title: Crystal structure of the DNA binding domain of the heat shock transcription factor.
abstract: The structure of the DNA binding domain, determined at 1.8 angstrom resolution, contains a three-helix bundle that is capped by a four-stranded antiparallel beta sheet. This structure is a variant of the helix-turn-helix motif, typified by catabolite activator protein. In the heat shock transcription factor, the first helix of the motif (alpha 2) has an alpha-helical bulge and a proline-induced kink. The angle between the two helices of the motif (alpha 2 and alpha 3) is about 20 degrees smaller than the average for canonical helix-turn-helix proteins. Nevertheless, the relative positions of the first and third helices of the bundle (alpha 1 and alpha 3) are conserved. It is proposed here that the first helix of the three-helix bundle be considered a component of the helix-turn-helix motif.
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley 94720.
authors.forename: C J
authors.initials: CJ
authors.lastname: Harrison
authors.forename: A A
authors.initials: AA
authors.lastname: Bohm
authors.forename: H C
authors.initials: HC
authors.lastname: Nelson
mesh_terms: D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; D018257:Helix-Loop-Helix Motifs; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D014157:Transcription Factors / Q000737:chemistry*
chemical_list: D004268:DNA-Binding Proteins; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; D014157:Transcription Factors; D004247:DNA