Solution structure of the IRF-2 DNA-binding domain: a novel subgroup of the winged helix–turn–helix family

摘要: Abstract Background: The transcription of interferon (IFN) and IFN-inducible genes is mainly regulated by the regulatory factor (IRF) family proteins, which recognize a unique AAGTGA hexamer repeat motif in region IFN genes. A DNA-binding domain approximately 100 amino acids has been commonly found IRF but it no sequence homology to known motifs. Elucidation structures members therefore useful understanding regulation evolution immune system at structural level. Results: solution structure factor-2 (IRF-2) determined NMR spectroscopy. It composed four-stranded antiparallel β sheet three α helices, its global fold similar those winged helix–turn–helix (wHTH) proteins. long loop (Pro37–Asp51) immediately before HTH motif, not other wHTH signals residues this loop, as well second helix are strongly affected upon addition DNA, suggesting that these elements participate DNA recognition binding. Conclusions: similarity IRF-2 with proteins shows belong family, even though there apparent among two families. sequential alignment program (SSAP) slightly different from typical orientation 2. should be categorized into subfamily family. evidence here implies evolutional pathway distinct words, diverged an stem early stage.