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Import of periplasmic bacteriocins targeting the murein

Volkmar Braun1, Stephanie Helbig, Silke I Patzer

  • 1Department of Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany. volkmar.braun@tuebingen.mpg.de

Biochemical Society Transactions
|November 27, 2012
PubMed

Insights

Colicin M and pesticin are bacteriocins that target the outer membrane of Escherichia coli, offering a simplified model for studying protein import mechanisms. Their import requires energy and involves unfolding, with Colicin M

Area of Science:

  • Microbiology
  • Molecular Biology
  • Structural Biology

Background:

  • Colicins are proteins imported by Escherichia coli, serving as models for protein import.
  • Most colicins target intracellular components or the cytoplasmic membrane.
  • Cma (colicin M) and Pst (pesticin) are bacteriocins targeting the periplasm, requiring only outer membrane translocation.

Purpose of the Study:

  • To investigate the protein import mechanism using Cma and Pst as simplified models.
  • To understand the translocation process across the outer membrane.
  • To elucidate the role of energy and chaperones in bacteriocin import.

Main Methods:

  • Analysis of bacteriocin structure and function.
  • Investigation of protein translocation across the outer membrane.
  • Studying the energy requirements and chaperone involvement in import.

Main Results:

  • Cma and Pst are imported across the outer membrane, representing a simple protein import system.
  • Both bacteriocins, Cma and Pst, undergo unfolding during import.
  • Import requires energy supplied by the Ton system and is influenced by periplasmic factors like FkpA PPIase for Cma.

Conclusions:

  • Cma and Pst provide a simplified model for studying outer membrane protein import in E. coli.
  • Bacteriocin import is an energy-dependent process involving protein unfolding.
  • Periplasmic chaperones can modulate the activity and import of certain colicins.

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