Collaborative Research: Mechanism of Manganese(IV) Oxide Biomineralization by a Bacterial Manganese Oxidase

合作研究：细菌锰氧化酶生物矿化锰（IV）氧化物的机制

• 批准号: 1951498
• 负责人: Bradley Tebo
• 金额: $ 28.23万
• 依托单位: Oregon Health & Science University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-15 至 2021-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1951498&HistoricalAwards=false
• 关键词: Collaborative; Research; Mechanism; Manganese; IV

Manganese (Mn) is a biologically vital element, supporting life through its use by many enzymes, including those that produce oxygen in plants and that defend many living organisms against reactive oxygen species. Thus, the manganese cycle—the interconversion between bioavailable Mn ions (Mn(II)) and insoluble Mn oxide minerals (MnO2)—is globally important. Microorganisms play a significant part in driving the manganese cycle: some bacteria use MnO2 for respiration, in the process converting the mineral to dissolved Mn(II), while other bacteria can oxidize Mn(II), forming the MnO2 deposits that can be found in many environments. The latter process, biomineralization, is a less-understood field in manganese biogeochemistry. With this award, Dr. Bradley Tebo and Dr. Thomas Spiro will develop a comprehensive picture of bacterial manganese oxide biomineralization, which is essential for understanding how MnO2 are processed in nature, and how this insight might be applied to the burgeoning uses of MnO2 minerals in environmental remediation and bioenergy production. The project will enhance the training of the next generation of scientists and embrace outreach activities, including mentoring students and programs that seek to attract underserved/underrepresented middle and high school students to science majors. A set of artistic illustrations to communicate the project to a broader audience will be created and made available through various channels.In many Mn(II)-oxidizing bacteria, multicopper oxidase (MCO) enzymes have been implicated to be the catalysts for Mn(II) oxidation. In Mn(II)-oxidizing Bacillus species, dormant spores oxidize Mn(II) and form MnO2 minerals, catalyzed by MCOs residing in the exosporium—a complex structure that surrounds the spores. However, the molecular mechanism of MnO2 production remains to be elucidated. With the first purified bacterial manganese oxidizing complex, Mnx, and a collection of manganese-oxidizing bacteria, this project will reveal how bacteria control the formation of MnO2 nanoparticles. Specifically, investigators will characterize how the protein guides the formation of mineral units, how they are expelled into the solution and further grow to form the mineral found in nature, and how complexities of natural environment—biological matter of whole cells, complexing agents, and dissolved iron—affect the final biomineral. The project is highly leveraged through a collaborative and integrated approach of multiple state-of-the-art techniques, including cryoEM, SAXS, EXAFS, liquid-cell TEM, and computational methods to offer a unique molecular-level view of manganese oxide biomineralization. Additionally, the project will expand the use of state-of-the-art microscopic techniques, primarily used in biomedical and materials science research, to address questions of geochemical significance.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.

锰（MN）是生物学上至关重要的元素，通过许多酶的使用，包括在植物中产生氧气并捍卫许多活生物体免受活性氧气的氧气的生命。这是全球重要的，锰周期（MN（II））与不溶性Mn氧化物矿物质（MNO2）之间的相互转换至关重要。微生物在驱动锰周期中起着重要的作用：在将矿物转化为溶解的Mn（II）的过程中，一些细菌使用MNO2进行呼吸，而其他细菌可以氧化物MN（II）形成在许多环境中可以发现的MNO2沉积物。后一个过程是生物矿化，是锰生物地球化学中不太了解的领域。有了这个奖项，布拉德利·泰博（Bradley Tebo）博士和托马斯·斯皮罗（Thomas Spiro）博士将制定锰氧化物生物矿化的全面图片，这对于理解MNO2在自然界中的处理至关重要，以及如何将这种见解应用于MNO2矿物在环境补救和生产中的MNO2矿物的迅速用途。该项目将增强对下一代科学家的培训，并接受宣传活动，包括旨在吸引服务不足/代表不足的中学生和高中生进入科学专业的计划。将通过各种渠道创建并提供了一系列将项目传达给更广泛受众的艺术插图。在许多MN（II）（II）氧化细菌中，已暗示已氧化细菌（MCO）酶是MN（II）氧化的催化剂。在Mn（II）氧化芽孢杆菌物种中，休眠的孢子氧化物Mn（II）和形成MNO2矿物质，由位于外孢子中的MCO催化，这是一种围绕孢子的复杂结构。然而，使用首次纯化的细菌氧化复合物，MNX和锰氧化细菌的MNO2产生的分子机制，该项目将揭示细菌如何控制MNO2纳米颗粒的形成。具体而言，研究者将表征蛋白质如何指导矿物单元的形成，如何探索溶液并进一步生长以形成在自然界中发现的矿物质，以及自然环境的复杂性（整个细胞的生物学问题，络合剂和溶解的铁）如何影响最终的生物学。该项目通过多种最先进技术的协作和集成方法高度利用，包括冷冻，SAXS，EXAFS，Liquid-Cell TEM和计算方法，以提供独特的分子氧化物生物矿化视图。此外，该项目将扩大最先进的微观技术的使用，主要用于生物医学和材料科学研究，以解决地球化学意义的问题。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子优点和更广泛影响的审查标准来通过评估来通过评估来支持的。