FIG. 4.

Structures of the main muropeptides as separated in Fig. 3, based on amino acid and hexosamine composition. Glucosamine, Ala, Glu, A₂pm, and Lys were detected after acid hydrolysis of HPLC-purified muropeptides in the following ratios (taking Glu as reference): MA3, 0.95/0.92/1/0.95/0; ML3, 1.07/1.02/1/0/1.03; MA4, 0.97/1.95/1/1.05/0; ML4, 0.97/2.1/1/0/0.97; DAA, 0.95/1.97/1/1/0; and DLA, 1.04/1.9/1/0.48/0.45 (abbreviations are as defined for Fig. 3). When the two latter muropeptides were dinitrophenylated before acid hydrolysis, half of the A₂pm from DAA and all of the lysine, but not the A₂pm, from DLA were lost.