Nucleotide sequence and transcriptional organization of the Escherichia coli enterobactin biosynthesis cistrons entB and entA

Nahlik, M S; Brickman, Timothy J.; Ozenberger, Bradley A.; McIntosh, Mark A.

doi:10.1128/jb.171.2.784-790.1989

Cited by 64 publications

(50 citation statements)

References 31 publications

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“…Figure 6A shows a schematic map of the enterobactin gene cluster, including the transcrip- (8,34,52,77). Consistent with the idea that cytoplasmic proteins found in "shockates" have an affinity for membranes, a small fraction of each was found in membrane preparations (34).…”

Section: Introductionmentioning

confidence: 59%

“…Transport of ferric enterobactin into the cell cytosol requires the products of at least five additional genes (34,77,90,104).…”

Section: Geneticsmentioning

confidence: 99%

“…Enterobactin was first purified and characterized from Salmonella enterica serovar Typhimurium and E. coli culture supernatants (34,77,84,90,108). Figure 6A shows a schematic map of the enterobactin gene cluster, including the transcrip- (8,34,52,77).…”

Section: Introductionmentioning

confidence: 99%

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Genetics and Assembly Line Enzymology of Siderophore Biosynthesis in Bacteria

Crosa

Walsh

2002

Microbiol Mol Biol Rev

726

697

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The regulatory logic of siderophore biosynthetic genes in bacteria involves the universal repressor Fur, which acts together with iron as a negative regulator. However in other bacteria, in addition to the Fur-mediated mechanism of regulation, there is a concurrent positive regulation of iron transport and siderophore biosynthetic genes that occurs under conditions of iron deprivation. Despite these regulatory differences the mechanisms of siderophore biosynthesis follow the same fundamental enzymatic logic, which involves a series of elongating acyl-S-enzyme intermediates on multimodular protein assembly lines: nonribosomal peptide synthetases (NRPS). A substantial variety of siderophore structures are produced from similar NRPS assembly lines, and variation can come in the choice of the phenolic acid selected as the N-cap, the tailoring of amino acid residues during chain elongation, the mode of chain termination, and the nature of the capturing nucleophile of the siderophore acyl chain being released. Of course the specific parts that get assembled in a given bacterium may reflect a combination of the inventory of biosynthetic and tailoring gene clusters available. This modular assembly logic can account for all known siderophores. The ability to mix and match domains within modules and to swap modules themselves is likely to be an ongoing process in combinatorial biosynthesis. NRPS evolution will try out new combinations of chain initiation, elongation and tailoring, and termination steps, possibly by genetic exchange with other microorganisms and/or within the same bacterium, to create new variants of iron-chelating siderophores that can fit a particular niche for the producer bacterium

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Section: Introductionmentioning

confidence: 59%

“…Transport of ferric enterobactin into the cell cytosol requires the products of at least five additional genes (34,77,90,104).…”

Section: Geneticsmentioning

confidence: 99%

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Genetics and Assembly Line Enzymology of Siderophore Biosynthesis in Bacteria

Crosa

Walsh

2002

Microbiol Mol Biol Rev

726

697

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“…This suggests that the chromosomal entA and entB genes are not expressed at levels adequate to synthesize detectable quantities of DHBA. It is suspected that the cloned entB and entA genes are transcribed from vector promoters, since no chromosomal promoters are present on the plasmids carrying these genes (27). It is likely that the complementation data for these genes, and perhaps other cloned enterobactin genes, reveal little concerning the native chromosomal expression but rather are only indicative of whether a gene product is functional.…”

Section: Discussionmentioning

confidence: 99%

Genetic analysis of the enterobactin gene cluster in Shigella flexneri

Schmitt

Payne

1991

J Bacteriol

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The genes for transport and synthesis of the phenolate siderophore enterobactin are present on the chromosomes of both Ent' and Ent-clinical isolates of Shigellaflexneri. To determine why Ent-S. flexneri isolates fail to express a functional enterobactin system, the structure and expression of enterobactin genes were examined. Several alterations may be responsible for the inability of S. flexneri to express enterobactin. (i) The mRNA levels produced from the eniC and fepB genes were not derepressed in low-iron media. (ii) DNA sequence analysis of the entC-fepB intergenic region revealed an 83-bp noncontiguous deletion in the putative fepB leader sequence. The deleted sequences are in a region which would be capable of forming extensive stem-and-loop structures. (iii) An amber codon in the 5' portion of the eniC gene was also detected. (iv) An IS) element, previously mapped to the Ent-S.flexneri enterobactin gene cluster, was found to lie within a potential transcriptional termination sequence in the entF-fepE intergenic region. (v) A mutation responsible for the inactivation of the entF gene was mapped to the entF coding region by using entF hybrid gene fusions. (vi) A comparison of outer membrane profiles from an E. coli strain harboring the cloned fepA gene from either an

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“…Using this approach, a cluster of five ORFs was identified. Four of the ORFs showed a high degree of homology to proteins necessary for early steps in the biosynthesis of the DHBA-containing siderophores enterobactin in E. coli and vibriobactin in Vibrio cholerae (31,41,55): ORF D (EntD, VibD), ORF B (EntB, VibB), ORF E (EntE, VibE), and ORF C (EntC, VibC) ( Fig. 1).…”

Section: Identification Of Orfs Within the Taf Regionmentioning

confidence: 99%

The Overlapping angB and angG Genes Are Encoded within the trans -Acting Factor Region of the Virulence Plasmid in Vibrio anguillarum : Essential Role in Siderophore Biosynthesis

2000

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Products encoded in the trans-acting factor (TAF) region are necessary for the biosynthesis of anguibactin and for maximal expression of iron transport and biosynthesis genes in the plasmid-encoded iron-scavenging system of Vibrio anguillarum. Here we identify angB, a locus located in the TAF region, which encodes products essential for anguibactin biosynthesis. We demonstrate that a 287-amino-acid polypeptide, encoded by angB and designated AngB, has an isochorismate lyase activity necessary for the synthesis of 2,3-dihydroxybenzoic acid, an anguibactin biosynthesis intermediate. Complementation of various angB mutations provided evidence that an additional, overlapping gene exists at this locus. This second gene, designated angG, also has an essential biosynthetic function. The angG gene directs the expression of three polypeptides when overexpressed in Escherichia coli, all of which are translated in the same frame as AngB. The results of site-directed mutagenesis and in vivo phosphorylation experiments suggest that the carboxy-terminal end of AngB and the AngG polypeptide(s) function as aryl carrier proteins involved in the assembly of the anguibactin molecule. Our results also show that the regulatory functions of the TAF are encoded in a region, TAFr, which is distinct from and independent of the angB and angG genes.

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Nucleotide sequence and transcriptional organization of the Escherichia coli enterobactin biosynthesis cistrons entB and entA

Cited by 64 publications

References 31 publications

Genetics and Assembly Line Enzymology of Siderophore Biosynthesis in Bacteria

Genetics and Assembly Line Enzymology of Siderophore Biosynthesis in Bacteria

Genetic analysis of the enterobactin gene cluster in Shigella flexneri

The Overlapping angB and angG Genes Are Encoded within the trans -Acting Factor Region of the Virulence Plasmid in Vibrio anguillarum : Essential Role in Siderophore Biosynthesis

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