NMR evidence for similarities between the DNA-binding regions of Drosophila melanogaster heat shock factor and the helix-turn-helix and HNF-3/forkhead families of transcription factors.
Heteronuclear multidimensional NMR experiments of residues 33-163 of the DNA-binding domain of Drosophila heat shock factor, dHSF(33-163), were recorded, using only 3 mg of uniformly 15N-labeled or 2 mg of uniformly 15N/13C-labeled protein. The polypeptide consists of a structured part comprising three helices, a three-stranded antiparallel beta-sheet, with the first two strands connected by a four-residue type I tight turn. The second helix is disrupted at its C-terminal end by a proline residue and is followed by an extended turn, leading to the third helix. The dHSF(33-163) protein is unstructured at its N- and C-termini, and a third unstructured region is found from Thr113 to Arg124. Exchange broadening of the 15N-1H correlations upon titration of 15N labeled HSF with a 13-base-pair DNA duplex suggests a DNA-binding motif in which the third helix acts as the recognition helix. Both the secondary structure and DNA-binding pattern of dHSF(33-163) suggest that the overall topology resembles that the helix-turn-helix bacterial activator CAP [Weber, I. T., & Steitz, T. A. (1987) J. Mol. Biol. 198, 311-326] and the liver-specific transcription factor HNF-3 gamma, the prototype of the HNF-3/forkhead protein family [Clark, K. L., Halay, E. D., Lai, E., & Burley, S. K. (1993) Nature 364, 412-420].
Vuister
G W
GW
Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892.
Kim
S J
SJ
Wu
C
C
Bax
A
A
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism; D018257:Helix-Loop-Helix Motifs; D051543:Hepatocyte Nuclear Factor 3-gamma; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008961:Models, Structural; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D014157:Transcription Factors
D004268:DNA-Binding Proteins; D006360:Heat-Shock Proteins; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; D051543:Hepatocyte Nuclear Factor 3-gamma; D004247:DNA