Chemical and spectroscopic characterisation of the phosphatidylinositol manno-oligosaccharides from Mycobacterium bovis AN5 and WAg201 and Mycobacterium smegmatis mc2 155

Two classes of phosphatidylinositol manno-oligosaccharides (PIMs) were isolated from each of Mycobacterium bovis AN5 and WAg201 and Mycobacterium smegmatis mc(2) 155. The deacylated PIMs (dPIMs), were identified as hexasaccharide (dPIM-6) and disaccharide (dPIM-2) species composed of mannose, myo-inositol, glycerol and phosphate residues in the proportions of 6:1:1:1 and 2:1:1:1, respectively. Structural analysis, employing a combination of microanalytical methods, nuclear magnetic resonance spectroscopy, and mass spectrometric techniques established that the sequence of residues within dPIM-6, as shown below, was identical in the three mycobacterial strains investigated. [GRAPHICS] Enzymic degradation of dPIM-6 with an alpha-(1-2)-D-mannosidase resulted in the formation of a tetrasaccharide (dPIM-4) whose structure, along with that of dPIM-2, were identified as truncated versions of dPIM-6. The H-1 and C-13 NMR resonances of both native dPIM species and the dPIM-6 degradation product were fully assigned by homo- and hetero-nuclear chemical shift correlation methods, and the location of the phosphodiester group was determined by a 2D H-1-P-31 chemical shift correlation experiment. (C) 1998 Elsevier Science Ltd. All rights reserved.