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Border crossings: colicins and transporters
Karen S Jakes1, William A Cramer
1Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461, USA. karen.jakes@einstein.yu.edu
Annual Review of Genetics
|September 1, 2012
Summary
Colicins, protein toxins from Escherichia coli, hijack bacterial nutrient transporters to cross cell membranes. These toxins utilize unique mechanisms distinct from normal nutrient uptake for cellular import.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Colicins are protein toxins produced by Escherichia coli.
- These toxins target and kill related bacteria by entering their cells.
- Colicins must breach the bacterial outer membrane (OM) and sometimes the inner membrane (IM).
Purpose of the Study:
- To elucidate the mechanisms by which colicins cross bacterial cell membranes.
- To understand how colicins utilize host cell machinery for import.
- To investigate the evolutionary strategies of colicins in cell entry.
Main Methods:
- Analysis of colicin structure and function.
- Investigation of interactions between colicins and bacterial membrane proteins.
- Study of colicin translocation pathways across the OM and IM.
Main Results:
- Colicins exploit E. coli nutrient transporters and other membrane proteins for cellular import.
- Colicins employ mechanisms distinct from physiological substrate uptake.
- Extended binding domains facilitate colicin interaction with OM translocators.
- Import involves N-terminal domain entry into translocators and subsequent IM insertion.
Conclusions:
- Colicins have evolved sophisticated strategies to hijack bacterial transport systems for cell entry.
- The process involves specific interactions with OM and IM proteins.
- Understanding these mechanisms offers insights into bacterial cell envelope biology and potential antimicrobial strategies.
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