The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Sylvie Rebuffat - One of the best experts on this subject based on the ideXlab platform.
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Phenomic and genomic approaches to studying the inhibition of multiresistant Salmonella enterica by Microcin J25
Environmental microbiology, 2020Co-Authors: Laila Ben Said, Sylvie Rebuffat, Séverine Zirah, Jean-guillaume Emond-rheault, Samira Soltani, Sofiane Telhig, Moussa S. Diarra, Lawrence Goodridge, Roger C. Levesque, Ismail FlissAbstract:In livestock production, antibiotics are used to promote animal growth, control infections and thereby increase profitability. This practice has led to the emergence of multiresistant bacteria such as Salmonella, of which some serovars are disseminated in the environment. The objective of this study is to evaluate Microcin J25 as an inhibitor of Salmonella enterica serovars of various origins including human, livestock and food. Among the 116 isolates tested, 37 (31.8%) were found resistant to at least one antibiotic, and 28 were multiresistant with 19 expressing the penta-resistant phenotype ACSSuT. Microcin J25 inhibited all isolates, with minimal inhibitory concentration values ranging from 0.06 μg/ml (28.4 nM) to 400 μg/ml (189 μM). Interestingly, no cross-resistance was found between Microcin J25 and antibiotics. Multiple sequence alignments of genes encoding for the different proteins involved in the recognition and transport of Microcin J25 showed that only ferric-hydroxamate uptake is an essential determinant for susceptibility of S. enterica to Microcin J25. Examination of Salmonella strains exposed to Microcin J25 by transmission electronic microscopy showed for the first-time involvement of a pore formation mechanism. Microcin J25 was a strong inhibitor of several multiresistant isolates of Salmonella and may have a great potential as an alternative to antibiotics.
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Microcins in action: amazing defence strategies of Enterobacteria.
Biochemical Society transactions, 2012Co-Authors: Sylvie RebuffatAbstract:Probably the oldest and most widespread antimicrobial strategy in living organisms is the use of antimicrobial peptides. Bacteria secrete such defence peptides, termed bacteriocins, that they use for microbial competitions. Microcins are bacteriocins of less than 10 kDa produced by Escherichia coli and related enterobacteria through the ribosomal pathway. They are synthesized as linear precursors, which can further undergo complex post-translational modifications resulting from dedicated maturation enzymes encoded in the Microcin gene clusters, and are processed by proteolytic cleavage. Microcins exert potent bactericidal activities that use subtle and clever mechanisms to cross outer and inner membranes of Gram-negative bacteria. To cross the outer membrane, siderophore-Microcins hijack receptors involved in iron acquisition. The lasso-peptide Microcin J25, which is characterized by a knotted arrangement where the C-terminal tail is threaded through an N-terminal macrolactam ring, uses a hydroxamate siderophore receptor and the inner-membrane protein SbmA for import in sensitive bacteria, where it inhibits bacterial transcription through binding to RNAP (RNA polymerase). Microcin C produced as a heptapeptide adenylate, requires an outer-membrane porin and an inner-membrane ABC (ATP-binding-cassette) transporter to reach the cytoplasm of target bacteria, where it is processed by proteases into a non-hydrolysable aspartyl-adenylate analogue. Therefore, despite showing different killing mechanisms and the absence of any structural homology, Microcins have the common characteristic to use Trojan horse strategies to destroy their competitors. They offer new and promising tracks for further design and engineering of novel efficient antibiotics.
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Isolation and Characterization of Two Members of the Siderophore-Microcin Family, Microcins M and H47
Antimicrobial agents and chemotherapy, 2009Co-Authors: Gaëlle Vassiliadis, D. Destoumieux-garzón, Sylvie Rebuffat, Carine Lombard, Jean PeduzziAbstract:In this paper we provide the first biochemical evidence of the existence of a family of structure-related antimicrobial peptides, the siderophore-Microcins, in the Enterobacteriaceae family. We isolated and characterized two novel siderophore-Microcins, MccM and MccH47, previously characterized through genetic studies. MccM and MccH47 were expressed from several Escherichia coli strains containing the Microcin gene clusters. The spectra of their bactericidal activities were found to be restricted to some species of the Enterobacteriaceae. MccM and MccH47 were unable to inhibit the growth of strains carrying mutations in the fepA, cir, and fiu genes, which showed the requirement of the iron-catecholate receptors for their recognition. The MccM and MccH47 peptide moieties contain 77 and 60 residues, respectively, and are derived from the Microcin precursors McmA and MchB, respectively. In addition, both peptides carried a C-terminal posttranslational modification containing a salmochelin-like siderophore moiety also found in MccE492 (X. Thomas et al., J. Biol. Chem., 279:28233-28242, 2004). Interestingly, when MccM was isolated from E. coli Nissle 1917, which lacks the two genes necessary for modification biosynthesis, it was devoid of posttranslational modification. Those two genes could be complemented by their homologues from the MccH47 gene cluster, thereby showing their functional interchangeability between at least two members of the siderophore-Microcin family. Finally, from the sequence analysis of the MccE492 gene cluster, we hypothesized the existence of an additional member of the siderophore-Microcin family. Therefore, we propose that the siderophore-Microcin family contains five representatives.
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The siderophore Microcin family: from the genetic systems to the antimicrobial peptides
2008Co-Authors: Gaëlle Vassiliadis, Jean Peduzzi, Sylvie RebuffatAbstract:Microcins are low molecular weight antimicrobial peptides secreted by enterobacteria and involved in microbial competitions within the intestinal tract. They are synthesized by the ribosomal pathway. We have isolated the first siderophore peptide, a post-translationally modified form of the chromosomally encoded Microcin E492 (MccE492) from Klebsiella pneumoniae, having a potent bactericidal activity mainly directed against Escherichia coli. The post-translational modification consists of a glycosylated catechol-type siderophore linked to the C-terminus. We have recently identified the genes responsible for the acquisition of this modification and proposed a model for its biosynthesis. In order to identify novel siderophore peptides, we analyzed the genetic systems of several Microcinogenic strains. Based on the genetic organization of the Microcin gene clusters, three Microcins which had never been isolated until now, MccM, MccH47 and MccI47, were hypothesized to carry a post-translational modification similar to MccE492, putatively forming the siderophore Microcin family. The gene clusters of these Microcins were found in the genomic DNA of four E. coli strains (Nissle 1917 [the probiotic agent Mutaflor® used against intestinal diseases] H47, CA46, CA58). They are closely interwoven, but genes mchA and mchS1, putatively responsible for the post-translational modification are lacking in strain Nissle 1917. Complementation experiments showed that MccM and MccH47 carry the same post-translational modification as MccE492. MccM and MccH47 were isolated for the first time under their unmodified and modified forms. They were identified by MALDI-TOF MS. These two Microcins become new members of the siderophore Microcin family.
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Insight into Siderophore-Carrying Peptide Biosynthesis: Enterobactin Is a Precursor for Microcin E492 Posttranslational Modification
Antimicrobial agents and chemotherapy, 2007Co-Authors: Gaëlle Vassiliadis, Jean Peduzzi, Sylvie Rebuffat, Séverine Zirah, Xavier Thomas, D. Destoumieux-garzónAbstract:Microcin E492-producing bacteria secrete both unmodified and posttranslationally modified Microcins. The modification consists of a C-glucosylated linear trimer of N -(2,3-dihydroxybenzoyl)-l-serine, a catecholate siderophore related to salmochelins and enterobactin. We show here that repression of enterobactin biosynthesis inhibits the acquisition of Microcin E492 posttranslational modification, as monitored by high-performance liquid chromatography and mass spectrometry. Furthermore, exogenous enterobactin restored the production of posttranslationally modified Microcin in a bacterial strain deficient in enterobactin synthesis. We thus concluded that enterobactin serves as a precursor for the synthesis of the posttranslationally modified Microcin and that the unmodified Microcin is an incompletely processed form of mature Microcin E492. Gene disruption experiments showed that MceC and MceD, two enzymes encoded by the mceABCDEFGHIJ gene cluster, are involved in the synthesis of the Microcin E492 posttranslational modification, as followed by mass spectrometry. Genes homologous to iroB and iroD , required for the conversion (linearization and C-glycosylation) of enterobactin into salmochelins, efficiently complemented mceC and mceD , respectively. Based on our results, a model is proposed for the biosynthesis of the mature siderophore-carrying peptide.
Jean Peduzzi - One of the best experts on this subject based on the ideXlab platform.
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Isolation and Characterization of Two Members of the Siderophore-Microcin Family, Microcins M and H47
Antimicrobial agents and chemotherapy, 2009Co-Authors: Gaëlle Vassiliadis, D. Destoumieux-garzón, Sylvie Rebuffat, Carine Lombard, Jean PeduzziAbstract:In this paper we provide the first biochemical evidence of the existence of a family of structure-related antimicrobial peptides, the siderophore-Microcins, in the Enterobacteriaceae family. We isolated and characterized two novel siderophore-Microcins, MccM and MccH47, previously characterized through genetic studies. MccM and MccH47 were expressed from several Escherichia coli strains containing the Microcin gene clusters. The spectra of their bactericidal activities were found to be restricted to some species of the Enterobacteriaceae. MccM and MccH47 were unable to inhibit the growth of strains carrying mutations in the fepA, cir, and fiu genes, which showed the requirement of the iron-catecholate receptors for their recognition. The MccM and MccH47 peptide moieties contain 77 and 60 residues, respectively, and are derived from the Microcin precursors McmA and MchB, respectively. In addition, both peptides carried a C-terminal posttranslational modification containing a salmochelin-like siderophore moiety also found in MccE492 (X. Thomas et al., J. Biol. Chem., 279:28233-28242, 2004). Interestingly, when MccM was isolated from E. coli Nissle 1917, which lacks the two genes necessary for modification biosynthesis, it was devoid of posttranslational modification. Those two genes could be complemented by their homologues from the MccH47 gene cluster, thereby showing their functional interchangeability between at least two members of the siderophore-Microcin family. Finally, from the sequence analysis of the MccE492 gene cluster, we hypothesized the existence of an additional member of the siderophore-Microcin family. Therefore, we propose that the siderophore-Microcin family contains five representatives.
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The siderophore Microcin family: from the genetic systems to the antimicrobial peptides
2008Co-Authors: Gaëlle Vassiliadis, Jean Peduzzi, Sylvie RebuffatAbstract:Microcins are low molecular weight antimicrobial peptides secreted by enterobacteria and involved in microbial competitions within the intestinal tract. They are synthesized by the ribosomal pathway. We have isolated the first siderophore peptide, a post-translationally modified form of the chromosomally encoded Microcin E492 (MccE492) from Klebsiella pneumoniae, having a potent bactericidal activity mainly directed against Escherichia coli. The post-translational modification consists of a glycosylated catechol-type siderophore linked to the C-terminus. We have recently identified the genes responsible for the acquisition of this modification and proposed a model for its biosynthesis. In order to identify novel siderophore peptides, we analyzed the genetic systems of several Microcinogenic strains. Based on the genetic organization of the Microcin gene clusters, three Microcins which had never been isolated until now, MccM, MccH47 and MccI47, were hypothesized to carry a post-translational modification similar to MccE492, putatively forming the siderophore Microcin family. The gene clusters of these Microcins were found in the genomic DNA of four E. coli strains (Nissle 1917 [the probiotic agent Mutaflor® used against intestinal diseases] H47, CA46, CA58). They are closely interwoven, but genes mchA and mchS1, putatively responsible for the post-translational modification are lacking in strain Nissle 1917. Complementation experiments showed that MccM and MccH47 carry the same post-translational modification as MccE492. MccM and MccH47 were isolated for the first time under their unmodified and modified forms. They were identified by MALDI-TOF MS. These two Microcins become new members of the siderophore Microcin family.
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Insight into Siderophore-Carrying Peptide Biosynthesis: Enterobactin Is a Precursor for Microcin E492 Posttranslational Modification
Antimicrobial agents and chemotherapy, 2007Co-Authors: Gaëlle Vassiliadis, Jean Peduzzi, Sylvie Rebuffat, Séverine Zirah, Xavier Thomas, D. Destoumieux-garzónAbstract:Microcin E492-producing bacteria secrete both unmodified and posttranslationally modified Microcins. The modification consists of a C-glucosylated linear trimer of N -(2,3-dihydroxybenzoyl)-l-serine, a catecholate siderophore related to salmochelins and enterobactin. We show here that repression of enterobactin biosynthesis inhibits the acquisition of Microcin E492 posttranslational modification, as monitored by high-performance liquid chromatography and mass spectrometry. Furthermore, exogenous enterobactin restored the production of posttranslationally modified Microcin in a bacterial strain deficient in enterobactin synthesis. We thus concluded that enterobactin serves as a precursor for the synthesis of the posttranslationally modified Microcin and that the unmodified Microcin is an incompletely processed form of mature Microcin E492. Gene disruption experiments showed that MceC and MceD, two enzymes encoded by the mceABCDEFGHIJ gene cluster, are involved in the synthesis of the Microcin E492 posttranslational modification, as followed by mass spectrometry. Genes homologous to iroB and iroD , required for the conversion (linearization and C-glycosylation) of enterobactin into salmochelins, efficiently complemented mceC and mceD , respectively. Based on our results, a model is proposed for the biosynthesis of the mature siderophore-carrying peptide.
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Insight into siderophore-carrying peptide biosynthesis: Enterobactin is a precursor for Microcin E492 post-translational modification.
Antimicrobial Agents and Chemotherapy, 2007Co-Authors: Gaëlle Vassiliadis, Jean Peduzzi, Sylvie Rebuffat, Séverine Zirah, Xavier Thomas, D. Destoumieux-garzónAbstract:Microcin E492-producing bacteria secrete both unmodified and post-translationally modified Microcins. The modification consists of a C-glucosylated linear trimer of N-(2,3-dihydroxybenzoyl)-L-serine, a catecholate siderophore related to salmochelins and enterobactin. We showed here that repression of enterobactin biosynthesis inhibits the acquisition of Microcin E492 post-translational modification, as monitored by high-performance liquid chromatography and mass spectrometry. Furthemore, exogenous enterobactin restored the production of post-translationally modified Microcin in a bacterial strain deficient in enterobactin synthesis. We thus concluded that enterobactin serves as a precursor for the synthesis of the post-translationally modified Microcin and that the unmodified Microcin is an incompletely processed form of the mature Microcin E492. Gene disruption experiments showed that MceC and MceD, two enzymes encoded by the mceABCDEFGHIJ gene cluster, are involved in the synthesis of Microcin E492 post-translational modification, as followed by mass spectrometry. Genes homologous to iroB and iroD, required for the conversion (linearization and C-glycosylation) of enterobactin into salmochelins, efficiently complemented mceC and mceD, respectively. Based on our results, a model is proposed for the biosynthesis of the mature siderophore-carrying peptide.
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Microcins, gene-encoded antibacterial peptides from enterobacteria
Natural product reports, 2007Co-Authors: S. Duquesne, D. Destoumieux-garzón, Jean Peduzzi, Sylvie RebuffatAbstract:Covering 1982 to 2006 Microcins are gene-encoded antibacterial peptides, with molecular masses below 10 kDa, produced by enterobacteria. They are secreted under conditions of nutrient depletion and exert potent antibacterial activity against closely related species. Typical gene clusters encoding the Microcin precursor, the self-immunity factor, the secretionproteins and frequently the post-translational modification enzymes are located either on plasmids or on the chromosome. In contrast to most of the antibiotics of microbial origin, which are non-ribosomally synthesized by multimodular enzymes termed peptide synthetases, Microcins are ribosomally synthesized as precursors, which are further modified enzymatically. They form a restricted class of potent antibacterial peptides. Fourteen Microcins have been reported so far, among which only seven have been isolated and characterized. Despite the low number of known representatives, Microcins exhibit a diversity of structures and antibacterial mechanisms. This review provides an updated overview of Microcin structures, antibacterial activities, genetic systems and biosyntheses, as well as of their mechanisms of action.
S. Rebuffat - One of the best experts on this subject based on the ideXlab platform.
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Microcins, gene-encoded antibacterial peptides from enterobacteria.
Natural Product Reports, 2007Co-Authors: S. Duquesne, J. Peduzzi, D. Destoumieux-garzón, S. RebuffatAbstract:Microcins are gene-encoded antibacterial peptides, with molecular masses below 10 kDa, produced by enterobacteria. They are secreted under conditions of nutrient depletion and exert potent antibacterial activity against closely related species. Typical gene clusters encoding the Microcin precursor, the self-immunity factor, the secretion proteins and frequently the post-translational modification enzymes are located either on plasmids or on the chromosome. Contrary to most of the antibiotics of microbial origin, which are synthesized by multimodular enzymes termed peptide synthetases, Microcins are ribosomally-synthesized as precursors further modified enzymatically. They form a restricted class of potent antibacterial peptides. Fourteen Microcins have been reported until now, among which only seven have been isolated and characterized. Despite the low number of known representatives, Microcins exhibit a diversity of structures and antibacterial mechanisms. This review gives an updated overview of Microcin structures, biosyntheses, antibacterial activities and mechanisms of action. It shows how fascinating, clever and complex the mechanisms used by Microcins are to kill target bacteria. Covering 1982 to 2006.
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Maturation of the antibacterial siderophore-peptide Microcin E492
2007Co-Authors: G. Vassiliadis, J. Peduzzi, S. Rebuffat, X. Thomas, S. Zirah, D. Destoumieux-garzónAbstract:Microcins are gene-encoded antibacterial peptides secreted by enterobacteria. They are involved in microbial competition within the intestinal tract. Besides the antibacterial peptide, Microcin gene clusters encode modification enzymes, export and self-immunity factors. Microcin E492 (MccE492) is a 84-residue peptide secreted by Klebsiella pneumoniae. It is post-translationally modified by a glycosylated linear trimer of N-(2, 3 dihydroxybenzoyl)-L-serine (DHBS) similar to enterobactin/salmochelins. It was the first natural siderophore-peptide to be isolated The siderophore-type post-translational modification was shown to be required for optimal antibacterial activity, probably because the Microcin uses the iron-siderophore receptors for recognition at the outer membrane of Escherichia coli. Since under particular culture conditions, MccE492 was also isolated as a less potent unmodified peptide (u-MccE492), we have investigated the maturation process that provides the peptide with higher antibacterial activity. We first showed that the siderophore enterobactin (a cyclic trimer of DHBS) serves as a substrate for MccE492 post-translational modification. Indeed, we found that high iron concentration or free aromatic acids repress both enterobactin synthesis and the acquisition of the MccE492 post-translational modification. Consistently, addition of exogenous enterobactin restored the modification in an enterobactin-deficient strain unable to express mature MccE492. We then identified the enzymes involved in MccE492 maturation through gene-disruption and functional complementation. We showed that both mceC and mceD genes from MccE492 gene cluster are required for MccE492 maturation. These genes, homologous to iroB and iroD, respectively encode a C-glycosyltranferase and an enterobactin-esterase, which convert enterobactin into salmochelins. A tentative model was proposed for MccE492 maturation. Enterobactin would be C-glycosylated by MceC, further hydrolyzed by MceD and finally transferred onto MccE492 Ser84 carboxyl group by unidentified enzymes likely to include MceI and J. Because mceC, D, I and J homologues are found in gene clusters encoding MccH47, MccI47 and/or MccM, this enzyme machinery is believed to be common to all known siderophore-Microcins.
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Structural and Functional Diversity of Microcins, Gene-Encoded Antibacterial Peptides from Enterobacteria.
Journal of Molecular Microbiology and Biotechnology, 2007Co-Authors: S. Duquesne, V. Petit, J. Peduzzi, S. RebuffatAbstract:Microcins are a peculiar class of gene-encoded low-molecular-mass antibacterial peptides secreted by enterobacteria. They contribute to the regulation of microbial competitions within the intestinal microbiota. The genetic systems involved in Microcin biosynthesis share a conserved organization. Similar to bacteriocins of Gram-positive bacteria, Microcins exert potent antibacterial activity directed against phylogenetically-related bacterial strains, with minimal inhibitory concentrations in the nanomolar range. In contrast to bacteriocins, they display a great structural diversity among the few representatives well characterized until now, that makes difficult the description of Microcin subclasses. This review focuses on three Microcins, MccE492m that carries a C-terminal posttranslational modification containing a catechol-type siderophore, MccJ25, a cyclic peptide with a unique 'lasso-type' structure and MccC7 or C51, with a common N-formylated heptapeptide-nucleotide structure. We show these Microcins exhibit 'Trojan horse' mechanisms of antibacterial activity: either (i) the Microcin structure is a mime of an essential element, permitting its recognition by outer membrane receptors used for vital functions in bacteria and further translocation into the periplasmic space, or (ii) it is secreted as a harmless molecule and further processed in susceptible bacteria to form the toxic entity. When inside target bacteria, Microcins bind essential enzymes or interact with the inner membrane to form a bacterial killing structure.
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Biosynthesis of siderophore-peptides, a class of potent antimicrobial peptides from enterobacteria, requires two precursors
2007Co-Authors: G. Vassiliadis, J. Peduzzi, D. Destoumieux-garzón, X. Thomas, S. Zirah, S. RebuffatAbstract:Microcins are gene-encoded potent antimicrobial peptides secreted by enterobacteria. Microcin E492 is secreted by the wild type Klebsiella pneumoniae and recombinant E. coli strains under both an unmodified (u- MccE492) and a post-translationally modified form (MccE492), endowed with higher activity. The modification consists of a C-glucosylated linear trimer of N-(2,3-dihydroxybenzoyl)-L-serine, a catecholate siderophore related to salmochelins and enterobactin. MccE492 was thus the first siderophore-peptide to be isolated. MccE492 was produced under conditions inhibiting various biosynthetic pathways. HPLC and mass spectrometry were used to monitor MccE492/u-MccE492 production. Free aromatic amino acids and high iron concentrations inhibited the acquisition of the post-translational modification. Exogenous enterobactin restored this biosynthesis in a bacterial strain deficient in enterobactin synthesis. Gene disruption experiments allowed identifying the mceABCDEFGHIJ-encoded enzymes responsible for the posttranslational modification of the precursor MceA. mceC and mceD are required for the synthesis of MccE492 post-translational modification. Moreover, those genes are efficiently complemented by genes homologous to iroB and iroD, which are involved in salmochelin biosynthesis. Thus, two precursors, MceA and enterobactin, are the substrates of the MccE492 enzyme machinery and u-MccE492 is an incompletely processed form of the Microcin. Modification of MccE492 would involve this sequence of events: enterobactin C-glycosylation by MceC, hydrolyzis of C-glucosylated enterobactin by MceD, transfer of the linearized enterobactin onto MceA by MceI and J, and finally concomitant cleavage and export of the mature siderophore-peptide.
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Structural and functional diversity of Microcins, gene-encoded antibacterial peptides from Enterobacteriaceae
2006Co-Authors: S. Duquesne, V. Petit, J. Peduzzi, S. RebuffatAbstract:Microcins are gene-encoded low-molecular-weight antibacterial peptides secreted by Enterobacteriaceae. They are involved in the regulation of microbial competitions within the intestinal microflora. Similar to bacteriocins from lactic acid bacteria, Microcins exert potent bactericidal activity directed against phylogenetically-related bacterial strains, with low minimal inhibitory concentrations in the nanomolar range. However, they distinguish from bacteriocins by displaying a great structural diversity among the less than ten representatives characterized until now. Nonetheless, genetic systems encoding Microcins share a conserved organization. Microcins exhibit very complex mechanisms of bactericidal activity involving several steps: (i) recognition by outer membrane receptors used for vital functions in bacteria that have been piratized by Microcins; (ii) translocation of the antibacterial peptide into the periplasm; (iii) bacterial killing process that involves either interaction with the inner membrane to form a toxic structure, or passage through the inner membrane to interact with a cytoplasmic target. Microcin E492m (MccE492m) is a hydrophobic and anionic 84-amino acid peptide endowed with a C-terminal posttranslational modification, which mimics a catechol type siderophore; it targets the inner membrane of sensible bacteria in a TonB- and energy-dependent manner. Microcin J25 (MccJ25) is a 21-residue cyclic peptide with a unique lasso-type three-dimensional structure that inhibits RNA polymerase. Despite their low structural homology and different killing mechanisms, these Microcins have a similar import pathway into sensible bacteria that uses siderophore receptors responsible for iron transport into bacteria. Microcin C7/C51 (MccC7/C51) is a short peptide linked to a nucleotide. It is not recognized by these receptors. In order to identify the structural regions involved in the recognition/translocation step and the killing mechanism, we studied the structure-function relationships for these three Microcins.
D. Destoumieux-garzón - One of the best experts on this subject based on the ideXlab platform.
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Isolation and Characterization of Two Members of the Siderophore-Microcin Family, Microcins M and H47
Antimicrobial agents and chemotherapy, 2009Co-Authors: Gaëlle Vassiliadis, D. Destoumieux-garzón, Sylvie Rebuffat, Carine Lombard, Jean PeduzziAbstract:In this paper we provide the first biochemical evidence of the existence of a family of structure-related antimicrobial peptides, the siderophore-Microcins, in the Enterobacteriaceae family. We isolated and characterized two novel siderophore-Microcins, MccM and MccH47, previously characterized through genetic studies. MccM and MccH47 were expressed from several Escherichia coli strains containing the Microcin gene clusters. The spectra of their bactericidal activities were found to be restricted to some species of the Enterobacteriaceae. MccM and MccH47 were unable to inhibit the growth of strains carrying mutations in the fepA, cir, and fiu genes, which showed the requirement of the iron-catecholate receptors for their recognition. The MccM and MccH47 peptide moieties contain 77 and 60 residues, respectively, and are derived from the Microcin precursors McmA and MchB, respectively. In addition, both peptides carried a C-terminal posttranslational modification containing a salmochelin-like siderophore moiety also found in MccE492 (X. Thomas et al., J. Biol. Chem., 279:28233-28242, 2004). Interestingly, when MccM was isolated from E. coli Nissle 1917, which lacks the two genes necessary for modification biosynthesis, it was devoid of posttranslational modification. Those two genes could be complemented by their homologues from the MccH47 gene cluster, thereby showing their functional interchangeability between at least two members of the siderophore-Microcin family. Finally, from the sequence analysis of the MccE492 gene cluster, we hypothesized the existence of an additional member of the siderophore-Microcin family. Therefore, we propose that the siderophore-Microcin family contains five representatives.
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Microcins, gene-encoded antibacterial peptides from enterobacteria.
Natural Product Reports, 2007Co-Authors: S. Duquesne, J. Peduzzi, D. Destoumieux-garzón, S. RebuffatAbstract:Microcins are gene-encoded antibacterial peptides, with molecular masses below 10 kDa, produced by enterobacteria. They are secreted under conditions of nutrient depletion and exert potent antibacterial activity against closely related species. Typical gene clusters encoding the Microcin precursor, the self-immunity factor, the secretion proteins and frequently the post-translational modification enzymes are located either on plasmids or on the chromosome. Contrary to most of the antibiotics of microbial origin, which are synthesized by multimodular enzymes termed peptide synthetases, Microcins are ribosomally-synthesized as precursors further modified enzymatically. They form a restricted class of potent antibacterial peptides. Fourteen Microcins have been reported until now, among which only seven have been isolated and characterized. Despite the low number of known representatives, Microcins exhibit a diversity of structures and antibacterial mechanisms. This review gives an updated overview of Microcin structures, biosyntheses, antibacterial activities and mechanisms of action. It shows how fascinating, clever and complex the mechanisms used by Microcins are to kill target bacteria. Covering 1982 to 2006.
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Insight into Siderophore-Carrying Peptide Biosynthesis: Enterobactin Is a Precursor for Microcin E492 Posttranslational Modification
Antimicrobial agents and chemotherapy, 2007Co-Authors: Gaëlle Vassiliadis, Jean Peduzzi, Sylvie Rebuffat, Séverine Zirah, Xavier Thomas, D. Destoumieux-garzónAbstract:Microcin E492-producing bacteria secrete both unmodified and posttranslationally modified Microcins. The modification consists of a C-glucosylated linear trimer of N -(2,3-dihydroxybenzoyl)-l-serine, a catecholate siderophore related to salmochelins and enterobactin. We show here that repression of enterobactin biosynthesis inhibits the acquisition of Microcin E492 posttranslational modification, as monitored by high-performance liquid chromatography and mass spectrometry. Furthermore, exogenous enterobactin restored the production of posttranslationally modified Microcin in a bacterial strain deficient in enterobactin synthesis. We thus concluded that enterobactin serves as a precursor for the synthesis of the posttranslationally modified Microcin and that the unmodified Microcin is an incompletely processed form of mature Microcin E492. Gene disruption experiments showed that MceC and MceD, two enzymes encoded by the mceABCDEFGHIJ gene cluster, are involved in the synthesis of the Microcin E492 posttranslational modification, as followed by mass spectrometry. Genes homologous to iroB and iroD , required for the conversion (linearization and C-glycosylation) of enterobactin into salmochelins, efficiently complemented mceC and mceD , respectively. Based on our results, a model is proposed for the biosynthesis of the mature siderophore-carrying peptide.
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Insight into siderophore-carrying peptide biosynthesis: Enterobactin is a precursor for Microcin E492 post-translational modification.
Antimicrobial Agents and Chemotherapy, 2007Co-Authors: Gaëlle Vassiliadis, Jean Peduzzi, Sylvie Rebuffat, Séverine Zirah, Xavier Thomas, D. Destoumieux-garzónAbstract:Microcin E492-producing bacteria secrete both unmodified and post-translationally modified Microcins. The modification consists of a C-glucosylated linear trimer of N-(2,3-dihydroxybenzoyl)-L-serine, a catecholate siderophore related to salmochelins and enterobactin. We showed here that repression of enterobactin biosynthesis inhibits the acquisition of Microcin E492 post-translational modification, as monitored by high-performance liquid chromatography and mass spectrometry. Furthemore, exogenous enterobactin restored the production of post-translationally modified Microcin in a bacterial strain deficient in enterobactin synthesis. We thus concluded that enterobactin serves as a precursor for the synthesis of the post-translationally modified Microcin and that the unmodified Microcin is an incompletely processed form of the mature Microcin E492. Gene disruption experiments showed that MceC and MceD, two enzymes encoded by the mceABCDEFGHIJ gene cluster, are involved in the synthesis of Microcin E492 post-translational modification, as followed by mass spectrometry. Genes homologous to iroB and iroD, required for the conversion (linearization and C-glycosylation) of enterobactin into salmochelins, efficiently complemented mceC and mceD, respectively. Based on our results, a model is proposed for the biosynthesis of the mature siderophore-carrying peptide.
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Microcins, gene-encoded antibacterial peptides from enterobacteria
Natural product reports, 2007Co-Authors: S. Duquesne, D. Destoumieux-garzón, Jean Peduzzi, Sylvie RebuffatAbstract:Covering 1982 to 2006 Microcins are gene-encoded antibacterial peptides, with molecular masses below 10 kDa, produced by enterobacteria. They are secreted under conditions of nutrient depletion and exert potent antibacterial activity against closely related species. Typical gene clusters encoding the Microcin precursor, the self-immunity factor, the secretionproteins and frequently the post-translational modification enzymes are located either on plasmids or on the chromosome. In contrast to most of the antibiotics of microbial origin, which are non-ribosomally synthesized by multimodular enzymes termed peptide synthetases, Microcins are ribosomally synthesized as precursors, which are further modified enzymatically. They form a restricted class of potent antibacterial peptides. Fourteen Microcins have been reported so far, among which only seven have been isolated and characterized. Despite the low number of known representatives, Microcins exhibit a diversity of structures and antibacterial mechanisms. This review provides an updated overview of Microcin structures, antibacterial activities, genetic systems and biosyntheses, as well as of their mechanisms of action.
Gaëlle Vassiliadis - One of the best experts on this subject based on the ideXlab platform.
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Isolation and Characterization of Two Members of the Siderophore-Microcin Family, Microcins M and H47
Antimicrobial agents and chemotherapy, 2009Co-Authors: Gaëlle Vassiliadis, D. Destoumieux-garzón, Sylvie Rebuffat, Carine Lombard, Jean PeduzziAbstract:In this paper we provide the first biochemical evidence of the existence of a family of structure-related antimicrobial peptides, the siderophore-Microcins, in the Enterobacteriaceae family. We isolated and characterized two novel siderophore-Microcins, MccM and MccH47, previously characterized through genetic studies. MccM and MccH47 were expressed from several Escherichia coli strains containing the Microcin gene clusters. The spectra of their bactericidal activities were found to be restricted to some species of the Enterobacteriaceae. MccM and MccH47 were unable to inhibit the growth of strains carrying mutations in the fepA, cir, and fiu genes, which showed the requirement of the iron-catecholate receptors for their recognition. The MccM and MccH47 peptide moieties contain 77 and 60 residues, respectively, and are derived from the Microcin precursors McmA and MchB, respectively. In addition, both peptides carried a C-terminal posttranslational modification containing a salmochelin-like siderophore moiety also found in MccE492 (X. Thomas et al., J. Biol. Chem., 279:28233-28242, 2004). Interestingly, when MccM was isolated from E. coli Nissle 1917, which lacks the two genes necessary for modification biosynthesis, it was devoid of posttranslational modification. Those two genes could be complemented by their homologues from the MccH47 gene cluster, thereby showing their functional interchangeability between at least two members of the siderophore-Microcin family. Finally, from the sequence analysis of the MccE492 gene cluster, we hypothesized the existence of an additional member of the siderophore-Microcin family. Therefore, we propose that the siderophore-Microcin family contains five representatives.
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The siderophore Microcin family: from the genetic systems to the antimicrobial peptides
2008Co-Authors: Gaëlle Vassiliadis, Jean Peduzzi, Sylvie RebuffatAbstract:Microcins are low molecular weight antimicrobial peptides secreted by enterobacteria and involved in microbial competitions within the intestinal tract. They are synthesized by the ribosomal pathway. We have isolated the first siderophore peptide, a post-translationally modified form of the chromosomally encoded Microcin E492 (MccE492) from Klebsiella pneumoniae, having a potent bactericidal activity mainly directed against Escherichia coli. The post-translational modification consists of a glycosylated catechol-type siderophore linked to the C-terminus. We have recently identified the genes responsible for the acquisition of this modification and proposed a model for its biosynthesis. In order to identify novel siderophore peptides, we analyzed the genetic systems of several Microcinogenic strains. Based on the genetic organization of the Microcin gene clusters, three Microcins which had never been isolated until now, MccM, MccH47 and MccI47, were hypothesized to carry a post-translational modification similar to MccE492, putatively forming the siderophore Microcin family. The gene clusters of these Microcins were found in the genomic DNA of four E. coli strains (Nissle 1917 [the probiotic agent Mutaflor® used against intestinal diseases] H47, CA46, CA58). They are closely interwoven, but genes mchA and mchS1, putatively responsible for the post-translational modification are lacking in strain Nissle 1917. Complementation experiments showed that MccM and MccH47 carry the same post-translational modification as MccE492. MccM and MccH47 were isolated for the first time under their unmodified and modified forms. They were identified by MALDI-TOF MS. These two Microcins become new members of the siderophore Microcin family.
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Insight into Siderophore-Carrying Peptide Biosynthesis: Enterobactin Is a Precursor for Microcin E492 Posttranslational Modification
Antimicrobial agents and chemotherapy, 2007Co-Authors: Gaëlle Vassiliadis, Jean Peduzzi, Sylvie Rebuffat, Séverine Zirah, Xavier Thomas, D. Destoumieux-garzónAbstract:Microcin E492-producing bacteria secrete both unmodified and posttranslationally modified Microcins. The modification consists of a C-glucosylated linear trimer of N -(2,3-dihydroxybenzoyl)-l-serine, a catecholate siderophore related to salmochelins and enterobactin. We show here that repression of enterobactin biosynthesis inhibits the acquisition of Microcin E492 posttranslational modification, as monitored by high-performance liquid chromatography and mass spectrometry. Furthermore, exogenous enterobactin restored the production of posttranslationally modified Microcin in a bacterial strain deficient in enterobactin synthesis. We thus concluded that enterobactin serves as a precursor for the synthesis of the posttranslationally modified Microcin and that the unmodified Microcin is an incompletely processed form of mature Microcin E492. Gene disruption experiments showed that MceC and MceD, two enzymes encoded by the mceABCDEFGHIJ gene cluster, are involved in the synthesis of the Microcin E492 posttranslational modification, as followed by mass spectrometry. Genes homologous to iroB and iroD , required for the conversion (linearization and C-glycosylation) of enterobactin into salmochelins, efficiently complemented mceC and mceD , respectively. Based on our results, a model is proposed for the biosynthesis of the mature siderophore-carrying peptide.
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Insight into siderophore-carrying peptide biosynthesis: Enterobactin is a precursor for Microcin E492 post-translational modification.
Antimicrobial Agents and Chemotherapy, 2007Co-Authors: Gaëlle Vassiliadis, Jean Peduzzi, Sylvie Rebuffat, Séverine Zirah, Xavier Thomas, D. Destoumieux-garzónAbstract:Microcin E492-producing bacteria secrete both unmodified and post-translationally modified Microcins. The modification consists of a C-glucosylated linear trimer of N-(2,3-dihydroxybenzoyl)-L-serine, a catecholate siderophore related to salmochelins and enterobactin. We showed here that repression of enterobactin biosynthesis inhibits the acquisition of Microcin E492 post-translational modification, as monitored by high-performance liquid chromatography and mass spectrometry. Furthemore, exogenous enterobactin restored the production of post-translationally modified Microcin in a bacterial strain deficient in enterobactin synthesis. We thus concluded that enterobactin serves as a precursor for the synthesis of the post-translationally modified Microcin and that the unmodified Microcin is an incompletely processed form of the mature Microcin E492. Gene disruption experiments showed that MceC and MceD, two enzymes encoded by the mceABCDEFGHIJ gene cluster, are involved in the synthesis of Microcin E492 post-translational modification, as followed by mass spectrometry. Genes homologous to iroB and iroD, required for the conversion (linearization and C-glycosylation) of enterobactin into salmochelins, efficiently complemented mceC and mceD, respectively. Based on our results, a model is proposed for the biosynthesis of the mature siderophore-carrying peptide.