CYP701A: A Family of Multifunctional Plant Cytochromes P450 in Terpenoid Biosynthesis

萜类化合物是天然产物中最大的一类，具有广泛的生物和工业功能。大多数萜类化合物，实际上在所有天然产品中，都是完全由植物产生的。作为这种代谢能力的结果，植物比其他生物编码更多的细胞色素P450(P450)。这些单加氧酶催化许多代谢物的生物合成和解毒的关键步骤。尽管它们在生产有价值的天然产品方面很重要，但用植物提取的P450进行的机械工作很少。该项目以P450的CYP701A家族为目标，该家族主要由来自不同物种的高岭烯氧化酶组成。高岭烯氧化酶是一种普遍存在的植物P450，在二萜类赤霉素植物生长激素的生物合成中催化三个连续的反应。此外，相关功能被归因于水稻中发现的一组CYP701AP450。因此，对这组同源P450中的单个酶的功能表征将创建一个模型系统，用于研究差异功能的酶基础，从而澄清这些植物细胞色素P450的底物选择性和催化活性的结构/功能基础。更广泛的影响：在研究这些微粒体P450的过程中，参与该研究项目的本科生和研究生将在关键的膜生物化学领域接受广泛的培训。这些学生还将接受功能基因组学方法的培训，因为植物物种现在可以获得广泛的序列信息。此外，该项目产生的技术、战略和知识将不仅加强大学层面的教学，而且还将促进针对中小学教师的努力。因此，该项目产生的知识将通过科学文献和广泛的教育努力得到广泛传播。最后，这些研究可能会产生一些商业影响，因为植物P450在有价值的天然产物代谢物的生物合成中的重要性以及它们在工业过程中的潜在用途。

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.