Figure 1.
MEP Pathway. The MEP pathway is used by many eubacteria, as well as plants and apicomplexan protozoa. Pyruvate is condensed with glyceraldehyde 3-phosphate to yield 1-deoxy-d-xylulose 5-phosphate, DXP.39 1-deoxy-d-xylulose 5-phosphate reductoisomerase (IspC) catalyzes the reduction and isomerization of DXP to yield 2-C-methylerythritol 4-phosphate (MEP).40 Isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP) are produced after an additional five enzymatic steps.37,41−46 IPP and DMAPP are precursors for isoprenoids, such as bacterial hopanoids, bactoprenols, ubiquinone, and menaquinone.33,36