| Proton motive force dissipation precludes interaction of microcin J25 with RNA polymerase, but enhances reactive oxygen species overproduction. | |
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MedLine Citation:
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PMID: 19616604 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: Microcin J25 targets the RNA polymerase as well as bacterial membranes. Because there is scarce information on the relationship between the uptake and the activity, a fluorescent microcin J25-derivative was used to further characterize its mechanism of action. METHODS: MccJ25 I13K was labeled with FITC and its uptake by sensitive cells was assessed by fluorescence measurements from supernatants of MccJ25-Escherichia coli suspensions. The interaction of the peptide with bacterial membranes was investigated by fluorescence resonance energy transfer. Oxygen consumption was measured with Clark-type electrode. RNA synthesis was evaluated in vivo by incorporation of [3H]uridine. ROS production was assayed by measuring the fluorescence emission of the ROS-sensitive probe 5(and 6)-carboxy-2',7'-dichlorodihydrofluorescein diacetate. RESULTS: The protonophore 2,4-dinitrophenol decreased 80% of the MccJ25 uptake and prevented inhibition of transcriptional activity, the antibiotic intracellular target. On the other hand, peptide binding to bacterial membranes was not affected and antibacterial activity remained nearly unchanged. Proton gradient dissipation by protonophore accelerated cell oxygen consumption rates and enhanced MccJ25-related reactive oxygen species overproduction. GENERAL SIGNIFICANCE: The deleterious reactive oxygen species would be produced as a consequence of the minor fraction of MccJ25 that interacts with the bacterial plasma membrane from the periplasmic side. These results show the first evidence of the mechanism underlying ROS production in sensitive bacteria. |
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Authors:
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Fernando G Dupuy; Mar??a V Niklison Chirou; Beatriz Fern??ndez de Arcuri; Carlos J Minahk; Roberto D Morero |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2009-07-16 |
Journal Detail:
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Title: Biochimica et biophysica acta Volume: 1790 ISSN: 0006-3002 ISO Abbreviation: Biochim. Biophys. Acta Publication Date: 2009 Oct |
Date Detail:
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Created Date: 2009-09-14 Completed Date: 2010-01-07 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 0217513 Medline TA: Biochim Biophys Acta Country: Netherlands |
Other Details:
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Languages: eng Pagination: 1307-13 Citation Subset: IM |
Affiliation:
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Departamento de Bioqu??mica de la Nutrici??n, Instituto Superior de Investigaciones Biol??gicas, Chacabuco 461. San Miguel de Tucum??n T4000ILI, Argentina. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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2,4-Dinitrophenol
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pharmacology Amino Acid Substitution Anti-Bacterial Agents / metabolism, pharmacology Bacteriocins / genetics, metabolism*, pharmacology Cell Membrane / drug effects, metabolism DNA-Directed RNA Polymerases / metabolism* Escherichia coli / drug effects, genetics, metabolism Escherichia coli Proteins / genetics, metabolism*, pharmacology Gene Expression Regulation, Bacterial / drug effects Microbial Sensitivity Tests Mutation Oxygen Consumption / drug effects Protein Binding / drug effects Proton-Motive Force Reactive Oxygen Species / metabolism* Uncoupling Agents / pharmacology |
| Chemical | |
Reg. No./Substance:
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0/Anti-Bacterial Agents; 0/Bacteriocins; 0/Escherichia coli Proteins; 0/Reactive Oxygen Species; 0/Uncoupling Agents; 1403-96-9/microcin; 51-28-5/2,4-Dinitrophenol; EC 2.7.7.6/DNA-Directed RNA Polymerases |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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