RUI: Pyruvate,Phosphate Dikinase Regulatory Protein in C3 Plants

RUI：C3 植物中的丙酮酸、磷酸二激酶调节蛋白

• 批准号: 0642190
• 负责人: Chris Chastain
• 金额: $ 20.58万
• 依托单位: Minnesota State University Moorhead
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-04-15 至 2010-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0642190&HistoricalAwards=false
• 关键词: RUI; Pyruvate; Phosphate; Dikinase; Regulatory

Enzymes that catalyze metabolic reactions in plants are highly regulated in order to prevent detrimental inefficiencies in biosynthesis and energy production. One of the most prevalent mechanisms plant cells use to regulate the activity of metabolic enzymes is enzyme-catalyzed bonding of a phosphate molecule to an amino acid within the enzyme's protein structure. This form of enzyme regulation, termed reversible protein-phosphorylation is the mechanism controlling thousands of enzymes in the cell. The plant metabolic enzyme pyruvate,phosphate dikinase (PPDK), the subject of this research, is an example of an enzyme regulated by reversible phosphorylation. PPDK catalyzes the synthesis phosphoenolpyruvate, a "building block" for a diverse set of molecules such as amino acids and cell-wall polymers. Conferring regulation of PPDK is the enzyme RP (PPDK Regulatory Protein). RP, the primary focus of this research project, had been demonstrated by previous studies to have unprecedented, one-of-a-kind catalytic properties. However, the structural basis for these properties has remained a mystery as the gene for RP had resisted cloning until this year, when the PI and coworkers isolated the gene from Arabidopsis. Their analysis of the encoded polypeptide showed that RP represents a fundamentally new kind of phosphorylating-regulatory enzyme hitherto unknown in plants or animals. This research aims to capitalize on the cloning of the RP gene by elucidating the structural basis of the enzyme's unique catalytic properties. In so doing, the poorly understood mechanism that governs RP's regulation of PPDK will also be revealed. These aims will be achieved by determining the three-dimensional structure of the Arabidopsis RP protein. Molecular and genetic tools will further establish how the two distinct RP genes represented in the Arabidopsis genome are spatially expressed in planta. Finally, a combined biochemical and molecular-genetic approach will elucidate the functional differences between these two RP enzymes. Broader impacts include (i) increasing our knowledge base in plant carbon metabolism for developing cellulosic ethanol biofuels, and (ii) the recruitment and training of undergraduate students as future scientists for our Nation's bourgeoning biotechnology sector.

催化植物代谢反应的酶受到严格监管，以防止生物合成和能量生产出现有害的低效率。植物细胞用来调节代谢酶活性的最普遍机制之一是酶催化磷酸盐分子与酶蛋白质结构内的氨基酸的键合。这种酶调节形式，称为可逆蛋白质磷酸化，是控制细胞中数千种酶的机制。本研究的主题植物代谢酶丙酮酸磷酸二激酶 (PPDK) 是受可逆磷酸化调节的酶的一个例子。 PPDK 催化磷酸烯醇丙酮酸的合成，磷酸烯醇丙酮酸是氨基酸和细胞壁聚合物等多种分子的“结构单元”。酶 RP（PPDK 调节蛋白）对 PPDK 进行调节。 RP是该研究项目的主要焦点，之前的研究已证明其具有前所未有的、独一无二的催化性能。然而，这些特性的结构基础仍然是个谜，因为 RP 基因一直无法克隆，直到今年 PI 和同事从拟南芥中分离出该基因。他们对编码多肽的分析表明，RP 代表了一种迄今为止在植物或动物中未知的全新磷酸化调节酶。本研究旨在通过阐明酶独特催化特性的结构基础来利用 RP 基因的克隆。在此过程中，人们对 RP 对 PPDK 的调节知之甚少的机制也将被揭示。这些目标将通过确定拟南芥 RP 蛋白的三维结构来实现。分子和遗传工具将进一步确定拟南芥基因组中代表的两个不同的 RP 基因如何在植物中空间表达。最后，生物化学和分子遗传学相结合的方法将阐明这两种 RP 酶之间的功能差异。更广泛的影响包括（i）增加我们在植物碳代谢方面的知识基础，以开发纤维素乙醇生物燃料，以及（ii）招募和培训本科生作为我们国家蓬勃发展的生物技术领域的未来科学家。