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 研究钼固氮酶唯一的金属辅因子M-簇是如何 组装成一个功能单元。具体地说，我们将研究间隙碳化物是如何 通过自由基SAM依赖机制插入，伴随着两个4Fe模块的融合 进入M-团簇的8Fe核心，什么是体内9硫的供体/载体以及这是如何 硫被插入到8Fe核的催化重要带区，以及Mo是如何 被动员并插入8Fe核心形成成熟的M-簇。通过我们提议的 研究中，我们希望进一步完善独特的金属辅因子的生物合成途径。 固氮酶，这将提供对这一结构-功能关系的关键见解。 重要的酶，揭示了络合物组装机制的一些一般原理 生物系统中的金属团簇。

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-cluster, the unique metallocofactor of molybdenum nitrogenase, is assembled into a functional unit. Specifically, we will investigate how an interstitial carbide is inserted via a radical SAM-dependent mechanism concomitant with fusion of two 4Fe modules into an 8Fe core of the M-cluster, what is the in vivo donor/carrier of the “9th sulfur” and how this sulfur is inserted into the catalytically important belt region of the 8Fe core, and how Mo is mobilized and inserted into the 8Fe core to form a mature M-cluster. Through our proposed studies, we expect to further refine the biosynthetic pathway of the unique metallocofactor 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.