Diversity and impact of 2-oxoglutarate dependent dioxygenases in plant metabolism.

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Impact

Analysis of the protein products of Absicisic-acid insensitive (ABIs −3, −4, and −5) mutant causing genes. These function as integrators of stimulus-responsive cascades. This is in part, due to a bimodal binding pattern, i.e., cytosolic elements and DNA-binding, that typifies many of these proteins. Evidence indicates that the non-catalytic ABIs form intra- and inter- protein networks, and regulate their cytosolic-nuclear levels by forming self-limiting feedback mechanisms. Domain analysis of these sequences for 2-OG binding motifs suggests the presence of basic (DNA-binding, B3; AP2; bZIP) and acidic amino acids which may coordinate iron and/or form protein-protein interactions with well characterized 2-oxoglutarate members. (#) Abbreviations: Kundu, 2012: ALKB, Alk-B like demethylase; ARGI, Arginine hydroxylase; ASPA, Aspartyl:Asparaginyl hydroxylase; CHLO, Chlorination; CLAS, Clavaminate synthase; COLY, Collagen lysyl dioxygenase; CP3H, Collagen prolyl 3-hydroxylase; CP4H, Collagen prolyl 4-hydroxylase; CYCL, Cyclization; DACS, Deacetoxycephalosporin-C synthase; DSAT, Desaturase; ECTO, Ectoine hydroxylase; FLAV, 2S-Flavones; GBBH, γ – butyrobetaine hydroxylase; GIAC, Gibberellic acid; HILY, Histone lysyl demethylase; HP4H, Hypoxia prolyl 4-hydroxylase; HYOS, Hyoscyamine; NUHY, Nucleotide/side hydroxylase; OGFD, Eukaryotic initiation factor 2α (eIF2α); PHYT, Phytanoyl-CoA; SULF, Sulfate cleaving; TFDA, 2,4-Diphenoxyacetic acid metabolizing; THYD, Thymidine dioxygenase; THYE, Thymine dioxygenase; XANT, Xanthine hydroxylase.

Original Research

15 July 2015

Co-operative intermolecular kinetics of 2-oxoglutarate dependent dioxygenases may be essential for system-level regulation of plant cell physiology

Siddhartha Kundu

5,032 views

8 citations

Original Research

11 March 2015

Unity in diversity, a systems approach to regulating plant cell physiology by 2-oxoglutarate-dependent dioxygenases

Siddhartha Kundu

4,341 views

12 citations

Coumarin biosynthetic pathway in plants. Simple coumarins, coumarin (1), umbelliferone (2), esculetin (3), and scopoletin (4) have modifications in their benzene ring. They are biosynthesized from the phenylpropanoid pathway via ortho-hydroxylation of cinnamate (10), p-coumarate (11), caffeate (12), and ferulate (13), respectively. The ortho-positions are shown by red arrows. Oxygen atoms introduced by ortho-hydroxylation are also highlighted in red. The ortho-hydroxylases from Arabidopsis (AtF6′H1), Ruta graveolens (RgC2′H), and Ipomoea batatas (Ib1 and Ib2) were functionally analyzed. AtF6′H1 and Ib1 catalyze ortho-hydroxylation of feruloyl-CoA (15), whereas RgC2′H and Ib2 were capable of reacting to both feruloyl-CoA (15) and p-coumaroyl-CoA (14) as the substrates. After hydroxylation, trans/cis isomerization and lactonization occur, resulting in the production of their respective coumarins. Umbelliferone (2) is a key intermediate of prenylcoumarin biosynthesis, from which furanocoumarins and pyranocoumarins (examples: psoralen and xanthyletin, respectively) are derived. No report has described cloning and functional analysis of the hydroxylases that introduce an ortho-hydroxy group to cinnamate and caffeate to form coumarin (1) and esculetin (3), respectively (hashed arrows). Coumarins substituted in the pyrone ring are thought to be derived from different pathways.

Mini Review

03 November 2014

2-Oxoglutarate-dependent dioxygenases in the biosynthesis of simple coumarins

Bun-Ichi Shimizu

8,812 views

49 citations

Major enzymatic reactions of 2-ODD involved in GA and plant secondary metabolism. 2-ODDs involved in (A) GA, (B) glucosinolate, (C) flavonoid, (D) tropan alkaloid, (E) isoquinorine biosynthesis are described. GA20ox, GA20-oxidase; GA3ox, GA3β-hydroxylase; GA2ox, GA 2-oxidase; AOP, alkenyl/hydroxy (OH) alkyl producing enzymes; GSL-OH, glucosinolate 2-oxoacid-dependant dioxygenase gene; FS-I, flavone synthase I; FLS, flavonol synthase, F3H, flavanone 3-hydroxylase, ANS, anthocyanin synthase; H6H, hyoscyamine 6-hydroxylase; T6ODM, 6-demethylase; CODM, codeine O-demehtylase.

Mini Review

15 October 2014

2-Oxoglutarate: linking TCA cycle function with amino acid, glucosinolate, flavonoid, alkaloid, and gibberellin biosynthesis

Wagner L. Araújo

, 2 more and

Takayuki Tohge

The tricarboxylic acid (TCA) cycle intermediate 2-oxoglutarate (2-OG) is used as an obligatory substrate in a range of oxidative reactions catalyzed by 2-OG-dependent dioxygenases. These enzymes are widespread in nature being involved in several important biochemical processes. We have recently demonstrated that tomato plants in which the TCA cycle enzyme 2-OG dehydrogenase (2-ODD) was antisense inhibited were characterized by early senescence and modified fruit ripening associated with differences in the levels of bioactive gibberellin (GA). Accordingly, there is now compelling evidence that the TCA cycle plays an important role in modulating the rate of flux from 2-OG to amino acid metabolism. Here we discuss recent advances in the biochemistry and molecular biology of 2-OG metabolism occurring in different biological systems indicating the importance of 2-OG and 2-OG dependent dioxygenases not only in glucosinolate, flavonoid and alkaloid metabolism but also in GA and amino acid metabolism. We additionally summarize recent findings regarding the impact of modification of 2-OG metabolism on biosynthetic pathways involving 2-ODDs.

29,822 views

132 citations

Review

09 October 2014

Functional diversity of 2-oxoglutarate/Fe(II)-dependent dioxygenases in plant metabolism

Scott C. Farrow

and

Peter J. Facchini

Oxidative enzymes catalyze many different reactions in plant metabolism. Among this suite of enzymes are the 2-oxoglutarate/Fe(II)-dependent dioxygenases (2-ODDs). Cytochromes P450 (CYPs) as often considered the most versatile oxidative enzymes in nature, but the diversity and complexity of reactions catalyzed by 2-ODDs is superior to the CYPs. The list of oxidative reactions catalyzed by 2-ODDs includes hydroxylations, demethylations, desaturations, ring closure, ring cleavage, epimerization, rearrangement, halogenation, and demethylenation. Furthermore, recent work, including the discovery of 2-ODDs involved in epigenetic regulation, and others catalyzing several characteristic steps in specialized metabolic pathways, support the argument that 2-ODDs are among the most versatile and important oxidizing biological catalysts. In this review, we survey and summarize the pertinent literature with a focus on several key reactions catalyzed by 2-ODDs, and discuss the significance and impact of these enzymes in plant metabolism.

25,726 views

162 citations

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