The Methylerythritol Phosphate (MEP) Synthase (DXR) Inhibitor Screen (K-2000C) will evaluate compounds for inhibition of DXR activity. This medium throughput inhibitor screen provides a valuable tool for the identification of potential antimicrobials, specifically inhibitors of the MEP Synthase (DXR) enzyme in the MEP pathway.
Sample Type: Compounds for inhibition of DXR activity
Assay sensitivity: IC50 of Fosmidomycin ~ 130 nM
Assay Incubation time: Ten minutes (Continuous Kinetic Readout)
Sample Considerations: Run compounds in ≤ 5% overall DMSO concentration
The MEP pathway is used by most bacteria, including all Gram-negative bacteria, for isoprenoid biosynthesis. Isoprenoids comprise one of the most diverse classes of compounds found in nature. With over 50,000 different isoprenoids identified to date, they exhibit a broad range of structural complexity and are involved in a variety of biological functions  including Electron transport (quinones), stabilization of cell membranes (hopanoids and sterols), cell wall biosynthesis (dolichols), signal transduction (prenylated proteins), photosynthesis (chlorophylls) and modification of tRNAs.  Isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP) are the precursors for all isoprenoid compounds and the MEP pathway is one of two unrelated essential pathways existing in nature for their biosynthesis. These two precursors are produced by either the mevalonate (MVA) or MEP pathway. The MVA pathway is found primarily in eukaryotes, including humans, plant cytosol, Archaea, and some Gram-positive bacteria, while the MEP pathway is utilized by most bacteria and plant chloroplasts. Due to this natural distribution, the MEP pathway represents a promising target for development of novel antibacterial agents and herbicides. 
In the first pathway-specific reaction of the methylerythritol phosphate (MEP) pathway for isoprenoid biosynthesis, MEP Synthase (DXR) catalyzes the rearrangement of 1-deoxy-D-xylulose-5-phosphate (DXP) to generate 2-C-methyl-D-erythritol-4-phosphate (MEP) in the presence of ?-nicotinamide adenine dinucleotide phosphate (NADPH) and a divalent cation.  Fosmidomycin is a natural product inhibitor of MEP synthase and has validated the MEP pathway as an antibiotic target.
Echelon’s MEP Synthase (DXR) assay will evaluate compounds for inhibition of DXR activity. The assay monitors the depletion of ?-NADPH which is detected spectrophotometrically. By measuring this depletion of ?-NADPH one can infer the conversion of the DXP substrate to the MEP product. Fosmidomycin is supplied in this assay as a control inhibitor.
Keywords: Methylerythritol Phosphate Pathway, MEP Pathway, antibacterial, non-mevalonate pathway, MEP, Methylerythritol Phosphate, Isoprenoid biosynthesis, Isoprenoid, DXP, MEP Synthase, IspC, 1-Deoxy-D-xylulose-5-phosphate, 1-Deoxyxylulose 5-phosphate, Deoxyxylulose phosphate, DOXP, 2-C-methyl-D-erythritrol, Fosmidomycin, MEP Pathway Inhibitor Screen