Conversion of guaiacyl to syringyl moieties on the cinnamyl alcohol pathway during the biosynthesis of lignin in angiosperms

Matsui, Naoyuki; Chen, Fang; Yasuda, Seiichi; Fukushima, Kazuhiko

doi:10.1007/s004250050686

Cited by 45 publications

(27 citation statements)

References 20 publications

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“…This secondary 3-Omethylation activity likely accounts for the slight decreases in levels of G-lignin in OMT1-deficient transgenic ryegrass (Tu et al, 2010). Again, this observed activity of Lp OMT1 is in agreement with the properties of COMTs from other plant species (Maury et al, 1999;Dixon et al, 2001;Parvathi et al, 2001;Do et al, 2007;Ma and Xu, 2008;Guillaumie et al, 2008): in Arabidopsis thaliana, the retained ability to synthesize both G-and S-lignin in CCoAOMT knockouts but not CCoAOMT/COMT double knockouts (Do et al, 2007); and radiochemical labeling studies that demonstrate the incorporation of exogenously supplied caffeoyl alcohol and caffeoyl aldehyde ultimately into both G-and S-subunits of angiosperm lignin (Matsui et al, 2000). Finally, the permissiveness in substrate acceptance by the COMTs intriguingly suggests that developmental adjustments in the in vivo levels of monolignol precursors may be sufficient to modulate the biosynthesis and availability of specific monolignols that are then incorporated through polymerization into lignin.…”

Section: Insight Into the Substrate Preferences Of Comtssupporting

confidence: 81%

Structure-Function Analyses of a Caffeic Acid O-Methyltransferase from Perennial Ryegrass Reveal the Molecular Basis for Substrate Preference

et al. 2010

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Lignin forms from the polymerization of phenylpropanoid-derived building blocks (the monolignols), whose modification through hydroxylation and O-methylation modulates the chemical and physical properties of the lignin polymer. The enzyme caffeic acid O-methyltransferase (COMT) is central to lignin biosynthesis. It is often targeted in attempts to engineer the lignin composition of transgenic plants for improved forage digestibility, pulping efficiency, or utility in biofuel production. Despite intensive investigation, the structural determinants of the regiospecificity and substrate selectivity of COMT remain poorly defined. Reported here are x-ray crystallographic structures of perennial ryegrass (Lolium perenne) COMT (Lp OMT1) in open conformational state, apo-and holoenzyme forms and, most significantly, in a closed conformational state complexed with the products S-adenosyl-L-homocysteine and sinapaldehyde. The product-bound complex reveals the postmethyl-transfer organization of COMT's catalytic groups with reactant molecules and the fully formed phenolic-ligand binding site. The core scaffold of the phenolic ligand forges a hydrogen-bonding network involving the 4-hydroxy group that anchors the aromatic ring and thereby permits only metahydroxyl groups to be positioned for transmethylation. While distal from the site of transmethylation, the propanoid tail substituent governs the kinetic preference of ryegrass COMT for aldehydes over alcohols and acids due to a single hydrogen bond donor for the C9 oxygenated moiety dictating the preference for an aldehyde.

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Section: Insight Into the Substrate Preferences Of Comtssupporting

confidence: 81%

Structure-Function Analyses of a Caffeic Acid O-Methyltransferase from Perennial Ryegrass Reveal the Molecular Basis for Substrate Preference

et al. 2010

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“…Consistent with this, alfalfa COMT has a strong kinetic preference for both of these caffeoyl substrates , and radiochemical labeling studies demonstrated the incorporation of caffeoyl alcohol and caffeoyl aldehyde into both G and S subunits (Matsui et al, 2000). Recombinant COMT protein from wheat showed the highest level of catalytic activity toward both caffeoyl aldehyde and 5-hydroxyconiferaldehyde (Ma and Xu, 2008).…”

Section: Discussion Functional Analysis Of the Omt1 Gene In Perennialsupporting

confidence: 54%

Functional Analyses of Caffeic Acid O-Methyltransferase and Cinnamoyl-CoA-Reductase Genes from Perennial Ryegrass (Lolium perenne)

et al. 2010

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Cinnamoyl CoA-reductase (CCR) and caffeic acid O-methyltransferase (COMT) catalyze key steps in the biosynthesis of monolignols, which serve as building blocks in the formation of plant lignin. We identified candidate genes encoding these two enzymes in perennial ryegrass (Lolium perenne) and show that the spatio-temporal expression patterns of these genes in planta correlate well with the developmental profile of lignin deposition. Downregulation of CCR1 and caffeic acid O-methyltransferase 1 (OMT1 ) using an RNA interference-mediated silencing strategy caused dramatic changes in lignin level and composition in transgenic perennial ryegrass plants grown under both glasshouse and field conditions. In CCR1-deficient perennial ryegrass plants, metabolic profiling indicates the redirection of intermediates both within and beyond the core phenylpropanoid pathway. The combined results strongly support a key role for the OMT1 gene product in the biosynthesis of both syringyl-and guaiacyl-lignin subunits in perennial ryegrass. Both field-grown OMT1-deficient and CCR1-deficient perennial ryegrass plants showed enhanced digestibility without obvious detrimental effects on either plant fitness or biomass production. This highlights the potential of metabolic engineering not only to enhance the forage quality of grasses but also to produce optimal feedstock plants for biofuel production.

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“…Lipases, oxidases, and esterases along with LiP that may enter the cell wall and break the lignin barrier (Zeng et al 2014). Glucosides were employed as effective precursors in lignin biosynthesis (Matsui et al 2000).…”

Section: Lignin Degradationmentioning

confidence: 99%

Transcriptomic Profile of Lignocellulose Degradation from Trametes versicolor on Poplar Wood

Zhang

Wang

et al. 2017

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The Trametes versicolor genome is predicted to encode many enzymes that effectively degrade lignin, making it a potentially useful tool for biopulping. However, the wood degradation mechanism of T. versicolor is not clear. To identify the enzymes that contribute to lignocellulose degradation, changes in the T. versicolor transcriptome during growth on poplar wood, relative to growth on glucose medium, were evaluated. Eight hundred and fifty-three genes were differentially expressed, with 360 genes up-regulated and 493 genes were down-regulated on poplar wood. Notably, most genes involved in lignin degradation were upregulated, including eight lignin peroxidase (LiP) genes. Genes encoding cellulose and hemicellulose degrading-enzymes were mostly downregulated, including six endo-β-1,4-glucanase genes and three cellobiohydrolase I genes. These results characterized transcriptomic changes related to lignocellulose degradation. This information could be used to develop T. versicolor as a tool to improve the efficiency of lignin degradation or to provide a theoretical foundation for a new paper pulp manufacturing process.

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Conversion of guaiacyl to syringyl moieties on the cinnamyl alcohol pathway during the biosynthesis of lignin in angiosperms

Cited by 45 publications

References 20 publications

Structure-Function Analyses of a Caffeic Acid O-Methyltransferase from Perennial Ryegrass Reveal the Molecular Basis for Substrate Preference

Structure-Function Analyses of a Caffeic Acid O-Methyltransferase from Perennial Ryegrass Reveal the Molecular Basis for Substrate Preference

Functional Analyses of Caffeic Acid O-Methyltransferase and Cinnamoyl-CoA-Reductase Genes from Perennial Ryegrass (Lolium perenne)

Transcriptomic Profile of Lignocellulose Degradation from Trametes versicolor on Poplar Wood

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