Microcin 7: Purification and properties

Garcia-Bustos, Jose; Pezzi, Nieves; Asensio, Carlos

doi:10.1016/s0006-291x(84)80318-6

Cited by 33 publications

(29 citation statements)

References 10 publications

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“…4). Given (19), and its production has been correlated with the induction of transcription from a plasmid AppR-dependent promoter (16). Here we show that transcription from this promoter is also blocked in the presence of many copies of mprA.…”

Section: Discussionmentioning

confidence: 62%

“…Microcin C7 (MccC7) is a 1,000-dalton (Da) peptide antibiotic which inhibits protein synthesis in Escherichia coli (19,20). Microcin B17 (MccB17) is a bactericidal peptide of about 3,200 Da which inhibits DNA replication, induces the SOS repair system, and finally causes DNA degradation (15,30).…”

mentioning

confidence: 99%

“…Microcin B17 (MccB17) is a bactericidal peptide of about 3,200 Da which inhibits DNA replication, induces the SOS repair system, and finally causes DNA degradation (15,30). Both microcins are plasmid encoded and are produced when cultures cease exponential growth and enter the stationary phase (19,28). Thus, microcins constitute a good model system for investigating the molecular mechanisms regulating gene expression in nongrowing cells.…”

mentioning

confidence: 99%

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mprA, an Escherichia coli gene that reduces growth-phase-dependent synthesis of microcins B17 and C7 and blocks osmoinduction of proU when cloned on a high-copy-number plasmid

1990

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Microcins B17 and C7 are plasmid-determined, peptide antibiotics produced by Escherichia coli when cells enter the stationary phase of growth. Microcinogenic strains are immune to the action of the microcin they synthesize. A well-characterized deficient-immunity phenotype is exhibited by microcin B17-producing cells in the absence of the immunity gene mcbG (M.C. Garrido, M. Herrero, R. Kolter, and F. Moreno, EMBO J. 7:1853-1862, 1988). A 14.6-kilobase-pair EcoRI chromosomal fragment was isolated by its ability to suppress this phenotype when cloned into a multicopy vector. This fragment was mapped to 57.5 min on the E. coli genetic map. The position of the gene responsible for suppression, designated mprA, was determined by insertional mutagenesis and deletion analysis. mprA was shown to be transcribed clockwise on the E. coli chromosome, and its product was identified as a 19-kilodalton polypeptide. Suppression was shown to be achieved by decreasing microcin B17 production. Increased mprA gene dosage also caused a decrease in microcin C7 production and blocked the osmoinduction of the proU locus in high-osmolarity media. Our results suggest that the mprA gene product could play a regulatory role on expression of several E. coli genes, this control being exerted at the transcriptional level.

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Section: Discussionmentioning

confidence: 62%

mentioning

confidence: 99%

mentioning

confidence: 99%

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mprA, an Escherichia coli gene that reduces growth-phase-dependent synthesis of microcins B17 and C7 and blocks osmoinduction of proU when cloned on a high-copy-number plasmid

1990

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“…MccC7 is a 1,000-Da peptide antibiotic which inhibits protein synthesis in E. coli (8,9). It is produced by strains harboring plasmid pMccC7.…”

mentioning

confidence: 99%

“…Both microcins are produced when cultures cease exponential growth and enter the stationary phase (8,14). Therefore, the mcb and mcc plasmid operons constitute excellent model systems for investigating the regulation of gene expression in nongrowing cells.…”

mentioning

confidence: 99%

Nucleotide sequence of the Escherichia coli regulatory gene mprA and construction and characterization of mprA-deficient mutants

et al. 1991

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In high copy number, the Escherichia coli mprA gene reduces the synthesis of peptide microcins B17 and C7 (MccB17 and MccC7) and blocks the osmoinduction of the proU operon at the transcriptional level. mprA has been sequenced and shown to encode a polypeptide of 176 amino acids (Mr,20,563). Insertion and deletion mutant mprA alleles were constructed and then transferred to the chromosome by allelic replacement. In these mutants, expression of two mcb-lacZ fusions was fivefold derepressed, indicating a negative regulatory role of mprA on the mcb operon (MccB17). In contrast, no effect of the MprA-mutations on the expression of mcc operon (MccC7) or on the osmoinduction of proU operon was observed.

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How Nature Morphs Peptide Scaffolds into Antibiotics

Nolan

Walsh

2008

ChemBioChem

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The conventional notion that peptides are poor candidates for orally available drugs because of protease-sensitive peptide bonds, intrinsic hydrophilicity, and ionic charges contrasts with the diversity of antibiotic natural products with peptide-based frameworks that are synthesized and utilized by Nature. Several of these antibiotics, including penicillin and vancomycin, are employed to treat bacterial infections in humans and have been best-selling therapeutics for decades. Others might provide new platforms for the design of novel therapeutics to combat emerging antibioticresistant bacterial pathogens.

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Microcin 7: Purification and properties

Cited by 33 publications

References 10 publications

mprA, an Escherichia coli gene that reduces growth-phase-dependent synthesis of microcins B17 and C7 and blocks osmoinduction of proU when cloned on a high-copy-number plasmid

mprA, an Escherichia coli gene that reduces growth-phase-dependent synthesis of microcins B17 and C7 and blocks osmoinduction of proU when cloned on a high-copy-number plasmid

Nucleotide sequence of the Escherichia coli regulatory gene mprA and construction and characterization of mprA-deficient mutants

How Nature Morphs Peptide Scaffolds into Antibiotics

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