en
Scientific article
English

Bactericidal activity of both secreted and nonsecreted microcin E492 requires the mannose permease

Published inJournal of bacteriology, vol. 188, no. 20, p. 7049-7061
Publication date2006
Abstract

Microcin E492 (MccE492) is a bactericidal protein secreted by Klebsiella pneumoniae that is active against various species of Enterobacteriaceae. Interaction of MccE492 with target cells leads to the depolarization and permeabilization of their inner membranes. Several MccE492-specific proteins are required for the maturation and secretion of active MccE492. Surprisingly, the expression of only MceA, the polypeptide backbone of MccE492, is shown here to be toxic by itself. We refer to this phenomenon as endogenous MceA bactericidal activity to differentiate it from the action of extracellularly secreted MccE492. The toxicity of endogenous MceA is enhanced by an efficient targeting to the inner membrane. However, a periplasmic intermediate state is not required for MceA toxicity. Indeed, endogenous MceA remains fully active when it is fused to thioredoxin-1, a fast-folding protein that promotes retention of the C terminus of MceA in the cytoplasm. The C-terminal domain of MccE492 is required only for delivery from the extracellular environment to the periplasm, and it is not required for inner membrane damage. A common component is absolutely essential for the bactericidal activity of both endogenous MceA and extracellular MccE492. Indeed, toxicity is strictly dependent on the presence of ManYZ, an inner membrane protein complex involved in mannose uptake. Based on these findings, we propose a new model for cell entry, inner membrane insertion, and toxic activity of MccE492.

Keywords
  • Anti-Bacterial Agents/metabolism/toxicity
  • Bacterial Proteins/genetics/metabolism/toxicity
  • Bacteriocins/chemistry/genetics/ metabolism/ toxicity
  • Cell Membrane/metabolism
  • Escherichia coli/ drug effects/genetics
  • Escherichia coli Proteins/genetics/physiology
  • Klebsiella pneumoniae/ metabolism
  • Microbial Viability
  • Models, Biological
  • Phosphoenolpyruvate Sugar Phosphotransferase System/genetics/ metabolism
  • Protein Transport/genetics
Affiliation Not a UNIGE publication
Citation (ISO format)
BIELER, Sylvain et al. Bactericidal activity of both secreted and nonsecreted microcin E492 requires the mannose permease. In: Journal of bacteriology, 2006, vol. 188, n° 20, p. 7049–7061. doi: 10.1128/JB.00688-06
Main files (1)
Article
accessLevelRestricted
Identifiers
ISSN of the journal0021-9193
518views
0downloads

Technical informations

Creation08/27/2010 1:33:59 PM
First validation08/27/2010 1:33:59 PM
Update time03/14/2023 4:02:40 PM
Status update03/14/2023 4:02:40 PM
Last indexation02/12/2024 7:14:51 PM
All rights reserved by Archive ouverte UNIGE and the University of GenevaunigeBlack