View source for 5dhk


==Nicotiana tabacum 5-epi-aristolochene synthase mutant W273E - alkylated==
<StructureSection load='5dhk' size='340' side='right'caption='[[5dhk]], [[Resolution|resolution]] 2.43&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5dhk]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Nicotiana_tabacum Nicotiana tabacum]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5DHK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5DHK 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]] 2.43&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FAR:FARNESYL'>FAR</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</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=5dhk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5dhk OCA], [https://pdbe.org/5dhk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5dhk RCSB], [https://www.ebi.ac.uk/pdbsum/5dhk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5dhk ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/5EAS_TOBAC 5EAS_TOBAC] Catalyzes the cyclization of trans,trans-farnesyl diphosphate (FPP) to the bicyclic intermediate 5-epi-aristolochene, initial step in the conversion of FPP to the sesquiterpenoid antifungal phytoalexin capsidiol. Produces germacrene A as an enzyme-bound intermediate that is not released by the enzyme, but is further cyclized to produce the bicyclic 5-epi-aristolochene.
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== Publication Abstract from PubMed ==
Terpenes are ubiquitous natural chemicals with diverse biological functions spanning all three domains of life. In specialized metabolism, the active sites of terpene synthases (TPSs) evolve in shape and reactivity to direct the biosynthesis of a myriad of chemotypes for organismal fitness. As most terpene biosynthesis mechanistically involves highly reactive carbocationic intermediates, the protein surfaces catalyzing these cascade reactions possess reactive regions possibly prone to premature carbocation capture and potentially enzyme inactivation. Here, we show using proteomic and X-ray crystallographic analyses that cationic intermediates undergo capture by conserved active site residues leading to inhibitory self-alkylation. Moreover, the level of cation-mediated inactivation increases with mutation of the active site, upon changes in the size and structure of isoprenoid diphosphate substrates, and alongside increases in reaction temperatures. TPSs that individually synthesize multiple products are less prone to self-alkylation then TPSs possessing relatively high product specificity. In total, the results presented suggest that mechanism-based alkylation represents an overlooked mechanistic pressure during the evolution of cation-derived terpene biosynthesis.

Mechanism-Based Post-Translational Modification and Inactivation in Terpene Synthases.,Kersten RD, Diedrich JK, Yates JR 3rd, Noel JP ACS Chem Biol. 2015 Sep 17. PMID:26378620<ref>PMID:26378620</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5dhk" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Nicotiana tabacum]]
[[Category: Kersten RK]]
[[Category: Noel JP]]