title: Structure of the DNA-binding domain of zinc GAL4.
abstract: The yeast transcriptional activator GAL4 binds co-operatively to four related 17-base-pair sequences within an upstream activating sequence (UASG) to activate transcription of the GAL1 and GAL10 genes. It belongs to a class of gene regulatory proteins which all contain a highly conserved cysteine-rich region within their DNA-binding domains. This region binds zinc and it has been proposed that the cysteine residues coordinate the zinc, creating a structure analogous to one of the 'zinc fingers' of the transcription factor TFIIIA (ref. 8). Using 1H-113Cd two-dimensional nuclear magnetic resonance spectra of the cadmium form of the domain, we previously showed that the protein contains a Cd2Cys6 cluster where cysteines 11 and 28 act as bridging ligands. A similar study of a fragment of GAL4 has recently been published. We report here the solution structure of the DNA binding domain of GAL4; two helix-turn-strand motifs pack around a Zn2Cys6 cluster in a novel pseudo-symmetrical arrangement. The results show that the GAL4 zinc-binding domain differs significantly from both the TFIIIA-type zinc finger and the steroid hormone receptor DNA-binding domains.
authors.affiliation: Department of Biochemistry, University of Cambridge, UK.
authors.forename: P J
authors.initials: PJ
authors.lastname: Kraulis
authors.forename: A R
authors.initials: AR
authors.lastname: Raine
authors.forename: P L
authors.initials: PL
authors.lastname: Gadhavi
authors.forename: E D
authors.initials: ED
authors.lastname: Laue
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry*; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D011487:Protein Conformation; D029701:Saccharomyces cerevisiae Proteins; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors; D016335:Zinc Fingers / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D004247:DNA