New pyruvylated, glycosylated acyltrehaloses from Mycobacterium smegmatis strains, and their implications for phage resistance in mycobacteria.

Phage resistance and apparent lysogenization of Mycobacterium smegmatis due to infection with mycobacteriophage D29 results in the emergence of new variations of the pyruvylated, acylated trehaloses described by Saadat and Ballou, J. Biol. Chem. 258 (1983) 1813-1818. Thin-layer chromatography of the glycolipids from two strains of phage-resistant M. smegmatis (mc(2)22 and mc(2)11) and comparison with those from phage-sensitive strains revealed a new, more mobile glycolipid in each case. The structures of these acyltrehalose-containing lipooligosaccharides were elucidated by a combination of gas-liquid chromatography-mass spectrometry, methylation analysis, 1H and 13C NMR spectroscopy, and fast-atom bombardment mass spectrometry. The glycolipid from M. smegmatis mc(2)22 is beta-D-Glcp-(1-->3)-4,6-O-(1-methoxycarbonylethylidene)-beta-D-Glc p-(1-->4)- beta-D-Glcp-(1-->6)-2-O-acyl-alpha-D-Glcp-(<==>1)-3,4-O-acyl-alpha-D-Glc p and that from M. smegmatis mc(2)11 is 4,6-O-(1-methoxycarbonylethylidene)-3-O-Me-beta-D-Glcp-(1-->3)-4,6 -O- (1-methoxycarbonylethylidene)-beta-D-Glcp-(1-->4)-beta-D-Glcp-(1-- >6)-2-O-acyl- alpha-D-Glcp-(1<==>1)-3,4-di-O-acyl-alpha-D-Glcp. These differ from the original pyruvylated glycolipids of Saadat and Ballou in the extent of their O-acylation and O-methylation. The findings are the first example of the definition of a chemical basis for phage resistance and presumed lysogeny in mycobacteria, and show parallels to related changes in gram-negative enteric bacteria.