Staphylococcal peptidoglycan pentaglycine cross-bridge ((Gly)5 bridge)

The staphylococcal peptidoglycan pentaglycine cross-bridge is a specialized structural component of the cell wall in Staphylococcus aureus and certain other staphylococci (Schleifer and Kandler, 1972). It is composed of five glycine residues that form a bridge between the L-lysine of one peptidoglycan stem peptide and the D-alanine of another, facilitating extensive cross-linking of the glycan strands (Rohrer et al., 1999). This structure is essential for maintaining the mechanical integrity and osmotic stability of the bacterial cell. Because this specific pentaglycine motif is unique to staphylococci, it represents a highly selective target for antimicrobial therapy. The enzyme lysostaphin, a glycylglycine endopeptidase, specifically cleaves these bridges, leading to rapid bacterial lysis and death (Bastos et al., 2010). Research also focuses on inhibiting the Fem (factor essential for methicillin resistance) protein family, which catalyzes the assembly of the pentaglycine bridge, as a strategy to restore antibiotic sensitivity in resistant strains (Ehlert et al., 1997).

Other names

Pentaglycine interpeptide bridgePentaglycine cross-linkStaphylococcal peptidoglycan bridge(Gly)5 interpeptide bridge

Lysostaphin acts as a glycylglycine endopeptidase that specifically cleaves the pentaglycine cross-bridges, leading to bacterial cell lysis (Bastos et al., 2010). Fem inhibitors block the enzymes responsible for the sequential addition of glycine residues to the peptidoglycan precursor (Rohrer et al., 1999).