View source for 8yi8


==The complex structure of SdnG with product==
<StructureSection load='8yi8' size='340' side='right'caption='[[8yi8]], [[Resolution|resolution]] 1.33&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8yi8]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Sordaria_araneosa Sordaria araneosa]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8YI8 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8YI8 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]] 1.33&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=A1LZK:(5~{R})-5-methyl-5-[[(1~{R},2~{R},5~{R})-2-methyl-5-(3-oxidanylideneprop-1-en-2-yl)cyclopentyl]methyl]-2-propan-2-yl-cyclopenta-1,3-diene-1-carboxylic+acid'>A1LZK</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=8yi8 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8yi8 OCA], [https://pdbe.org/8yi8 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8yi8 RCSB], [https://www.ebi.ac.uk/pdbsum/8yi8 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8yi8 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/SDNG_SORAA SDNG_SORAA] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Iminium-catalyzed cycloaddition is one of the most prominent examples of organocatalysis, yet a biological counterpart has not been reported despite the wide-spread occurrence of iminium adducts in enzymes. Here, we present biochemical, structural, and computational evidence for iminium catalysis by the natural Diels-Alderase SdnG that catalyzes norbornene formation in sordarin biosynthesis. A Schiff base adduct between the epsilon-nitrogen of active site K127 and the aldehyde group of the enal dienophile was revealed by structural analysis and captured under catalytic conditions via borohydride reduction. This Schiff base adduct positions the substrate into near-attack conformation and decreases the transition state barrier of Diels-Alder cyclization by 8.3 kcal/mol via dienophile activation. A hydrogen bond network consisting of a catalytic triad is proposed to facilitate proton transfer required for iminium formation. This work establishes a new mode of catalysis for Diels-Alderases and points the way to the design of novel iminium based (bio)catalysts.

Iminium Catalysis in Natural Diels-Alderase.,Sun Z, Zang X, Zhou Q, Ohashi M, Houk KN, Zhou J, Tang Y Nat Catal. 2025 Mar;8(3):218-228. doi: 10.1038/s41929-025-01294-w. Epub 2025 Feb , 6. PMID:40881614<ref>PMID:40881614</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 8yi8" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Sordaria araneosa]]
[[Category: Yi T]]
[[Category: Zang X]]
[[Category: Zhou J]]