Mycobacterium tuberculosis, the causative organism of tuberculosis is responsible for approximately three million death cases annually and the mortality rate of infections caused by multiple drug-resistant strains of this bacterium exceed 80%. M. tuberculosis is coated by a number of polysaccharides of unusual structure. A unique component termed polysaccharide II is composed of alpha, 1,2-linked D-glucose residues. Schemes were designed to isolate this polysaccharide from polysaccharide- containing extracts of M. tuberculosis. We demonstrated that the major monosaccharide components in soluble polysaccharide fractions from Mycobacteria are arabinose, mannose and galactose. A polysaccharide fraction was also identified which contains mannose and glucose in approximately equal amounts. We demonstrated the presence of a glycogen- like polysaccharide as one of the extracellular polysaccharides of Mycobacteria. We developed a method for the chemical synthesis of oligosaccharides corresponding to the putative polysaccharide II. We showed that for such compounds the stepwise synthesis is the method of choice.
