Proteome‐Wide Data Guides the Discovery of Lysine‐Targeting Covalent Inhibitors Using DNA‐Encoded Chemical Libraries

Broadening the application of covalent inhibitors requires the exploration of nucleophilic residues beyond cysteine. The covalent DNA-encoded chemical library (CoDEL) represents an advanced technology for covalent drug discovery. However, its application in lysine-targeting inhibitors remains uncharted territory. Here, we report the utilization of CoDEL selection guided by proteome-wide data to identify lysine-targeting covalent inhibitors. A comprehensive assessment of activity-based protein profiling (ABPP) data on lysine distribution and ligandability reveals potential targets for selective covalent inhibition, including phosphoglycerate mutase 1 (PGAM1), bromodomain (BRD) family proteins, and ubiquitin-conjugating enzyme E2 N (UBE2N). The 10.7-million-member CoDELs, featuring diverse lysine-reactive warheads, enable the discovery of a series of covalent inhibitors, covering photo-covalent, reversible covalent, and irreversible covalent reaction mechanisms. In-depth characterization of binding sites and modes of action provides structural and functional insights. Notably, irreversible covalent inhibitors unveil a novel mechanism for regulating UBE2N-mediated ubiquitination by modulating the conformation of the protein complex. Our work adopts the ABPP-CoDEL strategy, offering an efficient and versatile selection method for the development of covalent inhibitors targeting functional lysines.