Fig. 1.

Schematic diagram of one glycan strand of the pneumococcal PG showing proteins containing PG hydrolytic domains (see Table 1 and text) and known or putative sites of PG cleavage. Most interpeptide cross-links are direct in strain D39 (solid line between l-Lys and d-Ala) without the addition of l-Ser–l-Ala or l-Ala–l-Ala interpeptide cross bridges (see reference 1). PG hydrolase activities that have not been confirmed by biochemical analyses are indicated by question marks. MurNAc, N-acetylmuramic acid; GlcNAc, N-acetylglucosamine. Additional glycan strands, deacetylations and other modifications, and sites of attachment of capsule, teichoic acids, and proteins covalently linked by sortase are omitted for simplicity (see references 61 and 62).