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> by generating an allosteric signal based on a conformational switch in the β-propeller region.
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>.  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.


==Function==
==Function==