Engineering Protein Assemblies with Stable, Selective and Reactive Metal Coordination Sites

在这项由生命过程化学计划支持的项目中，Akif Tezcan教授和他的研究小组旨在建立设计原则和实验策略，以构建一类新的具有功能金属中心的大环、多蛋白质络合物。研究人员此前已经建立了一种名为金属模板界面重新设计(MeTIR)的蛋白质工程策略，该策略的灵感来自于历史悠久的金属模板配体合成方法。利用MeTIR，他们将构建一系列寡聚蛋白质复合体，其稳定性和灵活性/刚性可以通过战略性放置的非共价相互作用和共价键来调节。这些配合物被设计成可调节的大环金属配体，这将允许检查支架刚性与金属结合的稳定性和选择性之间的基本关系，以及为催化活性金属中心构建界面结合位点。我们将测量这些人工合成的金属蛋白组件对几种模型水解反应的催化活性。为了提高人工金属酶的催化效率，将采用计算导向、活性定点突变技术。拟议的研究将探索蛋白质作为配位化学基石的可行性和范围，最终目的是提供线索，说明大自然是如何进化蛋白质来利用和利用金属活性的。蛋白质是自然界构建金属酶的主要构件，金属酶可被视为复杂的生物装置或具有不同金属功能的配位络合物。然而，对蛋白质组装或将其用作无机配位化学的合成构件的追求一直是有限的。这项研究需要在配位化学、分子生物学、蛋白质生物化学、结晶学和生物物理学方面使用广泛的技术技能。因此，参与这项拟议研究的研究生、本科生和高中生将获得广泛的跨学科培训。首席调查员将通过各种自我发起和校园支持的项目招募在科学界代表性不足的团体的成员，并参加当地小学的科学博览会，从而继续开展外联工作。

In this project supported by the Chemistry of Life Process Program, Prof. Akif Tezcan and his research group aim to establish design principles and experimental strategies for the construction of a new class of macrocyclic, multiprotein complexes with functional metal centers. The investigators have previously established a protein engineering strategy termed Metal-Templated Interface Redesign (MeTIR), which is inspired by the time-honored method of metal-templated, ligand synthesis. Using MeTIR, they will construct an array of oligomeric protein complexes whose stability and flexibility/rigidity can be modulated through strategically-placed, non-covalent interactions and covalent linkages. These complexes are designed to serve as tunable macrocyclic metal ligands, which will allow the examination of fundamental relationships between scaffold rigidity and the stability and selectivity of metal binding as well as the construction of interfacial binding sites for catalytically-active metal centers. The catalytic activity of these synthetic metalloprotein assemblies toward several model hydrolysis reactions will be measured. Computationally-guided, active site-directed mutagenesis will be employed in an effort to improve the catalytic efficiency of the artificial metalloenzymes. The proposed research will explore the viability and scope of proteins as building blocks for coordination chemistry with the ultimate aim of providing clues on how nature has evolved proteins to utilize and harness metal reactivity. Proteins are nature's premier building blocks for the construction of metalloenzymes that can be viewed as complex biological devices or as coordination complexes with diverse metal-based functions. Yet, the pursuit of the assembly of proteins or their use as synthetic building blocks for inorganic coordination chemistry has been limited. The investigation requires use of a wide array of technical skills in coordination chemistry, molecular biology, protein biochemistry, crystallography, and biophysics. Hence the graduate, undergraduate, and high school students involved in the proposed research will gain a broad and interdisciplinary training. The principal investigator will continue outreach efforts by recruiting members of groups underrepresented in science through various self-initiated and campus-supported programs and by participating in science fairs at local elementary schools.