title: An unexpected diterpene cyclase from rice: functional identification of a stemodene synthase.
abstract: We have cloned a novel diterpene synthase (OsKSL11) from rice that produces stemod-13(17)-ene from syn-copalyl diphosphate. Notably, this gene sequence was not predicted from the extensive sequence information available for rice, nor, despite extensive phytochemical investigations, has this diterpene or any derived natural product previously been reported in rice plants. OsKSL11 represents the first identified stemodene synthase, which catalyzes the committed step in biosynthesis of the stemodane family of diterpenoid natural products, some of which possess antiviral activity. In addition, OsKSL11 is highly homologous to the mechanistically similar stemarene synthase recently identified from rice, making this pair of diterpene cyclases an excellent model system for investigating the enzymatic determinants for differential product outcome. The unexpected nature of this cyclase and its product parallels recent observations of previously unrecognized natural products metabolism in Arabidopsis thaliana, suggesting that many, if not all, plant species will prove to have extensive biosynthetic capacity.
authors.affiliation: Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA.
authors.forename: Dana
authors.initials: D
authors.lastname: Morrone
authors.forename: Yinghua
authors.initials: Y
authors.lastname: Jin
authors.forename: Meimei
authors.initials: M
authors.lastname: Xu
authors.forename: Suh-Yeon
authors.initials: SY
authors.lastname: Choi
authors.forename: Robert M
authors.initials: RM
authors.lastname: Coates
authors.forename: Reuben J
authors.initials: RJ
authors.lastname: Peters
mesh_terms: D000595:Amino Acid Sequence; D019755:Carbon-Carbon Lyases / Q000737:chemistry* / Q000235:genetics; D004224:Diterpenes / Q000737:chemistry*; D004789:Enzyme Activation; D008969:Molecular Sequence Data; D012275:Oryza / Q000201:enzymology*; D011994:Recombinant Proteins / Q000737:chemistry
chemical_list: D004224:Diterpenes; D011994:Recombinant Proteins; D019755:Carbon-Carbon Lyases; C511059:stemodene synthase, Oryza sativa