title: Multiple interactions within the hepatitis C virus RNA polymerase repress primer-dependent RNA synthesis.
abstract: The hepatitis C virus (HCV) RNA-dependent RNA polymerase (RdRp) initiates RNA synthesis in vivo by a de novo mechanism. In vitro, however, the HCV RdRp can initiate de novo or extend from a primed template. A novel beta-loop near the RdRp active site was previously found to prevent the use of primed templates. We found that, in addition to the beta-loop, the C-terminal tail of the HCV RdRp and the de novo initiation GTP are required to exclude the use of primed-templates. GTP binding to the NTPi site of the HCV RdRp orchestrates the participation of other structures. The interactions of the beta-loop, C-terminal tail, and GTP provide an elegant solution to ensure de novo initiation of HCV RNA synthesis.
authors.affiliation: Department of Biology, Indiana University, Bloomington, IN 47405, USA.
authors.forename: C T
authors.initials: CT
authors.lastname: Ranjith-Kumar
authors.forename: Les
authors.initials: L
authors.lastname: Gutshall
authors.forename: Robert T
authors.initials: RT
authors.lastname: Sarisky
authors.forename: C Cheng
authors.initials: CC
authors.lastname: Kao
mesh_terms: D001483:Base Sequence; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D016174:Hepacivirus / Q000201:enzymology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009690:Nucleic Acid Conformation; D017434:Protein Structure, Tertiary; D012313:RNA / Q000096:biosynthesis*; D012367:RNA, Viral; D017361:Viral Nonstructural Proteins / Q000737:chemistry; D012324:RNA-Dependent RNA Polymerase
chemical_list: D012321:DNA-Directed RNA Polymerases; D006160:Guanosine Triphosphate; D012313:RNA; D012367:RNA, Viral; D017361:Viral Nonstructural Proteins; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase