Structure of a novel α-glucan substitute with the rare 6-deoxy-d-altrose from Lactarius lividatus (mushroom)

A novel α-glucan substituted rare 6-deoxy-d-altropyranose was isolated from edible fruiting bodies of a mushroom (Lactarius lividatus) grown in Okinawa, Japan. The polysaccharide consists of d-glucose, d-galactose and 6-deoxy-d-altrose in a molar ratio of 3.0:1.0:1.0. The specific rotation [α]589 was estimated as +64.3° (0.2% in water) at 25 °C. Based on results of IR, NMR (1H, 13C, 2D-COSY, 2D-HMQC, 2D-ROESY and 2D-HMBC), and methylation analyses, the structure of the polysaccharide was determined as ork is the first demonstration of rare 6-deoxy-d-altropyranose moiety on polysaccharides.