High-Throughput HDR Inhibitor Screening

Isopentenyl diphosphate (TPP) and dimethylallyl diphosphate (DMAPP), biochemical precursors of the isoprenoids, are biosynthesized by mevalonate pathway and methylerythritol phosphate (MEP) pathway. Because these two pathways are mutually exclusive in most organisms, inhibition of MEP pathway has become a target for the development of new bioactive materials, including antibiotics, antimalarial drugs, and herbicides. In the final step of MEP pathway, (E)-4-hydroxy-3-methylbut-2-enyl diphosphate reductase (HMBPP reductase, HDR) catalyzes reduction of HMBPP to IPP and DMAPP. HDR requires electron transfers to the Fe/S cluster in the active site for the catalysis, and methyl viologen has been used as a common redox mediator for in vitro studies. We developed a high throughput colorimetric HDR inhibitor screening method by utilizing microtiter-plate screening method. This method was applied to various plant extracts to measure HDR inhibition activity, and potent HDR inhibitor was successfully screened.