<i>Escherichia coli</i>
            RNA Polymerase Is the Target of the Cyclopeptide Antibiotic Microcin J25

Delgado, Mònica; Rintoul, María R.; Farı́as, Ricardo N.; Salomón, Raúl Armando

doi:10.1128/jb.183.15.4543-4550.2001

Cited by 156 publications

(178 citation statements)

References 36 publications

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“…The availability of highly pure solutions of MccJ25 and FhuA allowed us to perform both in vivo and in vitro assays, which permitted us to characterize the interaction between the microcin and its putative receptor independent of any other step of the antibacterial mechanism, such as the inhibition of the host RNA polymerase [6,7] [34]. In addition, ITC data indicated that, in vitro, MccJ25 binds to one single class of sites, with a stoichiometry consistent with two ligands per receptor (n = 1.9).…”

Section: Discussionmentioning

confidence: 99%

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The iron–siderophore transporter FhuA is the receptor for the antimicrobial peptide microcin J25: role of the microcin Val11–Pro16 β-hairpin region in the recognition mechanism

Destoumieux-Garzón

Duquesne

Péduzzi

et al. 2005

Biochemical Journal

121

109

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The role of the outer-membrane iron transporter FhuA as a potential receptor for the antimicrobial peptide MccJ25 (microcin J25) was studied through a series of in vivo and in vitro experiments. The requirement for both FhuA and the inner-membrane TonB-ExbB-ExbD complex was demonstrated by antibacterial assays using complementation of an fhuA − strain and by using isogenic strains mutated in genes encoding the protein complex respectively.

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Section: Discussionmentioning

confidence: 99%

“…Indeed, MccJ25 was shown to inhibit transcription by targeting the β subunit of RNA polymerase [6,7]. The molecular mechanism involves MccJ25 binding and obstruction of the RNA polymerase secondary channel, which in turn prevents the correct positioning of NTP substrates [8,9].…”

Section: Introductionmentioning

confidence: 99%

The iron–siderophore transporter FhuA is the receptor for the antimicrobial peptide microcin J25: role of the microcin Val11–Pro16 β-hairpin region in the recognition mechanism

Destoumieux-Garzón

Duquesne

Péduzzi

et al. 2005

Biochemical Journal

121

109

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“…It is important to note that a significant number of mutations listed in the catalogue (see Table S2 in the supplemental material) have not been described in this article (2,45,46,49,66,67,73,78,80,84,88,91,97,108,111,112,124,126,129,130,146,151,157,160,165,167,168,170,177,180,181,186,193,204). For most of them, only in vivo phenotypes have been described and no in vitro characterization has yet been performed.…”

Section: Discussionmentioning

confidence: 99%

Structural Perspective on Mutations Affecting the Function of Multisubunit RNA Polymerases

Trinh

Langelier

Archambault

et al. 2006

Microbiol Mol Biol Rev

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SUMMARY High-resolution crystallographic structures of multisubunit RNA polymerases (RNAPs) have increased our understanding of transcriptional mechanisms. Based on a thorough review of the literature, we have compiled the mutations affecting the function of multisubunit RNA polymerases, many of which having been generated and studied prior to the publication of the first high-resolution structure, and highlighted the positions of the altered amino acids in the structures of both the prokaryotic and eukaryotic enzymes. The observations support many previous hypotheses on the transcriptional process, including the implication of the bridge helix and the trigger loop in the processivity of RNAP, the importance of contacts between the RNAP jaw-lobe module and the downstream DNA in the establishment of a transcription bubble and selection of the transcription start site, the destabilizing effects of ppGpp on the open promoter complex, and the link between RNAP processivity and termination. This study also revealed novel, remarkable features of the RNA polymerase catalytic mechanisms that will require additional investigation, including the putative roles of fork loop 2 in the establishment of a transcription bubble, the trigger loop in start site selection, and the uncharacterized funnel domain in RNAP processivity.

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“…MccJ25 intake is mediated by the outer membrane receptor FhuA and the inner membrane proteins TonB, ExbB, ExbD, and SbmA (31,32). E. coli RNA polymerase is the target of antibiotic action (12,37). The binding site for MccJ25 is located in the secondary channel of the enzyme (1,21), which provides a route by which the nucleotide substrates reach the catalytic site.…”

mentioning

confidence: 99%

The Leucine-Responsive Regulatory Protein, Lrp, Modulates Microcin J25 Intrinsic Resistance inEscherichia coliby Regulating Expression of the YojI Microcin Exporter

2009

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Many Escherichia coli K-12 strains display an intrinsic resistance to the peptide antibiotic microcin J25. In this study, we present results showing that the leucine-responsive regulatory protein, Lrp, is involved in this phenotype by acting as a positive regulator of YojI, a chromosomally encoded efflux pump which expels microcin out of cells. Exogenous leucine antagonizes the effect of Lrp, leading to a diminished expression of the pump and an increased susceptibility to microcin J25.Microcin J25 (MccJ25) is a plasmid-encoded, 21-amino-acid antibacterial peptide produced by Escherichia coli (3,30). It is active against E. coli, Salmonella, and Shigella strains. MccJ25 intake is mediated by the outer membrane receptor FhuA and the inner membrane proteins TonB, ExbB, ExbD, and SbmA (31, 32). E. coli RNA polymerase is the target of antibiotic action (12, 37). The binding site for MccJ25 is located in the secondary channel of the enzyme (1, 21), which provides a route by which the nucleotide substrates reach the catalytic site. Thus, MccJ25 inhibits transcription by clogging the channel and blocking the access of substrates to the active center (1, 21).Four genes (mcjA, mcjB, mcjC, and mcjD) are required for MccJ25 synthesis, export, and immunity (34, 35). The mcjA gene encodes the primary structure of MccJ25 as a 58-aminoacid precursor, from which a 37-amino-acid N-terminal leader is removed. The 21-residue mature peptide has a compact, extraordinary structure, which consists of an eight-residue lariat ring and a C-terminal tail which folds on itself and passes through the ring, where it is sterically trapped (2, 29, 36). The mcjB and mcjC gene products are involved in this assembly process (14). The mcjD product has a dual role. It works as a dedicated ATP-binding cassette exporter of MccJ25 and, at the same time, provides immunity against both the endogenous MccJ25 synthesized in producer cells and the exogenous microcin that gains entry (11,35).We have observed that in twofold serial dilution assays on LB medium or M9 minimal medium plates with several E. coli K-12 strains as indicators (including the widely used strain MC4100), MccJ25 gives rise to turbid zones of growth inhibition. These observations suggested that E. coli strains have an intrinsic partial resistance to MccJ25. However, the polyauxotrophic strain AB1133 gives completely clear halos and is routinely used in our laboratory as an indicator strain. We reasoned that a study of this unusual sensitivity could give us a clue to understanding the origin of the natural resistance of other E. coli strains. In the present work, we demonstrate that the increased sensitivity of AB1133 depends on the leucine used to supplement the AB1133 auxotrophy for this amino acid. The leucine effect seems to be mediated by the global regulator Lrp, which acts as a positive regulator of an endogenous chromosome-encoded MccJ25 efflux pump, YojI. Exogenous leucine would antagonize the effect of Lrp, leading to a diminished expression of the pump and to the accumulation o...

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Escherichia coli RNA Polymerase Is the Target of the Cyclopeptide Antibiotic Microcin J25

Cited by 156 publications

References 36 publications

The iron–siderophore transporter FhuA is the receptor for the antimicrobial peptide microcin J25: role of the microcin Val11–Pro16 β-hairpin region in the recognition mechanism

The iron–siderophore transporter FhuA is the receptor for the antimicrobial peptide microcin J25: role of the microcin Val11–Pro16 β-hairpin region in the recognition mechanism

Structural Perspective on Mutations Affecting the Function of Multisubunit RNA Polymerases

The Leucine-Responsive Regulatory Protein, Lrp, Modulates Microcin J25 Intrinsic Resistance inEscherichia coliby Regulating Expression of the YojI Microcin Exporter

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