TolB: Difference between revisions
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==Structure== | ==Structure== | ||
TolB is a 44-kDa periplasmic protein associated with the outer membrane. It has two domains: an N-terminal α/β domain and a C-terminal six-bladed β-propeller (to which [[Pal]] and [[Colicin E9]] bind) <ref>PMID: 19696740</ref>. The β-propeller has a latching or ‘Velco’ strand which joins the first and last of the six blades, and is positioned in the domain-domain interface. When Pal binds to the C-terminus of TolB, the latching strand moves away from the interface and carries with it a proline residue. The movement of the latching strand opens up a canyon that would normally be buried between the N- and C-terminal domains of TolB. This canyon can now be used as a binding site for the N-terminal of TolB, which forms a helical half-turn and a β-sheet against the canyon. | TolB is a 44-kDa periplasmic protein associated with the outer membrane. It has two domains: an N-terminal α/β domain and a C-terminal six-bladed β-propeller (to which [[Pal]] and [[Colicin E9]] bind) <ref>PMID: 19696740</ref>. The β-propeller has a latching or ‘Velco’ strand which joins the first and last of the six blades, and is positioned in the domain-domain interface. When Pal binds to the C-terminus of TolB, the latching strand moves away from the interface and carries with it a proline residue. The movement of the latching strand opens up a canyon that would normally be buried between the N- and C-terminal domains of TolB. This canyon can now be used as a binding site for the N-terminal of TolB, which forms a helical half-turn and a β-sheet against the canyon. | ||
TolB forms a complex with Pal (see [[Tol-Pal Complex]]) which plays a role in maintaining the integrity of the outer membrane. | |||
==Function== | ==Function== | ||
Revision as of 13:40, 14 February 2011
TolB has been shown to be essential for the function of the Tol system in Escherichia coli[1] by generating an allosteric signal based on a conformational switch in the β-propeller region.
Structure
TolB is a 44-kDa periplasmic protein associated with the outer membrane. It has two domains: an N-terminal α/β domain and a C-terminal six-bladed β-propeller (to which Pal and Colicin E9 bind) [2]. The β-propeller has a latching or ‘Velco’ strand which joins the first and last of the six blades, and is positioned in the domain-domain interface. When Pal binds to the C-terminus of TolB, the latching strand moves away from the interface and carries with it a proline residue. The movement of the latching strand opens up a canyon that would normally be buried between the N- and C-terminal domains of TolB. This canyon can now be used as a binding site for the N-terminal of TolB, which forms a helical half-turn and a β-sheet against the canyon.
TolB forms a complex with Pal (see Tol-Pal Complex) which plays a role in maintaining the integrity of the outer membrane.
Function
The distal N-terminal 12 residues of TolB has two conformational states which are governed by protein-protein interactions with the β -propeller and results in the binding of TolA in the inner membrane.
Related Tol entries
References
- ↑ Bonsor DA, Hecht O, Vankemmelbeke M, Sharma A, Krachler AM, Housden NG, Lilly KJ, James R, Moore GR, Kleanthous C. Allosteric beta-propeller signalling in TolB and its manipulation by translocating colicins. EMBO J. 2009 Sep 16;28(18):2846-57. Epub 2009 Aug 20. PMID:19696740 doi:10.1038/emboj.2009.224
- ↑ Bonsor DA, Hecht O, Vankemmelbeke M, Sharma A, Krachler AM, Housden NG, Lilly KJ, James R, Moore GR, Kleanthous C. Allosteric beta-propeller signalling in TolB and its manipulation by translocating colicins. EMBO J. 2009 Sep 16;28(18):2846-57. Epub 2009 Aug 20. PMID:19696740 doi:10.1038/emboj.2009.224
