Type II fatty acid biosynthesis in P. falciparum requires three initiating genes: pfACP encoding acyl carrier protein, pfKASIII encodingβ-ketoacyl-ACP synthase III and pfMCAT encoding malonyl-coenzyme A:ACP transacylase.  The P. falciparum pfKASIII gene is the proposed plasmodial homolog of the essential fatty acid ketoacyl ACP synthase gene KASIII (FabH) in E. coli. Moreover, compounds that selectively inhibit this protein have been reported.

To produce a robust economical bacteria-based assay strain for PfKASIII, we have replaced the E. coli fabH gene with the P. falciparum KASIII (PfKASIII) homolog.  We have demonstrated that the pfKASIII containing E.coli strain grows equally well with or without supplementation of oleic acid, while the FabH Knockout control strain is unable to grow in the absence of supplemented oleic acid. The chimeric E coli strains dependent on pfKASIII are more sensitive to inhibitors of pfKASIII than the wild type strain. Non-specific inhibitions can be deconvoluted by performing bioassays in the presence and absence of exogenously added fatty acids, which have been demonstrated to chemically complement the loss of activity of KASIII enzymes.