RUI: Regulation of starch degradation by the pseudoamylase, BAM9

植物淀粉是人体的重要分子。淀粉除了是人类和许多家畜的主要营养来源外，还用于洗衣、食品、制药和造纸工业。尽管淀粉被广泛使用，但我们对植物如何合成和降解淀粉的理解是有限的。这两个过程都会影响淀粉的形状和形态，从而影响淀粉被人类利用的方式。本项目旨在了解模式植物拟南芥中淀粉降解的调控。这种植物有几种被称为淀粉酶的酶，它们具有不同的活性和明显的功能来降解淀粉。本项目将描述两种类型的淀粉酶- - -和- - -的分子和生化作用，因为它们在植物胁迫下共同降解淀粉。该项目的目标之一是对植物中淀粉的结构是如何控制的有新的认识。本项目的实验将在一所以本科生为主的院校进行，并涉及至少15名本科生。这些学生将进行大部分实验，并发展他们作为科学家的技术和专业技能，这将有助于他们未来的研究生教育和科学事业。此外，当地一所小学的教师和学生将参与一项研究项目，以培养学生对科学过程的理解。淀粉是一种复杂的生物分子，由直链淀粉和支链淀粉两种不同的亚结构组成，它们是葡萄糖的聚合物，具有不同的分支水平。淀粉通过几种不同的机制积累和降解，这些机制取决于植物种类、植物组织和外部因素，如一天中的时间和压力。虽然对这些机制有一个大致的了解，但许多细节，包括淀粉合成和降解的特定刺激和调节步骤，还不清楚。本项目旨在详细阐述-淀粉酶BAM9参与调节淀粉降解的结构、生化和分子机制。该蛋白没有明显的淀粉降解活性，但似乎可以增强α淀粉酶AMY3的活性。本项目将描述BAM9如何与AMY3相互作用以及BAM9的激活机制。进一步的实验将确定和描述在应激反应中调节BAM9导致AMY3激活和淀粉降解的细胞事件。最终，该项目将提供伪淀粉酶BAM9的第一个生化和机制表征，更广泛地说，是如何调节酶复合物降解淀粉的。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Plant starch is an important molecule for humans. In addition to being a primary source of nutrition for humans and many domestic animals, humans use starch in the laundry, food, pharmaceutical, and paper making industries. Despite the widespread use, our understanding of how starch is synthesized and degraded by plants is limited. Both processes affect the shape and form of starch, which affects the way the starch can be used by humans. This project aims to understand the regulation of starch degradation in the model plant Arabidopsis thaliana. This plant has several enzymes called amylases that degrade starch with distinct activities and apparent functions. This project will describe the molecular and biochemical action of two types of amylases, beta and alpha, as they work together to degrade starch during plant stress. One of the project’s goals is to develop new insights into how the structure of starch is controlled in plants. The experiments in this project will be carried out at a predominately undergraduate institution and involve at least 15 undergraduate students. These students will perform a majority of the experiments and develop their technical and professional skills as scientists which will aid them for future graduate education and careers in science. Additionally, teachers and students at a local elementary school will participate in a research project to develop the students’ understandings of the scientific process.Starch is a complex biomolecule composed of two distinct sub-structures, amylose and amylopectin, which are polymers of glucose with different levels of branching. Starch accumulates and is degraded through several different mechanisms that are dependent on the plant species, plant tissue, and external factors such as time of day and stress. While there is a general understanding of these mechanisms, many of the details including the specific stimuli and regulatory steps of starch synthesis and degradation are unclear. This project aims to detail the structural, biochemical, and molecular mechanism for the involvement of the beta-amylase BAM9 in regulated starch degradation. This protein does not have apparent starch degrading activity but does appear to enhance the activity the alpha amylase, AMY3. This project will characterize how BAM9 interacts with AMY3 and the activation mechanism of BAM9. Further experiments will identify and describe the cellular events that regulate BAM9 leading to activation of AMY3 and starch degradation in response to stress. Ultimately, this project will provide the first biochemical and mechanistic characterization of the pseudo-amylase BAM9, and more broadly, how regulated enzyme complexes degrade starch.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.