Abstract
The promoter region of the pColV-K30-encoded operon specifying biosynthesis and transport of the siderophore aerobactin was subjected to deletion analysis to determine the smallest DNA sequence affording iron regulation of a iucA'-'lacZ gene fusion. A 78-base-pair (bp) region containing the main (P1) promoter retained the character of inducibility under iron starvation. A 250-bp fragment carrying this sequence was examined for protection against DNase I by the Fur protein, the product of a gene (fur) required for negative control of several iron-regulated functions. The DNase I footprints, in the presence of various divalent heavy-metal ions added as corepressors, revealed two contiguous binding sites with different lengths and affinities for Fur. Increased concentrations of the protein appeared to elicit formation of repressor oligomers which bind to the upstream and downstream regions of the P1 promoter in a metal-dependent fashion, but with a presently undefined stoichiometry. The primary site for Fur binding spans 31 bp and contains two overlapping symmetry dyads which share the sequence 5'-TCATT-3'. It also contains extensive homology with a 19-bp consensus sequence for iron-regulated genes as deduced from comparison with the fhuA and fepA putative promoter sequences.
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- Bagg A., Neilands J. B. Mapping of a mutation affecting regulation of iron uptake systems in Escherichia coli K-12. J Bacteriol. 1985 Jan;161(1):450–453. doi: 10.1128/jb.161.1.450-453.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bindereif A., Neilands J. B. Promoter mapping and transcriptional regulation of the iron assimilation system of plasmid ColV-K30 in Escherichia coli K-12. J Bacteriol. 1985 Jun;162(3):1039–1046. doi: 10.1128/jb.162.3.1039-1046.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Coulton J. W., Mason P., Cameron D. R., Carmel G., Jean R., Rode H. N. Protein fusions of beta-galactosidase to the ferrichrome-iron receptor of Escherichia coli K-12. J Bacteriol. 1986 Jan;165(1):181–192. doi: 10.1128/jb.165.1.181-192.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fleming T. P., Nahlik M. S., Neilands J. B., McIntosh M. A. Physical and genetic characterization of cloned enterobactin genomic sequences from Escherichia coli K-12. Gene. 1985;34(1):47–54. doi: 10.1016/0378-1119(85)90293-8. [DOI] [PubMed] [Google Scholar]
- Gross R., Engelbrecht F., Braun V. Identification of the genes and their polypeptide products responsible for aerobactin synthesis by pColV plasmids. Mol Gen Genet. 1985;201(2):204–212. doi: 10.1007/BF00425661. [DOI] [PubMed] [Google Scholar]
- Hantke K. Cloning of the repressor protein gene of iron-regulated systems in Escherichia coli K12. Mol Gen Genet. 1984;197(2):337–341. doi: 10.1007/BF00330982. [DOI] [PubMed] [Google Scholar]
- Hantke K. Identification of an iron uptake system specific for coprogen and rhodotorulic acid in Escherichia coli K12. Mol Gen Genet. 1983;191(2):301–306. doi: 10.1007/BF00334830. [DOI] [PubMed] [Google Scholar]
- Hantke K. Regulation of ferric iron transport in Escherichia coli K12: isolation of a constitutive mutant. Mol Gen Genet. 1981;182(2):288–292. doi: 10.1007/BF00269672. [DOI] [PubMed] [Google Scholar]
- Hendrickson W., Schleif R. A dimer of AraC protein contacts three adjacent major groove regions of the araI DNA site. Proc Natl Acad Sci U S A. 1985 May;82(10):3129–3133. doi: 10.1073/pnas.82.10.3129. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Johnson A. D., Meyer B. J., Ptashne M. Interactions between DNA-bound repressors govern regulation by the lambda phage repressor. Proc Natl Acad Sci U S A. 1979 Oct;76(10):5061–5065. doi: 10.1073/pnas.76.10.5061. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lundrigan M. D., Kadner R. J. Nucleotide sequence of the gene for the ferrienterochelin receptor FepA in Escherichia coli. Homology among outer membrane receptors that interact with TonB. J Biol Chem. 1986 Aug 15;261(23):10797–10801. [PubMed] [Google Scholar]
- Neilands J. B. Iron absorption and transport in microorganisms. Annu Rev Nutr. 1981;1:27–46. doi: 10.1146/annurev.nu.01.070181.000331. [DOI] [PubMed] [Google Scholar]
- Pabo C. O., Sauer R. T. Protein-DNA recognition. Annu Rev Biochem. 1984;53:293–321. doi: 10.1146/annurev.bi.53.070184.001453. [DOI] [PubMed] [Google Scholar]
- Schäffer S., Hantke K., Braun V. Nucleotide sequence of the iron regulatory gene fur. Mol Gen Genet. 1985;200(1):110–113. doi: 10.1007/BF00383321. [DOI] [PubMed] [Google Scholar]
- Worsham P. L., Konisky J. Locus affecting regulation of the colicin I receptor by iron. J Bacteriol. 1985 Jan;161(1):428–431. doi: 10.1128/jb.161.1.428-431.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- de Lorenzo V., Bindereif A., Paw B. H., Neilands J. B. Aerobactin biosynthesis and transport genes of plasmid ColV-K30 in Escherichia coli K-12. J Bacteriol. 1986 Feb;165(2):570–578. doi: 10.1128/jb.165.2.570-578.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
- de Lorenzo V., Neilands J. B. Characterization of iucA and iucC genes of the aerobactin system of plasmid ColV-K30 in Escherichia coli. J Bacteriol. 1986 Jul;167(1):350–355. doi: 10.1128/jb.167.1.350-355.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]