Crystal Structure Based Mutagenesis of Cattleyene Synthase Leads to the Generation of Rearranged Polycyclic Diterpenes

The crystal structures of cattleyene synthase (apo‐CyS), and CyS complexed with geranylgeranyl pyrophosphate (GGPP) were solved. The CySC59A variant exhibited an increased production of cattleyene and other diterpenes with diverse skeletons. Its structure showed a widened active site cavity explaining the relaxed selectivity. Isotopic labeling experiments revealed a remarkable cyclization mechanism involving several skeletal rearrangements for one of the novel diterpenes. The crystal structure of the diterpene synthase CyS was solved, providing the structural basis for cattleyene biosynthesis. A CySC59A mutant generated diterpenes with novel carbon skeletons. The remarkable cyclization mechanism of one of these products was characterized by isotopic labeling experiments.