Structure and stereochemistry of mycolic acids of Mycobacterium marinum and Mycobacterium ulcerans.

Mycobacterium marinum and M. ulcerans were previously shown to synthesize lipid compounds which are stereochemically different from the corresponding molecules isolated from M. tuberculosis and other species. Stereochemical and biogenetic studies of mycolic acids isolated from M. marinum showed that the absolute configurations of the chiral centres occurring in the mycolates are identical to those of the other mycobacterial species examined so far. Furthermore, all the methyl branches were found to come from methionine whatever the configuration of the centre. The structures of the mycolates synthesized by M. marinum and M. ulcerans were found to be identical, consisting of dicyclopropyl and monocyclopropyl monoenoic mycolates, monoenoic keto- and methoxymycolates, thus reinforcing the taxonomical relationship between the two species.