Fig. 1.

(A) Engineering levopimaradiene synthesis in E. coli. A plant-derived pathway was constructed by introducing T. chinensis ggpps and G. biloba lps codon-optimized genes. To amplify the endogenous precursor pools of GGPPS substrates (IPP and DMAPP), copy numbers of rate-limiting steps (dxs, idi, ispD, ispF) in the MEP pathway were amplified by additional episomal expression. (B) General reaction mechanism of “LPS-type” enzymes. Levopimaradiene, the major product of G. biloba LPS is the gateway precursor of ginkgolides. Coproducts of LPS include abietadiene, neoabiatadiene, and sandaracopimaradiene that stem from the different deprotonation patterns throughout intermediates in the reaction cascade.