Characterization of an Extracellular Polysaccharide Elaborated by TX-1, a New Strain of Beijerinckia indica

抄録

An extracellular polysaccharide elaborated by a new species of Beijerinckia indica, named TX-1, was composed of D-glucose, L-fucose, D-glycero-D-manno-heptose, and D-glucuronic acid in a molar ratio of 5.0 : 1.0 : 2.0 : 0.9, in addition to 16.2% of the acetyl group. Among the polysaccharides of the Beijerinckia species, the present polysaccharide might be the first acidic type having an L-fucose residue. A methylation analysis, Smith degradation study and fragmentation analysis show that this polysaccharide consisted of non-reducing terminal D-glucose, O-4 substituted D-glucose, O-2 substituted D-glycero-D-manno-heptose, O-4 substituted D-glucuronic acid, O-3 and O-4 substituted D-glucose, and O-3 substituted L-fucose residues. A D-glucuronic acid residue was linked to the O-3 position of the L-fucose residue by an α-glycosidic linkage. Most of the D-glucose residues in the backbone chain were substituted at the O-3 position, with the side chain having non-reducing terminal D-glucose residues. It is suggested by the reaction with Con A that the anomeric configuration of the terminal D-glucose residues was β.