Isolation, characterization, and mode of action on Escherichia coli strains of microcin D93

Abstract

Microcin D93 is an antibiotic substance produced by Escherichia coli strains which harbor the 5.5-kilobase plasmid pMccD93. Its production is unaffected by the use of different carbon and ammonia sources, different phosphate concentrations, or mitomycin C. We developed a method for purifying this microcin based on gel permeation chromatography and reverse-phase high-pressure liquid chromatography. The antibiotic appears to be a small, hydrophilic, basic peptide, active on E. coli and Proteus, Citrobacter, and Pseudomonas species and much more active on recA strains than on their isogenic wild type. Diminution of the rate of DNA biosynthesis without any apparent effect on other macromolecules appears to be a primary effect in the action of microcin D93.

Microcins, gene-encoded antibacterial peptides from enterobacteria

“…Among the fourteen microcins identified so far, only seven have been structurally characterized. 10 were only evidenced by few partial biochemical studies, and will not be described further in this review article.…”

Microcins reveal natural mechanisms of bacterial manipulation to inform therapeutic development

“…gyrase (MccB17) [121] and aspartyl-tRNA synthetase (MccC) [21], with general inhibition of DNA biosynthesis indicated for MccD93 [122]. MccJ25 has a second cytotoxic effect: it inhibits respiratory chain enzymes and increases the production of reactive oxygen species [123].…”

“…The cytotoxic targets of Class I microcins are varied aspects of nucleic acid and protein synthesis, which contrasts with the currently known inner membrane-active mechanisms of the Class II microcins. Class I microcins have been shown to specifically inhibit RNA polymerase (MccJ25) [ 120 ], DNA gyrase (MccB17) [ 121 ] and aspartyl-tRNA synthetase (MccC) [ 21 ], with general inhibition of DNA biosynthesis indicated for MccD93 [ 122 ]. MccJ25 has a second cytotoxic effect: it inhibits respiratory chain enzymes and increases the production of reactive oxygen species [ 123 ].…”

Rapid identification of Escherichia coli microcin J25 producing strains using polymerase chain reaction and colony blot hybridization

“…(Laviña et al 1990;Wilkens et al 1997). Based on cross-immunity, biochemical, and genetic criteria, nine different microcins have been identified: MccB17 (Bayer et al 1995), MccC7 (Guijarro et al 1995), MccD93 (Martínez and Perez-Díaz 1986), MccE492 (Wilkens et al 1997), MccH47 (Gaggero et al 1993), MccJ25 (Salomón and Farías 1992), MccL (Gaillard-Gendron et al 2000), MccN24 (O'Brien and Mahanty 1996), and ColV (Fath et al 1994).…”