Structural characterization of the DAXX N-terminal helical bundle domain and its complex with Rassf1C

Structure. 2010 Dec 8;18(12):1642-53. doi: 10.1016/j.str.2010.09.016.

Abstract

DAXX is a scaffold protein with diverse roles including transcription and cell cycle regulation. Using NMR spectroscopy, we demonstrate that the C-terminal half of DAXX is intrinsically disordered, whereas a folded domain is present near its N terminus. This domain forms a left-handed four-helix bundle (H1, H2, H4, H5). However, due to a crossover helix (H3), this topology differs from that of the Sin3 PAH domain, which to date has been used as a model for DAXX. The N-terminal residues of the tumor suppressor Rassf1C fold into an amphipathic α helix upon binding this DAXX domain via a shallow cleft along the flexible helices H2 and H5 (K(D) ∼60 μM). Based on a proposed DAXX recognition motif as hydrophobic residues preceded by negatively charged groups, we found that peptide models of p53 and Mdm2 also bound the helical bundle. These data provide a structural foundation for understanding the diverse functions of DAXX.

Publication types

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

MeSH terms

  • Adaptor Proteins, Signal Transducing / chemistry*
  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism*
  • Binding Sites
  • Co-Repressor Proteins
  • Humans
  • Hydrophobic and Hydrophilic Interactions
  • Magnetic Resonance Spectroscopy
  • Models, Molecular
  • Molecular Chaperones
  • Multiprotein Complexes / chemistry
  • Multiprotein Complexes / metabolism
  • Mutant Proteins / chemistry
  • Mutant Proteins / genetics
  • Mutant Proteins / metabolism
  • Nuclear Proteins / chemistry*
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • Protein Interaction Domains and Motifs / physiology
  • Protein Interaction Mapping
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Sequence Analysis, Protein
  • Sequence Deletion
  • Tumor Suppressor Proteins / chemistry*
  • Tumor Suppressor Proteins / metabolism*

Substances

  • Adaptor Proteins, Signal Transducing
  • Co-Repressor Proteins
  • DAXX protein, human
  • Molecular Chaperones
  • Multiprotein Complexes
  • Mutant Proteins
  • Nuclear Proteins
  • RASSF1 protein, human
  • Tumor Suppressor Proteins