title: The amino terminus of Salmonella enterica serovar Typhimurium sigma(54) is required for interactions with an enhancer-binding protein and binding to fork junction DNA.
abstract: Transcription initiation by the sigma(54)-RNA polymerase holoenzyme requires an enhancer-binding protein that is thought to contact sigma(54) to activate transcription. To identify potential enhancer-binding protein contact sites in sigma(54), we compared the abilities of wild-type and truncated forms of Salmonella enterica serovar Typhimurium sigma(54) to interact with the enhancer-binding protein DctD in a chemical cross-linking assay. Removal of two regions in the amino-terminal portion of sigma(54), residues 57 to 105 and residues 144 to 179, prevented cross-linking, but removal of either region alone did not. In addition, deletion of 56 amino-terminal residues of sigma(54) (region I) reduced the affinity of the protein for a fork junction DNA probe.
authors.affiliation: Department of Microbiology, University of Georgia, Athens, Georgia 30602, USA.
authors.forename: M T
authors.initials: MT
authors.lastname: Kelly
authors.forename: T R
authors.initials: TR
authors.lastname: Hoover
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism*; D004268:DNA-Binding Proteins; D012321:DNA-Directed RNA Polymerases / Q000737:chemistry / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D016297:Mutagenesis, Site-Directed; D051877:RNA Polymerase Sigma 54; D019779:Salmonella enterica; D017384:Sequence Deletion; D012808:Sigma Factor / Q000737:chemistry / Q000378:metabolism*; D016962:Sinorhizobium meliloti / Q000378:metabolism; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D012808:Sigma Factor; D014157:Transcription Factors; C073788:dctD protein, Rhizobium meliloti; D012321:DNA-Directed RNA Polymerases; D051877:RNA Polymerase Sigma 54