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.

在植物中催化代谢反应的酶受到高度调控，以防止生物合成和能量生产中有害的低效。植物细胞用来调节代谢酶活性的最普遍的机制之一是酶催化磷酸盐分子与酶蛋白质结构中的氨基酸的结合。这种形式的酶调节，称为可逆的蛋白质磷酸化，是控制细胞中数千种酶的机制。植物代谢酶丙酮酸，磷酸二激酶(PPDK)，是本研究的主题，是一个由可逆磷酸化调节的酶。PPDK催化合成磷酸烯醇式丙酮酸，这是氨基酸和细胞壁聚合物等多种分子的“积木”。参与PPDK调控的酶是Rp(PPDK调节蛋白)。RP是本研究项目的主要焦点，先前的研究表明，它具有前所未有的、独一无二的催化性能。然而，这些特性的结构基础仍然是一个谜，因为RP的基因一直拒绝克隆，直到今年，PI和他的同事从拟南芥中分离出了这个基因。他们对编码的多肽的分析表明，RP代表了一种迄今为止在植物或动物中未知的全新的磷酸化调节酶。本研究旨在通过阐明该酶独特催化性质的结构基础来利用该基因的克隆。通过这样做，还将揭示鲜为人知的调控Rp调节PPDK的机制。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在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)为开发纤维素乙醇生物燃料增加我们在植物碳代谢方面的知识基础，以及(Ii)为我国新兴的生物技术部门招募和培训本科生作为未来的科学家。