Structural investigation of a heteroglycan isolated from the fruit bodies of an ectomycorrhizal fungus Astraeus hygrometricus

A polysaccharide fraction (AQS-II) has been isolated from the hot aqueous extract of the fruits of an ectomycorrhizal fungus Astraeus hygrometricus. It was found to contain 63% polysaccharide and 35% protein. The polysaccharide part contains glucose, galactose, and fucose in a 2:1:1 molar ratio. On the basis of total acid hydrolysis, methylation analysis, periodate oxidation, and NMR studies ((1)H, (13)C, DQF-COSY, TOCSY, NOESY, HMBC, and HSQC) the structure of the repeating unit of the polysaccharide was established as structure: see text].