Fig. 6: Model of xylan-cellulose interaction in sorghum secondary cell walls.
From: A grass-specific cellulose–xylan interaction dominates in sorghum secondary cell walls
Frequent and irregular arabinosyl substitution on the xylan backbone reduces the fraction of xylan in a two-fold screw conformation, and the majority of xylan is in a three-fold screw conformation. Three-fold screw xylan rarely docks on the hydrophilic surface of the highly ordered, flat-ribbon shape crystalline cellulose due to its helical shape. Instead, it is found in association with less ordered amorphous cellulose, likely via Van der Waal forces and limited hydrogen bonds. A large fraction of cellulose in the sorghum secondary cell walls is amorphous cellulose, which may facilitate the interactions between xylan and cellulose.
