%0 Journal Article %A Scheffler, Ulrike %A Rudolph, Wolfram %A Gebhardt, Julia %A Rohayem, Jacques %T Differential cleavage of the norovirus polyprotein precursor by two active forms of the viral protease %D 2007 %J Journal of General Virology, %V 88 %N 7 %P 2013-2018 %@ 1465-2099 %R https://doi.org/10.1099/vir.0.82797-0 %I Microbiology Society, %X Protein translation in noroviruses requires translational processing of a polyprotein precursor by the viral protease. So far, the molecular mechanisms of catalytic cleavage by the viral protease are poorly understood. In this study, the catalytic activities and substrate specificities of the viral protease were examined in vitro by using synthetic peptides (11–15 residues) corresponding to the cleavage sites of the norovirus polyprotein. Both predicted forms of the viral protease, the 3C-like protease (3Cpro) and the 3CD-like protease polymerase protein (3CDpropol), displayed a specific trans cleavage activity of peptides bearing Gln–Gly at the scissile bond. In contrast, peptides bearing Glu–Gly at the scissile bond (p20/VPg and 3Cpro/3Dpol junctions) were resistant to trans-cleavage by 3Cpro and 3CDpropol. Interestingly, the VPg/3Cpro scissile bond (Glu–Ala) was cleaved only by 3CDpropol, and examination of relative cleavage efficiencies revealed significant differences in processing of peptides, indicating differential cleavage patterns for 3Cpro and 3CDpropol. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/vir.0.82797-0