Glucuronic Acid Patterning on Xylan in Arabidopsis thaliana
type: CreativeWork
description: Plants represent the largest living source of biomass on Earth. Most of this biomass comes from the polysaccharide-rich secondary cell wall. Industrially, polysaccharides have a number of potential key uses. For these to be possible, it is important to understand how polysaccharides are synthesised and arranged to confer structural properties to the cell wall. The hemicellulose xylan is the second-most abundant secondary cell wall polysaccharide after cellulose. For angiosperms, the xylan backbone consists of repeating xylosyl residues and is decorated along its length by acetate and glucuronic acid (GlcA). It is likely that the position of these decorations, created by Trichome-Birefringence-Like (TBL) and Glucuronic acid substitution of Xylan (GUX) enzymes respectively, are key for the xylan molecule to perform a hypothesised linking function between cellulose and lignin, contributing to the wall’s recalcitrance to enzymatic degradation. While GUX1 is responsible for evenly spaced GlcA decoration, which covers the majority of the xylan backbone, GUX2 positions GlcA in clusters covering a smaller area. This work investigated the source of this activity difference and the impact of GlcA patterning on secondary cell wall structure and phenotype. The use of site directed mutagenesis in this work allowed investigation of the source of well-documented patterning differences between GUX2 from angiosperms, specifically AtGUX2, and gymnosperms, focusing on PtGUX2, and identified an SRF amino acid motif in PtGUX2, absent in angiosperms, crucial for creating consecutive GlcA decorations on the xylan backbone. Taken together with results from mutagenesis of the predicted active site of AtGUX1 and AtGUX2, this work suggested that the amino acid composition in the GUX catalytic C-terminus, including a GT8 domain, plays a key role in activity and patterning. However, creation of GUX chimeras showed that addition of the AtGUX1 N-terminal amino acid sequence to the C-terminus of A…
abstract: Plants represent the largest living source of biomass on Earth. Most of this biomass comes from the polysaccharide-rich secondary cell wall. Industrially, polysaccharides have a number of potential key uses. For these to be possible, it is important to understand how polysaccharides are synthesised and arranged to confer structural properties to the cell wall. The hemicellulose xylan is the second-most abundant secondary cell wall polysaccharide after cellulose. For angiosperms, the xylan backbone consists of repeating xylosyl residues and is decorated along its length by acetate and glucuronic acid (GlcA). It is likely that the position of these decorations, created by Trichome-Birefringence-Like (TBL) and Glucuronic acid substitution of Xylan (GUX) enzymes respectively, are key for the xylan molecule to perform a hypothesised linking function between cellulose and lignin, contributing to the wall’s recalcitrance to enzymatic degradation. While GUX1 is responsible for evenly spaced GlcA decoration, which covers the majority of the xylan backbone, GUX2 positions GlcA in clusters covering a smaller area. This work investigated the source of this activity difference and the impact of GlcA patterning on secondary cell wall structure and phenotype. The use of site directed mutagenesis in this work allowed investigation of the source of well-documented patterning differences between GUX2 from angiosperms, specifically AtGUX2, and gymnosperms, focusing on PtGUX2, and identified an SRF amino acid motif in PtGUX2, absent in angiosperms, crucial for creating consecutive GlcA decorations on the xylan backbone. Taken together with results from mutagenesis of the predicted active site of AtGUX1 and AtGUX2, this work suggested that the amino acid composition in the GUX catalytic C-terminus, including a GT8 domain, plays a key role in activity and patterning. However, creation of GUX chimeras showed that addition of the AtGUX1 N-terminal amino acid sequence to the C-terminus of A…
author: Davis, Katharine
language: eng
keywords: Arabidopsis thaliana, Cell wall, Glucuronic acid, xylan
license: https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/8d584cba-0881-413a-aace-47d72535f7cc/download
license: https://www.rioxx.net/licenses/all-rights-reserved/
date published: 2023-03-01
date modified: 2026-07-22T22:24:25Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.104721