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. 1978 Oct;136(1):219–226. doi: 10.1128/jb.136.1.219-226.1978

Effect of Tryptophan Analogs on Derepression of the Escherichia coli Tryptophan Operon by Indole-3-Propionic Acid

Robert J Pauley 1,†, Walter W Fredricks 1, Oliver H Smith 1
PMCID: PMC218652  PMID: 361689

Abstract

The abilities of 14 tryptophan analogs to repress the tryptophan (trp) operon have been studied in Escherichia coli cells derepressed by incubation with 0.25 mM indole-3-propionic acid (IPA). trp operon expression was monitored by measuring the specific activities of anthranilate synthase (EC 4.1.3.27) and the tryptophan synthase (EC 4.2.1.20) β subunit. Analogs characterized by modification or removal of the α-amino group or the α-carboxyl group did not repress the trp operon. The only analogs among this group that appeared to interact with the trp aporepressor were IPA, which derepressed the trp operon, and d-tryptophan. Analogs with modifications of the indole ring repressed the trp operon to various degrees. 7-Methyl-tryptophan inhibited anthranilate synthase activity and consequently derepressed the trp operon. Additionally, 7-methyltryptophan prevented IPA-mediated derepression but, unlike tryptophan, did so in a non-coordinate manner, with the later enzymes of the operon being relatively more repressed than the early enzymes. The effect of 7-methyltryptophan on IPA-mediated derepression was likely not due to the interaction of IPA with the allosteric site of anthranilate synthase, even though feedback-resistant mutants of anthranilate synthase were partially resistant to derepression by IPA. The effect of 7-methyltryptophan on derepression by IPA was probably due to the effect of the analog-aporepressor complex on trp operon expression.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Baker R. F., Yanofsky C. The periodicity of RNA polymerase initiations: a new regulatory feature of transcription. Proc Natl Acad Sci U S A. 1968 May;60(1):313–320. doi: 10.1073/pnas.60.1.313. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Baker T. I., Crawford I. P. Anthranilate synthetase. Partial purification and some kinetic studies on the enzyme from Escherichia coli. J Biol Chem. 1966 Dec 10;241(23):5577–5584. [PubMed] [Google Scholar]
  3. Bertrand K., Yanofsky C. Regulation of transcription termination in the leader region of the tryptophan operon of Escherichia coli involves tryptophan or its metabolic product. J Mol Biol. 1976 May 15;103(2):339–349. doi: 10.1016/0022-2836(76)90316-8. [DOI] [PubMed] [Google Scholar]
  4. Doolittle W. F., Yanofsky C. Mutants of Escherichia coli with an altered tryptophanyl-transfer ribonucleic acid synthetase. J Bacteriol. 1968 Apr;95(4):1283–1294. doi: 10.1128/jb.95.4.1283-1294.1968. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Hadar R., Slonim A., Kuhn J. Role of D-tryptophan oxidase in D-tryptophan utilization by Escherichia coli. J Bacteriol. 1976 Mar;125(3):1096–1104. doi: 10.1128/jb.125.3.1096-1104.1976. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Held W. A., Smith O. H. Mechanism of 3-methylanthranilic acid derepression of the tryptophan operon in Escherichia coli. J Bacteriol. 1970 Jan;101(1):209–217. doi: 10.1128/jb.101.1.209-217.1970. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
  8. McGeoch D., McGeoch J., Morse D. Synthesis of tryptophan operon RNA in a cell-free system. Nat New Biol. 1973 Oct 3;245(144):137–140. doi: 10.1038/newbio245137a0. [DOI] [PubMed] [Google Scholar]
  9. Morse D. E., Baker R. F., Yanofsky C. Translation of the tryptophan messenger RNA of Escherichia coli. Proc Natl Acad Sci U S A. 1968 Aug;60(4):1428–1435. doi: 10.1073/pnas.60.4.1428. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Morse D. E., Morse A. N. Dual-control of the tryptophan operon is mediated by both tryptophanyl-tRNA synthetase and the repressor. J Mol Biol. 1976 May 15;103(2):209–226. doi: 10.1016/0022-2836(76)90310-7. [DOI] [PubMed] [Google Scholar]
  11. Morse D. E., Mosteller R. D., Yanofsky C. Dynamics of synthesis, translation, and degradation of trp operon messenger RNA in E. coli. Cold Spring Harb Symp Quant Biol. 1969;34:725–740. doi: 10.1101/sqb.1969.034.01.082. [DOI] [PubMed] [Google Scholar]
  12. Rose J. K., Squires C. L., Yanofsky C., Yang H. L., Zubay G. Regulation of in vitro transcription of the tryptophan operon by purified RNA polymerase in the presence of partially purified repressor and tryptophan. Nat New Biol. 1973 Oct 3;245(144):133–137. doi: 10.1038/newbio245133a0. [DOI] [PubMed] [Google Scholar]
  13. Squires C. L., Lee F. D., Yanofsky C. Interaction of the trp repressor and RNA polymerase with the trp operon. J Mol Biol. 1975 Feb 15;92(1):93–111. doi: 10.1016/0022-2836(75)90093-5. [DOI] [PubMed] [Google Scholar]
  14. Squires C. L., Rose J. K., Yanofsky C., Yang H. L., Zubay G. Tryptophanyl-tRNA and tryptophanyl-tRNA synthetase are not required for in vitro repression of the tryptophan operon. Nat New Biol. 1973 Oct 3;245(144):131–133. doi: 10.1038/newbio245131a0. [DOI] [PubMed] [Google Scholar]
  15. VOGEL H. J., BONNER D. M. Acetylornithinase of Escherichia coli: partial purification and some properties. J Biol Chem. 1956 Jan;218(1):97–106. [PubMed] [Google Scholar]
  16. Zubay G., Morse D. E., Schrenk W. J., Miller J. H. Detection and isolation of the repressor protein for the tryptophan operon of Escherichia coli. Proc Natl Acad Sci U S A. 1972 May;69(5):1100–1103. doi: 10.1073/pnas.69.5.1100. [DOI] [PMC free article] [PubMed] [Google Scholar]

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