Peptidoglycan pentaglycyl bridging segment

The peptidoglycan pentaglycyl bridging segment is a vital structural element of the cell wall in certain Gram-positive bacteria, most notably Staphylococcus aureus (Schleifer & Kandler, 1972). It consists of five glycine residues that form a cross-link between the L-lysine of one muropeptide stem and the D-alanine of an adjacent stem, providing the cell wall with the tensile strength required to resist high internal osmotic pressure (Thumm & Götz, 1997). This specific bridge is the primary target for the antimicrobial enzyme lysostaphin, which acts as a zinc-dependent glycylglycine endopeptidase to cleave the glycine-glycine bonds (Bastos et al., 2010). Because this pentaglycine structure is highly characteristic of staphylococci, it allows for targeted lysis of these pathogens while sparing other bacterial species. Resistance can occur through the incorporation of serine residues into the bridge, mediated by the lif or epr genes, which reduces the binding and cleavage efficiency of bridge-targeting agents (DeHart et al., 1995). Understanding this target is crucial for developing 'enzybiotics' and other narrow-spectrum treatments for multidrug-resistant infections like MRSA.

Other names

Pentaglycine bridgePentaglycyl cross-linkGly5 bridgeInterpeptide bridgePentaglycine interpeptide bridge

Endopeptidase-mediated cleavage of the glycyl-glycine bonds within the pentaglycine bridge, leading to cell wall degradation and osmotic lysis.