title: Genetic evidence that an activation domain of GAL4 does not require acidity and may form a beta sheet.
abstract: Regulation of gene expression in eukaryotes relies on intricate protein-protein interactions. Transcription of the galactose genes in yeast has been a productive model for this type of interaction. The positive activator in this system, GAL4, has a bifunctional C-terminus. It contains both a prototypic acidic activation domain and a region that binds the negative regulator, GAL80. We have taken advantage of this colocalization of functions to subject the region to a constrained mutagenesis analysis: one function was maintained, while the other one was altered. This analysis and the experiments it suggested have led us to two conclusions: first, the acidic amino acids are not, as commonly thought, required for activation; second, this region is not unstructured or alpha helical, but its function may require a beta sheet.
authors.affiliation: Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235-8573.
authors.forename: K K
authors.initials: KK
authors.lastname: Leuther
authors.forename: J M
authors.initials: JM
authors.lastname: Salmeron
authors.forename: S A
authors.initials: SA
authors.lastname: Johnston
mesh_terms: D000595:Amino Acid Sequence; D000838:Anions; D004268:DNA-Binding Proteins / Q000737:chemistry; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017433:Protein Structure, Secondary; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000737:chemistry*
chemical_list: D000838:Anions; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; C055002:GAL80 protein, S cerevisiae; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors