Broad-Spectrum Antivirals against 3C or 3C-Like Proteases of Picornaviruses, Noroviruses, and Coronaviruses.
Kim, Y., Lovell, S., Tiew, K.C., Mandadapu, S.R., Alliston, K.R., Battaile, K.P., Groutas, W.C., Chang, K.O.(2012) J Virol 86: 11754-11762
- PubMed: 22915796 
- DOI: https://doi.org/10.1128/JVI.01348-12
- Primary Citation of Related Structures:  
3UR6, 3UR9, 4DCD, 4F49 - PubMed Abstract: 
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 attractive targets for the design of broad-spectrum antivirals for multiple viruses in the supercluster. We 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, i.e., an aldehyde (GC373), a bisulfite adduct (GC376), and an α-ketoamide (GC375), against viruses that belong to the supercluster. All compounds were highly effective against the majority of tested viruses, with half-maximal inhibitory concentrations in the high nanomolar or low micromolar range in enzyme- and/or cell-based assays and with high therapeutic indices. We also report the high-resolution X-ray cocrystal structures of NV 3CLpro-, poliovirus 3Cpro-, and transmissible gastroenteritis virus 3CLpro- GC376 inhibitor complexes, which 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.
Organizational Affiliation: 
Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA.