A schematic representation of bimodular PKS12 protein from M. tuberculosis, which is required for the biosynthesis of mycoketide. The two modules of PKS12 are colored in blue (AT specificity for methylmalonyl CoA) and buff (AT specificity for malonyl CoA), and the N- and Cters are indicated in green and red, respectively. Individual domains are drawn as small boxes in the two modules. Mycoketide chain originates from repetitive condensations of methylmalonate and malonate units with medium-chain fatty acyl starters. This saturated chain is released from PKS12 by an unknown mechanism, which is followed by reduction, phosphorylation, and mannosylation to form MPM.