Nitrogenase assembly mechanism

项目总结 固氮酶反应是可利用形式氮的主要来源，支持 人类人口的存在。因此，了解构建块有多小 组装成一个功能性固氮酶实体对人类健康具有重要意义。vbl.使用 结合遗传、生化、光谱和结构方法，我们建议 研究钼固氮酶的M-和P-簇是如何通过独特的 将生化反应转化为功能单位。具体来说，我们将调查两个4Fe 模块被重新排列并通过自由基SAM依赖耦合成M-团簇的8Fe核心 碳化物插入伴随着9号硫的加入，两个4Fe模块是如何 通过独特的氧化还原反应重排并耦合成8Fe P-簇，伴随着 8硫磺的去除，以及各种组装蛋白如何相互作用以 促进M-和P-簇的成熟。通过我们建议的研究，我们预计将 进一步完善固氮酶独特的金属簇的生物合成途径，这将 提供了对这种重要酶的结构-功能关系的重要见解 揭示了复杂金属团簇组装机理的一些一般规律 生物系统。

PROJECT SUMMARY Nitrogenase reaction represents a major source of the usable form of nitrogen that supports the existence of human population. As such, understanding how small building blocks are assembled into a functional nitrogenase entity is of significant relevance to human health. Using combined genetic, biochemical, spectroscopic and structural approaches, we propose to investigate how M- and P-clusters of molybdenum nitrogenase are assembled via unique biochemical reactions into functional units. Specifically, we will investigate how two 4Fe modules are rearranged and coupled into an 8Fe core of M-cluster via radical SAM-dependent carbide insertion concomitant with the incorporation of a “9th” sulfur, how two 4Fe modules are rearranged and coupled into an 8Fe P-cluster via unique redox reactions concomitant with the removal of an “8th” sulfur, and how various assembly proteins interact with one another to facilitate the maturation of M- and P-clusters. Through our proposed studies, we expect to further refine the biosynthetic pathways of the unique metalloclusters of nitrogenase, which will provide crucial insights into the structural-functional relationship of this important enzyme and reveal some general principles of the assembly mechanisms of complex metalloclusters in biological systems.