Figure 1
From: Cell wall structure and function in lactic acid bacteria
Schematic representation of the structure of peptidoglycan. This is the type of structure found in L. lactis and numerous lactobacilli. In other LAB species, the nature of the interpeptide cross-bridge (depicted as D-Asp/D-Asn in the figure) may vary, the third di-amino acid (L-Lys) may be replaced by mDAP or L-ornithine, and the D-Ala in position five of the stem peptide may be replaced by D-lactate. Possible modifications of the PG structure, such as O-acetylation (O-Ac), N-deacetylation (leading to GlcNH2), or amidation (NH2), are indicated in red. The cleavage sites of the different classes of PG hydrolases are indicated with arrows.