title: Analysis of truncated variants of the iron dependent transcriptional regulators from Corynebacterium diphtheriae and Mycobacterium tuberculosis.
abstract: Iron dependent regulatory proteins of the diphtheria toxin repressor family regulate transcription in a variety of bacterial species. These regulators have three domains. Domains 1 and 2 are required for DNA- and metal-binding while the role of the third domain is only partially defined. We compared full-length and carboxyl-terminally truncated variants of Corynebacterium diphtheriae DtxR and Mycobacterium tuberculosis IdeR for recognition by antibodies, DNA binding, and repressor activity. The third domain of DtxR contains immunodominant epitopes and is required for full repressor activity in an Escherichia coli reporter system, but it is not required for binding to DNA in vitro. In contrast, the third domain of IdeR is required both for full DNA binding activity in vitro and for repressor activity in vivo. DtxR and IdeR differ significantly in their requirements for domain 3 for DNA-binding and repressor activity.
authors.affiliation: Department of Microbiology, University of Colorado Health Sciences Center, Campus Box B-175, Denver, CO 80262, USA.
authors.forename: Diana Marra
authors.initials: DM
authors.lastname: Oram
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Must
authors.forename: Jennifer K
authors.initials: JK
authors.lastname: Spinler
authors.forename: Edda M
authors.initials: EM
authors.lastname: Twiddy
authors.forename: Randall K
authors.initials: RK
authors.lastname: Holmes
mesh_terms: D000907:Antibodies, Bacterial / Q000276:immunology; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D003353:Corynebacterium diphtheriae / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D014644:Genetic Variation; D007501:Iron / Q000378:metabolism*; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; C075586:DtxR protein, Corynebacterium diphtheriae; C096348:IdeR protein, Mycobacterium tuberculosis; D012097:Repressor Proteins; D007501:Iron