein–protein interactions.