title: Protease and helicase activities of hepatitis C virus genotype 4, 5, and 6 NS3-NS4A proteins.
abstract: The bifunctional NS3 protease-helicase of hepatitis C virus (HCV), together with its cofactor protein NS4A, is an important target for antiviral drugs which can cure HCV infections. HCV strains are divided into six major genotypes based on sequence diversity, and the great majority of reports on NS3 have focused exclusively on genotype 1 proteins. Here we report the cloning, expression, and preliminary characterization of NS3-NS4A gene products from HCV genotypes 4, 5, and 6. This work complements our earlier characterization of genotype 2 and 3 proteins [17]. We compare NS3-NS4A protease and helicase activities of genotypes 4a, 5a, and 6a to those of common reference strains Con1 (genotype 1b) and JFH1 (genotype 2a). The specific activities of the proteases of the newly isolated proteins were similar to those of the reference proteins. Furthermore, the reference inhibitor BILN 2061 had similar activity against all of the proteins except for that of JFH1, which had an apparent K(i) that was 11-fold higher relative to Con1. RNA and DNA unwinding activities were also similar for genotypes 1, 4, 5, and 6 proteins, but significantly higher for genotype 2 JFH1. With the availability of these proteins, inhibitors developed based on their activity against genotype 1 can be tested against all the other major genotypes, providing a path to improved treatment for all HCV patients.
authors: Boehringer Ingelheim (Canada) Ltd, Department of Biological Sciences, 2100 Cunard St, Laval, QC, Canada.
authors: Marie-Josée
authors: MJ
authors: Massariol
authors: Songping
authors: S
authors: Zhao
authors: Martin
authors: M
authors: Marquis
authors: Diane
authors: D
authors: Thibeault
authors: Peter W
authors: PW
authors: White
mesh_terms: D000595:Amino Acid Sequence; D000998:Antiviral Agents / Q000737:chemistry / Q000494:pharmacology; D002219:Carbamates / Q000494:pharmacology; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism; D005838:Genotype; D016174:Hepacivirus / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D047028:Macrocyclic Compounds / Q000494:pharmacology; D008969:Molecular Sequence Data; D011480:Protease Inhibitors / Q000737:chemistry / Q000494:pharmacology; D011804:Quinolines / Q000494:pharmacology; D012313:RNA / Q000378:metabolism; D020365:RNA Helicases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D013844:Thiazoles / Q000494:pharmacology; D017361:Viral Nonstructural Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D000998:Antiviral Agents; D002219:Carbamates; D002352:Carrier Proteins; D004247:DNA; D047908:Intracellular Signaling Peptides and Proteins; D047028:Macrocyclic Compounds; D011480:Protease Inhibitors; D011804:Quinolines; D012313:RNA; D020365:RNA Helicases; D013844:Thiazoles; D017361:Viral Nonstructural Proteins; D014764:Viral Proteins; C479555:BILN 2061; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C455041:NS4A cofactor peptide, Hepatitis C virus