Modulation of Metalloprotein Activities through Fine-tuning Reduction Potentials

在化学系生命过程化学（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节还原电位并将其与功能性质相关联。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由还原电位决定。在自然界中，每种金属蛋白都覆盖了其功能所需的一定还原电位范围。一个系统的理解，影响不同的金属蛋白在整个范围内的生理还原电位的还原电位的共同因素仍然难以捉摸。为了解决这一限制，Lu团队计划对蛋白质天青蛋白进行工程改造，以改变铜位点的还原电位，从而解决调节还原电位如何调节酶功能的问题，这些知识将适用于许多生物和化学系统。卢博士将通过为本科生和研究生课程开发讲座和实验室模块，将多学科的研究成果与教育相结合。PI将专注于从STEM（科学，技术，工程和数学）代表性不足的群体中招募学生，通过外联活动参与研究，并创造和维护多元化，公平和包容性的文化，使新兵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调整天青蛋白中1型铜中心的还原电位的基础上，以最小的主配位圈扰动跨越2 V生理Eº´范围。 它侧重于工程次级配位相互作用，包括氢键（H-键合）和疏水性来调节金属蛋白活性，包括（1）工程化天青蛋白中Cu位点的S-亚硝基化反应性和非血红素Fe位点的逐步亚硝基化，（2）小漆酶中T1 Cu中心的氧还原活性，以及（3）改变掺入天青蛋白的Fe-S簇的还原电位。这些目标的追求，预计将导致更深入的了解如何金属蛋白的还原电位可以调整和金属蛋白的功能可以扩展到电子转移之外。新的知识可以作为一个强有力的基础，为金属蛋白质和金属络合物的设计，可预测的还原电位，可用于应用，如太阳能转换，燃料电池，和小分子活化。这个奖项反映了NSF的法定使命，并已被认为是值得的支持，通过评估使用基金会的智力价值和更广泛的影响审查标准。

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.