Mycobacterium peptidoglycan (PG)

Mycobacterium peptidoglycan is a vital structural heteropolymer that forms a core part of the mycobacterial cell envelope, providing mechanical strength and maintaining cell shape against high internal osmotic stress (Kieser & Rubin, 2014, Nature Reviews Microbiology). It is uniquely characterized by the presence of N-glycolylmuramic acid, a modification from the standard N-acetylmuramic acid found in most other bacteria, which contributes to its resistance against host lysozymes (Raymond et al., 2005, Journal of Biological Chemistry). This layer is covalently anchored to the arabinogalactan-mycolic acid complex, creating the robust mycolyl-arabinogalactan-peptidoglycan (mAGP) structure essential for bacterial viability (Alderwick et al., 2015, Cold Spring Harbor Perspectives in Medicine). In the context of disease, particularly tuberculosis caused by Mycobacterium tuberculosis, this structure is a primary target for several antimicrobial agents. Drugs such as carbapenems (e.g., meropenem) and D-cycloserine exert bactericidal effects by inhibiting the enzymes responsible for peptidoglycan synthesis and cross-linking (Hugonnet et al., 2009, Science). Despite the historical focus on mycolic acid inhibitors like isoniazid, the peptidoglycan biosynthetic pathway remains a critical area for developing treatments against multi-drug resistant (MDR) and extensively drug-resistant (XDR) tuberculosis strains (Maitra et al., 2019, Chemical Science).

Other names

MureinBacterial cell wall peptidoglycanMycobacterial murein layerPeptidoglycan layer

Inhibition of peptidoglycan biosynthesis and cross-linking, specifically targeting transpeptidases (penicillin-binding proteins) or inhibiting enzymes like D-alanine-D-alanine ligase and alanine racemase (StatPearls, 2023; Hugonnet et al., 2009, Science).