View source for 3ej5


==complex of Ricin A chain and pyrimidine-based inhibitor==
<StructureSection load='3ej5' size='340' side='right'caption='[[3ej5]], [[Resolution|resolution]] 2.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3ej5]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Ricinus_communis Ricinus communis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3EJ5 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3EJ5 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]] 2.5&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=EJ5:4-[3-(2-AMINO-4-HYDROXY-6-OXO-1,6-DIHYDROPYRIMIDIN-5-YL)PROPYL]BENZOIC+ACID'>EJ5</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=3ej5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ej5 OCA], [https://pdbe.org/3ej5 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3ej5 RCSB], [https://www.ebi.ac.uk/pdbsum/3ej5 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3ej5 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/RICI_RICCO RICI_RICCO] Ricin is highly toxic to animal cells and to a lesser extent to plant cells. The A chain acts as a glycosidase that removes a specific adenine residue from an exposed loop of the 28S rRNA (A4324 in mammals), leading to rRNA breakage. As this loop is involved in elongation factor binding, modified ribosomes are catalytically inactive and unable to support protein synthesis. The A chain can inactivate a few thousand ribosomes per minute, faster than the cell can make new ones. Therefore a single A chain molecule can kill an animal cell. The B chain binds to beta-D-galactopyranoside moieties on cell surface glycoproteins and glycolipids and facilitates the entry into the cell of the A chain; B chains are also responsible for cell agglutination (Lectin activity).
== 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/ej/3ej5_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=3ej5 ConSurf].
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== Publication Abstract from PubMed ==
Ricin is a potent heterodimeric cytotoxin; the B chain binds eucaryotic cell surfaces aiding uptake and the A chain, RTA, reaches the cytoplasm where it enzymatically depurinates a key ribosomal adenine, inhibiting protein synthesis. Ricin is known to be an agent in bioterrorist repertoires and there is great interest in finding, or creating, efficacious inhibitors of the toxin as potential antidotes. We have previously identified two families of bicyclic RTA inhibitors, pterins and purines. Both classes have poor solubility which impairs inhibitor development. Here we report the use of 2-amino-4,6-dihydroxy-pyrimidines as RTA inhibitors. Unlike previously observed single ring inhibitor platforms, these displace Tyr 80 and bind deep in the RTA specificity pocket. These compounds are at least 10 times more soluble than pterin-based inhibitors and appear to be useful new class of ricin inhibitors.

The X-ray structure of ricin A chain with a novel inhibitor.,Bai Y, Monzingo AF, Robertus JD Arch Biochem Biophys. 2009 Mar 1;483(1):23-8. Epub 2008 Dec 30. PMID:19138659<ref>PMID:19138659</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 3ej5" style="background-color:#fffaf0;"></div>

==See Also==
*[[Ricin 3D structures|Ricin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Ricinus communis]]
[[Category: Bai Y]]
[[Category: Monzingo AF]]
[[Category: Robertus JD]]