Unwinding of nucleic acids by HCV NS3 helicase is sensitive to the structure of the duplex.

نویسندگان

  • A J Tackett
  • L Wei
  • C E Cameron
  • K D Raney
چکیده

Hepatitis C virus (HCV) helicase, non-structural protein 3 (NS3), is proposed to aid in HCV genome replication and is considered a target for inhibition of HCV. In order to investigate the substrate requirements for nucleic acid unwinding by NS3, substrates were prepared by annealing a 30mer oligonucleotide to a 15mer. The resulting 15 bp duplex contained a single-stranded DNA overhang of 15 nt referred to as the bound strand. Other substrates were prepared in which the 15mer DNA was replaced by a strand of peptide nucleic acid (PNA). The PNA-DNA substrate was unwound by NS3, but the observed rate of strand separation was at least 25-fold slower than for the equivalent DNA-DNA substrate. Binding of NS3 to the PNA-DNA substrate was similar to the DNA-DNA substrate, due to the fact that NS3 initially binds to the single-stranded overhang, which was identical in each substrate. A PNA-RNA substrate was not unwound by NS3 under similar conditions. In contrast, morpholino-DNA and phosphorothioate-DNA substrates were utilized as efficiently by NS3 as DNA-DNA substrates. These results indicate that the PNA-DNA and PNA-RNA heteroduplexes adopt structures that are unfavorable for unwinding by NS3, suggesting that the unwinding activity of NS3 is sensitive to the structure of the duplex.

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عنوان ژورنال:
  • Nucleic acids research

دوره 29 2  شماره 

صفحات  -

تاریخ انتشار 2001