PMID: 22915796
Kim Y, Lovell S, Tiew KC, Mandadapu SR, Alliston KR, Battaile KP, Groutas WC, Chang KO
Broad-Spectrum Antivirals against 3C or 3C-like Proteases of Picornaviruses, Noroviruses and Coronaviruses.
J Virol. 2012 Aug 22.
Phylogenetic analysis has demonstrated that some positive sense RNA viruses can be classified into the picornavirus-like supercluster, which includes picornaviruses, caliciviruses and coronaviruses. These viruses possess 3C or 3C-like proteases (3Cpro or 3CLpro, respectively) which contain a typical chymotrypsin-like fold and a catalytic triad (or dyad) with a Cys residue as a nucleophile. The conserved key sites of 3Cpro or 3CLpro may serve as an attractive target for the design of broad-spectrum antivirals for multiple viruses in the supercluster. We have previously reported the structure-based design and synthesis of potent protease inhibitors of Norwalk virus (NV), a member of the Caliciviridae family. We report herein the broad-spectrum antiviral activities of three compounds possessing a common dipeptidyl residue with different warheads, aldehyde (GC373), bisulfite adduct (GC376) and alpha-ketoamide (GC375), against viruses that belong to the supercluster. All compounds were highly effective against the majority of tested viruses with the half maximal inhibitory concentration in the high nanomolar or low micromolar range in the enzyme and/or cell-based assays with high therapeutic indices. We also report the high-resolution X-ray cocrystal structures of the NV 3CLpro-, poliovirus 3Cpro- or transmissible gastroenteritis virus 3CLpro-inhibitor GC376 complex that show the compound covalently bound to a nucleophilic Cys residue in the catalytic site of the corresponding protease. We conclude that these compounds have the potential to be developed as antiviral therapeutics aimed at a single virus or multiple viruses in the picornavirus-like supercluster by targeting 3Cpro or 3CLpro.