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. 1996 Jun;178(11):3252–3259. doi: 10.1128/jb.178.11.3252-3259.1996

Anaerobic biosynthesis of enterobactin Escherichia coli: regulation of entC gene expression and evidence against its involvement in menaquinone (vitamin K2) biosynthesis.

O Kwon 1, M E Hudspeth 1, R Meganathan 1
PMCID: PMC178078  PMID: 8655506

Abstract

In Escherichia coli, isochorismate is a common precursor for the biosynthesis of the siderophore enterobactin and menaquinone (vitamin K2). Isochorismate is formed by the shikimate pathway from chorismate by the enzyme isochorismate synthase encoded by the entC gene. Since enterobactin is involved in the aerobic assimilation of iron, and menaquinone is involved in anaerobic electron transport, we investigated the regulation of entC by iron and oxygen. An operon fusion between entC with its associated regulatory region and lacZ+ was constructed and introduced into the chromosome in a single copy. Expression of entC-lacZ was found to be regulated by the concentration of iron both aerobically and anaerobically. An established entC::kan mutant deficient in enterobactin biosynthesis was found to grow normally and synthesize wild-type levels of menaquinone under anaerobic conditions in iron-sufficient media. These results led to the demonstration of an alternate isochorismate synthase specifically involved in menaquinone synthesis encoded by the menF gene. Consistent with these findings, the entC+ strains were found to synthesize enterobactin anaerobically under iron-deficient conditions while the ent mutants failed to do so.

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Selected References

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  1. 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]
  2. Bentley R. The shikimate pathway--a metabolic tree with many branches. Crit Rev Biochem Mol Biol. 1990;25(5):307–384. doi: 10.3109/10409239009090615. [DOI] [PubMed] [Google Scholar]
  3. Brickman T. J., Ozenberger B. A., McIntosh M. A. Regulation of divergent transcription from the iron-responsive fepB-entC promoter-operator regions in Escherichia coli. J Mol Biol. 1990 Apr 20;212(4):669–682. doi: 10.1016/0022-2836(90)90229-F. [DOI] [PubMed] [Google Scholar]
  4. Calderwood S. B., Mekalanos J. J. Iron regulation of Shiga-like toxin expression in Escherichia coli is mediated by the fur locus. J Bacteriol. 1987 Oct;169(10):4759–4764. doi: 10.1128/jb.169.10.4759-4764.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Cotter P. A., Gunsalus R. P. Contribution of the fnr and arcA gene products in coordinate regulation of cytochrome o and d oxidase (cyoABCDE and cydAB) genes in Escherichia coli. FEMS Microbiol Lett. 1992 Feb 1;70(1):31–36. doi: 10.1016/0378-1097(92)90558-6. [DOI] [PubMed] [Google Scholar]
  6. Cotter P. A., Gunsalus R. P. Oxygen, nitrate, and molybdenum regulation of dmsABC gene expression in Escherichia coli. J Bacteriol. 1989 Jul;171(7):3817–3823. doi: 10.1128/jb.171.7.3817-3823.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Foster M. S., Carroll J. N., Niederhoffer E. C. Phenylalanine- and tyrosine-dependent production of enterobactin in Escherichia coli. FEMS Microbiol Lett. 1994 Mar 15;117(1):79–83. doi: 10.1111/j.1574-6968.1994.tb06745.x. [DOI] [PubMed] [Google Scholar]
  8. Guerinot M. L. Microbial iron transport. Annu Rev Microbiol. 1994;48:743–772. doi: 10.1146/annurev.mi.48.100194.003523. [DOI] [PubMed] [Google Scholar]
  9. Guest J. R. Anaerobic growth of Escherichia coli K12 with fumarate as terminal electron acceptor. Genetic studies with menaquinone and fluoroacetate-resistant mutants. J Gen Microbiol. 1979 Dec;115(2):259–271. doi: 10.1099/00221287-115-2-259. [DOI] [PubMed] [Google Scholar]
  10. Jones H. M., Gunsalus R. P. Regulation of Escherichia coli fumarate reductase (frdABCD) operon expression by respiratory electron acceptors and the fnr gene product. J Bacteriol. 1987 Jul;169(7):3340–3349. doi: 10.1128/jb.169.7.3340-3349.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Kaiser A., Leistner E. Role of the entC gene in enterobactin and menaquinone biosynthesis in Escherichia coli. Arch Biochem Biophys. 1990 Feb 1;276(2):331–335. doi: 10.1016/0003-9861(90)90728-h. [DOI] [PubMed] [Google Scholar]
  12. Lodge J. S., Emery T. Anaerobic iron uptake by Escherichia coli. J Bacteriol. 1984 Nov;160(2):801–804. doi: 10.1128/jb.160.2.801-804.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Meganathan R., Coffell R. Identity of the quinone in Bacillus alcalophilus. J Bacteriol. 1985 Nov;164(2):911–913. doi: 10.1128/jb.164.2.911-913.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Melville S. B., Gunsalus R. P. Mutations in fnr that alter anaerobic regulation of electron transport-associated genes in Escherichia coli. J Biol Chem. 1990 Nov 5;265(31):18733–18736. [PubMed] [Google Scholar]
  15. Neilands J. B. Siderophores of bacteria and fungi. Microbiol Sci. 1984 Apr;1(1):9–14. [PubMed] [Google Scholar]
  16. Ozenberger B. A., Brickman T. J., McIntosh M. A. Nucleotide sequence of Escherichia coli isochorismate synthetase gene entC and evolutionary relationship of isochorismate synthetase and other chorismate-utilizing enzymes. J Bacteriol. 1989 Feb;171(2):775–783. doi: 10.1128/jb.171.2.775-783.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Palaniappan C., Sharma V., Hudspeth M. E., Meganathan R. Menaquinone (vitamin K2) biosynthesis: evidence that the Escherichia coli menD gene encodes both 2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylic acid synthase and alpha-ketoglutarate decarboxylase activities. J Bacteriol. 1992 Dec;174(24):8111–8118. doi: 10.1128/jb.174.24.8111-8118.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Palaniappan C., Taber H., Meganathan R. Biosynthesis of o-succinylbenzoic acid in Bacillus subtilis: identification of menD mutants and evidence against the involvement of the alpha-ketoglutarate dehydrogenase complex. J Bacteriol. 1994 May;176(9):2648–2653. doi: 10.1128/jb.176.9.2648-2653.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Popp J. L., Berliner C., Bentley R. Vitamin K (menaquinone) biosynthesis in bacteria: high-performance liquid chromatographic assay of the overall synthesis of o-succinylbenzoic acid and of 2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylic acid synthase. Anal Biochem. 1989 May 1;178(2):306–310. doi: 10.1016/0003-2697(89)90643-x. [DOI] [PubMed] [Google Scholar]
  20. Popp J. L. Sequence and overexpression of the menD gene from Escherichia coli. J Bacteriol. 1989 Aug;171(8):4349–4354. doi: 10.1128/jb.171.8.4349-4354.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Simons R. W., Houman F., Kleckner N. Improved single and multicopy lac-based cloning vectors for protein and operon fusions. Gene. 1987;53(1):85–96. doi: 10.1016/0378-1119(87)90095-3. [DOI] [PubMed] [Google Scholar]
  22. Spencer M. E., Guest J. R. Isolation and properties of fumarate reductase mutants of Escherichia coli. J Bacteriol. 1973 May;114(2):563–570. doi: 10.1128/jb.114.2.563-570.1973. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Tummuru M. K., Brickman T. J., McIntosh M. A. The in vitro conversion of chorismate to isochorismate catalyzed by the Escherichia coli entC gene product. Evidence that EntA does not contribute to isochorismate synthase activity. J Biol Chem. 1989 Dec 5;264(34):20547–20551. [PubMed] [Google Scholar]
  24. Unden G. Differential roles for menaquinone and demethylmenaquinone in anaerobic electron transport of E. coli and their fnr-independent expression. Arch Microbiol. 1988;150(5):499–503. doi: 10.1007/BF00422294. [DOI] [PubMed] [Google Scholar]
  25. Young I. G., Batterham T. J., Gibson F. The isolation, identification and properties of isochorismic acid. An intermediate in the biosynthesis of 2,3-dihydroxybenzoic acid. Biochim Biophys Acta. 1969 May 6;177(3):389–400. doi: 10.1016/0304-4165(69)90301-8. [DOI] [PubMed] [Google Scholar]

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