Uptake across the cell envelope and insertion into the inner membrane of ion channel-forming colicins in E coli

Biochimie. 1990 Feb-Mar;72(2-3):123-30. doi: 10.1016/0300-9084(90)90137-6.


Pore-forming colicins exert their lethal effect on E coli through formation of a voltage-dependent channel in the inner (cytoplasmic-membrane) thus destroying the energy potential of sensitive cells. Their mode of action appears to involve 3 steps: i) binding to a specific receptor located in the outer membrane; ii) translocation across this membrane; iii) insertion into the inner membrane. Colicin A has been used as a prototype of pore-forming colicins. In this review, the 3 functional domains of colicin A respectively involved in receptor binding, translocation and pore formation, are defined. The components of sensitive cells implicated in colicin uptake and their interactions with the various colicin A domains are described. The 3-dimensional structure of the pore-forming domain of colicin A has been determined recently. This structure suggests a model of insertion into the cytoplasmic membrane which is supported by model membrane studies. The role of the membrane potential in channel functioning is also discussed.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / metabolism*
  • Biological Transport
  • Cell Membrane / metabolism*
  • Colicins / metabolism*
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins*
  • Ion Channels / metabolism*
  • Membrane Potentials
  • Models, Biological
  • Molecular Sequence Data
  • Peptide Hydrolases / metabolism
  • Protein Conformation
  • Receptors, Cell Surface*
  • Receptors, Immunologic / metabolism


  • Bacterial Proteins
  • Colicins
  • Escherichia coli Proteins
  • Ion Channels
  • Receptors, Cell Surface
  • Receptors, Immunologic
  • colicin receptor, E coli
  • Peptide Hydrolases