Structure and Mechanism of the Human Fe-S Cluster Assembly Complex

描述（由申请人提供）：金属离子对生命至关重要，因为它们增强氨基酸蛋白质化学，从而催化许多困难的生物反应。由于“游离”金属离子是有毒的，并且具有不加选择的反应性，因此关键蛋白质系统已经进化为螯合、陪伴和调节金属离子浓度。这些系统中的缺陷导致金属离子代谢疾病，并导致细胞、组织和全身病理学。铁-硫簇组装途径包含一组保守的金属伴侣蛋白，其识别并将Fe-S簇插入到载脂蛋白金属蛋白中。我们的工作模型是兄弟蛋白（Fxn）与Nfs 1/Isd 11/Isu 2复合物结合，并激活该复合物进行Fe-S簇生物合成。在这项提案中，我们的目标是建立在这些结果的基础上，进一步开发我们的体外系统，并提供组装复合物的结构特性，Fe-S簇合成的机理细节，并确定Friedreich共济失调临床变异中受损功能的基础。这项基础研究将为新兴的遗传结果和发现建立一个框架，并为理解与人类健康和疾病相关的铁硫簇代谢缺陷提供基础。

DESCRIPTION (provided by applicant): Metal ions are essential to life as they augment amino acid protein chemistry and thereby catalyze many difficult biological reactions. As "free" metal ions are toxic and indiscriminately reactive, critical protein systems have evolved to sequester, chaperone, and regulate metal ion concentrations. Defects in these systems lead to metal ion metabolic disease and result in cellular, tissue, and systemic pathology. The iron-sulfur cluster assembly pathway contains a conserved set of metallochaperone proteins that recognize and insert Fe-S clusters into apo metalloproteins. Our working model is that frataxin (Fxn) binds to a Nfs1/Isd11/Isu2 complex and activates the complex for Fe-S cluster biosynthesis. In this proposal, we aim to build on these results by further developing our in vitro system and providing structural properties for the assembly complexes, mechanistic details for Fe-S cluster synthesis, and determine the basis for the compromised function in Friedreich's ataxia clinical variants. This fundamental research will establish a framework for emerging genetic results and discoveries and provide a basis for understanding defects in iron-sulfur cluster metabolism relevant to human health and disease.