2brt
From Proteopedia
| Line 4: | Line 4: | ||
|PDB= 2brt |SIZE=350|CAPTION= <scene name='initialview01'>2brt</scene>, resolution 2.20Å | |PDB= 2brt |SIZE=350|CAPTION= <scene name='initialview01'>2brt</scene>, resolution 2.20Å | ||
|SITE= <scene name='pdbsite=AC1:Nar+Binding+Site+For+Chain+A'>AC1</scene> | |SITE= <scene name='pdbsite=AC1:Nar+Binding+Site+For+Chain+A'>AC1</scene> | ||
| - | |LIGAND= <scene name='pdbligand= | + | |LIGAND= <scene name='pdbligand=AKG:2-OXYGLUTARIC+ACID'>AKG</scene>, <scene name='pdbligand=FE2:FE+(II)+ION'>FE2</scene>, <scene name='pdbligand=NAR:NARINGENIN'>NAR</scene> |
| - | |ACTIVITY= [http://en.wikipedia.org/wiki/Leucocyanidin_oxygenase Leucocyanidin oxygenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.14.11.19 1.14.11.19] | + | |ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Leucocyanidin_oxygenase Leucocyanidin oxygenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.14.11.19 1.14.11.19] </span> |
|GENE= | |GENE= | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY= | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2brt FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2brt OCA], [http://www.ebi.ac.uk/pdbsum/2brt PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=2brt RCSB]</span> | ||
}} | }} | ||
| Line 27: | Line 30: | ||
[[Category: Turnbull, J J.]] | [[Category: Turnbull, J J.]] | ||
[[Category: Welford, R W.D.]] | [[Category: Welford, R W.D.]] | ||
| - | + | [[Category: 2-oxoglutarate dependent dioxygenase,dioxygenase]] | |
| - | + | ||
| - | + | ||
| - | [[Category: 2-oxoglutarate dependent dioxygenase | + | |
| - | + | ||
[[Category: flavonoid biosynthesis]] | [[Category: flavonoid biosynthesis]] | ||
[[Category: iron]] | [[Category: iron]] | ||
| Line 38: | Line 37: | ||
[[Category: vitamin c]] | [[Category: vitamin c]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 02:10:48 2008'' |
Revision as of 23:10, 30 March 2008
| |||||||
| , resolution 2.20Å | |||||||
|---|---|---|---|---|---|---|---|
| Sites: | |||||||
| Ligands: | , , | ||||||
| Activity: | Leucocyanidin oxygenase, with EC number 1.14.11.19 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
ANTHOCYANIDIN SYNTHASE FROM ARABIDOPSIS THALIANA COMPLEXED WITH NARINGENIN
Overview
During the biosynthesis of the tricyclic flavonoid natural products in plants, oxidative modifications to the central C-ring are catalysed by Fe(ii) and 2-oxoglutarate dependent oxygenases. The reactions catalysed by three of these enzymes; flavone synthase I, flavonol synthase and anthocyanidin synthase (ANS), are formally desaturations. In comparison, flavanone 3beta-hydroxylase catalyses hydroxylation at the C-3 pro-R position of 2S-naringenin. Incubation of ANS with the unnatural substrate (+/-)-naringenin results in predominantly C-3 hydroxylation to give cis-dihydrokaempferol as the major product; trans-dihydrokaempferol and the desaturation product, apigenin are also observed. Labelling studies have demonstrated that some of the formal desaturation reactions catalysed by ANS proceed via initial C-3 hydroxylation followed by dehydration at the active site. We describe analyses of the reaction of ANS with 2S- and 2R-naringenin substrates, including the anaerobic crystal structure of an ANS-Fe-2-oxoglutarate-naringenin complex. Together the results reveal that for the 'natural' C-2 stereochemistry of 2S-naringenin, C-3 hydroxylation predominates (>9 : 1) over desaturation, probably due to the inaccessibility of the C-2 hydrogen to the iron centre. For the 2R-naringenin substrate, desaturation is significantly increased relative to C-3 hydroxylation (ca. 1 : 1); this is probably a result of both the C-3 pro-S and C-2 hydrogen atoms being accessible to the reactive oxidising intermediate in this substrate. In contrast to the hydroxylation-elimination desaturation mechanism for some ANS substrates, the results imply that the ANS catalysed desaturation of 2R-naringenin to form apigenin proceeds with a syn-arrangement of eliminated hydrogen atoms and not via an oxygenated (gem-diol) flavonoid intermediate. Thus, by utilising flavonoid substrates with different C-2 stereochemistries, the balance between C-3 hydroxylation or C-2, C-3 desaturation mechanisms can be altered.
About this Structure
2BRT is a Single protein structure of sequence from Arabidopsis thaliana. Full crystallographic information is available from OCA.
Reference
Structural and mechanistic studies on anthocyanidin synthase catalysed oxidation of flavanone substrates: the effect of C-2 stereochemistry on product selectivity and mechanism., Welford RW, Clifton IJ, Turnbull JJ, Wilson SC, Schofield CJ, Org Biomol Chem. 2005 Sep 7;3(17):3117-26. Epub 2005 Aug 1. PMID:16106293
Page seeded by OCA on Mon Mar 31 02:10:48 2008
