Molecular Definition of the Unique Phenylpropanoid Radical Coupling Mechanisms of Dirigent Proteins, Their Homologues, and Associated Metabolism: A Discovery-Based Approach

Dirigent 蛋白质、其同系物和相关代谢的独特苯丙素自由基偶联机制的分子定义：基于发现的方法

• 批准号: 0417291
• 负责人: Norman Lewis
• 金额: --
• 依托单位: Washington State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0417291&HistoricalAwards=false
• 关键词: Molecular; Definition; Unique; Phenylpropanoid; Radical

The control of oxidative free radical coupling/polymerization chemistry in plants was a decisive adaptation of such organisms in order to access a land-based habitat. In so doing, these diverse plant forms elaborated new biochemistries to generate a plethora of phenylpropanoid (acetate) natural products with important roles, e.g. in plant defense and later with applications in human health (including as antiviral, anticancer and bactericidal agents). These metabolic pathways also gave the structurally complex biopolymers, the lignins, which largely determine woody textural properties, and the suberins (in cork tissue) that enabled plants to survive in desiccating environments. This contrasts with other organismal types (e.g. with mammals), where radical chemistry is not as well controlled, e.g. in humans, where this lack of control can lead to more rapid aging and increased susceptibility to various diseases.This project will investigate the basis of how such radical coupling/polymerization chemistries are actually controlled in plants, and how they evolved, as well as building upon discovery of dirigent proteins. The latter represents the first example of a protein controlling radical-radical coupling, and thus the research to be undertaken will determine the nature of the key features on the protein involved in radical binding, stabilization and ultimately its product formation. The technologies that will be used in this study are those of electron paramagnetic resonance spectroscopy, X-ray crystallography and site-directed mutagenesis, i.e. procedures, which will enable identification of the key features in dirigent proteins that control such radical chemistries, as well as those in related polyphenol oxidase and regiospecific coupling enzymes. This, in turn, will make it possible to establish how nature actually makes such diverse and complex natural products; this can be anticipated to be of immense value in many different undertakings, such as controlled radical polymerization processes leading to new materials, in nanotechnology, in medicine, and in the study of protein evolution.Broader ImpactThe broader impact of NSF support is in the ability to encourage and nurture young scientists (particularly from underrepresented and underserved groups) at the undergraduate, graduate, postdoctoral, visiting scientist and high school teacher levels in developing their careers. The latter mechanism gives an excellent avenue for introducing the latest technological insights and advances into schools. In addition to the scientific benefits described above, these investigators are involved in a number of other outreach activities including the Washington State University (WSU) Plant Biochemistry Summer Course, the annual WSU Nuclear Magnetic Resonance Workshop; and general talks to high school students and the general public, for example on the pros and cons of genetically modified foods and the diversity of dietary phytochemicals.

植物中氧化自由基偶联/聚合化学的控制是此类生物体为了进入陆地栖息地而做出的决定性适应。 通过这样做，这些不同的植物形式阐述了新的生物化学，以产生大量具有重要作用的苯丙素（乙酸盐）天然产物，例如用于植物防御，随后应用于人类健康（包括作为抗病毒、抗癌和杀菌剂）。 这些代谢途径还产生了结构复杂的生物聚合物、木质素（很大程度上决定了木质质地特性）和木栓质（在软木组织中），使植物能够在干燥的环境中生存。 这与其他生物类型（例如哺乳动物）形成鲜明对比，在其他生物类型中，自由基化学没有得到很好的控制，例如哺乳动物。在人类中，这种缺乏控制会导致更快的衰老和对各种疾病的易感性增加。该项目将研究植物中如何实际控制这种自由基偶联/聚合化学物质的基础，以及它们如何进化，以及建立在双联蛋白的发现基础上。 后者代表了蛋白质控制自由基-自由基偶联的第一个例子，因此即将进行的研究将确定参与自由基结合、稳定及其最终产物形成的蛋白质关键特征的性质。 本研究中将使用的技术包括电子顺磁共振波谱、X射线晶体学和定点诱变，即能够识别控制此类自由基化学的双联蛋白以及相关多酚氧化酶和区域特异性偶联酶的关键特征的程序。 反过来，这将有可能确定大自然实际上是如何制造如此多样化和复杂的天然产品的；预计这在许多不同的事业中都具有巨大的价值，例如在纳米技术、医学和蛋白质进化研究中产生新材料的受控自由基聚合过程。 更广泛的影响 NSF 支持的更广泛影响在于能够鼓励和培养本科生、研究生、博士后、访问科学家和高等院校的年轻科学家（特别是来自代表性不足和服务不足的群体）。 学校教师职业发展水平。 后一种机制为将最新的技术见解和进步引入学校提供了绝佳的途径。 除了上述科学效益外，这些研究人员还参与了许多其他外展活动，包括华盛顿州立大学 (WSU) 植物生物化学夏季课程、年度 WSU 核磁共振研讨会；以及向高中生和公众进行一般性讲座，例如转基因食品的利弊以及膳食植物化学物质的多样性。