Abstract
Using constructs that encode the individual West Nile virus (WNV) NS3helicase (NS3hel) and NS3hel linked to the hydrophilic, N-terminal 1-50 sequence of NS4A, we demonstrated that the presence of NS4A allows NS3hel to conserve energy in the course of oligonucleotide substrate unwinding. Using NS4A mutants, we also determined that the C-terminal acidic EELPD/E motif of NS4A, which appears to be functionally similar to the acidic EFDEMEE motif of hepatitis C virus (HCV) NS4A, is essential for regulating the ATPase activity of NS3hel. We concluded that, similar to HCV NS4A, NS4A of WNV acts as a cofactor for NS3hel and allows helicase to sustain the unwinding rate of the viral RNA under conditions of ATP deficiency.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Adenosine Triphosphate / metabolism
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Amino Acid Sequence
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Coenzymes / chemistry
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Coenzymes / genetics
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Coenzymes / metabolism*
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DNA Helicases / chemistry
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DNA Helicases / genetics
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DNA Helicases / metabolism*
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Gene Expression Regulation, Enzymologic*
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Gene Expression Regulation, Viral
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Molecular Sequence Data
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Sequence Alignment
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Viral Nonstructural Proteins / chemistry
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Viral Nonstructural Proteins / genetics
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Viral Nonstructural Proteins / metabolism*
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Viral Proteins / chemistry
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Viral Proteins / genetics
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Viral Proteins / metabolism*
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West Nile virus / chemistry
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West Nile virus / enzymology*
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West Nile virus / genetics
Substances
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Coenzymes
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Viral Nonstructural Proteins
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Viral Proteins
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Adenosine Triphosphate
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DNA Helicases