Specific Interaction of Hepatitis C Virus Protease/Helicase NS3 with the 3′-Terminal Sequences of Viral Positive- and Negative-Strand RNA

摘要: The hepatitis C virus (HCV)-encoded protease/helicase NS3 is likely to be involved in viral RNA replication. We have expressed and purified recombinant (protease helicase domains) ΔpNS3 (helicase domain only) examined their abilities interact with the 3′-terminal sequence of both positive negative strands HCV RNA. These regions were chosen because initiation synthesis occur at or near 3′ untranslated region (UTR). results presented here demonstrate that (and ΔpNS3) interacts efficiently specifically sequences positive- negative-strand but not corresponding complementary 5′-terminal sequences. interaction strand [called 3′(−) UTR127] was specific only homologous heterologous) competed binding reaction. A predicted stem-loop structure present terminus (nucleotides 5 20 from end) appears important for UTR. Deletion almost totally impaired binding. Additional mutagenesis showed three G-C pairs within stem critical helicase-RNA interaction. data also suggested a double-stranded 3′-proximal guanosine residues determinants protein In contrast relatively stringent requirement UTR binding, (or positive-strand [3′(+) UTR] require entire 3′(+) HCV. either 98-nucleotide conserved 5′ half containing variable poly(U) and/or poly(UC) stretch significantly RNA-protein implication replication discussed.