Peptidoglycan pentaglycine cross-bridge

The peptidoglycan pentaglycine cross-bridge is a structural element of the bacterial cell wall, found predominantly in Gram-positive bacteria such as *Staphylococcus aureus*. It consists of a short peptide chain of five glycine residues that links the peptide stems attached to N-acetylmuramic acid residues in adjacent glycan strands of peptidoglycan. This bridge cross-links the third amino acid of one stem peptide (usually L-lysine) to the fourth D-alanine of another peptide stem, resulting in a highly crosslinked, mesh-like sacculus that protects bacteria against osmotic lysis and environmental stresses[2][4][6][9]. The pentaglycine cross-bridge is synthesized by a dedicated set of enzymes, including FemX, FemA, and FemB, and is essential for staphylococcal cell wall architecture and viability[3]. It serves as a specific docking site and substrate for enzymes like lysostaphin, which cleave these bridges, leading to cell wall disruption—a mechanism exploited for antibacterial therapy[5][3]. Since this structure is present in pathogenic staphylococci but rare or absent in human cells and many commensal bacteria, it represents an effective, selective therapeutic target for anti-staphylococcal drugs[3][5].

Other names

Pentaglycine interpeptide bridgePentaglycine cross-linkPeptidoglycan pentaglycine interbridge

Cleavage of the pentaglycine cross-bridge by endopeptidase; Disruption of peptidoglycan mesh integrity