Detection and Isolation of the Repressor Protein for the Tryptophan Operon of
            <i>Escherichia coli</i>

Zubay, Geoffrey; Morse, Daniel E.; Schrenk, W. J.; Miller, Jeffrey H

doi:10.1073/pnas.69.5.1100

Cited by 119 publications

(78 citation statements)

References 13 publications

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“…The exact size of the native trp repressor is not known. Considering the subunit molecular weight, 12,356, previous estimates of the size of the native trp repressor (3,5) would be compatible with a tetrameric structure for the protein in solution.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Nucleotide sequence and expression of Escherichia coli trpR, the structural gene for the trp aporepressor.

Gunsalus¹,

Yanofsky²

1980

Proc. Natl. Acad. Sci. U.S.A.

242

146

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Section: Resultsmentioning

confidence: 99%

“…The gene trpR of Escherichia coli codes for a regulatory protein, the trp aporepressor (1)(2)(3). When complexed with its corepressor L-tryptophan, the aporepressor forms an active repressor complex that can bind at the operator region of the trp operon and prevent transcription initiation (4)(5)(6).…”

mentioning

confidence: 99%

Nucleotide sequence and expression of Escherichia coli trpR, the structural gene for the trp aporepressor.

Gunsalus¹,

Yanofsky²

1980

Proc. Natl. Acad. Sci. U.S.A.

242

146

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“…Optical densities were measured at OD 420 and OD 550 from the supernates after the cells were removed by centrifugation. ␤-Galactosidase was expressed in Miller units (35,53). Transformation assays.…”

Section: Methodsmentioning

confidence: 99%

Effects of Arginine on Streptococcus mutans Growth, Virulence Gene Expression, and Stress Tolerance

Chakraborty

Burne

2017

Appl Environ Microbiol

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Streptococcus mutans is a common constituent of oral biofilms and a primary etiologic agent of human dental caries. The bacteria associated with dental caries have potent abilities to produce organic acids from dietary carbohydrates and to grow and metabolize in acidic conditions. By contrast, many commensal bacteria produce ammonia through the arginine deiminase system (ADS), which moderates the pH of oral biofilms. Arginine metabolism by the ADS is a significant deterrent to the initiation and progression of dental caries. In this study, we observed how exogenously provided L-arginine affects the growth, the virulence properties, and the tolerance of environmental stresses of S. mutans. Supplementation with 1.5% arginine (final concentration) had an inhibitory effect on the growth of S. mutans in complex and chemically defined media, particularly when cells were exposed to acid or oxidative stress. The genes encoding virulence factors required for attachment/accumulation (gtfB and spaP), bacteriocins (nlmA, nlmB, nlmD, and cipB), and the sigma factor required for competence development (comX) were downregulated during growth with 1.5% arginine. Deep sequencing of RNA (RNA-Seq) comparing the transcriptomes of S. mutans growing in chemically defined media with and without 1.5% arginine revealed differential expression of genes encoding ATP-binding cassette transporters, metal transporters, and constituents required for survival, metabolism, and biofilm formation. Therefore, the mechanisms of action by which arginine inhibits dental caries include direct adverse effects on multiple virulence-related properties of the most common human dental caries pathogen.IMPORTANCE Metabolism of the amino acid arginine by the arginine deiminase system (ADS) of certain oral bacteria raises the pH of dental plaque and provides a selective advantage to health-associated bacteria, thereby protecting the host from dental caries (cavities). Here, we examine the effects of arginine on the cavitycausing bacterium Streptococcus mutans. We find that arginine negatively impacts the growth, the pathogenic potential, and the tolerance of environmental stresses in a way that is likely to compromise the ability of S. mutans to cause disease. Using genetic and genomic techniques, multiple mechanisms by which arginine exerts its influence on virulence-related properties of S. mutans are discovered. This report demonstrates that a primary mechanism of action by which arginine inhibits the initiation and progression of dental caries may be by reducing the pathogenic potential of S. mutans.

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“…The Escherichia coli trpR gene encodes a trans-acting negative regulator of tryptophan biosynthesis (Cohen and Jacob 1959;Yanofsky 1971;Zubay et al 1972). The product of the trpR gene is a small peptide of 108 amino acid residues that assembles as a dimer aporepressor molecule and binds the corepressor, L-tryptophan, to form an active repressor complex (Gunsalus and Yanofsky 1980;Joachimiak et al 1983;Arvidson et al 1986).…”

mentioning

confidence: 99%

DNA specificity determinants of Escherichia coli tryptophan repressor binding.

Bass¹,

Sugiono²,

Arvidson³

et al. 1987

Genes Dev.

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We have analyzed the sequence-specific interaction between the Escherichia coli tryptophan (Trp) repressor and its operator using challenge phage vectors. These phages, derivatives of Salmonella phage P22 that have substitutions of synthetic, symmetric trp operators for the P22 rant operator, provide a genetic assay for DNA binding in vivo. Phages carrying operators that retain the determinants of Trp repressor binding efficiently lysogenize cells producing repressor; in contrast, phages with operators missing critical determinants kill such hosts. The binding determinants revealed by this assay corroborate a simple docking model for the Trp repressor-operator interaction postulated from the repressor crystal structure, and account for both the specificity of repressor binding and the ability of Trp repressor to recognize multiple, tandem DNA sites.

show abstract

Detection and Isolation of the Repressor Protein for the Tryptophan Operon of Escherichia coli

Cited by 119 publications

References 13 publications

Nucleotide sequence and expression of Escherichia coli trpR, the structural gene for the trp aporepressor.

Nucleotide sequence and expression of Escherichia coli trpR, the structural gene for the trp aporepressor.

Effects of Arginine on Streptococcus mutans Growth, Virulence Gene Expression, and Stress Tolerance

DNA specificity determinants of Escherichia coli tryptophan repressor binding.

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