Fig. 1.

Functional characterization of MhIDS-1 (MhTPS) from M. histrionica. Recombinant MhIDS-1 protein was expressed in E. coli and Sf9 cells and partially purified by affinity chromatography. Proteins were incubated with (E,E)-FPP 2 in the presence of Mg²⁺ and products were analyzed by GC-MS. (A) GC-MS chromatograms of enzyme products. Sf9 control cells express a housefly cytochrome P450 reductase. *, nonenzyme product; 3, (1S,6S,7R)-sesquipiperitol; cu, γ-curcumene; far, (2E,6E)-farnesol; sesq, β-sesquiphellandrene; zi, α-zingiberene. (B) Mass spectra of enzymatic products with (1S,6S,7R)-sesquipiperitol standard 3. (C) Formation of sesquipiperitol 3 by M. histrionica TPS activity (boxed). A putative single or two-step pathway to murgantiol 1 is shown involving isomerization and epoxidation reactions. EV, empty vector; MdCPR, Musca domestica cytochrome P450 reductase.