TolB: Difference between revisions
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TolB has been shown to be essential for the function of the Tol system in ''Escherichia coli''<ref>PMID: 19696740</ref>. | TolB has been shown to be essential for the function of the Tol system in ''Escherichia coli''<ref>PMID: 19696740</ref> by generating an allosteric signal based on a conformational switch in the β-propeller region. | ||
{{STRUCTURE_1c5k | PDB=1c5k | SCENE= }} | {{STRUCTURE_1c5k | PDB=1c5k | SCENE= }} | ||
==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>. | 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. | ||
When Pal binds to TolB, | |||
==Function== | ==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== | ==Related Tol entries== | ||