PG fragments released from strains deficient in AmpG-mediated PG recycling. Strains were labeled with [3H]-glucosamine. (A) Deletion of ampG causes the release of significantly more PG monomers and free anhydrodisaccharide compared to wild-type. (B) The ltgA ampG and ltgD ampG mutants released 84.3% and 36.2% less PG monomer, respectively, compared to an ΔampG mutant. (C) Mutations affecting the lipidation of LtgA or LtgD had no significant effect on the amount of PG monomers released in an ampG deletion background. 1, tetrasaccharide dipeptides; 2, tetrasaccharide peptides; 3, anhydrodisaccharide peptide monomers; 4, free anhydrodisaccharide.