Penetration and interactions of the antimicrobial peptide, microcin J25, into uncharged phospholipid monolayers

Bellomio, Augusto; Oliveira, Rafael G.; Maggio, Bruno; Morero, Roberto D.

doi:10.1016/j.jcis.2004.11.025

Cited by 27 publications

(19 citation statements)

References 32 publications

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“…The bactericidal spectrum of activity was found to be restricted to Enterobacteriaceae and specifically directed against Escherichia (333) and Salmonella (320,397) species. The microcin inserts into the inner membrane, whereupon the potential becomes destabilized due to pore formation that leads to depolarization and permeabilization of the E. coli cytoplasmic membrane (25,84,328). Another mechanism of antibacterial activity has been reported for E. coli strain Nissle 1917 (129) that produces microcins (7).…”

Section: Barrier Effect Against Pathogensmentioning

confidence: 99%

The Front Line of Enteric Host Defense against Unwelcome Intrusion of Harmful Microorganisms: Mucins, Antimicrobial Peptides, and Microbiota

2006

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SUMMARY The intestinal tract is a complex ecosystem that combines resident microbiota and the cells of various phenotypes with complex metabolic activities that line the epithelial wall. The intestinal cells that make up the epithelium provide physical and chemical barriers that protect the host against the unwanted intrusion of microorganisms that hijack the cellular molecules and signaling pathways of the host and become pathogenic. Some of the organisms making up the intestinal microbiota also have microbicidal effects that contribute to the barrier against enteric pathogens. This review describes the two cell lineages present in the intestinal epithelium: the goblet cells and the Paneth cells, both of which play a pivotal role in the first line of enteric defense by producing mucus and antimicrobial peptides, respectively. We also analyze recent insights into the intestinal microbiota and the mechanisms by which some resident species act as a barrier to enteric pathogens. Moreover, this review examines whether the cells producing mucins or antimicrobial peptides and the resident microbiota act in partnership and whether they function individually and/or synergistically to provide the host with an effective front line of defense against harmful enteric pathogens.

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Section: Barrier Effect Against Pathogensmentioning

confidence: 99%

The Front Line of Enteric Host Defense against Unwelcome Intrusion of Harmful Microorganisms: Mucins, Antimicrobial Peptides, and Microbiota

2006

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“…The peptide inhibits the enzyme activity by obstructing the secondary channel and consequently preventing access of the substrates to its active sites (1,12,34,57). Later, it was demonstrated that MccJ25 can bind and penetrate into the phospholipid monolayer and disrupt the electric potential of liposomes composed of phospholipids from gram-negative bacteria (5,40). These results encouraged the study of the effect of MccJ25 on the bacterial membrane.…”

Section: Escherichia Coli Microcin J25 (Mccj25) Is a Lasso Peptide Anmentioning

confidence: 99%

Microcin J25 Has Dual and Independent Mechanisms of Action inEscherichia coli: RNA Polymerase Inhibition and Increased Superoxide Production

et al. 2007

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Microcin J25 (MccJ25) uptake by Escherichia coli requires the outer membrane receptor FhuA and the inner membrane proteins TonB, ExbD, ExbB, and SbmA. MccJ25 appears to have two intracellular targets: (i) RNA polymerase (RNAP), which has been described in E. coli and Salmonella enterica serovars, and (ii) the respiratory chain, reported only in S. enterica serovars. In the current study, it is shown that the observed difference between the actions of microcin on the respiratory chain in E. coli and S. enterica is due to the relatively low microcin uptake via the chromosomally encoded FhuA. Higher expression by a plasmid-encoded FhuA allowed greater uptake of MccJ25 by E. coli strains and the consequent inhibition of oxygen consumption. The two mechanisms, inhibition of RNAP and oxygen consumption, are independent of each other. Further analysis revealed for the first time that MccJ25 stimulates the production of reactive oxygen species (O 2˙؊ ) in bacterial cells, which could be the main reason for the damage produced on the membrane respiratory chain.MccJ25 is active on gram-negative bacteria related to the producer strain, including some pathogenic strains (43,44,55). Four plasmid genes, mcjABCD, are involved in MccJ25 production: mcjA, mcjB, and mcjC code for an MccJ25 precursor and two processing enzymes required for the in vivo synthesis of the mature peptide, respectively, and mcjD encodes the McjD immunity protein (53). McjD, a homologous ABC exporter family protein, participates in MccJ25 secretion (52). Thus, immunity is mediated by active efflux of the peptide, keeping its intracellular concentration below a critical level (53). Recently, it has been demonstrated that YojI, a chromosomal protein with ABC-type exporter homology (36), is also able to export MccJ25 from the cells (14). TolC, an E. coli outer membrane protein, is necessary for MccJ25 secretion mediated by either McjD or YojI (11,14). On the other hand, the uptake of MccJ25 by E. coli is dependent on the outer membrane receptor FhuA (15, 45) and the four inner membrane proteins TonB, ExbD, ExbB, and SbmA, the first three of which constitute the Ton complex (38), while the last one acts as a transporter (46).Convincing evidence showing that RNA polymerase (RNAP) is the target for MccJ25 action in E. coli was previously provided by our laboratory. The peptide inhibits the enzyme activity by obstructing the secondary channel and consequently preventing access of the substrates to its active sites (1,12,34,57). Later, it was demonstrated that MccJ25 can bind and penetrate into the phospholipid monolayer and disrupt the electric potential of liposomes composed of phospholipids from gram-negative bacteria (5, 40). These results encouraged the study of the effect of MccJ25 on the bacterial membrane. MccJ25 was found to disrupt the membrane potential inhibiting oxygen consumption in Salmonella enterica serovar Newport (41) and S. enterica serovar Typhimurium transformed with a plasmid carrying fhuA from E. coli (55), suggesting the presence of a se...

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“…However, for MccE492, it is a consequence of the permeabilization of the inner membrane after the insertion of MccE492 into this membrane, as shown in E. coli ML35p (15), or in artificial planar lipid bilayers (30). MccJ25 also was reported to disrupt the inner membrane integrity in S. enterica serovar Newport (46), in liposomes (45), and in uncharged phospholipid monolayers (3). However, these properties were specific to S. enterica serovars and were observed at concentrations much higher than the MIC.…”

Section: Discussionmentioning

confidence: 99%

“…The small-size microcins MccB17 and MccJ25 require an inner membrane protein, SbmA, to be internalized into the bacterial cytoplasm (31,52), where they target the DNA gyrase (27,58) and the RNA polymerase (14,61), respectively. MccJ25 also was reported to disrupt inner membrane integrity in Salmonella enterica serovar Newport (46), in liposomes (45), and in uncharged phospholipids monolayers (3). MccC7 targets translation by blocking the function of the aspartyl-tRNA synthetase (34), but its cytoplasmic membrane receptor still is unknown (23).…”

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confidence: 99%

Mechanism of Bactericidal Activity of Microcin L inEscherichia coliandSalmonella enterica

Morin

Lanneluc

Connil

et al. 2011

Antimicrob Agents Chemother

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For the first time, the mechanism of action of microcin L (MccL) was investigated in live bacteria. MccL is a gene-encoded peptide produced by Escherichia coli LR05 that exhibits a strong antibacterial activity against related Enterobacteriaceae, including Salmonella enterica serovars Typhimurium and Enteritidis. We first subcloned the MccL genetic system to remove the sequences not involved in MccL production. We then optimized the MccL purification procedure to obtain large amounts of purified microcin to investigate its antimicrobial and membrane properties. We showed that MccL did not induce outer membrane permeabilization, which indicated that MccL did not use this way to kill the sensitive cell or to enter into it. Using a set of E. coli and Salmonella enterica mutants lacking iron-siderophore receptors, we demonstrated that the MccL uptake required the outer membrane receptor Cir. Moreover, the MccL bactericidal activity was shown to depend on the TonB protein that transduces the proton-motive force of the cytoplasmic membrane to transport iron-siderophore complexes across the outer membrane. Using carbonyl cyanide 3-chlorophenylhydrazone, which is known to fully dissipate the proton-motive force, we proved that the proton-motive force was required for the bactericidal activity of MccL on E. coli. In addition, we showed that a primary target of MccL could be the cytoplasmic membrane: a high level of MccL disrupted the inner membrane potential of E. coli cells. However, no permeabilization of the membrane was detected.

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Penetration and interactions of the antimicrobial peptide, microcin J25, into uncharged phospholipid monolayers

Cited by 27 publications

References 32 publications

The Front Line of Enteric Host Defense against Unwelcome Intrusion of Harmful Microorganisms: Mucins, Antimicrobial Peptides, and Microbiota

The Front Line of Enteric Host Defense against Unwelcome Intrusion of Harmful Microorganisms: Mucins, Antimicrobial Peptides, and Microbiota

Microcin J25 Has Dual and Independent Mechanisms of Action inEscherichia coli: RNA Polymerase Inhibition and Increased Superoxide Production

Mechanism of Bactericidal Activity of Microcin L inEscherichia coliandSalmonella enterica

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