Team:Paris/Production overview Tol/Pal

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iGEM > Paris > Vesicle production system > Tol/Pal

Overview

A. Tol/Pal

E. Coli is gram-. Its membrane is complex included: the inner membrane and the outer membrane. Between both, there is a layer of peptidoglycan. The outer membrane presents lipo-polysaccharides (LPS). We find also porins and other proteins. There are receivers for the entrance of nourishing elements, receivers in pili ( bacterial conjugation), receivers where settles bacteriophage. It has properties of selective permeability, protection and support. This complex of proteins is in place to maintain the stability between the inner membrane and the outer membrane.


In particular the system called Tol-Pal consisted of five proteins, TolA, TolB, TolQ, TolR and Pal[1][2]. This complex allows to maintain the integrity of the membrane. Studies showed that if we destabilize this system, we also destabilize the membrane, leading then a production of vesicles. But when the membrane of the bacteria stays for such a long time in this state of destabilization, the bacteria produces too many vesicles and go in state of lysis[2].


What is Tol-Pal complex ?

The five proteins organised this complex[3]. The TolA/Q/R proteins form a protein complex in the inner membrane. TolB is a periplasmic protein associated with Pal, a lipoprotein. Pal is anchored to the outer membrane and interacts with the peptidoglycan layer. There are interactions with TolA–Pal and TolA–TolB.


Tol-Pal system

References

  1. ^Transmembrane a-helix interactions are required for the functional assembly of the escherichia coli Tol complex. Lazzaroni & Geli 1995 - 179564
  2. ^The Tol-Pal proteins of the Escherichia coli cell envelope an energized system required for outer membrane integrity. Lloubès & Journet 2001 - 11501670
  3. ^Improved methods for producing outer membrane vesicles in gram-negative bacteria. Henry & Lloubès 2004 - 15249060

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