View source for 5jy8


==An iron-bound structure of the isochorismate synthase EntC==
<StructureSection load='5jy8' size='340' side='right'caption='[[5jy8]], [[Resolution|resolution]] 2.94&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5jy8]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_O157:H7 Escherichia coli O157:H7]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5JY8 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5JY8 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]] 2.942&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FE:FE+(III)+ION'>FE</scene>, <scene name='pdbligand=ISJ:(3R,4R)-3-[(1-CARBOXYETHENYL)OXY]-4-HYDROXYCYCLOHEXA-1,5-DIENE-1-CARBOXYLIC+ACID'>ISJ</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=5jy8 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5jy8 OCA], [https://pdbe.org/5jy8 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5jy8 RCSB], [https://www.ebi.ac.uk/pdbsum/5jy8 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5jy8 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/ENTC_ECO57 ENTC_ECO57] Involved in the biosynthesis of the siderophore enterobactin (macrocyclic trimeric lactone of N-(2,3-dihydroxybenzoyl)-serine). Catalyzes the reversible conversion of chorismate to isochorismate.[UniProtKB:P0AEJ2]
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The shikimate pathway of bacteria, fungi, and plants generates chorismate, which is drawn into biosynthetic pathways that form aromatic amino acids and other important metabolites, including folates, menaquinone, and siderophores. Many of the pathways initiated at this branch point transform chorismate using an MST enzyme. The MST enzymes (menaquinone, siderophore, and tryptophan biosynthetic enzymes) are structurally homologous and magnesium-dependent, and all perform similar chemical permutations to chorismate by nucleophilic addition (hydroxyl or amine) at the 2-position of the ring, inducing displacement of the 4-hydroxyl. The isomerase enzymes release isochorismate or aminodeoxychorismate as the product, while the synthase enzymes also have lyase activity that displaces pyruvate to form either salicylate or anthranilate. This has led to the hypothesis that the isomerase and lyase activities performed by the MST enzymes are functionally conserved. Here we have developed tailored pre-steady-state approaches to establish the kinetic mechanisms of the isochorismate and salicylate synthase enzymes of siderophore biosynthesis. Our data are centered on the role of magnesium ions, which inhibit the isochorismate synthase enzymes but not the salicylate synthase enzymes. Prior structural data have suggested that binding of the metal ion occludes access or egress of substrates. Our kinetic data indicate that for the production of isochorismate, a high magnesium ion concentration suppresses the rate of release of product, accounting for the observed inhibition and establishing the basis of the ordered-addition kinetic mechanism. Moreover, we show that isochorismate is channeled through the synthase reaction as an intermediate that is retained in the active site by the magnesium ion. Indeed, the lyase-active enzyme has 3 orders of magnitude higher affinity for the isochorismate complex relative to the chorismate complex. Apparent negative-feedback inhibition by ferrous ions is documented at nanomolar concentrations, which is a potentially physiologically relevant mode of regulation for siderophore biosynthesis in vivo.

An Open and Shut Case: The Interaction of Magnesium with MST Enzymes.,Meneely KM, Sundlov JA, Gulick AM, Moran GR, Lamb AL J Am Chem Soc. 2016 Jul 19. PMID:27373320<ref>PMID:27373320</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5jy8" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli O157:H7]]
[[Category: Large Structures]]
[[Category: Gulick AM]]
[[Category: Lamb AL]]
[[Category: Meneely KM]]
[[Category: Sundlov JA]]