The peptidoglycan of Neisseria gonorrhoeae, with or without O-acetyl groups, contains anhydro-muramyl residues.

Muramidase digests of alkali-treated SDS-insoluble peptidoglycan from two strains of Neisseria gonorrhoeae were examined. Both strains contained disaccharide peptide monomers that had intramolecular 1,6-anhydro-muramyl ends. In contrast to strain 1L260, in which 50% of the monomer fraction is O-acetylated, the monomer fraction from strain RD5 was completely devoid of O-acetyl groups, as shown by HPLC. Penicillin decreased the O-acetylation of peptidoglycan but did not affect the proportion of anhydro-muramyl residues.