Crystal structure of an engrailed homeodomain-DNA complex at 2.8 A resolution: a framework for understanding homeodomain-DNA interactions

Cell. 1990 Nov 2;63(3):579-90. doi: 10.1016/0092-8674(90)90453-l.


The crystal structure of a complex containing the engrailed homeodomain and a duplex DNA site has been determined at 2.8 A resolution and refined to a crystallographic R factor of 24.4%. In this complex, two separate regions of the 61 amino acid polypeptide contact a TAAT subsite. An N-terminal arm fits into the minor groove, and the side chains of Arg-3 and Arg-5 make contacts near the 5' end of this "core consensus" binding site. An alpha helix fits into the major groove, and the side chains of IIe-47 and Asn-51 contact base pairs near the 3' end of the TAAT site. This "recognition helix" is part of a structurally conserved helix-turn-helix unit, but these helices are longer than the corresponding helices in the lambda repressor, and the relationship between the helix-turn-helix unit and the DNA is significantly different.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • DNA / metabolism
  • DNA / ultrastructure*
  • Drosophila / genetics*
  • Genes, Homeobox*
  • Hydrogen Bonding
  • Models, Molecular
  • Molecular Sequence Data
  • Nucleic Acid Conformation
  • Protein Conformation
  • X-Ray Diffraction


  • DNA