Solution structure of a baculoviral inhibitor of apoptosis (IAP) repeat

Nat Struct Biol. 1999 Jul;6(7):648-51. doi: 10.1038/10701.


Members of the inhibitor of apoptosis (IAP) family of proteins are able to inhibit cell death following viral infection, during development or in cell lines in vitro. All IAP proteins bear one or more baculoviral IAP repeats (BIRs). Here we describe the solution structure of the third BIR domain from the mammalian IAP homolog B (MIHB/c-IAP-1). The BIR domain has a novel fold that is stabilized by zinc tetrahedrally coordinated by one histidine and three cysteine residues. The structure consists of a series of short alpha-helices and turns with the zinc packed in an unusually hydrophobic environment created by residues that are highly conserved among all BIRs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Apoptosis*
  • Baculoviridae / chemistry*
  • Escherichia coli / chemistry
  • Inhibitor of Apoptosis Proteins
  • Magnetic Resonance Spectroscopy
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Structure, Secondary
  • Proteins / chemistry*
  • Recombinant Proteins / chemistry
  • Sequence Homology, Amino Acid
  • Zinc / chemistry


  • Inhibitor of Apoptosis Proteins
  • Proteins
  • Recombinant Proteins
  • Zinc

Associated data

  • GENBANK/L05494
  • GENBANK/L22564
  • GENBANK/U19251
  • GENBANK/U37546
  • GENBANK/U37547
  • GENBANK/U38809
  • GENBANK/U45880
  • PDB/1QBH