NifI Proteins of Methanococcus Maripaludis

华盛顿大学的约翰·利博士（Dr. John Leigh）获得了一笔资助，用于研究某些产甲烷古菌中氮调节新机制所涉及的蛋白质。产甲烷古生菌是一组产生甲烷作为代谢产物的微生物。此外，一些产甲烷古菌可以固定氮，即将大气中的氮转化为有价值的氨氮。固氮过程受到微生物的严格调控，因为只有当生物体处于缺氮状态时，才有利于通过固氮获得所需的氮。控制催化固氮的酶，即固氮酶的活性，是调控发生的一种方式。我们将研究maripaludis甲烷球菌（Methanococcus maripaludis）中氮酶活性的调控，这是一个特别好的实验室模型。重点将放在名为NifI1和NifI2的蛋白质上，这些蛋白质被认为可以感知氮饥饿的程度，并与其他蛋白质相互作用以实现调节。该项目将研究代谢中间体作为氮饥饿指标的作用，这些中间体与NifI1和NifI2的相互作用，NifI1和NifI2可能发生的修饰，以及NifI1和NifI2与其他可能参与固氮调节的蛋白的相互作用。该研究将为研究生、本科生和博士后提供重要的培训，他们将参与研究活动。该研究还将通过继续发展马里帕卢迪甲烷球菌作为古细菌研究的模式物种，为科学界提供可用的资源。其结果将直接关系到向学生讲授生物调节和氮同化的原理。固氮调控对人类农业具有广泛的意义。生物固氮具有巨大的环境和营养重要性，因为它是将氮从大气循环到生物圈的主要手段。这项工作应该会导致对这一过程在主要生物群体中的调节产生根本性的新见解。

A grant has been awarded to Dr. John Leigh at the University of Washington to study proteins involved in a novel mechanism of nitrogen regulation that occurs in certain methanogenic Archaea. Methanogenic Archaea are a group of microorganisms that produce methane as a metabolic product. In addition, some species of methanogenic Archaea can fix nitrogen, that is, convert atmospheric nitrogen to valuable ammonia nitrogen. The process of nitrogen fixation is rigorously regulated by microorganisms, because only when an organism is nitrogen-starved is it advantageous to obtain needed nitrogen via nitrogen fixation. The control of the activity of the enzyme that catalyses nitrogen fixation, nitrogenase, is one way in which the regulation occurs. Regulation of nitrogenase activity will be studied in Methanococcus maripaludis, a species that serves as a particularly good laboratory model. The focus will be on proteins called NifI1 and NifI2, which are hypothesized to sense the degree of nitrogen starvation and to interact with other proteins to effect regulation. The project will investigate the role of metabolic intermediates as indicators of nitrogen starvation, the interaction of those intermediates with NifI1 and NifI2, the modifications of NifI1 and NifI2 that might occur, and the interaction of NifI1 and NifI2 with other proteins that might be involved in the regulation of nitrogen fixation.The research will provide important training to graduate students, undergraduate students, and postdoctoral trainees, who will participate in the research activities. The research will also contribute to the resources available to the scientific community through the continued development of Methanococcus maripaludis as a model species for studies in the Archaea. The results will bear directly on teaching students the principles of regulation and of nitrogen assimilation by organisms. The regulation of nitrogen fixation has broad significance to human agriculture. Biological nitrogen fixation has huge environmental and nutritional importance because it is the primary means of cycling nitrogen from the atmosphere to the biosphere. The work should lead to fundamental new insights into the regulation of this process in a major group of organisms.