title: Differential cleavage of the norovirus polyprotein precursor by two active forms of the viral protease.
abstract: 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 (3C(pro)) and the 3CD-like protease polymerase protein (3CD(propol)), 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 3C(pro)/3D(pol) junctions) were resistant to trans-cleavage by 3C(pro) and 3CD(propol). Interestingly, the VPg/3C(pro) scissile bond (Glu-Ala) was cleaved only by 3CD(propol), and examination of relative cleavage efficiencies revealed significant differences in processing of peptides, indicating differential cleavage patterns for 3C(pro) and 3CD(propol).
authors.affiliation: 'The Calicilab', Institut für Virologie, Medizinische Fakultät Carl Gustav Carus, Fiedlerstrasse 42, D-01307 Dresden, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Scheffler
authors.affiliation: 'The Calicilab', Institut für Virologie, Medizinische Fakultät Carl Gustav Carus, Fiedlerstrasse 42, D-01307 Dresden, Germany.
authors.forename: Wolfram
authors.initials: W
authors.lastname: Rudolph
authors.affiliation: 'The Calicilab', Institut für Virologie, Medizinische Fakultät Carl Gustav Carus, Fiedlerstrasse 42, D-01307 Dresden, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Gebhardt
authors.affiliation: 'The Calicilab', Institut für Virologie, Medizinische Fakultät Carl Gustav Carus, Fiedlerstrasse 42, D-01307 Dresden, Germany.
authors.forename: Jacques
authors.initials: J
authors.lastname: Rohayem
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D066298:In Vitro Techniques; D029322:Norovirus / Q000235:genetics / Q000378:metabolism*; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism; D014176:Protein Biosynthesis; D011498:Protein Precursors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D013379:Substrate Specificity; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D010446:Peptide Fragments; D011498:Protein Precursors; D014764:Viral Proteins; D010447:Peptide Hydrolases