Structural characterization of the released polysaccharide of desiccation-tolerant Nostoc commune DRH-1.

The structure of the viscous extracellular polysaccharide (glycan) of desiccation-tolerant Nostoc commune DRH-1 was determined through chromatographic and spectroscopic methods. The polysaccharide is novel in that it possesses a 1-4-linked xylogalactoglucan backbone with D-ribofuranose and 3-O-[(R)-1-carboxyethyl]-D-glucuronic acid (nosturonic acid) pendant groups. The presence of D-ribose and nosturonic acid as peripheral groups is unusual, and their potential roles in modulating the rheological properties of the glycan are discussed.