title: GB virus B and hepatitis C virus NS3 serine proteases share substrate specificity.
abstract: GB virus B (GBV-B) is a recently discovered virus responsible for hepatitis in tamarins (Saguinus species). GBV-B belongs to the Flaviviridae family and is closely related to the human pathogen hepatitis C virus (HCV). Nonstructural protein 3 (NS3) of HCV has been shown to encompass a serine protease domain required for viral maturation. GBV-B and HCV share only about 30% of the amino acid sequence within the NS3 protease domain. The catalytic triad is conserved, and the residue Phe-154, presumed to be a crucial amino acid for determining the S1 specificity pocket of the HCV NS3 protease, is also conserved. We have expressed a synthetic gene encoding the GBV-B NS3 protease domain in Escherichia coli and have characterized the purified recombinant protein for its activity on HCV substrates. We have shown that the NS3 region of the GBV-B genome actually encodes a serine protease that, despite the low sequence homology, shares substrate specificity with the HCV NS3 protease.
authors.affiliation: Istituto di Ricerche di Biologia Molecolare P. Angeletti, Rome, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Scarselli
authors.forename: A
authors.initials: A
authors.lastname: Urbani
authors.forename: A
authors.initials: A
authors.lastname: Sbardellati
authors.forename: L
authors.initials: L
authors.lastname: Tomei
authors.forename: R
authors.initials: R
authors.lastname: De Francesco
authors.forename: C
authors.initials: C
authors.lastname: Traboni
mesh_terms: D000595:Amino Acid Sequence; D018067:Flaviviridae / Q000201:enzymology*; D016174:Hepacivirus / Q000201:enzymology*; D006801:Humans; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000378:metabolism*; D013379:Substrate Specificity; D017361:Viral Nonstructural Proteins / Q000378:metabolism*; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D011993:Recombinant Fusion Proteins; D012697:Serine Endopeptidases; D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases