1gp6

Anthocyanidin synthase from Arabidopsis thaliana complexed with trans-dihydroquercetin (with 30 min exposure to O2)Anthocyanidin synthase from Arabidopsis thaliana complexed with trans-dihydroquercetin (with 30 min exposure to O2)

Structural highlights

1gp6 is a 1 chain structure with sequence from Arabidopsis thaliana. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 1.75Å
Ligands:	, , , ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

LDOX_ARATH Involved in anthocyanin and protoanthocyanidin biosynthesis by catalyzing the oxidation of leucoanthocyanidins into anthocyanidins. Possesses low flavonol synthase activity in vitro towards dihydrokaempferol and dihydroquercetin producing kaempferol and quercitin, respectively.^[1] ^[2] ^[3] ^[4] ^[5]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Flavonoids are common colorants in plants and have long-established biomedicinal properties. Anthocyanidin synthase (ANS), a 2-oxoglutarate iron-dependent oxygenase, catalyzes the penultimate step in the biosynthesis of the anthocyanin class of flavonoids. The crystal structure of ANS reveals a multicomponent active site containing metal, cosubstrate, and two molecules of a substrate analog (dihydroquercetin). An additional structure obtained after 30 min exposure to dioxygen is consistent with the oxidation of the dihydroquercetin to quercetin and the concomitant decarboxylation of 2-oxoglutarate to succinate. Together with in vitro studies, the crystal structures suggest a mechanism for ANS-catalyzed anthocyanidin formation from the natural leucoanthocyanidin substrates involving stereoselective C-3 hydroxylation. The structure of ANS provides a template for the ubiquitous family of plant nonhaem oxygenases for future engineering and inhibition studies.

Structure and mechanism of anthocyanidin synthase from Arabidopsis thaliana.,Wilmouth RC, Turnbull JJ, Welford RW, Clifton IJ, Prescott AG, Schofield CJ Structure. 2002 Jan;10(1):93-103. PMID:11796114^[6]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Abrahams S, Lee E, Walker AR, Tanner GJ, Larkin PJ, Ashton AR. The Arabidopsis TDS4 gene encodes leucoanthocyanidin dioxygenase (LDOX) and is essential for proanthocyanidin synthesis and vacuole development. Plant J. 2003 Sep;35(5):624-36. PMID:12940955
↑ Welford RW, Kirkpatrick JM, McNeill LA, Puri M, Oldham NJ, Schofield CJ. Incorporation of oxygen into the succinate co-product of iron(II) and 2-oxoglutarate dependent oxygenases from bacteria, plants and humans. FEBS Lett. 2005 Sep 26;579(23):5170-4. PMID:16153644 doi:10.1016/j.febslet.2005.08.033
↑ Preuss A, Stracke R, Weisshaar B, Hillebrecht A, Matern U, Martens S. Arabidopsis thaliana expresses a second functional flavonol synthase. FEBS Lett. 2009 Jun 18;583(12):1981-6. doi: 10.1016/j.febslet.2009.05.006. Epub, 2009 May 10. PMID:19433090 doi:10.1016/j.febslet.2009.05.006
↑ Appelhagen I, Jahns O, Bartelniewoehner L, Sagasser M, Weisshaar B, Stracke R. Leucoanthocyanidin Dioxygenase in Arabidopsis thaliana: characterization of mutant alleles and regulation by MYB-BHLH-TTG1 transcription factor complexes. Gene. 2011 Sep 15;484(1-2):61-8. doi: 10.1016/j.gene.2011.05.031. Epub 2011 Jun, 12. PMID:21683773 doi:10.1016/j.gene.2011.05.031
↑ Welford RW, Clifton IJ, Turnbull JJ, Wilson SC, Schofield CJ. Structural and mechanistic studies on anthocyanidin synthase catalysed oxidation of flavanone substrates: the effect of C-2 stereochemistry on product selectivity and mechanism. Org Biomol Chem. 2005 Sep 7;3(17):3117-26. Epub 2005 Aug 1. PMID:16106293 doi:http://dx.doi.org/10.1039/b507153d
↑ Wilmouth RC, Turnbull JJ, Welford RW, Clifton IJ, Prescott AG, Schofield CJ. Structure and mechanism of anthocyanidin synthase from Arabidopsis thaliana. Structure. 2002 Jan;10(1):93-103. PMID:11796114

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OCA

[1] Abrahams S, Lee E, Walker AR, Tanner GJ, Larkin PJ, Ashton AR. The Arabidopsis TDS4 gene encodes leucoanthocyanidin dioxygenase (LDOX) and is essential for proanthocyanidin synthesis and vacuole development. Plant J. 2003 Sep;35(5):624-36. PMID:12940955

[2] Welford RW, Kirkpatrick JM, McNeill LA, Puri M, Oldham NJ, Schofield CJ. Incorporation of oxygen into the succinate co-product of iron(II) and 2-oxoglutarate dependent oxygenases from bacteria, plants and humans. FEBS Lett. 2005 Sep 26;579(23):5170-4. PMID:16153644 doi:10.1016/j.febslet.2005.08.033

[3] Preuss A, Stracke R, Weisshaar B, Hillebrecht A, Matern U, Martens S. Arabidopsis thaliana expresses a second functional flavonol synthase. FEBS Lett. 2009 Jun 18;583(12):1981-6. doi: 10.1016/j.febslet.2009.05.006. Epub, 2009 May 10. PMID:19433090 doi:10.1016/j.febslet.2009.05.006

[4] Appelhagen I, Jahns O, Bartelniewoehner L, Sagasser M, Weisshaar B, Stracke R. Leucoanthocyanidin Dioxygenase in Arabidopsis thaliana: characterization of mutant alleles and regulation by MYB-BHLH-TTG1 transcription factor complexes. Gene. 2011 Sep 15;484(1-2):61-8. doi: 10.1016/j.gene.2011.05.031. Epub 2011 Jun, 12. PMID:21683773 doi:10.1016/j.gene.2011.05.031

[5] Welford RW, Clifton IJ, Turnbull JJ, Wilson SC, Schofield CJ. Structural and mechanistic studies on anthocyanidin synthase catalysed oxidation of flavanone substrates: the effect of C-2 stereochemistry on product selectivity and mechanism. Org Biomol Chem. 2005 Sep 7;3(17):3117-26. Epub 2005 Aug 1. PMID:16106293 doi:http://dx.doi.org/10.1039/b507153d

[6] Wilmouth RC, Turnbull JJ, Welford RW, Clifton IJ, Prescott AG, Schofield CJ. Structure and mechanism of anthocyanidin synthase from Arabidopsis thaliana. Structure. 2002 Jan;10(1):93-103. PMID:11796114

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