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

该奖项将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。这一化学过程产生的锰氧化物是广泛存在的、高活性、高效的催化剂，在元素生物地球化学循环中发挥着重要作用。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。这个项目揭示了细菌氧化锰的产生途径，使用的是第一个纯化的活性锰-氧化酶复合体。该项目可能揭示两个过程--锰氧化和矿物形成--是如何实现的生物化学，为未来生物来源的锰氧化物在清洁水技术以及能源储存和生产中的应用奠定基础。该项目加强了对下一代科学家的跨学科方法的培训，并作为推广计划的载体，让本科生、初中生和高中生参与与环境科学相关的微生物学和生物化学研究。此外，博士后研究员还针对6-8年级或9-12年级的学生开发了一门周六学院课程，重点关注与环境科学相关的微生物学和生物化学的重要性。星期六学院为博士后导师提供专业发展。该项目代表了一项研究，即纯化的蛋白质如何完成困难的两电子氧化Mn(II)，形成纳米颗粒MnO2矿物产品。到目前为止的结果表明，该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执行催化。研究的重点是通过分解锰氧化中间体和用一系列光谱技术研究关键突变的影响，从分子水平上建立催化的详细机理。光谱研究得到建模、结晶学和冷冻电子显微镜工作的补充，以得出酶的三维原子结构。在更广泛的环境适用性的背景下，这项研究探索了环境中存在的其他金属对锰氧化的酶催化作用的影响。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.