Mycolic Acids
Mycolic acids are long chain fatty acids that contain an alkyl side chain and a hydroxy group at the α and β positions, respectively. While they are primarily found attached to the peptidoglycan-arabinogalactan complex of the mycobacterial cell wall, they are also constituents of the outer cell wall envelope and can exist as free mycolic acids. M tuberculosis produces three subclasses: α, methoxy, and keto mycolic acids; however, mycolic acids are not exclusive to mycobacteria and can be found in related genera such as Nocardia, Rhodococcus, and Corynebacterium. Mycolic acids are essential for bacterial viability and virulence making them attractive drug targets.
Reference:
Nataraj V, Varela C, Javid A, Singh A, Besra GS, Bhatt A. Mycolic acids: deciphering and targeting the Achilles' heel of the tubercle bacillus. Mol Microbiol. 2015 Oct;98(1):7-16. doi: 10.1111/mmi.13101. PMID: 26135034.