EAGER: Defining the function and mechanism of YUC1 in tryptophan-dependent indole-3-acetic acid metabolism

EAGER：定义YUC1在色氨酸依赖性吲哚-3-乙酸代谢中的功能和机制

• 批准号: 1203438
• 负责人: Jerry Cohen
• 金额: $ 7.5万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-12-15 至 2013-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1203438&HistoricalAwards=false
• 关键词: EAGER; Defining; function; mechanism; YUC1

For more than 60 years the question of how plants make the growth hormone auxin has been of major interest to plant biologists. Several issues have created significant confusion including the fact that auxin production at the low levels required for signaling appears to be closely linked to that of several compounds produced in much greater quantities. Auxin is involved in many aspects of plant growth, from early embryo development, to plant stature and form, to root initiation, to fruit development and ripening and plant responses to light, gravity and stress. Improving our understanding of auxin production and the mechanisms for regulation of auxin levels, therefore, has great potential for enhancing both our basic knowledge of these processes and our targeting of genetics for plant improvement. Researchers are now poised to solve the steps for the first pathway for auxin production using a combination of genetic and biochemical approaches. Recent genetic evidence makes it appear that two enzymes, an aminotransferase and a flavin monooxygenase, originally assigned to separate pathways, may together be sufficient for auxin synthesis from tryptophan. To fully define this pathway requires demonstration that the flavin monooxygenase can carry out the novel terminal reaction that has precedent only in enzymes from microbes. This project will test a working hypothesis that the most likely mechanism for the flavin monooxygenase involved in auxin production is a combination of two activities, the oxidative decarboxylation as shown by bacterial lactate monooxygenase and a catalytic cycle using NADPH similar to that of a bacterial phenylacetone monooxygenase. To date, however, no biochemical analysis of the action of the plant flavin monooxygenase protein has been reported on the expected substrate nor is the reaction mechanism known. It is the goal of this EAGER project to elucidate the biochemical reaction carried out by Arabidopsis YUC flavin-monooxygenase, to describe the reaction mechanism, and to determine if the reaction measured in vitro can be shown to occur in vivo.Broader Impacts: This project will support two graduate students and involve the students in both research and scientific writing. These laboratories also serve as a resource in plant metabolomics and to auxin researchers interested in analysis and measurement of hormones at low abundance levels and their metabolism in plants. These laboratories also maintain and encourage ties with several primarily undergraduate institutions, and have been welcome hosts to visitors who require the resources they develop.

60多年来，植物如何产生生长激素的问题一直是植物生物学家的主要兴趣。 有几个问题已经造成了严重的混乱，包括信号所需的低水平生长素生产似乎与大量生产的几种化合物密切相关。生长素参与植物生长的许多方面，从早期胚胎发育，到植物身材和形态，到根的发生，到果实发育和成熟以及植物对光、重力和胁迫的响应。 因此，提高我们对生长素生产和生长素水平调节机制的理解，对于提高我们对这些过程的基础知识和我们对植物改良遗传学的靶向具有巨大的潜力。 研究人员现在准备使用遗传和生物化学方法的组合来解决生长素生产的第一条途径的步骤。最近的遗传学证据表明，两种酶，氨基转移酶和黄素单加氧酶，最初被分配到不同的途径，可能一起足以从色氨酸合成生长素。 要完全确定这一途径，需要证明黄素单加氧酶可以进行新的终端反应，只有在微生物的酶的先例。该项目将测试一个工作假设，即参与生长素生产的黄素单加氧酶最可能的机制是两种活性的组合，细菌乳酸单加氧酶和类似于细菌苯丙酮单加氧酶的NADPH催化循环所示的氧化脱羧。 然而，到目前为止，没有生物化学分析的行动，植物黄素单加氧酶蛋白已被报道的预期底物，也是未知的反应机制。 EAGER项目的目标是阐明拟南芥YUC黄素单加氧酶进行的生化反应，描述反应机制，并确定体外测量的反应是否可以在体内发生。更广泛的影响：该项目将支持两名研究生，并让学生参与研究和科学写作。 这些实验室也是植物代谢组学和生长素研究人员的资源，他们对分析和测量低丰度水平的激素及其在植物中的代谢感兴趣。 这些实验室还保持和鼓励与几个主要的本科院校的联系，并一直欢迎游客谁需要他们开发的资源。