Arabinogalactan proteins are proteoglycans located in the plant cell wall. Most arabinogalactan proteins are composed of carbohydrate moieties of β-(1→3)-galactan main chains with β-(1→6)-galactan side chains terminated by other glycans. In this study, three novel endo-β-(1→3)-galactanases were identified and the substrate specificity was further studied using well-defined galactan oligomers. Linear and branched β-(1→3)-linked galactans, which resemble the carbohydrate core of the arabinogalactan protein, were used for the characterization of endo-β-(1→3)-galactanases. The identified enzymes required at least three consecutive galactose residues for activity. Non-substituted regions were preferred, but substituents in the -2 and +2 and in some cases also -1 and +1 subsites were tolerated to some extent, depending on the branching pattern, however at a significantly lower rate/frequency.
- Gum arabic
- Type II arabinogalactan
- Glycosyl hydrolase (GH) family 16
Kalomoiri, P., Holck, J., Coulomb, L., Boos, I., Enemark-Rasmussen, K., Spodsberg, N., Monrad, R. N., & Clausen, M. H. (2019). Substrate specificity of novel GH16 endo-β-(1→3)-galactanases acting on linear and branched β-(1→3)-1 galactooligosaccharides. Journal of Biotechnology, 290, 44-52. https://doi.org/10.1016/j.jbiotec.2018.12.006