Bacterial peptidoglycan (PGN) (PGN)

Bacterial peptidoglycan (PGN), also known as murein, is an essential and unique structural polymer that forms a mesh-like layer outside the cytoplasmic membrane of most bacteria (StatPearls, 2023). It consists of long glycan strands composed of alternating N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) residues, which are cross-linked by short peptide chains to provide mechanical strength and maintain cell shape (Nature Reviews Microbiology, 2019). This structure is critical for protecting the bacterium from osmotic lysis due to high internal pressure. Because peptidoglycan is absent in eukaryotic cells, it serves as a highly specific and effective target for antibacterial agents. Glycopeptide antibiotics, such as vancomycin, exert their effect by binding directly to the D-alanyl-D-alanine terminus of the peptidoglycan precursors, thereby inhibiting the assembly and cross-linking of the glycan strands (PubChem, 2024). Additionally, the enzyme lysozyme, a key component of the innate immune system, targets this molecule by hydrolyzing the beta-1,4-glycosidic bonds between NAM and NAG, leading to cell wall degradation and bacterial death (Microbiology and Molecular Biology Reviews, 2006).

Other names

MureinNAM-NAG polymerPeptidoglycan backboneCell wall glycanPeptidoglycan-linked NAM-NAG glycan strands

Inhibition of cell wall synthesis by binding to the D-alanyl-D-alanine terminus of peptidoglycan precursors, preventing polymerization and cross-linking of glycan strands (PubChem, 2024). Enzymatic hydrolysis of the beta-1,4-glycosidic bonds between N-acetylmuramic acid and N-acetylglucosamine residues in the glycan backbone (Microbiology and Molecular Biology Reviews, 2006).