Lysozyme digestion and chemical characterization of the peptidoglycan of Fusobacterium nucleatum Fev 1.

The amino acids in the peptidoglycan of Fusobacterium nucleatum Fev 1 are D-glutamic acid, meso-lanthionine, and D- (42%) and L-alanine (58%). About 70% of the lanthionine residues were not susceptible to dinitrophenylation, evidently because they are involved in cross-linkages. Consequently, lysozyme digestion of the peptidoglycan yielded 20 to 25% uncross-linked disaccharide tri- and tetrapeptides. A chemical analysis of isolated glycopeptides indicated that the structure of the building block of this peptidoglycan is N-acetylgucosamine-N-acetylmuramic acid-L-alanine-D-glutamic acid-meso-lanthionine(-D-alanine). I present evidence which supports the classification of the F. nucleatum Fev 1 peptidoglycan as a new A1 delta, directly cross-linked, meso-lanthionine-containing peptidoglycan.