Regulation of Assimilatory Nitrate Reductase

同化硝酸还原酶的调节

• 批准号: 9317557
• 负责人: Larry Solomonson
• 金额: $ 28.8万
• 依托单位: University of South Florida
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-03-15 至 1998-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9317557&HistoricalAwards=false
• 关键词: Regulation; Assimilatory; Nitrate; Reductase

Solomonson 9317557 The nitrate assimilatory pathway is the major route by which inorganic nitrogen is converted to a biologically useful organic form. Regulation of the first step in this pathway, catalyzed by nitrate reductase (NR), is important to prevent toxic accumulation of intermediates (nitrite and ammonia), to assure efficient utilization of nitrate, and to permit rapid adaptation to changes in environmental conditions. Results of previous studies have indicated that NR is regulated at several different levels by multiple effectors and environmental factors reflecting the key role of this enzyme and the biological importance of pathway regulation. Our research will focus on elucidating molecular determinants and mechanisms which are important for the regulation of NR at the molecular (enzyme) level and establishing interrelationships between various modes of regulation. Specific aims will include: a) identification of functional groups involved in NR turnover, catalysis, binding or regulation, and the localization of these groups with respect to functional domain or primary sequence site on the enzyme; and b) determination of effects of possible activity modulators such as protein kinases/phosphatases, metal binding effectors (e.g., nitric oxide or cyanide), or other effectors on NR turnover and catalytic efficiency. The ultimate goal of our research is to obtain information from this and other studies to develop procedures for increasing the catalytic efficiency of NR and for regulating its action in an effort to increase agricultural productivity. %%% Nitrate is the major source of organic nitrogen in biological organisms. The process by which nitrate is converted to a biologically useful, organic form, termed nitrate assimilation, occurs in a wide variety of organisms including bacteria, yeast, fungi and higher plants, which in turn supply the nutritional nitrogen requirements for other forms of life, including human. One of the goals of this r esearch is to develop strategies for increasing the catalytic efficiency and for regulating the activity of the key enzyme, nitrate reductase (NR), in the nitrate assimilation pathway. The focus of our current research program is to identify the functional groups of the NR molecule and other factors that will help us learn more about the protein. We may then use this information to engineer agriculturally interesting plants with more efficient nitrogen metabolism and increased production capacity. Plants with improved nitrogen metabolism will result in decreased need to supply chemical fertilizers to our crops. ***

硝酸盐同化途径是无机氮转化为生物有用的有机形式的主要途径。 硝酸还原酶（NR）催化的这一途径的第一步的调节对于防止中间体（亚硝酸盐和氨）的毒性积累、确保硝酸盐的有效利用以及允许快速适应环境条件的变化是重要的。 以往的研究结果表明，NR在几个不同的水平上受到多种效应子和环境因素的调节，反映了这种酶的关键作用和途径调节的生物学重要性。 我们的研究将集中在阐明分子决定因素和机制，这是重要的NR的调节在分子（酶）水平和建立各种模式之间的相互关系的调节。 具体目标将包括：a）鉴定参与NR周转、催化、结合或调节的官能团，以及这些基团相对于酶上的功能结构域或一级序列位点的定位;和B）确定可能的活性调节剂如蛋白激酶/磷酸酶、金属结合效应物（例如，一氧化氮或氰化物），或NR周转和催化效率的其它效应物。 我们研究的最终目标是从这项研究和其他研究中获得信息，以开发提高NR催化效率和调节其作用以提高农业生产力的程序。 硝酸盐是生物有机体中有机氮的主要来源。 硝酸盐转化为生物有用的有机形式的过程，称为硝酸盐同化，发生在各种各样的生物体中，包括细菌，酵母，真菌和高等植物，这反过来又为其他形式的生命提供营养氮需求，包括人类。 本研究的目的之一是开发策略，以提高催化效率和调节硝酸盐同化途径中的关键酶，硝酸还原酶（NR）的活性。 我们目前研究计划的重点是确定NR分子的官能团和其他因素，这将有助于我们更多地了解蛋白质。 然后，我们可以使用这些信息来设计农业上有趣的植物，使其具有更有效的氮代谢和增加的生产能力。 改善氮代谢的植物将导致减少对作物化肥的需求。 ***