CHEMISTRY OF THE LYXOSE-CONTAINING MYCOBACTERIOPHAGE RECEPTORS OF MYCOBACTERIUM-PHLEI MYCOBACTERIUM-SMEGMATIS

Mycobacterium phlei (strain Timothy) (Mycobacterium smegmatis ATCC 192 49) is characterized by the presence of a family of alkali-labile glyc olipids, reminiscent of the trehalose-containing lipooligosaccharide c lass of antigens but lacking the nonreducing trehalose core, Through a combination of methylation analyses, H-1 and C-13 NMR, two-dimensiona l H-1/H-1 and H-1/C-13 NMR, fast atom bombardment-mass spectrometry, g as chromatography-mass spectrometry, and other analytical techniques, these new structures were shown to possess three distinct features. Fi rstly, they contained the pentose D-lyxose (Lyx), rarely found in biol ogy, but an epimer of D-arabinose, a key component of the mycobacteria l cell wall arabinogalactan and lipoarabinomannnan. Thus, it was appar ent that these glycolipids are the same as those described by Bisso et al. and attributed with phage receptor properties [Bisso, G., Casteln uovo, G., Nardelli, M.-G., Orefici, G., Arancia, G., Laneelle, G., Ass elineau, C., & Asselineau, J. (1976) Biochemie 58, 87-97]. Secondly, t he complex oligosaccharides within the glycolipids contain the repeati ng units Lyx(n)(6-0-CH3-Glc)(m) and Lyx(n)(6-0-CH3-Glc)(m)Man(1), wher e n + m equal to approximately 16 glycosyl residues. Thirdly, the M. p hlei glycolipids were found to be heavily 0-acylated, such that every D-Lyx residue invariably possesses an acyl function at position -2 and , in some instances, at both positions -2 and -4. The chemical charact erization of these glycolipids, not feasible 20 years ago, clearly dem onstrates that they are distinct from the type- and species-specific g lycopeptidolipids, lipooligosaccharides, phenolic glycolipids, and the genus-specific phosphatidylinositol-based lipoglycans of mycobacteria . This present and previous studies begin to define the precise struct ural requirements responsible for the attachment of mycobacteriophage to the host cell wall.