The Patterned Structure of Galactoglucomannan Suggests It May Bind to Cellulose in Seed Mucilage.
Authors
Yu, Xiaolan
Li, An
Publication Date
2018-11Journal Title
Plant Physiol
ISSN
0032-0889
Publisher
Oxford University Press (OUP)
Volume
178
Issue
3
Pages
1011-1026
Language
eng
Type
Article
Physical Medium
Print-Electronic
Metadata
Show full item recordCitation
Yu, L., Lyczakowski, J. J., Pereira, C. S., Kotake, T., Yu, X., Li, A., Mogelsvang, S., et al. (2018). The Patterned Structure of Galactoglucomannan Suggests It May Bind to Cellulose in Seed Mucilage.. Plant Physiol, 178 (3), 1011-1026. https://doi.org/10.1104/pp.18.00709
Abstract
The interaction between mannan polysaccharides and cellulose microfibrils contributes to cell wall properties in some vascular plants, but the molecular arrangement of mannan in the cell wall and the nature of the molecular bonding between mannan and cellulose remain unknown. Previous studies have shown that mannan is important in maintaining Arabidopsis (Arabidopsis thaliana) seed mucilage architecture, and that Cellulose Synthase-Like A2 (CSLA2) synthesizes a glucomannan backbone, which Mannan α-Galactosyl Transferase1 (MAGT1/GlycosylTransferase-Like6/Mucilage Related10) might decorate with single α-Gal branches. Here, we investigated the ratio and sequence of Man and Glc and the arrangement of Gal residues in Arabidopsis mucilage mannan using enzyme sequential digestion, carbohydrate gel electrophoresis, and mass spectrometry. We found that seed mucilage galactoglucomannan has a backbone consisting of the repeating disaccharide [4)-β-Glc-(1,4)-β-Man-(1,], and most of the Man residues in the backbone are substituted by single α-1,6-Gal. CSLA2 is responsible for the synthesis of this patterned glucomannan backbone and MAGT1 catalyses the addition of α-Gal. In vitro activity assays revealed that MAGT1 transferred α-Gal from UDP-Gal only to Man residues within the CSLA2 patterned glucomannan backbone acceptor. These results indicate that CSLAs and galactosyltransferases are able to make precisely defined galactoglucomannan structures. Molecular dynamics simulations suggested this patterned galactoglucomannan is able to bind stably to some hydrophilic faces and to hydrophobic faces of cellulose microfibrils. A specialization of the biosynthetic machinery to make galactoglucomannan with a patterned structure may therefore regulate the mode of binding of this hemicellulose to cellulose fibrils.
Keywords
Cell Wall, Arabidopsis, Seeds, Cellulose, Glycosyltransferases, Galactosyltransferases, Glucosyltransferases, Polysaccharides, Mannans, Arabidopsis Proteins, Plant Mucilage
Sponsorship
Biotechnology and Biological Sciences Research Council (BB/L014130/1)
Biotechnology and Biological Sciences Research Council (BB/J014540/1)
Leverhulme Trust (RP2013-SL-008)
Identifiers
External DOI: https://doi.org/10.1104/pp.18.00709
This record's URL: https://www.repository.cam.ac.uk/handle/1810/285049
Rights
Licence:
http://creativecommons.org/licenses/by/4.0/
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