Investigation of the Molybdenum Cofactor through Chemical, Biochemical and Biophysical Studies

标题：通过化学、生化和生物物理研究对钼辅助因子进行研究。 钼辅因子(MoCo)是一种生命所必需的生物分子。许多酶依赖于正常的功能 Moco的缺乏和未能生物合成Moco会导致严重的生理痛苦和儿童早期死亡。 在蛋白质环境之外，这种辅因子是不稳定的，还没有被化学合成。MOCO 有几个氧化还原活性成分，这些成分加在一起可以进行多达十个电子 化学，而底物转换只需要两个电子。要了解不同的组件如何 稳定支持反应性的电子结构，我们将研究离散分子 功能。该提案中概述的工作旨在完成MOCO的第一次化学合成。而在美国， 还原状态的MoCO在蛋白质环境外是不稳定的，它在蛋白质内如何稳定也不是 安全。该提案还试图了解DMSO还原酶家族中MOCO的几何性质 以周质硝酸还原酶(NPA)及其变异体为模型的酶 生物物理学研究。该方案的具体目标是：1)合成蝶呤钼中心和钼=X(X=S，O) 允许研究与反应性有关的几何和电子结构的络合物；2) 以NaPA为基础理解DMSOR家族中Mo中心的几何和功能性质 模特。总体而言，将产生关于结构-功能的新的重要的分子水平知识 对人类健康很重要的一类酶。

Title: Investigation of the Molybdenum Cofactor through Chemical, Biochemical and Biophysical Studies. Molybdenum cofactor (Moco) is an essential biomolecule for life. Numerous enzymes rely on proper functioning of Moco and failure to biosynthesize Moco causes severe physiological distress and early childhood death. Outside the protein environment, this cofactor is unstable and has not yet been synthesized chemically. Moco has several redox active components and, together, these components can carry out up to ten-electron chemistry, while substrate transformation requires only two electrons. To understand how different components stabilize the electronic structure that supports reactivity, we will investigate discrete molecules with defined features. The work outlined in this proposal seeks to complete the first chemical synthesis of Moco. While in the reduced state Moco is unstable outside the protein environment, and how it is stabilized within a protein is not clear. The proposal also seeks to understand geometric properties of Moco in the DMSO reductase family of enzymes using periplasmic nitrate reductase (NapA) and its variants as a model through biochemical and biophysical studies. The specific aims of the proposal are: 1) to synthesize pterin Mo-centers and Mo=X (X=S,O) complexes allowing investigation of their geometric and electronic structures in relation to reactivity; 2) understanding the geometric and functional properties of the Mo-center in the DMSOR family using NapA as a model. Overall, new important molecular level knowledge will be generated about the structure-function for a class of enzymes important to human health.