Structurally novel highly potent proteasome inhibitors created by the structure-based hybridization of nonpeptidic belactosin derivatives and peptide boronates
We previously developed highly potent proteasome inhibitor 1 (IC50= 5.7 nM) and its nonpeptide derivative 2 (IC50= 29 nM) by systematic structure–activity relationship studies of the peptidic natural product belactosin A and subsequent rational topology-based scaffold hopping, respectively. Their cell growth inhibitory activities, however, were only moderate (IC50= 1.8 μM (1) and> 10 μM (2)). We therefore planned to replace the unstable β- ...