Physiological Functions and Biochemical Properties of Plant Cytochromes b561

植物细胞色素b561的生理功能和生化特性

• 批准号: 0416742
• 负责人: Donald Weeks
• 金额: --
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-15 至 2007-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0416742&HistoricalAwards=false
• 关键词: Physiological; Functions; Biochemical; Properties; Plant

Proposal: 0416742ABSTRACTAscorbate (vitamin C) has the ability to protect plants against the damaging affects of stress situations, such as drought, wounding, exposure to pollutants, high salt and pathogen attack. In addition, it is a cofactor to numerous metabolic enzymes and is involved in the biosynthesis of plant hormones. Therefore, ascorbate plays a key role in the control of plant growth and development, defense against pathogens and oxidative stress and in the regulation of cellular redox status.While knowledge of ascorbate biosynthesis and catabolism is rapidly expanding, little is known about the mechanisms by which ascorbate exerts its effects, and how it is regenerated. The objective of the current proposal is to determine the physiological role of a newly-identified class of membrane proteins, cytochromes (Cyts) b561, in ascorbate metabolism and regeneration, using Arabidopsis thaliana as a model system. Based on previous work, the central hypothesis is that Cyts b561 contributes to ascorbate-mediated cellular processes by catalyzing trans-membrane electron transport with ascorbate as the electron donor. Partially-oxidized ascorbate (mono-dehydroascorbate) can be re-reduced to ascorbate in this reaction, thereby replenishing cellular ascorbate pools. The objective of this proposal will be attained by: 1) determining the spatial and temporal expression patterns of A. thaliana Cyts b561; 2) determining the physiological role of Cyts b561 by altering its expression levels, and 3) determining the biochemical properties of A. thaliana Cyts b561. The proposed research is significant in that it is aimed at a class of poorly-studied membrane proteins involved in ascorbate-mediated reactions. Insight into the function of these proteins should contribute to our understanding of ascorbate regulation and metabolism in plants. Broader Impacts: The multidisciplinary approaches in the laboratory of the PI provide an opportunity for training and professional development of students and postdoctoral researchers. The PI will take part in university outreach programs to underrepresented groups, and results from this work will be broadly disseminated.

提案：0416742摘要抗坏血酸（维生素C）有能力保护植物免受干旱、受伤、接触污染物、高盐和病原体攻击等应激情况的破坏性影响。此外，它是许多代谢酶的辅因子，并参与植物激素的生物合成。因此，抗坏血酸在控制植物生长发育、抵御病原体和氧化胁迫以及调节细胞氧化还原状态等方面起着重要作用。虽然抗坏血酸的生物合成和催化作用的知识正在迅速扩展，但人们对抗坏血酸发挥作用的机制以及它是如何再生的却知之甚少。目前的建议的目的是确定的生理作用的一类新确定的膜蛋白，细胞色素（细胞色素）b561，在抗坏血酸代谢和再生，拟南芥作为一个模型系统。基于以前的工作，中心假设是，细胞色素b561有助于抗坏血酸介导的细胞过程，通过催化跨膜电子传递与抗坏血酸作为电子供体。部分氧化的抗坏血酸盐（单脱氢抗坏血酸盐）可以在该反应中再还原为抗坏血酸盐，从而补充细胞抗坏血酸盐库。 本研究的目的是通过以下几个方面来实现的：1）确定A. thaliana Cyts b561; 2）通过改变Cyts b561的表达水平来确定其生理作用;拟南芥Cyts b561. 拟议的研究是重要的，因为它是针对一类研究不足的膜蛋白参与抗坏血酸介导的反应。深入了解这些蛋白质的功能应有助于我们了解抗坏血酸调节和植物代谢。 更广泛的影响：PI实验室的多学科方法为学生和博士后研究人员的培训和专业发展提供了机会。PI将参加大学针对代表性不足群体的外联方案，并将广泛传播这项工作的成果。