AT6

AT6 is a PROTAC AT1 analogue, which is a PROTAC connected by ligands for von Hippel-Lindau and BRD4 with highly selectivity to bromodomain (Brd4). In Vitro: PROTACs (proteolysis-targeting chimaeras) are bifunctional molecules that recruit a target protein in proximity to an E3 ubiquitin ligase to trigger protein degradation. Structural elucidation of the key ternary ligase: PROTAC: target species and how this impacts target degradation selectivity remains elusive. The ligand folds into itself to allow formation of specific intermolecular interactions in the ternary complex. Isothermal titration calorimetry studies, supported by surface mutagenesis and proximity assays, are consistent with pronounced cooperative formation of ternary complexes with Brd4^BD2. Structure-based-designed compound AT1 exhibits highly selective depletion of Brd4 in cells^[1].