Functional Characterization and Screening of Promiscuous Kinases and Isopentenyl Phosphate Kinases for the Synthesis of DMAPP via a One-Pot Enzymatic Cascade

Dimethylallyl diphosphate (DMAPP) is a key intermediate metabolite in the synthesis of isoprenoids and is also the prenyl donor for biosynthesizing prenylated flavonoids. However, it is difficult to prepare DMAPP via chemical and enzymatic methods. In this study, three promiscuous kinases fromShigella flexneri(SfPK),Escherichia coli(EcPK), andSaccharomyces cerevisiae(ScPK) and three isopentenyl phosphate kinases fromMethanolobus tindarius(MtIPK),Methanothermobacter thermautotrophicusstr. Delta H (MthIPK), andArabidopsis thaliana(AtIPK) were cloned and expressed inEscherichia coli. The enzymatic properties of recombinant enzymes were determined. TheKcat/Kmvalue of SfPK for DMA was 6875 s−1M−1, which was significantly higher than those of EcPK and ScPK. TheKcat/Kmvalue of MtIPK for DMAP was 402.9 s−1M−1, which was ~400% of that of MthIPK. SfPK was stable at pH 7.0–9.5 and had a 1 h half-life at 65 °C. MtIPK was stable at pH 6.0–8.5 and had a 1 h half-life at 50 °C. The stability of SfPK and MtIPK was better than that of the other enzymes. Thus, SfPK and MtIPK were chosen to develop a one-pot enzymatic cascade for producing DMAPP from DMA because of their catalytic efficiency and stability. The optimal ratio between SfPK and MtIPK was 1:8. The optimal pH and temperature for the one-pot enzymatic cascade were 7.0 and 35 °C, respectively. The optimal concentrations of ATP and DMA were 10 and 80 mM, respectively. Finally, maximum DMAPP production reached 1.23 mM at 1 h under optimal conditions. Therefore, the enzymatic method described herein for the biosynthesis of DMAPP from DMA can be widely used for the synthesis of isoprenoids and prenylated flavonoids.Keywords:dimethylallyl diphosphate;promiscuous kinase;isopentenyl phosphate kinase;one-pot enzymatic cascade