Structure of Arabinogalactan
Arabinogalatctans are structurally highly complex polysaccharides consisting predominantly of Galacose (Gal) and Arabinose (Ara) sugars. Arabinogalactans are the major component of gums. They are attached to diverse cell wall proteins via a hydroxyproline in arabinogalactan proteins (AGPs). The polysaccharide component, however, can account for more than 90% of the AGP, suggesting that the arabinogalactan is sometimes the functional part of the molecule.
We used a set of specific carbohydrate-active enzymes to reduce the complexity of the structure, analysed the oligosaccharides by mass spectrometry (MS). The structure of the oligosaccharides revealed the complexity and highly branched nature of arabinogalactan of wheat endosperm AGPs. The cleavage sites of different carbohydrate-active enzymes (arrowheads) are depicted in the structure of arabinogalactan in Figure 1
Figure 1: Structure of wheat arabinogalactan