Giuseppe
Emeritus
Structural basis for suppression of a host antiviral response by influenza A virus
Kalyan Das*,?, Li-Chung Ma*,?, Rong Xiao*,?, Brian Radvansky*,?, James Aramini*,?, Li Zhao*,?, Jesper Marklund?, Rei-Lin Kuo?, Karen Y. Twu?, Eddy Arnold*,?,‖, Robert M. Krug?,‖, and Gaetano T. Montelione*,?,?,‖
*Center for Advanced Biotechnology and Medicine and - ?Departments of Chemistry and Chemical Biology and ?Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854; ?Department of Biochemistry, Robert Wood Johnson Medical School, Piscataway, NJ 08854; and ?Institute for Cellular and Molecular Biology, Section of Molecular Genetics and Microbiology, University of Texas, Austin, TX 78712 - Communicated by Aaron J. Shatkin, Center for Advanced Biotechnology and Medicine, Piscataway, NJ, June 11, 2008 (received for review March 24, 2008)
Abstract
Influenza A viruses are responsible for seasonal epidemics and high mortality pandemics.
A major function of the viral NS1A protein, a virulence factor, is the inhibition of the production of IFN-β mRNA and other antiviral mRNAs.
The NS1A protein of the human influenza A/Udorn/72 (Ud) virus inhibits the production of these antiviral mRNAs by binding the cellular 30-kDa subunit of the cleavage and polyadenylation specificity factor (CPSF30), which is required for the 3′ end processing of all cellular pre-mRNAs.
Here we report the 1.95-? resolution X-ray crystal structure of the complex formed between the second and third zinc finger domain (F2F3) of CPSF30 and the C-terminal domain of the Ud NS1A protein.
The complex is a tetramer, in which each of two F2F3 molecules wraps around two NS1A effector domains that interact with each other head-to-head.
This structure identifies a CPSF30 binding pocket on NS1A comprised of amino acid residues that are highly conserved among human influenza A viruses.
Single amino acid changes within this binding pocket eliminate CPSF30 binding, and a recombinant Ud virus expressing an NS1A protein with such a substitution is attenuated and does not inhibit IFN-β pre-mRNA processing.
This binding pocket is a potential target for antiviral drug development.
The crystal structure also reveals that two amino acids outside of this pocket, F103 and M106, which are highly conserved (>99%) among influenza A viruses isolated from humans, participate in key hydrophobic interactions with F2F3 that stabilize the complex.
Keywords: antiviral drug discovery bird flu vaccine engineering virology X-ray crystallography
Footnotes
‖To whom correspondence may be addressed. E-mail: guy@cabm.rutgers.edu, rkrug@mail.utexas.edu, or arnold@cabm.rutgers.edu
Author contributions: K.D., L.-C.M., R.X., E.A., R.M.K., and G.T.M. designed research; K.D., L.-C.M., R.X., B.R., J.A., L.Z., J.M., R.-L.K., and K.Y.T. performed research; R.X., B.R., L.Z., J.M., R.-L.K., and K.Y.T. contributed new reagents/analytic tools; K.D., L.-C.M., R.X., B.R., J.A., J.M., R.-L.K., K.Y.T., E.A., R.M.K., and G.T.M. analyzed data; and K.D., L.-C.M., J.A., E.A., R.M.K., and G.T.M. wrote the paper.
The authors declare no conflict of interest.
Freely available online through the PNAS open access option.
? 2008 by The National Academy of Sciences of the USA
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http://www.pnas.org/content/early/2008/08/22/0805213105.abstract
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Kalyan Das*,?, Li-Chung Ma*,?, Rong Xiao*,?, Brian Radvansky*,?, James Aramini*,?, Li Zhao*,?, Jesper Marklund?, Rei-Lin Kuo?, Karen Y. Twu?, Eddy Arnold*,?,‖, Robert M. Krug?,‖, and Gaetano T. Montelione*,?,?,‖
*Center for Advanced Biotechnology and Medicine and - ?Departments of Chemistry and Chemical Biology and ?Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854; ?Department of Biochemistry, Robert Wood Johnson Medical School, Piscataway, NJ 08854; and ?Institute for Cellular and Molecular Biology, Section of Molecular Genetics and Microbiology, University of Texas, Austin, TX 78712 - Communicated by Aaron J. Shatkin, Center for Advanced Biotechnology and Medicine, Piscataway, NJ, June 11, 2008 (received for review March 24, 2008)
Abstract
Influenza A viruses are responsible for seasonal epidemics and high mortality pandemics.
A major function of the viral NS1A protein, a virulence factor, is the inhibition of the production of IFN-β mRNA and other antiviral mRNAs.
The NS1A protein of the human influenza A/Udorn/72 (Ud) virus inhibits the production of these antiviral mRNAs by binding the cellular 30-kDa subunit of the cleavage and polyadenylation specificity factor (CPSF30), which is required for the 3′ end processing of all cellular pre-mRNAs.
Here we report the 1.95-? resolution X-ray crystal structure of the complex formed between the second and third zinc finger domain (F2F3) of CPSF30 and the C-terminal domain of the Ud NS1A protein.
The complex is a tetramer, in which each of two F2F3 molecules wraps around two NS1A effector domains that interact with each other head-to-head.
This structure identifies a CPSF30 binding pocket on NS1A comprised of amino acid residues that are highly conserved among human influenza A viruses.
Single amino acid changes within this binding pocket eliminate CPSF30 binding, and a recombinant Ud virus expressing an NS1A protein with such a substitution is attenuated and does not inhibit IFN-β pre-mRNA processing.
This binding pocket is a potential target for antiviral drug development.
The crystal structure also reveals that two amino acids outside of this pocket, F103 and M106, which are highly conserved (>99%) among influenza A viruses isolated from humans, participate in key hydrophobic interactions with F2F3 that stabilize the complex.
Keywords: antiviral drug discovery bird flu vaccine engineering virology X-ray crystallography
Footnotes
‖To whom correspondence may be addressed. E-mail: guy@cabm.rutgers.edu, rkrug@mail.utexas.edu, or arnold@cabm.rutgers.edu
Author contributions: K.D., L.-C.M., R.X., E.A., R.M.K., and G.T.M. designed research; K.D., L.-C.M., R.X., B.R., J.A., L.Z., J.M., R.-L.K., and K.Y.T. performed research; R.X., B.R., L.Z., J.M., R.-L.K., and K.Y.T. contributed new reagents/analytic tools; K.D., L.-C.M., R.X., B.R., J.A., J.M., R.-L.K., K.Y.T., E.A., R.M.K., and G.T.M. analyzed data; and K.D., L.-C.M., J.A., E.A., R.M.K., and G.T.M. wrote the paper.
The authors declare no conflict of interest.
Freely available online through the PNAS open access option.
? 2008 by The National Academy of Sciences of the USA
-
http://www.pnas.org/content/early/2008/08/22/0805213105.abstract
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