Oxygenated mycolic acids are necessary for virulence of Mycobacterium tuberculosis in mice

Members of the Mycobacterium tuberculosis group synthesize a family of long -chain fatty acids, mycolic acids, which are located in the cell envelope. These include the non-oxygenated alpha-mycolic acid and the oxygenated keto - and methoxymycolic acids. The function in bacterial virulence, if any, of these various types of mycolic acids is unknown. We have constructed a mut ant strain of M. tuberculosis with an inactivated hma (cmaA, mma4) gene; th is mutant strain no longer synthesizes oxygenated mycolic acids, has profou nd alterations in its envelope permeability and is attenuated in mice.