Streptococcus pneumoniae peptidoglycan (PGN)

Streptococcus pneumoniae peptidoglycan is a vital structural heteropolymer that forms a thick, protective layer around the bacterial cell membrane, maintaining cell shape and preventing osmotic lysis (Vollmer et al., 2008). It consists of glycan strands of alternating N-acetylglucosamine and N-acetylmuramic acid units, which are extensively cross-linked by stem peptides containing D-amino acids (Ghuysen, 1991). This rigid framework is essential for the survival of the pathogen within the host and serves as a scaffold for the attachment of other virulence factors, such as teichoic acids (Kadioglu et al., 2008). As a primary therapeutic target, its synthesis is disrupted by beta-lactam antibiotics, which inhibit the transpeptidase activity of penicillin-binding proteins, and glycopeptides, which sequester the D-Ala-D-Ala termini of the peptide precursors (Kohanski et al., 2010). Beyond its structural role, peptidoglycan fragments released during infection are potent proinflammatory mediators recognized by host pattern recognition receptors like NOD2, contributing to the severe inflammation characteristic of pneumococcal pneumonia and meningitis (Davis et al., 2011). The emergence of penicillin-resistant strains, characterized by altered PBPs with reduced affinity for drugs, remains a significant challenge in treating infections caused by this organism (StatPearls, 2023).

Other names

MureinPneumococcal peptidoglycanCell wall peptidoglycanS. pneumoniae PGN

Inhibition of peptidoglycan biosynthesis through the inactivation of transpeptidases (Penicillin-Binding Proteins) or by binding to D-alanyl-D-alanine precursors to prevent polymer cross-linking.