Covalent interactions between lignin and hemicelluloses in plant secondary cell walls

Terrett, Oliver M.; Dupree, Paul

doi:10.1016/j.copbio.2018.10.010

Cited by 257 publications

(183 citation statements)

References 65 publications

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“…Lignin-(poly)saccharide binding has long fascinated plant cell wall researchers (Terrett and Dupree, 2019). Apart from the well-authenticated example in which ferulates on arabinoxylans in commelinid monocots provide a powerful mechanism for extensive cell wall cross-linking (Ralph, 2010), securing definitive evidence for other types of lignin-polysaccharide crosslinking, particularly in noncommelinids, has been a challenge essentially unmet.…”

Section: Implications For Prior Claims Of Lignin Glucosidesmentioning

confidence: 99%

Hydroxystilbene Glucosides Are Incorporated into Norway Spruce Bark Lignin

et al. 2019

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Recent investigations have revealed that, in addition to monolignols, some phenolic compounds derived from the flavonoid and hydroxystilbene biosynthetic pathways can also function as true lignin monomers in some plants. In this study, we found that the hydroxystilbene glucosides isorhapontin (isorhapontigenin-O-glucoside) and, at lower levels, astringin (piceatannol-O-glucoside) and piceid (resveratrol-O-glucoside) are incorporated into the lignin polymer in Norway spruce (Picea abies) bark. The corresponding aglycones isorhapontigenin, piceatannol, and resveratrol, along with glucose, were released by derivatization followed by reductive cleavage, a chemical degradative method that cleaves b-ether bonds in lignin, indicating that the hydroxystilbene glucosides are (partially) incorporated into the lignin structure through b-ether bonds. Twodimensional NMR analysis confirmed the occurrence of hydroxystilbene glucosides in this lignin, and provided additional information regarding their modes of incorporation into the polymer. The hydroxystilbene glucosides, particularly isorhapontin and astringin, can therefore be considered genuine lignin monomers that participate in coupling and crosscoupling reactions during lignification in Norway spruce bark.

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Section: Implications For Prior Claims Of Lignin Glucosidesmentioning

confidence: 99%

Hydroxystilbene Glucosides Are Incorporated into Norway Spruce Bark Lignin

et al. 2019

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“…ignin-carbohydrate complexes (LCCs) play an integral role in maintaining plant cell wall integrity and recalcitrance of lignocellulosic biomass 1,2 . LCCs represent a major obstacle for the complete utilization of all plant cell wall components, which is a cornerstone in the future bioeconomy-based society because lignin is an important natural resource for replacing fossil-based products and materials with sustainable alternatives 3 .…”

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confidence: 99%

The structural basis of fungal glucuronoyl esterase activity on natural substrates

et al. 2020

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Structural and functional studies were conducted of the glucuronoyl esterase (GE) from Cerrena unicolor (CuGE), an enzyme catalyzing cleavage of lignin-carbohydrate ester bonds. CuGE is an α/β-hydrolase belonging to carbohydrate esterase family 15 (CE15). The enzyme is modular, comprised of a catalytic and a carbohydrate-binding domain. SAXS data show CuGE as an elongated rigid molecule where the two domains are connected by a rigid linker. Detailed structural information of the catalytic domain in its apo-and inactivated form and complexes with aldouronic acids reveal well-defined binding of the 4-O-methyl-aD -glucuronoyl moiety, not influenced by the nature of the attached xylo-oligosaccharide. Structural and sequence comparisons within CE15 enzymes reveal two distinct structural subgroups. CuGE belongs to the group of fungal CE15-B enzymes with an open and flat substrate-binding site. The interactions between CuGE and its natural substrates are explained and rationalized by the structural results, microscale thermophoresis and isothermal calorimetry.

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“…Many xylan arabinose side chains are esterified with ferulic acid, which can form extensive diferulate covalent bonds with other glucuronoarabinoxylans. Ferulic acid can also act as a nucleation site for the polymerization of lignin (Grabber et al, 2004;Terrett and Dupree, 2019). These properties make ferulic acid a significant contributor to the recalcitrance of grass biomass.…”

Section: Xylanmentioning

confidence: 99%

Engineering of Bioenergy Crops: Dominant Genetic Approaches to Improve Polysaccharide Properties and Composition in Biomass

Brandon

Scheller

2020

Front. Plant Sci.

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Large-scale, sustainable production of lignocellulosic bioenergy from biomass will depend on a variety of dedicated bioenergy crops. Despite their great genetic diversity, prospective bioenergy crops share many similarities in the polysaccharide composition of their cell walls, and the changes needed to optimize them for conversion are largely universal. Therefore, biomass modification strategies that do not depend on genetic background or require mutant varieties are extremely valuable. Due to their preferential fermentation and conversion by microorganisms downstream, the ideal bioenergy crop should contain a high proportion of C6-sugars in polysaccharides like cellulose, callose, galactan, and mixed-linkage glucans. In addition, the biomass should be reduced in inhibitors of fermentation like pentoses and acetate. Finally, the overall complexity of the plant cell wall should be modified to reduce its recalcitrance to enzymatic deconstruction in ways that do no compromise plant health or come at a yield penalty. This review will focus on progress in the use of a variety of genetically dominant strategies to reach these ideals. Due to the breadth and volume of research in the field of lignin bioengineering, this review will instead focus on approaches to improve polysaccharide component plant biomass. Carbohydrate content can be dramatically increased by transgenic overexpression of enzymes involved in cell wall polysaccharide biosynthesis. Additionally, the recalcitrance of the cell wall can be reduced via the overexpression of native or non-native carbohydrate active enzymes like glycosyl hydrolases or carbohydrate esterases. Some research in this area has focused on engineering plants that accumulate cell wall-degrading enzymes that are sequestered to organelles or only active at very high temperatures. The rationale being that, in order to avoid potential negative effects of cell wall modification during plant growth, the enzymes could be activated post-harvest, and post-maturation of the cell wall. A potentially significant limitation of this approach is that at harvest, the cell wall is heavily lignified, making the substrates for these enzymes inaccessible and their activity ineffective. Therefore, this review will only include research employing enzymes that are at least partially active under the ambient conditions of plant growth and cell wall development.

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Covalent interactions between lignin and hemicelluloses in plant secondary cell walls

Cited by 257 publications

References 65 publications

Hydroxystilbene Glucosides Are Incorporated into Norway Spruce Bark Lignin

Hydroxystilbene Glucosides Are Incorporated into Norway Spruce Bark Lignin

The structural basis of fungal glucuronoyl esterase activity on natural substrates

Engineering of Bioenergy Crops: Dominant Genetic Approaches to Improve Polysaccharide Properties and Composition in Biomass

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