Molecular architecture of araban, galactoglucan and welan

The debranched plant polysaccharide araban exhibits fat mimic properties. Among the Rhizobium family of bacterial polysaccharides, a galactoglucan, having a disaccharide repeating unit, is equally effective in root nodulation as the complex succinoglycan and similar polysaccharides having branched octasaccharide repeating units. The branched polymer welan, belonging to the gellan family of polysaccharides, has excellent affinity for calcium and shows very high viscosity in aqueous solution up to 130°C. The three-dimensional structures of these polymers have been determined to varying degrees by using X-ray diffraction and computer modeling methods. The structural details help to understand the molecular basis of the functional properties of these polysaccharides.