RUI: The Synthesis and Degradation of a Unique Bacterial Polymer

9728609艾伦该研究的目的是研究唯一已知的非蛋白质聚合物的合成和降解，其功能是储存氮，使用多学科方法，涉及化学，生物化学和生物科学的三名教师和本科女生。 蓝藻素（多-L-乙酰基聚L-天冬氨酸）的代谢将通过酶的分析和纯化，并在体内和体外的NMR光谱标记蓝藻与15 N-标记的氮源后进行研究。 氮代谢将在正常生长期间和在各种营养胁迫条件下的生长期间进行研究。 将设计实验来确定蓝藻素是否在蓝藻代谢中具有动态作用。 蓝藻素是唯一已知的非蛋白质聚合物，其功能是储存 氮气 虽然它在营养胁迫和固氮过程中大量积累，但对其合成和降解机制知之甚少。 当蓝细菌缺乏氮时，它被动员起来。 如果蓝藻素是氮流入代谢池的强制性中间体，则其在蓝藻代谢中的作用将是中心的。 因此，重要的是要了解调控策略以及储存如何与中间代谢相结合。 这些研究还将有助于确定大量营养素限制和压力如何改变细胞中的代谢通量。 积累氮的策略，当它是可用的，并使用它以后必须赋予一个重要的选择优势，生物体采用这种策略。 对特定环境反应机制的研究将提供有关基因调控和从环境信号感知到酶活性调控的途径的新信息。

9728609 Allen The objective of the research is to study the synthesis and degradation of the only known nonprotein polymer whose function is the storage of nitrogen, using a multidisciplinary approach involving three faculty members and undergraduate women students in chemistry, biological chemistry and biological sciences. The metabolism of cyanophycin (multi-L-arginyl poly L-aspartic acid ) will be investigated by enzyme analysis and purification and by in vivo and in vitro NMR spectroscopy after labeling cyanobacteria with 15 N-labeled nitrogen sources. Nitrogen metabolism will be studied during normal growth and during growth under various conditions of nutrient stress. Experiments will be designed to determine whether cyanophycin has a dynamic role in cyanobacterial metabolism. Cyanophycin is the only known nonprotein polymer whose function is the storage of nitrogen. Little is known about mechanisms of its synthesis and degradation although it accumulates in large amounts during nutrient stress and during nitrogen fixation. It is mobilized when cyanobacteria are starved for nitrogen. If cyanophycin is an obligatory intermediate in the flow of nitrogen into the metabolic pool, its role in cyanobacterial metabolism will be central. It is therefore important to understand regulatory strategies and how storage is integrated with intermediary metabolism. These studies will also help define how macronutrient limitation and stress alter metabolic fluxes in cells. The strategy of accumulating nitrogen when it is available and using it later must impart an important selective advantage to the organism employing that strategy. Studies of the mechanisms involved in specific environmental responses will provide new information about gene regulation and pathways leading from the sensing of environmental signals to the regulation of enzymatic activities.