Structural basis for ubiquitin-like ISG 15 protein binding to the NS1 protein of influenza B virus: A protein-protein interaction function that is not shared by the corresponding N-terminal domain of the NS1 protein of influenza A virus

Weiming Yuan, James M. Aramini, Gaetano T. Montelione, Robert M. Krug

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

The N-terminal domains of the NS1 protein of influenza B virus (NS1B protein) and the NS1 protein of influenza A virus (NS1A protein) share one function: binding double-stranded RNA (dsRNA). Here we show that the N-terminal domain of the NS1B protein possesses an additional function that is not shared by its NS1A counterpart: binding the ubiquitin-like ISG15 protein that is induced by influenza B virus infection. Homology modeling predicts that the dimeric six-helical N-terminal domain of the NS1B protein differs from its NS1A protein counterpart in containing large loops between helices 1 and 2 (loops 1 and 1′) and between helices 2 and 3 (loops 2 and 2′). Mutagenesis establishes that residues located in loop 1/1′ together with residues located in polypeptide segment 94-103 form the ISG15 protein-binding site of NS1B protein. Loop 1/1′ is not required for dsRNA binding, which instead requires arginine residues R50, R53, R50′, and R53′ located in antiparallel helices 1 and 1′. Further, we demonstrate that the binding sites for RNA and protein are independent of each other. In particular, ISG15 and dsRNA can bind simultaneously; the binding of the ISG15 protein does not have a detectable effect on the binding of dsRNA, and vice versa.

Original languageEnglish (US)
Pages (from-to)291-301
Number of pages11
JournalVirology
Volume304
Issue number2
DOIs
StatePublished - 2002

All Science Journal Classification (ASJC) codes

  • Virology

Keywords

  • Double-stranded RNA
  • Homology modeling
  • ISG15 protein
  • Influenza A virus
  • Influenza B virus
  • Influenza virus NS1 protein
  • Protein-protein interactions
  • RNA-protein interactions

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