title: Evidence of an unusually long operator for the fur repressor in the aerobactin promoter of Escherichia coli.
abstract: Production of the siderophore aerobactin in Escherichia coli is transcriptionally metalloregulated through the iron-dependent binding of the Fur (ferric uptake regulator) to a large region (>100 base pairs) within the cognate promoter in the pColV-K30 plasmid. We show in this article that such an unusually long operator results from the specific addition of degenerate repeats 5'-NAT(A/T)AT-3' and not from a fortuitous occupation of the DNA adjacent to the primary binding sites by an excess of the repressor. Furthermore, the protection pattern revealed by DNase I and hydroxyl radical footprinting reflected a side-by-side oligomerization of the protein along an extended DNA stretch. This type of DNA-protein interactions is more like those observed in some eukaryotic factors and nucleoid-associated proteins than typical of specific prokaryotic regulators.
authors.affiliation: Department of Microbial Biotechnology, Centro Nacional de Biotecnologia CSIC, Campus de Cantoblanco, 28049 Madrid, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Escolar
authors.forename: J
authors.initials: J
authors.lastname: Pérez-Martín
authors.forename: V
authors.initials: V
authors.lastname: de Lorenzo
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D018983:DNA Footprinting; D003850:Deoxyribonuclease I; D004926:Escherichia coli / Q000235:genetics*; D016368:Frameshift Mutation; D014644:Genetic Variation; D006877:Hydroxamic Acids / Q000378:metabolism*; D017665:Hydroxyl Radical; D007501:Iron / Q000378:metabolism; D008969:Molecular Sequence Data; D009875:Operator Regions, Genetic; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000302:isolation & purification / Q000378:metabolism*; D017262:Siderophores / Q000378:metabolism
chemical_list: D020121:5' Untranslated Regions; D001426:Bacterial Proteins; D006877:Hydroxamic Acids; D012097:Repressor Proteins; D017262:Siderophores; C068477:ferric uptake regulating proteins, bacterial; C031819:aerobactin; D017665:Hydroxyl Radical; D007501:Iron; D003850:Deoxyribonuclease I