1h1m: Difference between revisions
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[[Image:1h1m.gif|left|200px]]<br /><applet load="1h1m" size=" | [[Image:1h1m.gif|left|200px]]<br /><applet load="1h1m" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1h1m, resolution 1.90Å" /> | caption="1h1m, resolution 1.90Å" /> | ||
'''CRYSTAL STRUCTURE OF QUERCETIN 2,3-DIOXYGENASE ANAEROBICALLY COMPLEXED WITH THE SUBSTRATE KAEMPFEROL'''<br /> | '''CRYSTAL STRUCTURE OF QUERCETIN 2,3-DIOXYGENASE ANAEROBICALLY COMPLEXED WITH THE SUBSTRATE KAEMPFEROL'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
1H1M is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Aspergillus_japonicus Aspergillus japonicus] with NAG, CU, KMP and MPD as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Quercetin_2,3-dioxygenase Quercetin 2,3-dioxygenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.13.11.24 1.13.11.24] Known structural/functional Site: <scene name='pdbsite=CUA:Cu Binding Site For Chain D'>CUA</scene>. Full crystallographic information is available from [http:// | 1H1M is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Aspergillus_japonicus Aspergillus japonicus] with <scene name='pdbligand=NAG:'>NAG</scene>, <scene name='pdbligand=CU:'>CU</scene>, <scene name='pdbligand=KMP:'>KMP</scene> and <scene name='pdbligand=MPD:'>MPD</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Quercetin_2,3-dioxygenase Quercetin 2,3-dioxygenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.13.11.24 1.13.11.24] Known structural/functional Site: <scene name='pdbsite=CUA:Cu+Binding+Site+For+Chain+D'>CUA</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1H1M OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: oxidoreductase]] | [[Category: oxidoreductase]] | ||
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Revision as of 10:45, 3 February 2008
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CRYSTAL STRUCTURE OF QUERCETIN 2,3-DIOXYGENASE ANAEROBICALLY COMPLEXED WITH THE SUBSTRATE KAEMPFEROL
OverviewOverview
Quercetin 2,3-dioxygenase (2,3QD) is the only firmly established copper, dioxygenase known so far. Depending solely on a mononuclear Cu center, it, catalyzes the breakage of the O-heterocycle of flavonols, producing more, easily degradable phenolic carboxylic acid ester derivatives. In the, enzymatic process, two CC bonds are broken and concomitantly carbon, monoxide is released. The x-ray structures of Aspergillus japonicus 2,3QD, anaerobically complexed with the substrate kaempferol and the natural, substrate quercetin have been determined at 1.90- and 1.75-A resolution, respectively. Flavonols coordinate to the copper ion as monodentate, ligands through their 3OH group. They occupy a shallow and overall, hydrophobic cavity proximal to the metal center. As a result of a van der, Waals contact between the most outward flavonol A-ring and Pro(164), a, flexible loop in front of the active site becomes partly ordered., Interestingly, flavonols bound to 2,3QD are bent at the C2 atom, which is, pyramidalized. The increased local sp(3) character at this atom may, stabilize a carbon-centered radical activated for dioxygen attack. Glu(73), coordinates the copper through its O epsilon 1 atom. The short distance of, about 2.55 A between its O epsilon 2 atom and the flavonol O3 atom, suggests that a hydrogen bond exists between the two atoms, indicating, that Glu(73) can act as a base in flavonol deprotonation and that it, retains the proton. Structure-based geometric considerations indicate O(2), binding to the flavonol C2 atom as the preferred route for flavonol, dioxygenation.
About this StructureAbout this Structure
1H1M is a Single protein structure of sequence from Aspergillus japonicus with , , and as ligands. Active as Quercetin 2,3-dioxygenase, with EC number 1.13.11.24 Known structural/functional Site: . Full crystallographic information is available from OCA.
ReferenceReference
Anaerobic enzyme.substrate structures provide insight into the reaction mechanism of the copper-dependent quercetin 2,3-dioxygenase., Steiner RA, Kalk KH, Dijkstra BW, Proc Natl Acad Sci U S A. 2002 Dec 24;99(26):16625-30. Epub 2002 Dec 16. PMID:12486225
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