Metal Selectivity of Nickel Metalloproteins

我的研究项目将研究处理镍的细胞蛋白质的化学性质和活性。镍是许多生命形式所必需的营养物质，但如果不控制分布和积累，这种金属也可能是有毒的。出于这个原因，需要镍的生物有许多种蛋白质，可以确保金属离子的安全使用。在其他类型的生理相关金属离子存在的情况下，这些蛋白质必须对镍具有选择性，但尚不清楚金属选择性是如何实现的。这是一个有趣的基本问题，需要详细研究所涉及的蛋白质的生物无机化学、生化活性和结构，以及关于这些系统的生物学背景的知识。到目前为止，我们的研究已经提供了有关镍途径的各个组成部分的详细信息。我们现在正处于激动人心的阶段，以解决我们所学到的关于这些系统的中心问题。这项建议描述了研究金属选择性是如何在关键的镍稳态蛋白质中实现的实验。我们将定义不同类型金属周围的配位环境，以及它们如何影响蛋白质的结构和活性。这些目标将通过利用生物化学、无机光谱学和结构生物学的跨学科方法来实现，为受训者提供丰富的教育环境。具体目标包括描述几种GTPase蛋白中金属选择性配位和酶活性调节之间的关系。我们还将从结构上定义高亲和力金属结合序列的金属络合物，并确定是否存在对该位点功能的金属选择性控制。此外，我们将产生一个基因编码的镍传感器，以解决细胞内有多少金属可用，以及这种变化如何响应生物体新陈代谢和/或环境的变化，这是镍稳态的关键方面。这个项目将帮助我们实现我们的最终目标，即在分子水平上了解控制细胞内过渡金属动态平衡的化学机制，这是生命的一个基本方面。了解这一具有挑战性的问题将对生物技术、医学和环境补救等领域产生重大影响。

My research program will examine the chemical properties and activities of cellular proteins that handle nickel. Nickel is an essential nutrient for many forms of life, but this metal can also be toxic if the distribution and accumulation is not controlled. For this reason, the organisms that need nickel have many types of proteins that ensure the safe use of the metal ion. These proteins must be selective for nickel in the presence of other types of physiologically-relevant metal ions but it is not clear how metal selectivity is achieved. This is an intriguing fundamental problem that requires a detailed study of the bioinorganic chemistry, biochemical activities, and structures of the proteins involved, as well as knowledge about the biological context of these systems. Our research to date has provided detailed information about the individual components of the nickel pathways. We are now at the exciting stage of building on what we have learned to address central issues about these systems.This proposal describes experiments to study how metal selectivity is realized in key nickel homeostasis proteins. We will define the coordination environments around the different types of metals, and how they impact the structures and activities of the proteins. These goals will be achieved by using an interdisciplinary approach that draws from biochemistry, inorganic spectroscopy, and structural biology, providing a rich educational environment for trainees. Specific goals include delineating the relationship between metal-selective coordination and modulation of enzymatic activity in several GTPase proteins. We will also structurally define the metal complexes of a high-affinity metal-binding sequence and determine if there is metal-selective control of the function of this site. Furthermore, we will generate a genetically-encoded nickel sensor to address the question of how much intracellular metal is available and how this changes in response to shifts in the metabolism and/or environment of the organism, a critical aspect of nickel homeostasis. This program will help us achieve our ultimate objective, which is to learn the chemical mechanisms that govern intracellular transition metal homeostasis at a molecular level, a fundamental aspect of life. Understanding this challenging problem will have significant impact on areas such as biotechnology, medicine, and environmental remediation.