Resveratrol is a naturally occurring defense compound produced by limited number of plants in response to stresses. Besides cardiovascular benefits, this health-promoting has been reported extend life spans yeasts, flies, worms, and fish. To biosynthesize resveratrol de novo, tyrosine ammonia lyase (TAL), 4-coumarate CoA-ligase (4CL), stilbene synthase (STS) were isolated from Rhodobacter sphaeroides, Arabidopsis thaliana, Vitis vinifera, respectively. Yeast cells expressing 4CL STS produce...

Abstract Very-long-chain fatty acids (VLCFAs) with chain lengths from 20 to 34 carbons are involved in diverse biological functions such as membrane constituents, a surface barrier, and seed storage compounds. The first step VLCFA biosynthesis is the condensation of two an acyl-coenzyme A, which catalyzed by 3-ketoacyl-coenzyme A synthase (KCS). In this study, amino acid sequence homology messenger RNA expression patterns 21 Arabidopsis (Arabidopsis thaliana) KCSs were compared. planta role...

In plants, cysteine biosynthesis plays a central role in fixing inorganic sulfur from the environment and provides only metabolic sulfide donor for generation of methionine, glutathione, phytochelatins, iron-sulfur clusters, vitamin cofactors, multiple secondary metabolites. O-Acetylserine sulfhydrylase (OASS) catalyzes final step biosynthesis, pyridoxal 5'-phosphate (PLP)-dependent conversion O-acetylserine into cysteine. Here we describe 2.2 A resolution crystal structure OASS Arabidopsis...

Abstract Indian mustard ( Brassica juncea L.) is known to both accumulate and tolerate high levels of heavy metals from polluted soils. To gain a comprehensive understanding the effect cadmium (Cd) treatment on B. roots, two quantitative proteomics approaches – fluorescence two‐dimensional difference gel electrophoresis (2‐D DIGE) multiplexed isobaric tagging technology (iTRAQ) were implemented. Several proteins involved in sulfur assimilation, redox homeostasis, xenobiotic detoxification...

Glutathione biosynthesis is a key component in the network of plant stress responses that counteract oxidative damage and maintain intracellular redox environment. Using combination mass spectrometry site-directed mutagenesis, we examined response Arabidopsis thaliana glutamate-cysteine ligase (GCL) to changes Mass identified two disulfide bonds (Cys186-Cys406 Cys349-Cys364) GCL. Mutation either Cys-349 or Cys-364 Ser reduced reaction rate by twofold, but substitution for Cys-186 Cys-406...

Summary Seed oils enriched in omega‐7 monounsaturated fatty acids, including palmitoleic acid (16:1∆9) and cis ‐vaccenic (18:1∆11), have nutraceutical industrial value for polyethylene production biofuels. Existing oilseed crops accumulate only small amounts (<2%) of these novel acids their seed oils. We demonstrate a strategy enhanced camelina ( Camelina sativa ) soybean Glycine max that is dependent on redirection metabolic flux from the typical ∆9 desaturation stearoyl (18:0)‐acyl...

In plants, glutathione accumulates in response to different stress stimuli as a protective mechanism, but only limited biochemical information is available on the plant enzymes that synthesize glutathione. Glutamatecysteine ligase (GCL) catalyzes first step biosynthesis and plays an important role regulating intracellular redox environment. Because putative Arabidopsis thaliana GCL (AtGCL) displays no significant homology from bacteria other eukaryotes, identity of this protein has been...

The biosynthesis of the tocotrienol and tocopherol forms vitamin E is initiated by prenylation homogentisate. Geranylgeranyl diphosphate (GGDP) prenyl donor for synthesis, whereas phytyl (PDP) synthesis. We have previously shown that synthesis in monocot seeds homogentisate geranylgeranyl transferase (HGGT). This enzyme related to phytyltransferase (HPT), which catalyzes step Here we show HGGT localized plastid expressed primarily seed endosperm. Despite close structural relationship HPT,...

It is not known how plants make the benzenoid ring of ubiquinone, a vital respiratory cofactor. Here, we demonstrate that Arabidopsis thaliana uses for purpose two separate biosynthetic branches stemming from phenylalanine and tyrosine. Gene network modeling characterization T-DNA mutants indicated acyl-activating enzyme encoded by At4g19010 contributes to biosynthesis ubiquinone specifically phenylalanine. CoA ligase assays verified prefers para-coumarate, ferulate, caffeate as substrates....

Abstract Glycosyl inositol phosphorylceramide (GIPC) sphingolipids are a major class of lipids in fungi, protozoans, and plants. GIPCs abundant the plasma membrane plants, comprising around quarter total these membranes. Plant contain unique glycan decorations that include conserved glucuronic acid (GlcA) residue various additional sugars; however, no proteins responsible for glycosylating have been identified to date. Here, we show Arabidopsis thaliana protein INOSITOL PHOSPHORYLCERAMIDE...

Ceramide synthases catalyze an N-acyltransferase reaction using fatty acyl-coenzyme A (CoA) and long-chain base (LCB) substrates to form the sphingolipid ceramide backbone are targets for inhibition by mycotoxin fumonisin B1 (FB1). Arabidopsis (Arabidopsis thaliana) contains three genes encoding with distinct substrate specificities: LONGEVITY ASSURANCE GENE ONE HOMOLOG1 (LOH1; At3g25540)- LOH3 (At1g19260)-encoded use very-long-chain acyl-CoA trihydroxy LCB substrates, LOH2...

Summary Vitamin E tocotrienol synthesis in monocots requires homogentisate geranylgeranyl transferase ( HGGT ), which catalyzes the condensation of and unsaturated C20 isoprenoid diphosphate GGDP ). By contrast, vitamin tocopherol is mediated by phytyltransferase HPT condenses saturated phytyl PDP An ‐independent pathway for has also been shown to occur de‐regulation synthesis. In this paper, basis its impact on production when combined with are explored. Arabidopsis line was initially...

Summary Glucosylceramides (GlcCer), glucose‐conjugated sphingolipids, are major components of the endomembrane system and plasma membrane in most eukaryotic cells. Yet quantitative significance cellular functions GlcCer not well characterized plants other multi‐organ eukaryotes. To address this, we examined Arabidopsis lines that were lacking or deficient by insertional disruption RNA interference ( i) suppression single gene for synthase GCS , At2g19880 ), enzyme catalyzes synthesis. Null...

Chlorophyll synthase catalyzes the final step in chlorophyll biosynthesis: esterification of chlorophyllide with either geranylgeranyl diphosphate or phytyl (PDP). Recent studies have pointed to involvement chlorophyll-linked reduction by reductase as a major pathway for synthesis PDP precursor tocopherols. This indirect suggests key role tocopherol production generate geranylgeranyl-chlorophyll substrate reductase. In this study, contributions formation Arabidopsis (Arabidopsis thaliana)...

Maintenance of sphingolipid homeostasis is critical for cell growth and programmed death (PCD). Serine palmitoyltransferase (SPT), composed LCB1 LCB2 subunits, catalyzes the primary regulatory point synthesis. Small subunits SPT (ssSPT) that strongly stimulate activity have been identified in mammals, but role ssSPT eukaryotic cells unclear. Candidate Arabidopsis thaliana ssSPTs, ssSPTa ssSPTb, were characterized. Expression these 56-amino acid polypeptides a Saccharomyces cerevisiae null...

Summary Sphingolipids are a major component of plant plasma membranes and endomembranes, mediate diverse range biological processes. Study the highly glycosylated glycosyl inositol phosphorylceramide ( GIPC ) sphingolipids has been slow as result challenges associated with extractability s, their functions in remain poorly characterized. We recently discovered an Arabidopsis glucuronosyltransferase, INOSITOL PHOSPHORYLCERAMIDE GLUCURONOSYLTRANSFERASE 1 IPUT 1), which is first enzyme...

Soybean (Glycine max) is a major plant source of protein and oil produces important secondary metabolites beneficial for human health. As tool gene function discovery improvement this crop, mutant population was generated using fast neutron irradiation. Visual screening mutagenized seeds identified line, designated MO12, which produced brown as opposed to the yellow by unmodified Williams 82 parental cultivar. Using forward genetic methods combined with comparative genome hybridization...

Seed oils of many Cuphea sp. contain >90% medium-chain fatty acids, such as decanoic acid (10:0). These seed oils, which are among the most compositionally variant in plant kingdom, arise from specialized biosynthetic enzymes and acyltransferases. include lysophosphatidic acyltransferases (LPAT) diacylglycerol (DGAT) that required for successive acylation acids sn-2 sn-3 positions triacylglycerols (TAGs). Here we report identification a cDNA DGAT1-type enzyme, designated CpuDGAT1,...

The development of nematicides targeting parasitic nematodes animals and plants requires the identification biochemical targets not found in host organisms. Recent studies suggest that Caenorhabditis elegans synthesizes phosphocholine through action PEAMT (S-adenosyl-L-methionine:phosphoethanolamine N-methyltransferases) convert phosphoethanolamine into phosphocholine. Here, we examine function a from C. (gene: pmt-1; protein: PMT-1). Our analysis shows PMT-1 only catalyses conversion...

In plants and Plasmodium falciparum, the synthesis of phosphatidylcholine requires conversion phosphoethanolamine to phosphocholine by methyltransferase (PEAMT). This pathway differs from metabolic route used in mammals and, on basis bioinformatics, was postulated function nematode Caenorhabditis elegans. Here we describe cloning biochemical characterization a PEAMT C. elegans (gene, pmt-2; protein, PMT-2). Although similar size plants, which contain two tandem domains, PMT-2 retains only...

Diacylglycerol acyltransferase (DGAT) catalyses the last step in acyl-CoA-dependent triacylglycerol (TAG) biosynthesis and is an important determinant of cellular oil content quality. In this study, a gene, designated TaDGAT2, encoding type 2 DGAT (DGAT2)-related enzyme was identified from oleaginous marine protist Thraustochytrium aureum. The deduced TaDGAT2 sequence contains ~460 amino acid domain most closely related to DGAT2s Dictyostelium sp. (45-50% identity). Recombinant restored TAG...

Abstract Phytochelatin (PC) synthases are γ-glutamylcysteine (γ-Glu-Cys) dipeptidyl transpeptidases that catalyze the synthesis of heavy metal-binding PCs, (γ-Glu-Cys)nGly polymers, from glutathione (GSH) and/or shorter chain PCs. Here it is shown through investigations enzyme Arabidopsis (Arabidopsis thaliana; AtPCS1) that, although N-terminal half protein, alone, sufficient for core catalysis formation a single-site acyl intermediate, not acylation at second site and augmentative...