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

题目：钼辅因子的化学、生物化学和生物物理研究。 钼辅因子（Moco）是生命所必需的生物分子。许多酶的正常运作 Moco的合成和生物合成Moco的失败会导致严重的生理困扰和幼儿死亡。 在蛋白质环境之外，这种辅因子是不稳定的，并且尚未被化学合成。Moco 具有几种氧化还原活性组分，并且这些组分一起可以进行多达10个电子 化学，而基板转换只需要两个电子。为了了解不同的组件 为了稳定支持反应性的电子结构，我们将研究具有定义的 功能.本提案中概述的工作旨在完成Moco的首次化学合成。而在 还原态Moco在蛋白质环境外是不稳定的，而它在蛋白质内如何稳定则不清楚。 清楚该提案还试图了解Moco在DMSO还原酶家族中的几何性质， 酶使用周质硝酸还原酶（NapA）及其变体作为模型，通过生物化学和 生物物理学研究具体目标是：1）合成蝶呤Mo中心和Mo=X（X=S，O） 配合物允许研究其几何和电子结构与反应性的关系; 2） 理解DMSOR家族中Mo中心的几何和功能特性，使用NapA作为 模型总的来说，新的重要的分子水平的知识将产生的结构功能的一个 对人体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.