Terpenoids, which form the largest family of natural products, have extensive biological and industrial functions. The majority of terpenoids, indeed of all natural products, are exclusively produced by plants. As a consequence of such metabolic prowess, plants encode more cytochromes P450 (P450s) than other organisms. These monooxygenases catalyze key steps in the biosynthesis and detoxification of many metabolites. Despite their importance in the production of valuable natural products, little mechanistic work has been carried out with plant derived P450s. This project targets the CYP701A family of P450s, which is largely composed of kaurene oxidase from various species. Kaurene oxidase is a universal plant P450 catalyzing three consecutive reactions in diterpenoid gibberellin plant growth hormone biosynthesis. In addition, related functions have been ascribed to the group of CYP701A P450s found in rice. Thus, functional characterization of the individual enzymes within this group of homologous P450s will create a model system for investigating the enzymatic basis for differential function, leading to clarification of the structure/function basis for the substrate selectivity and catalytic activity of these plant cytochromes P450.
Broader Impact: In the course of investigating these microsomal P450s, the undergraduate and graduate students involved in this research project will receive broad training in the critical area of membrane biochemistry. The students also will be trained in functional genomics approaches, as extensive sequence information is now becoming available for plant species. Further, the techniques, strategies, and knowledge generated by this project will enhance teaching, not only at the university level, but also efforts targeted at primary and secondary school teachers. Thus, the knowledge generated by this project will be widely disseminated, both through the scientific literature, as well as broad educational efforts. Finally, these studies may have some commercial impact due to the importance of plant P450s in the biosynthesis of valuable natural product metabolites and their potential uses in industrial processes.
