STRUCTURAL STUDIES OF THE EXTRACELLULAR POLYSACCHARIDE ELABORATED BY AZOTOBACTER-VINELANDII STRAIN-1484

The structure of the extracellular polysaccharide from Azotobacter vinelandii strain 1484 has been investigated, specific degradations and n.m.r. spectroscopy being the main methods used. It is concluded that the polysaccharide is composed of tetrasaccharide repeating-units having the following structure. --> 4)-alpha-L-Rhap-(1 --> 3)-alpha-L-Rhap-(1 --> 3)-beta-L-Rhap-(1 --> 2 up 2 beta-Sugp in which Sug is 3-deoxy-D-threo-hexulosonic acid. The polysaccharide also contains a non-stoichiometric amount of O-acetyl groups, distributed over at least two positions.