Wild-type <i>Escherichia coli</i> producing microcins B17, D93, J25, and L; cloning of genes for microcin L production and immunity

Sablé, Sophie; Duarte, Márcia do Rocio; Bravo, Daniel; Lanneluc, Isabelle; Pons, Anne-Marie; Cottenceau, Gilles; Moreno, Felipe

doi:10.1139/w03-047

Cited by 13 publications

(18 citation statements)

References 13 publications

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“…Comparison of its deduced sequence with those in databases revealed that the protein encoded is nearly identical to the cvi gene product, the immunity MccV protein, differing by a single amino acid at position 34. This finding correlates with the experimental finding that the wild-type E. coli LR05 is not sensitive to an MccV-producing strain (41). Thus, the substitution of residue 34 (Gly3Glu) does not modify the immunity protein activity.…”

Section: Resultssupporting

confidence: 87%

“…A 13.5-kb HindIII-SalI DNA fragment issued from DNA plasmid was cloned into pUC19, resulting in pL102. It directs the production of MccL and immunity to MccL and MccV (41).…”

Section: Discussionmentioning

confidence: 99%

“…We demonstrated that it is the same for numerous microcin-producing bacteria (unpublished results). Thus, E. coli LR05 carries the genetic determinants of microcins L, B17, J25, and D93 as well as the immunity gene of MccV (41). The production of multiple microcins provides the microorganism an ecological advantage in a competitive bacterial environment, widening the target cell spectrum and increasing the effectiveness of target cell inhibition.…”

Section: Discussionmentioning

confidence: 99%

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Genetic Analysis and Complete Primary Structure of Microcin L

Pons

Delalande

Duarte

et al. 2004

Antimicrob Agents Chemother

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Escherichia coli LR05, in addition to producing MccB17, J25, and D93, secretes microcin L, a newly discovered microcin that exhibits strong antibacterial activity against related Enterobacteriaceae, including Salmonella enterica serovars Typhimurium and Enteritidis. Microcin L was purified using a two-step procedure including solid-phase extraction and reverse-phase C 18 high-performance liquid chromatography. A 4,901-bp region of the DNA plasmid of E. coli LR05 was sequenced revealing that the microcin L cluster consists of four genes, mclC, mclI, mclA, and mclB. As bacterial resistance to currently used antibiotics is increasing, new pathogenic agents are discovered, and traditional bacterial diseases reappear, increased efforts to search for new antibiotics are needed. Over the past 40 years, research has been restricted largely to improving those well-known compound classes that are active against a standard set of drug targets. As no new classes of antibiotic have been discovered, such insufficient chemical variability exists that there is a potential for serious escalation in clinical microbe resistance. Numerous living organisms are able to produce a variety of ribosomally synthesized antibacterial peptides or proteins involved in their innate defense against microorganisms. During the past 15 years, these compounds have attracted considerable attention, offering many exciting possibilities for the future of antibiotics, in the face of current declining efficacy of conventional treatment (20,22). Of the bacteriocins produced by bacteria, many direct activity against pathogens and, in particular, food-borne microorganisms, such as the grampositive bacterium Listeria monocytogenes (7, 10) and gramnegative bacteria Salmonella enterica and Escherichia coli (34,40).Microcins are secreted by members of the Enterobacteriaceae family, in particular strains of E. coli. They constitute a class of low-molecular-mass peptides (Ͻ10 kDa) that exhibit a narrow antimicrobial spectrum of activity directed against bacterial species phylogenetically related to the producing strains (33). To protect itself, the microcin-producing bacterium exhibits immunity to the action of its own microcin. Recent developments in the biochemical characterization and mode of action allowed us to propose a classification of these peptides into two classes (17, 36). Class I, which includes to date microcins B17, C7, D93, and J25, encompasses peptides with molecular mass below 5 kDa that are highly posttranslationally modified. These microcins display a range of unrelated chemical structures, which in turn results in a variety of action mechanisms (9). Class II includes microcins E492, H47, V, most likely microcin 24, and now microcin L. This second group is more homogeneous and shares several common structural properties with class IIa gram-positive bacteriocins: size ranging from 7 to 10 kDa, absence of modified amino acids, and presence of a consensus motif. Additionally, they are synthesized as precursor peptides with a double-glycine type ...

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Section: Resultssupporting

confidence: 87%

“…A 13.5-kb HindIII-SalI DNA fragment issued from DNA plasmid was cloned into pUC19, resulting in pL102. It directs the production of MccL and immunity to MccL and MccV (41).…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Genetic Analysis and Complete Primary Structure of Microcin L

Pons

Delalande

Duarte

et al. 2004

Antimicrob Agents Chemother

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“…The mcnR gene encodes for a putative regulator of 144 amino acids and shares 99% (143/144) identity with proteins ACA51174 from S. enterica ssp. This may explain why, despite their high similarity, microcin E492 and microcin N producers do not have cross-immunity (Sable et al, 2003). Between residues 19 and 142, McnR has a histone-like nucleoid protein (H-NS) domain (PRK10328).…”

Section: Microcin N Genetic Elementsmentioning

confidence: 99%

Purification and characterization of the antimicrobial peptide microcin N

Corsini

Karahanian

Tello

et al. 2010

FEMS Microbiology Letters

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Microcins are low-molecular-weight proteins secreted by certain bacteria that act by limiting the growth of other bacteria that share the same ecological niche. In the present work, the previous microcin 24 system was resequenced.We detected three nucleotide differences in the microcin-coding gene that partially change the amino acid sequence. According to the present microcin nomenclature, we renamed the five genes constituting this microcin system (mcnRINAB), which are arranged in an operon-like structure: mcnR codes for a putative histone-like nucleoid protein regulator; mcnI codes for the immunity protein; mcnN encodes microcin N; and mcnA and mcnB correspond to an ATP-binding cassette transporter system. Purified microcin N has a molecular weight of 7274.23 Da, as determined by MS. This peptide was stable up to 100°C, resistant to treatment with lipase, lysozyme, trypsin, and chymotrypsin, and susceptible to degradation by proteinase K.

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“…In most cases, further experiments would have to be performed in order to demonstrate with absolute certainty that the antimicrobial activities observed are indeed due to halocin biosynthesis. Besides, in the few cases for which the proteinaceous nature of the compound has been demonstrated, one cannot preclude the possibility that these halocins are in fact redundant with other known halocins, as observed in the case of HalH4 [29] or bacteriocins [52,53]. Halocins H2, H3 and H5 have been reported to be produced by the uncharacterized halophilic strains GLA22, GAA12 and MA220, respectively, all being isolated from a solar saltern in Alicante in Spain [21].…”

Section: Other Putative Halocinsmentioning

confidence: 99%