title: The activity of microcin E492 from Klebsiella pneumoniae is regulated by a microcin antagonist.
abstract: Microcin E492 is a polypeptide antibiotic that is produced and excreted by Klebsiella pneumoniae. Different growth conditions of the producer strain affect microcin activity. The production of a microcin antagonist is responsible for the changes in microcin activity. The microcin antagonist is induced when cells are iron-deprived, resulting in a low microcin activity. The microcin antagonist was purified using a procedure developed for the isolation of a catechol-type siderophore, and its activity was titrated using purified microcin. The inhibitory effect of the microcin antagonist is not observed when this compound is forming a complex with iron. The same inhibitory effect on microcin activity was obtained using purified enterochelin from Escherichia coli. The microcin antagonist was identified as enterochelin through thin-layer chromatography.
authors.affiliation: Departamento de Biología, Universidad de Chile, Santiago.
authors.forename: C
authors.initials: C
authors.lastname: Orellana
authors.forename: R
authors.initials: R
authors.lastname: Lagos
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D001430:Bacteriocins / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D003470:Culture Media; D004758:Enterobactin / Q000494:pharmacology*; D007501:Iron / Q000378:metabolism; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D003470:Culture Media; C020411:microcin; D004758:Enterobactin; D007501:Iron