Vaccinia virus N1L protein resembles a B cell lymphoma-2 (Bcl-2) family protein

Protein Sci. 2007 Jan;16(1):118-24. doi: 10.1110/ps.062454707. Epub 2006 Nov 22.


Poxviruses encode immuno-modulatory proteins capable of subverting host defenses. The poxvirus vaccinia expresses a small 14-kDa protein, N1L, that is critical for virulence. We report the crystal structure of N1L, which reveals an unexpected but striking resemblance to host apoptotic regulators of the B cell lymphoma-2 (Bcl-2) family. Although N1L lacks detectable Bcl-2 homology (BH) motifs at the sequence level, we show that N1L binds with high affinity to the BH3 peptides of pro-apoptotic Bcl-2 family proteins in vitro, consistent with a role for N1L in modulating host antiviral defenses.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Crystallography, X-Ray
  • Dimerization
  • Hydrophobic and Hydrophilic Interactions
  • In Vitro Techniques
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Binding
  • Protein Conformation
  • Protein Structure, Quaternary
  • Proto-Oncogene Proteins c-bcl-2 / chemistry
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • Sequence Homology, Amino Acid
  • Vaccinia virus / chemistry*
  • Vaccinia virus / genetics
  • Viral Proteins / chemistry*
  • Viral Proteins / genetics


  • N1L protein, Vaccinia virus
  • Proto-Oncogene Proteins c-bcl-2
  • Viral Proteins