¹⁹F NMR Reveals Multiple Conformations at the Dimer Interface of the Nonstructural Protein 1 Effector Domain from Influenza A Virus

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• 作者：James M. Aramini¹ ; ² ; ⁷ ; ^{jma@cabm.rutgers.edu" class="auth_mail} ; Keith Hamilton¹ ; ² ; ⁷ ; Li-Chung Ma¹ ; ² ; G.V.T. Swapna¹ ; ² ; Paul G. Leonard³ ; ⁴ ; John E. Ladbury³ ; ⁴ ; Robert M. Krug⁵ ; Gaetano T. Montelione¹ ; ² ; ⁶ ; ^{guy@cabm.rutgers.edu" class="auth_mail}
• 刊名：Structure
• 出版年：8 April, 2014
• 年：2014
• 卷：22
• 期：4
• 页码：515-525
• 全文大小：1587 K

文摘

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Summary

Nonstructural protein 1 of influenza A virus (NS1A) is a聽conserved virulence factor comprised of an N-terminal double-stranded RNA (dsRNA)-binding domain and a multifunctional C-terminal effector domain (ED), each of which can independently form symmetric homodimers. Here we apply ¹⁹F NMR to NS1A from influenza A/Udorn/307/1972 virus (H3N2) labeled with 5-fluorotryptophan, and we demonstrate that the聽¹⁹F signal of Trp187 is a sensitive, direct monitor of the ED helix:helix dimer interface. ¹⁹F relaxation dispersion data reveal the presence of conformational dynamics within this functionally important protein:protein interface, whose rate is more than three orders of magnitude faster than the kinetics of ED dimerization. ¹⁹F NMR also affords direct spectroscopic evidence that Trp187, which mediates intermolecular ED:ED interactions required for cooperative dsRNA binding, is solvent exposed in full-length NS1A at concentrations below aggregation. These results have important implications for the diverse roles of this NS1A epitope during influenza virus infection.