title: In vitro DNA-binding properties of VirB, the Shigella flexneri virulence regulatory protein.
abstract: The DNA-binding activity of the Shigella flexneri VirB transcription factor was studied in vitro. The protein was found to bind non-specifically to DNA, but showed preferential binding to VirB-dependent promoter sequences. DNA binding was contingent on the presence of an intact helix-turn-helix motif. While high molecular mass protein-DNA complexes were formed in both specific and non-specific interactions with DNA, mutant derivatives of VirB lacking a leucine zipper domain or a carboxyl-terminal-located oligomerisation domain formed discrete complexes, indicating that an ability to oligomerise on DNA was responsible for the formation of high molecular mass complexes by the wild-type protein.
authors.affiliation: Department of Microbiology, Moyne Institute of Preventive Medicine, University of Dublin, Trinity College, 2, Dublin, Ireland.
authors.forename: Sorcha
authors.initials: S
authors.lastname: McKenna
authors.forename: Christophe
authors.initials: C
authors.lastname: Beloin
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Dorman
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D019077:Helix-Turn-Helix Motifs; D066298:In Vitro Techniques; D016350:Leucine Zippers; D008957:Models, Genetic; D008970:Molecular Weight; D009154:Mutation; D009842:Oligopeptides / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000378:metabolism; D012763:Shigella flexneri / Q000235:genetics / Q000472:pathogenicity*; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D014774:Virulence / Q000235:genetics*; D037521:Virulence Factors
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D009842:Oligopeptides; D011994:Recombinant Proteins; D014157:Transcription Factors; D037521:Virulence Factors; D004247:DNA