Tol: Difference between revisions
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{{STRUCTURE_2ivz | PDB=2ivz | SCENE= Tol-Colicin_Complex/Tolcol/1 }}. | {{STRUCTURE_2ivz | PDB=2ivz | SCENE= Tol-Colicin_Complex/Tolcol/1 }}. | ||
==Regulation== | ==Regulation== | ||
Revision as of 09:28, 22 April 2011
Structure
The Tol system, also known as Tol-Pal, is a multi-protein complex found in the cell envelope of many gram-negative bacteria. It contains 7 proteins (TolQ, TolR, TolA, TolB, Pal, YbgF, YbgC), whose respective genes are organized into two operons as seen in the diagram.
Function
As of yet, the cellular role of the Tol protein is unclear. However, the system components are thought to be involved in the maintenance of the outer membrane as mutations of Tol proteins result in cells which leak the contents of the periplasm, as well as a hypersensitivity to some detergents, antibiotics and other agents.[4]
Interaction of Tol proteins
It was first suggested in 1994 that the Tol proteins interact to form a multiprotein complex of precise stoichiometry by Guihard et al, who showed that the level of Tol proteins at certain sites in the cell increases at a similar ratio with respect to one another when purified Colicin A is added to the whole cell.[5]
Interaction of Tol with Colicins
A yeast two-hybrid screen was carried out in order to determine the interactions between colicins and the Tol-Pal system during the import of colicin.Cite error: Closing </ref> missing for <ref> tag In studies with E. coli, the tol-pal genes have been induced by RcsC in response to cell envelope stress. [6] RcsC is a transmembrane sensor kinase, and along with the cytoplasmic response regulator RcsB, makes up the RcsBC regulatory system. [7] RcsBC is involved in the regulation of cps genes which code for the biosynthsis machinery of a major component for the capsula, cholanic acid.
References
- ↑ Witty M, Sanz C, Shah A, Grossmann JG, Mizuguchi K, Perham RN, Luisi B. Structure of the periplasmic domain of Pseudomonas aeruginosa TolA: evidence for an evolutionary relationship with the TonB transporter protein. EMBO J. 2002 Aug 15;21(16):4207-18. PMID:12169623
- ↑ https://ecoliwiki.net/colipedia/index.php/tolA:Expression
- ↑ https://ecoliwiki.net/colipedia/index.php/tolB:Expression
- ↑ Dennis JJ, Lafontaine ER, Sokol PA. Identification and characterization of the tolQRA genes of Pseudomonas aeruginosa. J Bacteriol. 1996 Dec;178(24):7059-68. PMID:8955385
- ↑ Guihard G, Boulanger P, Benedetti H, Lloubes R, Besnard M, Letellier L. Colicin A and the Tol proteins involved in its translocation are preferentially located in the contact sites between the inner and outer membranes of Escherichia coli cells. J Biol Chem. 1994 Feb 25;269(8):5874-80. PMID:8119930
- ↑ Clavel T, Lazzaroni JC, Vianney A, Portalier R. Expression of the tolQRA genes of Escherichia coli K-12 is controlled by the RcsC sensor protein involved in capsule synthesis. Mol Microbiol. 1996 Jan;19(1):19-25. PMID:8821933
- ↑ Majdalani N, Heck M, Stout V, Gottesman S. Role of RcsF in signaling to the Rcs phosphorelay pathway in Escherichia coli. J Bacteriol. 2005 Oct;187(19):6770-8. PMID:16166540 doi:10.1128/JB.187.19.6770-6778.2005
