Modulation of Metalloprotein Activities through Fine-tuning Reduction Potentials

在化学学部生命过程化学（CLP）项目的支持下，伊利诺伊大学香槟分校的Yi Lu博士计划通过微调还原电位来调节金属蛋白的活性。在此过程中，该研究将有助于从根本上理解如何调整还原电位并将其与功能特性联系起来。许多化学和生物过程涉及氧化还原反应，其效率在很大程度上取决于还原电位。在自然界中，每种金属蛋白都有其功能所需的一定还原电位范围。在整个生理还原电位范围内，对影响不同金属蛋白还原电位的共同因素的系统理解仍然难以捉摸。为了解决这一限制，Lu小组计划设计蛋白质azurin来改变铜位点的还原电位，以解决如何调节还原电位可以调节酶功能的问题，这一知识将适用于许多生物和化学系统。陆博士将通过开发本科和研究生课程的讲座和实验模块，结合多学科研究成果，将研究与教育结合起来。该项目将重点从STEM（科学、技术、工程和数学）中代表性不足的群体中招募学生，通过外展活动参与研究，并创造和维护多元化、公平和包容的文化，使新成员能够在学习和研究中茁壮成长。该项目建立在Lu博士实验室先前成功的基础上，在对初级配位球扰动最小的情况下，调整azurin中1型铜中心的还原电位，使其跨越2 V生理Eº'范围。重点研究了工程二级配位球相互作用，包括氢键（h键）和疏水性，以调节金属蛋白的活性，包括：(1)工程azurin中Cu位点的s -亚硝基化反应活性和非血红素Fe位点的逐步亚硝基化反应活性，(2)小漆酶中T1Cu中心的氧还原活性，以及(3)改变纳入azurin的Fe- s簇的还原电位。对这些目标的追求有望对金属蛋白的还原电位如何调节以及金属蛋白的功能如何扩展到电子转移之外有更深入的了解。这一新发现为设计具有可预测还原电位的金属蛋白和金属配合物提供了坚实的基础，可用于太阳能转换、燃料电池和小分子活化等应用。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Chemistry of Life Processes (CLP) Program in the Chemistry Division, Dr. Yi Lu from the University of Illinois at Urbana-Champaign plans to modulate metalloprotein activities through fine-tuning reduction potentials. In the process, the research will contribute to the fundamental understanding of how to tune reduction potentials and correlate it with functional properties. Many chemical and biological processes involve redox reactions, whose efficiency is largely defined by reduction potentials. In Nature, each metalloprotein covers a certain reduction potential range required for its function. A systematic understanding of common factors that affect the reduction potential of different metalloproteins across the entire range of physiological reduction potentials remains elusive. To address this limitation, the Lu group plans to engineer the protein azurin to vary the reduction potential of the copper site to address the question of how tuning reduction potentials can modulate enzymatic functions, knowledge that would be applicable to many biological and chemical systems. Dr. Lu will integrate research with education through developing lecture and lab modules for undergraduate and graduate courses that incorporate multidisciplinary research results. The PI will focus on recruiting students from groups underrepresented in STEM (science, technology, engineering and mathematics) to participate in the research through outreach activities and on creating and maintaining a diverse, equitable, and inclusive culture to allow the recruits to thrive in learning and research. This project builds on the previous success in Dr. Lu’s lab in tuning the reduction potential of the type 1 copper center in azurin to span a 2 V physiological Eº´ range with minimal perturbation of the primary coordination sphere. It focuses on the engineering secondary coordination sphere interactions, including hydrogen bonding (H-bonding) and hydrophobicity to modulate metalloprotein activities, including (1) the S-nitrosylation reactivity of a Cu site and stepwise nitrosylation of a nonheme Fe site in an engineered azurin, (2) the oxygen reduction activity of the T1Cu center in a small laccase, and (3) changing the reduction potential of an Fe-S cluster incorporated into azurin. The pursuit of these objectives is expected to result in deeper insights into how reduction potentials of metalloproteins can be tuned and how the functions of metalloproteins can be expanded beyond electron transfer. The new knowledge could serve as a strong basis for the design of metalloproteins and metal complexes with predictable reduction potentials that can be used in applications such as solar energy conversion, fuel cells, and small molecule activation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.