Collaborative Research: How bacteria control manganese(IV) oxide biomineralization using a multicopper oxidase complex

化学部生命过程化学项目将通过该奖项资助俄勒冈健康与科学大学的Bradley Tebo博士和华盛顿大学的Thomas Spiro博士，研究细菌如何将溶解的锰（Mn）转化为氧化锰矿物。这种化学过程产生的锰氧化物是广泛存在的、高活性的、高效的催化剂，在元素生物地球化学循环中起着重要作用。虽然这些氧化物主要是由微生物过程产生的，但人们对它们形成的生物学手段知之甚少。本项目利用首次纯化的活性锰氧化酶复合物，揭示了细菌氧化锰生产的途径。该项目可能会揭示锰氧化和矿物形成这两个过程是如何实现的生物化学原理，为未来生物衍生的锰氧化物在清洁水技术和能源储存和生产中的应用奠定基础。该项目加强了跨学科方法对下一代科学家的培训，并作为推广项目的工具，吸引本科生、中学生和高中生学习与环境科学相关的微生物学和生物化学。此外，博士后还针对6-8年级或9-12年级的学生开设了周六学院课程，重点介绍微生物学和生物化学与环境科学相关的重要性。星期六学院作为导师为博士后提供专业发展。该项目代表了对纯化蛋白质如何完成Mn（II）的困难双电子氧化，形成纳米颗粒MnO2矿物产品的研究。迄今为止的结果表明，活性蛋白属于众所周知的多铜氧化酶家族，但具有独特的能力，以适应锰的多核化学来进行催化。研究重点是通过分解锰氧化中间体和利用一系列光谱技术研究关键突变的影响，建立分子水平上的详细催化机制。光谱研究由建模、晶体学和低温电子显微镜工作补充，以得出酶的三维原子结构。在更广泛的环境适用性背景下，本研究探讨了环境中发生的其他金属对锰氧化酶催化的影响。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 this award, the Chemistry of Life Processes Program in the Chemistry Division is funding Dr. Bradley Tebo from Oregon Health & Science University and Dr. Thomas Spiro from the University of Washington to find out how bacteria change dissolved manganese (Mn) into manganese oxide minerals. This chemical process produces manganese oxides that are widespread, highly reactive, efficient catalysts that play important roles in elemental biogeochemical cycles. Although these oxides are primarily made by microbial processes, the biological means for their formation are poorly understood. This project reveals the pathway of bacterial manganese oxide production, using the first purified active manganese-oxidizing enzyme complex. The project may uncover the biochemistry of how two processes-manganese oxidation and mineral formation-are achieved, laying the foundation for future application of biologically-derived manganese oxides in clean water technologies and energy storage and production. This project enhances the training of the next generation of scientists in interdisciplinary methods, and serves as a vehicle in outreach programs to engage undergraduate, middle, and high school students in studies of microbiology and biochemistry, as related to environmental science. In addition, postdoctoral fellows develop a Saturday Academy course targeting either 6-8 or 9-12 grade students and focusing on the importance of microbiology and biochemistry as related to environmental science. The Saturday Academy provides professional development for the postdoctoral fellow as the instructor.The project represents an investigation of how a purified protein can accomplish the difficult two-electron oxidation of Mn(II), forming a nanoparticulate MnO2 mineral product. Results to date indicate that the active protein belongs to the well-known multicopper oxidase family of enzymes, but with a unique ability to adapt the polynuclear chemistry of manganese to perform the catalysis. The research efforts are focused on establishing a molecular-level detailed mechanism of the catalysis, by resolving manganese oxidation intermediates and studying the effects of key mutations with an array of spectroscopic techniques. The spectroscopic studies are complemented by modeling, crystallography, and cryo-electron microscopy work to derive the 3D atomic structure of the enzyme. In the context of broader environmental applicability, the research explores the effect of other metals occurring in the environment on the enzymatic catalysis of manganese oxidation.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.