Structural Determinant of Human La Protein Critical for Internal Initiation of Translation of Hepatitis C Virus RNA
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
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| Title |
Structural Determinant of Human La Protein Critical for Internal Initiation of Translation of Hepatitis C Virus RNA
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| Creator |
Mondal, Tanmoy
Ray, Upasana Manna, Asit Kumar Gupta, Romi Roy, Siddhartha Das, Saumitra |
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| Subject |
Cell Biology & Physiology
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| Description |
Human La protein has been implicated in facilitating internal ribosome entry site (IRES)-mediated translation
of hepatitis C virus (HCV). Earlier, we demonstrated that the RNA recognition motif (RRM) encompassing
residues 112 to 184 of La protein [La (112–184)] interacts with the HCV IRES near the initiator AUG
codon. A synthetic peptide, LaR2C (24-mer), derived from La RRM (112–184), retains RNA binding ability,
competes with La protein binding to the HCV IRES, and inhibits translation. The peptide interferes with the
assembly of 48S complexes, resulting in the accumulation of preinitiation complexes that are incompetent for
the 60S ribosomal subunit joining. Here, nuclear magnetic resonance spectroscopy of the HCV IRES-bound
peptide complex revealed putative contact points, mutations that showed reduced RNA binding and translation
inhibitory activity. The residues responsible for RNA recognition were found to form a turn in the RRM
(112–184) structure. A 7-mer peptide comprising this turn showed significant translation inhibitory activity.
The bound structure of the peptide inferred from transferred nuclear Overhauser effect experiments suggests
that it is a � turn. This conformation is significantly different from that observed in the free RRM (112–184)
NMR structure, suggesting paths toward a better-stabilized mimetic peptide. Interestingly, addition of hexaarginine
tag enabled the peptide to enter Huh7 cells and showed inhibition of HCV IRES function. More
importantly, the peptide significantly inhibited replication of the HCV monocistronic replicon. Elucidation of
the structural determinant of the peptide provides a basis for developing small peptidomimetic structures as
potent anti-HCV therapeutics.
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| Date |
2008
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://www.eprints.iicb.res.in/165/1/JOURNAL_OF_VIROLOGY%2C_82(23)%2C11927%2D11938%2C2008[5].pdf
Mondal, Tanmoy and Ray, Upasana and Manna, Asit Kumar and Gupta, Romi and Roy, Siddhartha and Das, Saumitra (2008) Structural Determinant of Human La Protein Critical for Internal Initiation of Translation of Hepatitis C Virus RNA. Journal of Virology, 82 (23). pp. 11927-11938. |
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| Relation |
htp://dx.doi.org/10.1128/JVI.00924-08
http://www.eprints.iicb.res.in/165/ |
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