Biosyntheses of FeMo-co and FeV-co of Nitrogenase

超出所提供的空间。固氮酶将N2转化为铵，铵是一种更容易为人类提供营养的N形式。在raj编码的固氮酶活性位点，钼固氮酶含有铁钼辅因子FeMo-co，vn/-编码的固氮酶含有结构相似的铁钒辅因子FeV-co。本课题的总体目标是确定固氮原核生物棕色固氮菌（Azotobacter vinelandii）中FeMo-co和FeV-co的生物合成途径。nifBUSV基因产物是合成两种辅因子所必需的。此外，合成FeMo-Co需要nifNE、nifH和nifX产物。当细胞在V代替Mo上生长时，细胞合成vnfNE，vnfH和vnfX基因产物用于FeV-co的合成。本项目的具体目标是确定这些基因产物在FeMo-co/FeV-co合成中的作用。co，并建立在每个辅因子的合成过程中对Mo或V的特异性的基础。NifB的代谢产物NifB-co是FeMo-co和FeV-co的Fe和S供体;确定NifB-co的结构是本项目的目标。FeMo-co合成途径中的几种蛋白质（包括NifH）在FeMo-co的体外合成过程中积累来自55 Fe-NifB-co或来自“MoO 42-”的标记，并且55 Fe和“Mo将用于跟踪该途径中的步骤。同样，49 V在FeV-co合成过程中积累在几种蛋白质上，并且55 Fe和49 V将用于遵循FeV-co途径的步骤。VnfX最近被鉴定为在FeV-co合成期间积累V和Fe的蛋白质，并且研究VnfX在FeV-co合成中的作用将是该项目的主要目标。所有生物体都需要微量元素，本项目中获得的信息将增加我们对活细胞同化，积累和区分微量元素的机制的理解，这些微量元素用于构建对细胞至关重要的许多氧化还原反应所需的复杂辅因子。人体健康取决于适当的代谢和利用微量元素，如那些正在研究中。性能现场=

EXCEED THE SPACEPROVIDED. Nitrogenases carry out the conversion of N2 to ammonium, a form of N that is more readily available for human nutrition. At the active site of raj-encoded, molybdenum nitrogenase is the iron-molybdenum cofactor, FeMo-co. The vn/-encoded nitrogenase contains the structurally similar iron-vanadium cofactor, FeV-co. The overall goal of this project is to determine the pathways of biosynthesis of FeMo-co and FeV- co in the nitrogen-fixing procaryote, Azotobacter vinelandii. The nifBUSV gene products are required for synthesis of both cofactors. In addition, the nifNE, nifH and nifX products are required for the synthesis of FeMo-co. When cells are grown on V in place of Mo, the cell synthesizes vnfNE, vnfH and vnfX gene products for the synthesis of FeV-co. The specific goals of this project are to define the roles of these gene products in the syntheses of FeMo-co/FeV-co and to establish the basis for the specificity for Mo or V during synthesis of each cofactor. NifB-co, the metabolic product of NifB,is an Fe and S donor to FeMo- co and FeV-co; the determination of the structure of NifB-co is a goal of this project. Several proteins in the FeMo-co synthesis pathway including NifH accumulate label from 55Fe-NifB-co or from "MoO42- during the in vitro synthesis of FeMo-co, and55Fe and "Mo will be used to follow the steps in the pathway. Likewise, 49V accumulates on several proteins during FeV-co synthesis, and55Fe and49V will be used to follow the steps of the FeV-co pathway. VnfX has recently been identified as a protein that accumulates V and Fe during FeV-co synthesis, and the investigation of the role of VnfX in FeV-co synthesis will be a major goal of the project. All organisms require trace elements, and the information gained in this project will increase our understanding of the mechanisms by which living cells assimilate, accumulate, and discriminate between trace elements that are used to build complex cofactors required for many redox reactions crucial to the cell. Human health is dependent on proper metabolism and utilization of trace elements such as those being investigated in this study. PERFORMANCE SITE ========================================Section End===========================================