STRUCTURE OF CELL WALL PEPTIDOGLYCAN OF LACTOBACILLUS CASEI RO94

The cell wall peptidoglycan of Lactobacillus casei R094 contains almost equimolar proportions of D-glutamic acid, D-alanine, L-alanine, L-lysine, D-aspartic acid, N-acetylmuramic acid, N-acetylglucosamine, and two molar proportions of ammonia. Glycan chains of alternating, β-1,4-linked residues of N-acetylglucosamine and TV-acetylmuramic acid have an average chain length of about ten disaccharides and are substituted on every muramic acid residue by the pentapeptide Nα-(L-alanyl-D-isoglutaminy)-Nϵ-(D-isoasparaginyl)-L-lysyl-D-alanine, randomly cross-linked between D-alanine and D-isoasparagine to the extent of 55 %. The Myxobacter AL-1 enzyme hydrolyses all of the D-alanyl-D-isoasparaginyl linkages and most of the TV-acetylmuramyl-L-alanine linkages in the peptidoglycan resulting in the production of hexosamine-free peptide monomers and of an almost peptide-free complex of glycan and group C-specific polysaccharide. The group C-specific polysaccharide is linked to the glycan by highly acid-labile phosphodiester linkages and hydrolysis of the complex gives rise to muramic acid 6-phosphate. © 1969, American Chemical Society. All rights reserved.