title: Crystal structure of an engrailed homeodomain-DNA complex at 2.8 A resolution: a framework for understanding homeodomain-DNA interactions.
abstract: 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.
authors.affiliation: Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
authors.forename: C R
authors.initials: CR
authors.lastname: Kissinger
authors.forename: B S
authors.initials: BS
authors.lastname: Liu
authors.forename: E
authors.initials: E
authors.lastname: Martin-Blanco
authors.forename: T B
authors.initials: TB
authors.lastname: Kornberg
authors.forename: C O
authors.initials: CO
authors.lastname: Pabo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000378:metabolism / Q000648:ultrastructure*; D004330:Drosophila / Q000235:genetics*; D005801:Genes, Homeobox; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011487:Protein Conformation; D014961:X-Ray Diffraction
chemical_list: D004247:DNA