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.
Using combined genetic, biochemical, spectroscopic and structural approaches, we propose to investigate how M- and P-clusters of molybdenum nitrogenase are assembled into functional units. Through our proposed studies, we expect to refine the biosynthetic mechanisms of these catalytically-important and chemically-unprecedented metalloclusters, which will provide crucial insights into the structural-functional relationship of nitrogenase and the general principles of the assembly of complex metalloclusters in biological systems.
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