title: Rational design of improved aziridine-based inhibitors of cysteine proteases.
abstract: Quantum chemical computations on appropriate model systems are used for a rational design of aziridine-based inhibitors of cysteine proteases. They predict that already inductive electron-withdrawing substituents at the aziridine nitrogen strongly accelerate the alkylation step of the inhibition process in neutral and alkaline media, but also for more acidic environments improvements are predicted. With this we generalize previous findings that found similar effects for N-formylated compounds. Furthermore, the new substituents possess the additional advantage that they do not open up reaction pathways other than the nucleophilic ring opening. To verify the hypotheses selected compounds were synthesized and tested. These tests approved the predictions and showed that the corresponding derivatives of aziridine-2,3-dicarboxylate are potent irreversible inhibitors of cysteine proteases. On the basis of measured inhibition data the new inhibitors offer an up to 2,300-fold increase in inhibition potency compared to the unsubstituted inhibitor. Additionally, the kinetics of a selected reaction with 4-methoxy thiophenolate as model thiol were measured in solution to ascertain that the inhibition mechanism is the irreversible alkylation of the cysteine residue of the protease's active site under ring opening of the new inhibitors.
authors.affiliation: Institut fur Pharmazie and Lebensmittelchemie, Institut fur Organische Chemie, Universitat Wurzburg, Am Hubland, D-97074 Wurzburg, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Buback
authors.forename: Milena
authors.initials: M
authors.lastname: Mladenovic
authors.forename: Bernd
authors.initials: B
authors.lastname: Engels
authors.forename: Tanja
authors.initials: T
authors.lastname: Schirmeister
mesh_terms: D001388:Aziridines / Q000737:chemistry* / Q000494:pharmacology; D003198:Computer Simulation; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000737:chemistry* / Q000494:pharmacology*; D015195:Drug Design; D008956:Models, Chemical; D011789:Quantum Theory
chemical_list: D001388:Aziridines; D015853:Cysteine Proteinase Inhibitors; C033132:aziridine; D003546:Cysteine Endopeptidases