The case of the mycomembrane: Investigating the composition and properties of the mycobacterial outer membrane

Mycobacteria, which include the human pathogen Mycobacterium tuberculosis, are distinguished by a chemically and structurally complex multi-layer cell envelope. This envelope includes a second, outer lipid membrane that is commonly called the mycomembrane because its structure and composition differ from the better-understood outer membrane of gram-negative bacteria like E. coli. A few biophysical studies have provided the basis for the oft-cited impermeability of the mycomembrane, which is thought to contribute to the inherent resistance of mycobacteria to antibiotics.