Redox Reactivity of Thioredoxin Disulfide Bonds

知识价值。虽然二硫键是生物学中普遍存在的氧化还原活性辅助因子，用于催化，结构和信号传导作用，但对控制二硫键反应性的分子水平的理解已被证明是难以捉摸的。在这项工作中，直接电化学将被用作表征蛋白质序列和结构对硫氧还蛋白（Trx）超家族蛋白质氧化还原特性影响的主要工具。Trx蛋白在生命的所有领域中都有发现：这是一种基于二硫化物的电荷转移和氧化还原稳态机制的范例。虽然Trx蛋白参与多种功能，并作为复杂生物功能的一部分模块，但我们对Trx蛋白如何调整为特异性反应的理解存在知识空白。因此，该项目将直接测试二硫键如何在生物学中使用的模型，这是一个对生物化学许多领域至关重要的问题，其中二硫键氧化还原状态是决定反应性，信号传导和蛋白质折叠的基本特征。该项目解决的一个核心问题是，“大自然是如何调节二硫键的氧化还原化学的？”在这个项目中，PI将(1)评估在Trx蛋白中发现的自然范围还原电位，(2)确定序列和结构对还原电位的影响，以及(3)检查二硫键：铁硫簇配合物的稳定性。由于该方法的高度敏感、快速和定量性质，该项目涉及使用蛋白质电化学。该项目的结果将提供一个新的详细了解硫氧还毒素是如何在自然界的多样性中使用来维持氧化还原稳态的。更广泛的影响最直接的影响将是培养各级科学家（本科生、研究生、博士后教师）在氧化还原生物化学领域进行定量和化学思考。然而，由于二硫键氧化还原化学、氧化还原稳态和氧化应激在所有生命的生物化学中起着普遍和核心的作用，这项工作的更广泛的影响将深入触及化学和生物学的界面。无论是在植物生物化学、生物能源科学还是微生物生理学中，硫氧还毒素都是理解二硫键如何用于实现生命化学变化的范例。以一种基本的方式阐明这一过程将转化为对基础生物学的新认识。PI的研究工作与课堂上的教育活动相结合，向新生化学观众介绍当代生物化学，通过博士后教员计划培训波士顿大学的教师学者博士后，并在即将到来的生物无机化学研究生/博士后培训课程中担任讲师（将于2012年在宾夕法尼亚州立大学举行）。它将把蛋白质电化学的实验方法传播给更广泛的受众。

Intellectual Merit.While disulfide bonds are ubiquitous redox-active cofactors used in biology for catalytic, structural and signaling roles, a molecular level understanding of the principles that govern disulfide bond reactivity has proven elusive. In this work, direct electrochemistry will be used as a primary tool to characterize the influence of protein sequence and structure upon the redox properties of the thioredoxin (Trx) superfamily of proteins. Trx proteins are found throughout all the kingdoms of life: a paradigm of disulfide-based mechanisms for charge transfer and redox-homeostasis. While Trx proteins engage in diverse functions, and serve as modules that are a part of complex biological functions, there is a knowledge-gap in our understanding of how Trx proteins are tuned to be specifically reactive. Thus, this project will directly test models of how disulfide bonds are used in Biology, a question critical to many areas of biological chemistry, where the disulfide bond redox state is an essential trait to determine reactivity, signaling, and protein folding. A central question addressed in the project is, "How does Nature tune the redox chemistry of a disulfide bond?" In this project, the PI will (1) Assess the natural range reduction potentials found in Trx proteins, (2) Determine the influence of sequence and structure on reduction potentials, and (3) Examine the stability of disulfide-bond:iron-sulfur cluster complexes. The project involves the use of protein electrochemistry due to the highly sensitive, rapid and quantitative nature of the methodology. The results of the project will provide a new detailed understanding of how thioredoxins are used in Nature's diversity to maintain redox homeostasis.Broader ImpactThe most immediate impact will be upon the training of scientists at all levels (undergraduates, graduate students, post-doctoral faculty fellows) to think quantitatively and chemically in the field of redox biochemistry. However, due to the pervasive and central role that disulfide bond redox chemistry, redox homeostasis and oxidative stress play in the biological chemistry of all life, the broader impacts of this work will touch deeply upon the interface of chemistry and biology. Whether in plant biochemistry, bioenergy sciences or microbial physiology - thioredoxins are a paradigm of understanding how disulfide bonds are used to achieve chemical change in Life. Illuminating this process in a fundamental way will translate into new appreciation of fundamental biology.The research efforts of the PI are paired with education activities in the classroom that brings contemporary biological chemistry to the freshman chemistry audience, training of teacher-scholar postdoctoral fellows at Boston University via the Postdoctoral Faculty Fellow Program, and serving as an instructor in an upcoming graduate/postdoctoral training course in Bioinorganic Chemistry (to be held at Penn State University in 2012), which will disseminate the experimental methodologies of protein electrochemistry to a much broader audience.