Structure and Mechanism of Anthocyanidin Synthase from Arabidopsis thaliana

Wilmouth, R.C.; Turnbull, Jonathan J.; Welford, Richard W. D.; Clifton, I.J.; Prescott, Andy G.; Schofield, Christopher J.

doi:10.1016/s0969-2126(01)00695-5

Cited by 319 publications

(319 citation statements)

References 45 publications

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“…If, as previously proposed, C-3 oxidation is the initial step in catalysis (48,49), together with (i), this is consistent with a mechanism in which the initially introduced hydroxyl group is subsequently lost.…”

Section: O Environments and Mechanistic Insights Into The 2og-dependesupporting

confidence: 86%

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Mechanistic Studies on Three 2-Oxoglutarate-dependent Oxygenases of Flavonoid Biosynthesis

Turnbull¹,

Nakajima

Welford³

et al. 2004

Journal of Biological Chemistry

191

154

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Anthocyanidin synthase (ANS), flavonol synthase (FLS), and flavanone 3␤-hydroxylase (FHT) are involved in the biosynthesis of flavonoids in plants and are all members of the family of 2-oxoglutarate-and ferrous iron-dependent oxygenases. ANS, FLS, and FHT are closely related by sequence and catalyze oxidation of the flavonoid "C ring"; they have been shown to have overlapping substrate and product selectivities. In the initial steps of catalysis, 2-oxoglutarate and dioxygen are thought to react at the ferrous iron center producing succinate, carbon dioxide, and a reactive ferryl intermediate, the latter of which can then affect oxidation of the flavonoid substrate.

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Section: O Environments and Mechanistic Insights Into The 2og-dependesupporting

confidence: 86%

“…Recent crystallographic work has demonstrated that ANS contains the double-stranded ␤-helix common to other 2OG oxygenases and identified the residues involved in substrate binding (38,48).…”

mentioning

confidence: 99%

Mechanistic Studies on Three 2-Oxoglutarate-dependent Oxygenases of Flavonoid Biosynthesis

Turnbull¹,

Nakajima

Welford³

et al. 2004

Journal of Biological Chemistry

191

154

View full text Add to dashboard Cite

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“…2B). Based on the crystal structure of similar proteins, the LBO catalytic domain contains hallmark amino acid residues His-235, His-293, and Asp-237 for iron binding and Arg-303 for substrate interaction (27)(28)(29).…”

Section: Resultsmentioning

confidence: 99%

LATERAL BRANCHING OXIDOREDUCTASEacts in the final stages of strigolactone biosynthesis inArabidopsis

Brewer

Yoneyama

Filardo

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

218

256

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Strigolactones are a group of plant compounds of diverse but related chemical structures. They have similar bioactivity across a broad range of plant species, act to optimize plant growth and development, and promote soil microbe interactions. Carlactone, a common precursor to strigolactones, is produced by conserved enzymes found in a number of diverse species. Versions of the MORE AXILLARY GROWTH1 (MAX1) cytochrome P450 from rice and Arabidopsis thaliana make specific subsets of strigolactones from carlactone. However, the diversity of natural strigolactones suggests that additional enzymes are involved and remain to be discovered. Here, we use an innovative method that has revealed a missing enzyme involved in strigolactone metabolism. By using a transcriptomics approach involving a range of treatments that modify strigolactone biosynthesis gene expression coupled with reverse genetics, we identified LATERAL BRANCHING OXIDOREDUCTASE (LBO), a gene encoding an oxidoreductase-like enzyme of the 2-oxoglutarate and Fe(II)-dependent dioxygenase superfamily. Arabidopsis lbo mutants exhibited increased shoot branching, but the lbo mutation did not enhance the max mutant phenotype. Grafting indicated that LBO is required for a graft-transmissible signal that, in turn, requires a product of MAX1. Mutant lbo backgrounds showed reduced responses to carlactone, the substrate of MAX1, and methyl carlactonoate (MeCLA), a product downstream of MAX1. Furthermore, lbo mutants contained increased amounts of these compounds, and the LBO protein specifically converts MeCLA to an unidentified strigolactone-like compound. Thus, LBO function may be important in the later steps of strigolactone biosynthesis to inhibit shoot branching in Arabidopsis and other seed plants.plant | branching | strigolactone | biosynthesis | Arabidopsis

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“…This Escherichia coli protein is a member of a rapidly expanding enzyme superfamily that utilizes mononuclear Fe(II) active sites to catalyze a diverse range of chemical transformations, usually coupled to the oxidative decarboxylation of an ␣-keto acid (2)(3)(4). Other family members include enzymes that modify protein side chains (5,6), repair alkylation-damaged DNA (7), degrade compounds in the environment (8)(9)(10)(11), and synthesize antibiotics (12)(13)(14), plant metabolites (15,16), or other small molecules (17,18). Most representatives carry out specific hydroxylation reactions, but examples of enzymes catalyzing desaturations, ring closures, and ring expansion reactions have also been documented (19).…”

mentioning

confidence: 99%

Interconversion of two oxidized forms of taurine/α-ketoglutarate dioxygenase, a non-heme iron hydroxylase: Evidence for bicarbonate binding

Ryle

Koehntop

Liu

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

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Taurine͞␣-ketoglutarate (␣KG) dioxygenase, or TauD, is a mononuclear non-heme iron hydroxylase that couples the oxidative decarboxylation of ␣KG to the decomposition of taurine, forming sulfite and aminoacetaldehyde. Prior studies revealed that taurine-free TauD catalyzes an O 2-and ␣KG-dependent selfhydroxylation reaction involving Tyr-73, yielding an Fe(III)-catecholate chromophore with a max of 550 nm. Here, a chromophore ( max 720 nm) is described and shown to arise from O2-dependent self-hydroxylation of TauD in the absence of ␣KG, but requiring the product succinate. A similar chromophore rapidly develops with the alternative oxidant H 2O2. Resonance Raman spectra indicate that the Ϸ700-nm chromophore also arises from an Fe(III)-catecholate species, and site-directed mutagenesis studies again demonstrate Tyr-73 involvement. The Ϸ700-nm and 550-nm species are shown to interconvert by the addition or removal of bicarbonate, consistent with the ␣KG-derived CO2 remaining tightly bound to the oxidized metal site as bicarbonate. The relevance of the metal-bound bicarbonate in TauD to reactions of other members of this enzyme family is discussed.T aurine͞␣-ketoglutarate (␣KG) dioxygenase, or TauD, catalyzes the conversion of taurine (2-aminoethanesulfonic acid) to sulfite and aminoacetaldehyde in the presence of O 2 , ␣KG, and Fe(II) as shown in Scheme 1 (1). This Escherichia coli protein is a member of a rapidly expanding enzyme superfamily that utilizes mononuclear Fe(II) active sites to catalyze a diverse range of chemical transformations, usually coupled to the oxidative decarboxylation of an ␣-keto acid (2-4). Other family members include enzymes that modify protein side chains (5, 6), repair alkylation-damaged DNA (7), degrade compounds in the environment (8-11), and synthesize antibiotics (12-14), plant metabolites (15, 16), or other small molecules (17,18). Most representatives carry out specific hydroxylation reactions, but examples of enzymes catalyzing desaturations, ring closures, and ring expansion reactions have also been documented (19). Regardless of their overall chemistry, these enzymes generally are thought to form a highvalent iron-oxo intermediate; however, such an intermediate has never been directly observed.Recent studies of TauD and the herbicide-degrading enzyme TfdA, which share Ϸ30% sequence identity, have provided important insights into the reactivity of this group of enzymes (e.g., refs. 20-28). In the absence of substrates, Fe(II) is coordinated by three amino acid side chains in a two-His-one-carboxylate motif [His-99, Asp-101, and His-255 in TauD; and His-114, Asp-116, and His-262 in TfdA (23, 26)] and three water molecules to afford a six-coordinate metal center. ␣KG chelates to the Fe(II) and displaces two water molecules, binding through the 1-carboxylate and 2-keto moieties. The primary substrate binds near, but not directly to, the Fe(II), promoting loss of the final water ligand to yield a five-coordinate metal center (26), as illustrated in Fig. 1. The site vacated by wate...

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Structure and Mechanism of Anthocyanidin Synthase from Arabidopsis thaliana

Cited by 319 publications

References 45 publications

Mechanistic Studies on Three 2-Oxoglutarate-dependent Oxygenases of Flavonoid Biosynthesis

Mechanistic Studies on Three 2-Oxoglutarate-dependent Oxygenases of Flavonoid Biosynthesis

LATERAL BRANCHING OXIDOREDUCTASEacts in the final stages of strigolactone biosynthesis inArabidopsis

Interconversion of two oxidized forms of taurine/α-ketoglutarate dioxygenase, a non-heme iron hydroxylase: Evidence for bicarbonate binding

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