View source for 2ivz


==Structure of TolB in complex with a peptide of the colicin E9 T- domain==
<StructureSection load='2ivz' size='340' side='right'caption='[[2ivz]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2ivz]] is a 8 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2IVZ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2IVZ FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2ivz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2ivz OCA], [https://pdbe.org/2ivz PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2ivz RCSB], [https://www.ebi.ac.uk/pdbsum/2ivz PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2ivz ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/TOLB_ECOLI TOLB_ECOLI] Involved in the TonB-independent uptake of group A colicins (colicins A, E1, E2, E3 and K). Necessary for the colicins to reach their respective targets after initial binding to the bacteria.[HAMAP-Rule:MF_00671]
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/iv/2ivz_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2ivz ConSurf].
<div style="clear:both"></div>
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== Publication Abstract from PubMed ==
The natively disordered N-terminal 83-aa translocation (T) domain of E group nuclease colicins recruits OmpF to a colicin-receptor complex in the outer membrane (OM) as well as TolB in the periplasm of Escherichia coli, the latter triggering translocation of the toxin across the OM. We have identified the 16-residue TolB binding epitope in the natively disordered T-domain of the nuclease colicin E9 (ColE9) and solved the crystal structure of the complex. ColE9 folds into a distorted hairpin within a canyon of the six-bladed beta-propeller of TolB, using two tryptophans to bolt the toxin to the canyon floor and numerous intramolecular hydrogen bonds to stabilize the bound conformation. This mode of binding enables colicin side chains to hydrogen-bond TolB residues in and around the channel that runs through the beta-propeller and that constitutes the binding site of peptidoglycan-associated lipoprotein (Pal). Pal is a globular binding partner of TolB, and their association is known to be important for OM integrity. The structure is therefore consistent with translocation models wherein the colicin disrupts the TolB-Pal complex causing local instability of the OM as a prelude to toxin import. Intriguingly, Ca(2+) ions, which bind within the beta-propeller channel and switch the surface electrostatics from negative to positive, are needed for the negatively charged T-domain to bind TolB with an affinity equivalent to that of Pal and competitively displace it. Our study demonstrates that natively disordered proteins can compete with globular proteins for binding to folded scaffolds but that this can require cofactors such as metal ions to offset unfavorable interactions.

Competitive recruitment of the periplasmic translocation portal TolB by a natively disordered domain of colicin E9.,Loftus SR, Walker D, Mate MJ, Bonsor DA, James R, Moore GR, Kleanthous C Proc Natl Acad Sci U S A. 2006 Aug 15;103(33):12353-8. Epub 2006 Aug 7. PMID:16894158<ref>PMID:16894158</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 2ivz" style="background-color:#fffaf0;"></div>

==See Also==
*[[Colicin 3D structures|Colicin 3D structures]]
*[[TolB|TolB]]
*[[TonB|TonB]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Bonsor DA]]
[[Category: James R]]
[[Category: Kleanthous C]]
[[Category: Loftus SR]]
[[Category: Mate MJ]]
[[Category: Moore GR]]
[[Category: Walker D]]