Multivariate-modular approach for isoprenoid pathway optimization

Multivariate-modular approach for isoprenoid pathway optimization. To increase the flux through the upstream MEP pathway, we targeted reported enzymatic bottlenecks (dxs, idi, ispD, and ispF) (gray) for over-expression by an operon (dxs-idi-ispDF) (). To channel the overflow flux from the universal isoprenoid precursors, IPP and DMAPP, toward Taxol biosynthesis, we constructed a synthetic operon of downstream genes GGPP synthase (G) and taxadiene synthase (T) (). Both pathways were placed under the control of inducible promoters in order to control their relative gene expression. In the E. coli metabolic network, the MEP isoprenoid pathway is initiated by the condensation of the precursors glyceraldehyde-3 phosphate (G3P) and pyruvate (PYR) from glycolysis. The Taxol pathway bifurcation starts from the universal isoprenoid precursors IPP and DMAPP to form geranylgeranyl diphosphate, and then the taxadiene. The cyclic olefin taxadiene undergoes multiple rounds of stereospecific oxidations, acylations, and benzoylation to form the late intermediate Baccatin III and side chain assembly to, ultimately, form Taxol.

Publication

Isoprenoid Pathway Optimization for Taxol Precursor Overproduction in Escherichia coli. () Parayil Kumaran Ajikumar, et al. Science. ;330(6000):70-74. Figure: F1. Escherichia coli str. K-12 substr. MG1655

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