Cell‐Active, Arginine‐Targeting Irreversible Covalent Inhibitors for Non‐Kinases and Kinases

Targeted covalent inhibitors (TCIs) play an essential role in the fields of kinase research and drug discovery. Most existing TCIs are however cysteine‐ or lysine‐reactive, thus severely limiting their potential applications. New types of TCIs capable of covalently targeting other nucleophilic amino acids that are readily available in proteins are urgently needed. We report herein a glyoxal‐based, arginine‐reactive strategy to generate potent and selective small‐molecule TCIs of Mcl‐1 (an important anti‐apoptotic protein) by selectively targeting the conserved arginine (R263) in the protein. We further validated the generality of this strategy by developing glyoxal‐based, irreversible covalent inhibitors of AURKA (a cancer‐related kinase) that showed exclusive reactivity with a solvent‐exposed arginine (R220) of this enzyme. We showed the resulting compounds were potent, selective and cell‐active, capable of covalently engaging endogenous AURKA in MV‐4‐11 cells with long residence time. Finally, we showed the potential application of glyoxal‐based TCIs in targeting an acquired drug‐resistance mutant of ALK kinase (G1202R).