of the carbon skeleton in the indole diterpenes, paxilline, and emindole DA was examined. Intact incorporation of multiply (2)H-labeled 3-geranylgeranylindole into two different fungal metabolites proves 3-geranylgeranylindole to be a biosynthetic intermediate. These results give evidence that indole diterpenes are biosynthesized via epoxidation of a common intermediate, and the subsequent cationic
Cephalotene synthase (CsCTS), a new diterpene synthase from Cephalotaxus sinensis responsible for forming the core skeleton of cephalotane-type diterpenoids, was functionally identified. The cyclization cascade was studied in depth through isotopic labeling experiments and DFT calculations. Site-directed mutagenesis guided by molecular docking revealed the critical amino acid residues for the unique