View source for 4zqw


==CdiI from Escherichia coli EC869 in complex with a macrocyclic peptide==
<StructureSection load='4zqw' size='340' side='right'caption='[[4zqw]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4zqw]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] and [https://en.wikipedia.org/wiki/Escherichia_coli_O157:H7_str._EC869 Escherichia coli O157:H7 str. EC869]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4ZQW OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4ZQW 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]] 2.001&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=ORN:L-ORNITHINE'>ORN</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=4zqw FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4zqw OCA], [https://pdbe.org/4zqw PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4zqw RCSB], [https://www.ebi.ac.uk/pdbsum/4zqw PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4zqw ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CDII4_ECO5C CDII4_ECO5C] Immunity protein component of a toxin-immunity protein module, which functions as a cellular contact-dependent growth inhibition (CDI) system. CDI modules allow bacteria to communicate with and inhibit the growth of closely related neighboring bacteria in a contact-dependent fashion. Neutralizes the toxic activity of cognate toxin CdiA (C-terminal 289 residue CT fragment). Does not inhibit toxic activity of CdiA from other toxin-immunity modules or strains of E.coli.<ref>PMID:21829394</ref>   Expression of this locus confers protection against other bacteria carrying the locus.<ref>PMID:21829394</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Contact-dependent growth inhibition (CDI) is a widespread mechanism of inter-bacterial competition mediated by the CdiB/CdiA family of two-partner secretion proteins. CdiA effectors carry diverse C-terminal toxin domains (CdiA-CT), which are delivered into neighboring target cells to inhibit growth. CDI(+) bacteria also produce CdiI immunity proteins that bind specifically to cognate CdiA-CT toxins and protect the cell from auto-inhibition. Here, we compare the structures of homologous CdiA-CT/CdiI complexes from Escherichia coli EC869 and Yersinia pseudotuberculosis YPIII to explore the evolution of CDI toxin/immunity protein interactions. Both complexes share an unusual beta-augmentation interaction, in which the toxin domain extends a beta-hairpin into the immunity protein to complete a six-stranded anti-parallel sheet. However, the specific contacts differ substantially between the two complexes. The EC869 beta-hairpin interacts mainly through direct H-bond and ion-pair interactions, whereas the YPIII beta-hairpin pocket contains more hydrophobic contacts and a network of bridging water molecules. In accord with these differences, we find that each CdiI protein only protects target bacteria from its cognate CdiA-CT toxin. The compact beta-hairpin binding pocket within the immunity protein represents a tractable system for the rationale design of small molecules to block CdiA-CT/CdiI complex formation. We synthesized a macrocyclic peptide mimic of the beta-hairpin from EC869 toxin and solved its structure in complex with cognate immunity protein. These latter studies suggest that small molecules could potentially be used to disrupt CDI toxin/immunity complexes.

Diversification of beta-Augmentation Interactions between CDI Toxin/Immunity Proteins.,Morse RP, Willett JL, Johnson PM, Zheng J, Credali A, Iniguez A, Nowick JS, Hayes CS, Goulding CW J Mol Biol. 2015 Nov 20;427(23):3766-84. doi: 10.1016/j.jmb.2015.09.020. Epub, 2015 Oct 9. PMID:26449640<ref>PMID:26449640</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4zqw" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Escherichia coli]]
[[Category: Escherichia coli O157:H7 str. EC869]]
[[Category: Large Structures]]
[[Category: Goulding CW]]
[[Category: Morse RP]]