Structure and Function of Nifl1-2, A Novel Inhibitor of Nitrogenase Activity in th Earchaeon Methanococcus Maripaludis

生物固氮是一种广泛的代谢过程，通过某些微生物的生物活性将大气中的氮转化为肥料。该项目跟踪了一种新发现的机制，许多生物体通过这种机制调节固氮酶的活性，这种酶催化导致固氮的生化反应。该机制涉及一个称为PII蛋白的蛋白质家族，该蛋白质家族调节各种生物体中的氮代谢功能。在这项研究中要研究的特定蛋白质是NifI蛋白质，其构成了以前未表征的PII蛋白质亚家族。NifI及其对固氮酶活性调节的新特性包括NifI与固氮酶的铁蛋白形成直接复合物，以及NifI与自身复合形成新的高级结构。该研究将涉及生物化学，遗传和蛋白质结构的研究，使用模式微生物物种甲烷球菌maripaludis，一个成员的系统发育域pestinea。该研究的更广泛的影响是环境，农业和教育。生物固氮有助于微生物和与它们相关的植物的营养，而没有与化学肥料相关的不利环境影响。这项工作还将导致对微生物学和生物化学领域的人员进行培训，包括将蛋白质结构与固氮生物学结合起来。最后，这项工作为研究人员的教学和推广工作提供了支持，其中包括微生物代谢课程，参与华盛顿大学天体生物学跨学科研究生课程，以及参与K-12推广计划称为Astrobio项目。

Biological nitrogen fixation is a widespread metabolic process that converts atmospheric nitrogen into fertilizer through the biological activity of certain microorganisms. This project follows up on a newly discovered mechanism by which many organisms regulate the activity of nitrogenase, the enzyme that catalyses the biochemical reactions that result in nitrogen fixation. The mechanism involves a family of proteins called PII proteins that regulates nitrogen metabolic functions in a variety of organisms. The particular proteins to be studied in this research are the NifI proteins, which constitute a previously uncharacterized subfamily of PII proteins. Novel features of NifI and its regulation of nitrogenase activity include the formation a direct complex between NifI and the molybdenum-iron protein of nitrogenase, and formation of novel higher order structures of NifI complexed with itself. The research will involve biochemical, genetic, and protein structural studies using the model microbial species Methanococcus maripaludis, a member of the phylogenetic domain Archaea.The broader impacts of the research are environmental, agricultural, and educational. Biological nitrogen fixation contributes to the nutrition of microorganisms and the plants with which they associate, without the adverse environmental effects associated with chemical fertilizers. The work will also result in the training of personnel in the areas of microbiology and biochemistry, including the integration of protein structure with the biology of nitrogen fixation. Finally, the work feeds into the investigator's teaching and outreach efforts, which include courses featuring microbial metabolism, participation in the University of Washington's interdisciplinary graduate program in Astrobiology, and participation in a K-12 outreach program called project Astrobio.