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Wu, Qindong; Preisig, Carol L.; VanEtten, Hans D.

doi:10.1023/a:1005836508844

Cited by 53 publications

(6 citation statements)

References 20 publications

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“…2). Both polypeptides had a high degree of similarity (about 40% identity) to the isoflavone 7-O-methyltransferase of alfalfa (15), 6a-hydroxymaackiain 3-O-methyltransferase of pea (16), and hydroxycinnamic acids/hydroxycinnamoyl CoA esters O-methyltransferase of lobolly pine (17). SMT had greater similarity to the caffeic acid 3-O-methyltransferases and catechol O-methyltransferases of several plant species.…”

Section: Isolation Of Cdnas Of the 41-and 40-kdamentioning

confidence: 99%

Molecular Characterization of the S-Adenosyl-l-methionine:3′-Hydroxy-N-methylcoclaurine 4′-O-Methyltransferase Involved in Isoquinoline Alkaloid Biosynthesis in Coptis japonica

Morishige

Tsujita

Yamada

et al. 2000

Journal of Biological Chemistry

179

168

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S-Adenosyl-L-methionine:3-hydroxy-N-methylcoclaurine 4-O-methyltransferase (4-OMT) catalyzes the conversion of 3-hydroxy-N-methylcoclaurine to reticuline, an important intermediate in synthesizing isoquinoline alkaloids. In an earlier step in the biosynthetic pathway to reticuline, another O-methyltransferase, S-adenosyl-L-methionine:norcoclaurine 6-O-methyltransferase (6-OMT), catalyzes methylation of the 6-hydroxyl group of norcoclaurine. We isolated two kinds of cDNA clones that correspond to the internal amino acid sequences of a 6-OMT/4-OMT preparation from cultured Coptis japonica cells. Heterologously expressed proteins had 6-OMT or 4-OMT activities, indicative that each cDNA encodes a different enzyme. 4-OMT was purified using recombinant protein, and its enzymological properties were characterized. It had enzymological characteristics similar to those of 6-OMT; the active enzyme was the dimer of the subunit, no divalent cations were required for activity, and there was inhibition by Fe 2؉ , Cu 2؉ , Co 2؉ , Zn 2؉ , or Ni 2؉ , but none by the SH reagent. 4-OMT clearly had different substrate specificity. It methylated (R,S)-6-O-methylnorlaudanosoline, as well as (R,S)-laudanosoline and (R,S)-norlaudanosoline. Laudanosoline, an N-methylated substrate, was a much better substrate for 4-OMT than norlaudanosoline. 6-OMT methylated norlaudanosoline and laudanosoline equally. Further characterization of the substrate saturation and product inhibition kinetics indicated that 4-OMT follows an ordered Bi Bi mechanism, whereas 6-OMT follows a Ping-Pong Bi Bi mechanism. The molecular evolution of these two related O-methyltransferases is discussed.

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Section: Isolation Of Cdnas Of the 41-and 40-kdamentioning

confidence: 99%

Molecular Characterization of the S-Adenosyl-l-methionine:3′-Hydroxy-N-methylcoclaurine 4′-O-Methyltransferase Involved in Isoquinoline Alkaloid Biosynthesis in Coptis japonica

Morishige

Tsujita

Yamada

et al. 2000

Journal of Biological Chemistry

179

168

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“…Most of the OMTs bear strict substrate specificities and define specific physiological roles in vivo ( Ibrahim et al, 1998 ; Bureau et al, 2007 ). For example, pea 6α-hydroxy-maackiain 3-OMT catalyzes the final O -methylation step in the biosynthesis of the antimicrobial compound pisatin, suggesting a role for OMTs against biotic stresses in plants ( Wu et al, 1997 ). Methylated isoflavonoids also show medicinal effects such as anti-cancer (e.g., formononetin), neuroprotective (e.g., biochanin A), antifungal (e.g., 4′,7-dimethoxyisoflavone), and osteogenic (e.g., isoformononetin) activities ( Pandey et al, 2002 ; Kumar et al, 2011 ; Lo and Wang, 2013 ; Tan et al, 2013 ).…”

Section: Introductionmentioning

confidence: 99%

An Alternative Pathway for Formononetin Biosynthesis in Pueraria lobata

Gou

et al. 2016

Front. Plant Sci.

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The O-methylation is an important tailing process in Pueraria lobata isoflavone metabolism, but the molecular mechanism governing it remains not elucidated. This manuscript describes the mining of key O-methyltransferases (OMTs) involved in the process. Using our previously constructed P. lobata transcriptome, the OMT candidates were searched, extensively analyzed, and their functions were investigated by expression in yeast, Escherichia coli, or Glycine max hairy roots. Here, we report the identification of the key OMT gene responsible for formononetin production in P. lobata (designated as PlOMT9). PlOMT9 primarily functions as an isoflavone-specific 4′-O-methyltransferase, although it shows high sequence identities with isoflavone 7-O-methyltransferases. Moreover, unlike the previously reported OMTs that catalyze the 4′-O-methylation for formononetin biosynthesis at the isoflavanone stage, PlOMT9 performs this modifying step at the isoflavone level, using daidzein rather than 2,7,4′-trihydroxy-isoflavanone as the substrate. Gene expression analyses and metabolite profiling supported its proposed roles in P. lobata. Using the system of transgenic G. max hairy roots, the role of PlOMT9 in the biosynthesis of formononetin was further demonstrated in vivo.

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“…Clade BII contains two peyote unigenes ( UN03053 and UN05101 ) that were grouped with two plant caffeoyl-CoA 3-o-methyltransferases (from Stellaria longipes and Petroselinum crispum ; respectively) [ 69 , 70 ]. Finally, clade BIII, which contained no peyote unigenes, includes some flavonoid OMTs [ 58 , 71 – 73 ].…”

Section: Resultsmentioning

confidence: 99%

De novo sequencing and analysis of Lophophora williamsii transcriptome, and searching for putative genes involved in mescaline biosynthesis

Ibarra-Laclette¹,

Zamudio-Hernández²,

Pérez-Torres³

et al. 2015

BMC Genomics

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BackgroundLophophora williamsii (commonly named peyote) is a small, spineless cactus with psychoactive alkaloids, particularly mescaline. Peyote utilizes crassulacean acid metabolism (CAM), an alternative form of photosynthesis that exists in succulents such as cacti and other desert plants. Therefore, its transcriptome can be considered an important resource for future research focused on understanding how these plants make more efficient use of water in marginal environments and also for research focused on better understanding of the overall mechanisms leading to production of plant natural products and secondary metabolites.ResultsIn this study, two cDNA libraries were generated from L. williamsii. These libraries, representing buttons (tops of stems) and roots were sequenced using different sequencing platforms (GS-FLX, GS-Junior and PGM, respectively). A total of 5,541,550 raw reads were generated, which were assembled into 63,704 unigenes with an average length of 564.04 bp. A total of 25,149 unigenes (62.19 %) was annotated using public databases. 681 unigenes were found to be differentially expressed when comparing the two libraries, where 400 were preferentially expressed in buttons and 281 in roots. Some of the major alkaloids, including mescaline, were identified by GC-MS and relevant metabolic pathways were reconstructed using the Kyoto encyclopedia of genes and genomes database (KEGG). Subsequently, the expression patterns of preferentially expressed genes putatively involved in mescaline production were examined and validated by qRT-PCR.ConclusionsHigh throughput transcriptome sequencing (RNA-seq) analysis allowed us to efficiently identify candidate genes involved in mescaline biosynthetic pathway in L. williamsii; these included tyrosine/DOPA decarboxylase, hydroxylases, and O-methyltransferases. This study sets the theoretical foundation for bioassay design directed at confirming the participation of these genes in mescaline production.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1821-9) contains supplementary material, which is available to authorized users.

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Untitled

Cited by 53 publications

References 20 publications

Molecular Characterization of the S-Adenosyl-l-methionine:3′-Hydroxy-N-methylcoclaurine 4′-O-Methyltransferase Involved in Isoquinoline Alkaloid Biosynthesis in Coptis japonica

Molecular Characterization of the S-Adenosyl-l-methionine:3′-Hydroxy-N-methylcoclaurine 4′-O-Methyltransferase Involved in Isoquinoline Alkaloid Biosynthesis in Coptis japonica

An Alternative Pathway for Formononetin Biosynthesis in Pueraria lobata

De novo sequencing and analysis of Lophophora williamsii transcriptome, and searching for putative genes involved in mescaline biosynthesis

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