Peptidoglycan in Mycobacteria: chemistry, biology and intervention.

Peptidoglycan, a major glycoconjugate in the mycobacterial cell envelope provides strength to resist osmotic stress and plays a pivotal role in maintaining the cellular morphology. Several unique growth stage specific structural alterations occur in its constituent monosaccharides and peptides that allow Mycobacterium to survive nutrient starvation and environmental stress. Here, we discuss the enzymes involved in its intricate biosynthesis that are novel targets for therapeutic intervention and provide an opportunity for potential antibiotic adjuvants. We also revisit the enzymatic steps which are critical for maintaining the equilibrium between peptidoglycan synthesis and hydrolysis during cellular growth and division specifically focused on the importance of cell wall remodelling during "exit from dormancy" in Mycobacterium, a phenomenon with tremendous physiological and therapeutic importance for intervention in mycobacterial infections.