β-Glucosidases and Glucosyltransferases in Lignifying Tissues

Dharmawardhana, D. Palitha; Ellis, Brian E.

doi:10.1021/bk-1998-0697.ch006

Cited by 11 publications

(5 citation statements)

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“…1) Coniferin and coniferin-specific b-glucosidase have been found in the cambial sap of representative gymnospermous trees when lignification is in progress (Freudenberg and Harkin 1963;Dharmawardhana et al 1995;Dharmawardhana and Ellis 1998).…”

Section: Validity Of the 13 C-enrichment Techniquementioning

confidence: 99%

2D-NMR (HSQC) difference spectra between specifically ¹³C-enriched and unenriched protolignin of Ginkgo biloba obtained in the solution state of whole cell wall material

Terashima¹,

Akiyama

Ralph

et al. 2009

HFSG

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In the structural analysis of lignins by 13 C-NMR, signal overlap limits definitive assignment and accurate intensity measurement. Selective labeling by 13 C-enrichment of a specific carbon in lignin enhances its signal intensity in the spectrum. Further enhancement of the specifically labeled carbons can be realized via difference spectra created from the enriched and unenriched samples. Difference 2D 13 C-1 H correlation (HSQC) NMR spectra, derived from the spectra of specifically 13 C-enriched lignin model polymers (so-called dehydrogenation polymers) and their unenriched counterparts, take advantage of the enhanced dispersion afforded by both 13 C and 1 H chemical shifts, diminishing the difficulties arising from the signal-overlap problem and aiding in definitive signal assignments. In this research, protolignin in xylem cell walls was specifically 13 C-enriched at all of the individual phenylpropanoid side-chain carbons by feeding 13 Cenriched coniferins to growing stems of Ginkgo biloba. The whole xylem fractions containing 13 C-enriched and unenriched protolignins were dissolved in a mixture of N-methylimidazole and DMSO, and then acetylated. Solution state 2D-NMR (HSQC) spectra of the acetylated whole cell wall were acquired. Difference spectra between the walls containing 13 C-enriched and unenriched lignins afforded simplified 2D spectra in which well-separated signals were assigned exclusively to the specifically enriched carbons. This novel NMR technique provides a useful tool for elucidation of entire protolignin in the cell wall of ginkgo xylem.

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Section: Validity Of the 13 C-enrichment Techniquementioning

confidence: 99%

2D-NMR (HSQC) difference spectra between specifically ¹³C-enriched and unenriched protolignin of Ginkgo biloba obtained in the solution state of whole cell wall material

Terashima¹,

Akiyama

Ralph

et al. 2009

HFSG

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“…Considerable progress has been made in the characterization of genes and enzymes regulating different metabolic processes in the differentiating xylem, in particular cellulose and lignin biosynthesis (e.g., Delmer and Amor, 1995 [10] ; Boudet et al, 1998 [5] ; Dean et al, 1998 [8] ; Dharmawardhana and Ellis, 1998 [9] ; Lewis et al, 1998 [20] ; Ros Barcelo et al, 1998 [23] ; Savidge et al, 1998 [31] ; Savidge, 2000 [30] ). Progress has also been made with regard to the formation, orientation and deposition of cellulose microfibrils (e.g., Herth, 1985 [16] ; Abe et al, 1995 [1] ; Funada et al, 1997 [14] ; Chaffey, 2000 [7] ; Emons and Mulder, 2000 [12] ), the localization of hemicelluloses (e.g., Awano et al, 1998 [2] , 2000 [3] ; Maeda et al, 2000 [21] ), and the incorporation of lignin in woody cell walls (e.g., Terashima and Fukushima, 1988 [35] ; Yoshinaga et al, 1997 [41] ; Terashima, 2000 [34] ).…”

Section: Introductionmentioning

confidence: 99%

On the Cytochemistry of Cell Wall Formation in Poplar Trees

Grünwald¹,

Ruel

Kim

et al. 2002

Plant Biology

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The ultrastructure of cell walls and the mechanisms of cell wall formation are still not fully understood. The objective of our study was therefore to obtain additional fine structural details on the deposition of cell wall components during the differentiation of xylem cells in hybrid aspen (Populus tremula L. ×P. tremuloides Michx.) we used as a model tree. At the electron microscope level, PATAg staining revealed a successive deposition of polysaccharides with increasing distance from the cambium. Staining with potassium permanganate and UV microspectrophotometry showed that the cell walls were lignified, with some delay to the deposition of polysaccharides. Immunogold labelling of three lignin types in developing cell walls varied with progressive deposition of cell wall layers. Condensed lignin subunits were localized in corners of cells adjacent to the cambium prior to S1 formation, whereas non‐condensed lignin subunits became labelled only in later stages ‐ in secondary walls near cell corners and simultaneously with the completion of S1 formation. As S2 polysaccharide deposition progressed, the labelling extended towards the lumen. Labelling of peroxidases revealed their presence in cell corner regions of young xylem cells, still lacking a secondary wall, implying that peroxidases are incorporated into the developing cell wall at early developmental stages. A weak labelling of middle lamella regions and secondary walls could also be seen at later stages. The results are discussed in relation to current knowledge on the succession of polysaccharide and lignin deposition in woody cell walls.

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“…It is a natural polyphenolic polymer composed of the p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) units, which are derived from oxidative polymerization of the corresponding monolignols, p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol, respectively [2]. It is well-known that monolignols are synthesized via the phenylalanine pathway and either directly secreted to the cell wall or glucosylated by uridine diphosphate glucosyltransferase to generate monolignol glucosides, including p-coumaryl alcohol glucoside, coniferin, and syringin [3][4][5][6]. These monolignol glucosides are mostly found in the lignifying secondary cell wall of gymnosperms and are expected to be storage forms of monolignols, although they do not seem to be required for lignin synthesis [4,[7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Structural analysis of rice Os4BGlu18 monolignol β-glucosidase

et al. 2021

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Monolignol glucosides are storage forms of monolignols, which are polymerized to lignin to strengthen plant cell walls. The conversion of monolignol glucosides to monolignols is catalyzed by monolignol β-glucosidases. Rice Os4BGlu18 β-glucosidase catalyzes hydrolysis of the monolignol glucosides, coniferin, syringin, and p-coumaryl alcohol glucoside more efficiently than other natural substrates. To understand more clearly the basis for substrate specificity of a monolignol β-glucosidase, the structure of Os4BGlu18 was determined by X-ray crystallography. Crystals of Os4BGlu18 and its complex with δ-gluconolactone diffracted to 1.7 and 2.1 Å resolution, respectively. Two protein molecules were found in the asymmetric unit of the P212121 space group of their isomorphous crystals. The Os4BGlu18 structure exhibited the typical (β/α)8 TIM barrel of glycoside hydrolase family 1 (GH1), but the four variable loops and two disulfide bonds appeared significantly different from other known structures of GH1 β-glucosidases. Molecular docking studies of the Os4BGlu18 structure with monolignol substrate ligands placed the glycone in a similar position to the δ-gluconolactone in the complex structure and revealed the interactions between protein and ligands. Molecular docking, multiple sequence alignment, and homology modeling identified amino acid residues at the aglycone-binding site involved in substrate specificity for monolignol β-glucosides. Thus, the structural basis of substrate recognition and hydrolysis by monolignol β-glucosidases was elucidated.

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β-Glucosidases and Glucosyltransferases in Lignifying Tissues

Cited by 11 publications

References 0 publications

2D-NMR (HSQC) difference spectra between specifically ¹³C-enriched and unenriched protolignin of Ginkgo biloba obtained in the solution state of whole cell wall material

2D-NMR (HSQC) difference spectra between specifically ¹³C-enriched and unenriched protolignin of Ginkgo biloba obtained in the solution state of whole cell wall material

On the Cytochemistry of Cell Wall Formation in Poplar Trees

Structural analysis of rice Os4BGlu18 monolignol β-glucosidase

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β-Glucosidases and Glucosyltransferases in Lignifying Tissues

Cited by 11 publications

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2D-NMR (HSQC) difference spectra between specifically 13C-enriched and unenriched protolignin of Ginkgo biloba obtained in the solution state of whole cell wall material

2D-NMR (HSQC) difference spectra between specifically 13C-enriched and unenriched protolignin of Ginkgo biloba obtained in the solution state of whole cell wall material

On the Cytochemistry of Cell Wall Formation in Poplar Trees

Structural analysis of rice Os4BGlu18 monolignol β-glucosidase

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Product

Resources

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2D-NMR (HSQC) difference spectra between specifically ¹³C-enriched and unenriched protolignin of Ginkgo biloba obtained in the solution state of whole cell wall material

2D-NMR (HSQC) difference spectra between specifically ¹³C-enriched and unenriched protolignin of Ginkgo biloba obtained in the solution state of whole cell wall material