3w08

<StructureSection load='3w08' size='340' side='right'caption='[[3w08]], [[Resolution|resolution]] 1.80&Aring;' scene=''>

<table><tr><td colspan='2'>[[3w08]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3W08 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3W08 FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</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=3w08 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3w08 OCA], [https://pdbe.org/3w08 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3w08 RCSB], [https://www.ebi.ac.uk/pdbsum/3w08 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3w08 ProSAT]</span></td></tr>

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== Publication Abstract from PubMed ==

Aldoxime dehydratase (OxdA), which is a unique heme protein, catalyzes the dehydration of an aldoxime to a nitrile even in the presence of water in the reaction mixture. Unlike the utilization of H(2)O(2) or O(2) as a mediator of catalysis by other heme-containing enzymes (e.g., P450), OxdA is notable for the direct binding of a substrate to the heme iron. Here, we determined the crystal structure of OxdA. We then constructed OxdA mutants in which each of the polar amino acids lying within approximately 6 A of the iron atom of the heme was converted to alanine. Among the purified mutant OxdAs, S219A had completely lost and R178A exhibited a reduction in the activity. Together with this finding, the crystal structural analysis of OxdA and spectroscopic and electrostatic potential analyses of the wild-type and mutant OxdAs suggest that S219 plays a key role in the catalysis, forming a hydrogen bond with the substrate. Based on the spatial arrangement of the OxdA active site and the results of a series of mutagenesis experiments, we propose the detailed catalytic mechanism of general aldoxime dehydratases: (i) S219 stabilizes the hydroxy group of the substrate to increase its basicity; (ii) H320 acts as an acid-base catalyst; and (iii) R178 stabilizes the heme, and would donate a proton to and accept one from H320.

Crystal structure of aldoxime dehydratase and its catalytic mechanism involved in carbon-nitrogen triple-bond synthesis.,Nomura J, Hashimoto H, Ohta T, Hashimoto Y, Wada K, Naruta Y, Oinuma KI, Kobayashi M Proc Natl Acad Sci U S A. 2013 Feb 4. PMID:23382199<ref>PMID:23382199</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 3w08" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Hara, K]]

[[Category: Hashimoto, H]]

[[Category: Hashimoto, Y]]

[[Category: Hishiki, A]]

[[Category: Kobayashi, M]]

[[Category: Nomura, J]]

[[Category: Oinuma, K I]]

[[Category: Wada, K]]

[[Category: Lyase]]