RNA template-mediated inhibition of hepatitis C virus RNA-dependent RNA polymerase activity.
The enzymatic activity of hepatitis C virus (HCV) RNA-dependent RNA polymerase NS5B is modulated by the molar ratio of NS5B enzyme and RNA template. Depending on the ratio, either template or enzyme can inhibit activity. Inhibition of NS5B activity by RNA template exhibited characteristics of substrate inhibition, suggesting the template binds to a secondary site on the enzyme forming an inactive complex. Template inhibition was modulated by primer. Increasing concentrations of primer restored NS5B activity and decreased the affinity of template for the secondary site. Conversely, increasing template concentration reduced the affinity of primer binding. The kinetic profiles suggest template inhibition results from the binding of template to a site that interferes with primer binding and the formation of productive replication complexes.
Department of Virology, Bristol Myers Squibb Co., Pharmaceutical Research Institute, 5 Research Parkway, Wallingford, CT 06492, USA. ying-kai.wang@bms.com
Ying-Kai
YK
Wang
Karen L
KL
Rigat
Jin-Hua
JH
Sun
Min
M
Gao
Susan B
SB
Roberts
D001665:Binding Sites; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D012313:RNA / Q000737:chemistry* / Q000378:metabolism*; D017361:Viral Nonstructural Proteins / Q000737:chemistry* / Q000378:metabolism*; D012324:RNA-Dependent RNA Polymerase
D004791:Enzyme Inhibitors; D012313:RNA; D017361:Viral Nonstructural Proteins; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase