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) 是一种生物重要元素，通过许多酶的使用来维持生命，包括那些在植物中产生氧气的酶，以及保护许多生物体免受活性氧侵害的酶，因此，锰循环——生物可利用的锰离子之间的相互转化。 Mn(II)) 和不溶性氧化锰矿物 (MnO2) — 在全球范围内都很重要，微生物在推动锰循环方面发挥着重要作用：一些细菌利用 MnO2 进行呼吸、在将矿物质转化为溶解的 Mn(II) 的过程中，而其他细菌可以氧化 Mn(II)，形成在许多环境中都可以找到的 MnO2 沉积物，后者的过程（生物矿化）是锰生物地球化学中不太了解的领域。凭借该奖项，Bradley Tebo 博士和 Thomas Spiro 博士将全面了解细菌氧化锰生物矿化，这对于了解 MnO2 的加工方式至关重要该项目将加强对下一代科学家的培训，并开展推广活动，包括指导学生和旨在吸引的项目。将创建一组艺术插图，以将项目传达给更广泛的受众，并通过各种渠道提供。在许多锰（II）氧化细菌中，多铜。氧化酶 (MCO) 被认为是 Mn(II) 氧化的催化剂。在 Mn(II) 氧化芽孢杆菌属物种中，休眠孢子在孢子外壁中的 MCO 的催化下氧化 Mn(II) 并形成 MnO2 矿物质。然而，MnO2 产生的分子机制仍有待了解。通过第一个纯化的细菌锰氧化复合物 Mnx 和一系列锰氧化细菌，该项目将揭示细菌如何控制 MnO2 纳米粒子的形成，具体而言，研究人员将表征蛋白质如何引导矿物质单元的形成，它们如何被排出到溶液中并进一步生长形成自然界中发现的矿物质，以及自然环境的复杂性（全细胞的生物物质、络合剂和溶解的铁）如何影响最终的该项目通过多种最先进技术的协作和集成方法得到高度利用，包括冷冻电镜、SAXS、EXAFS、液体细胞 TEM 和计算方法，以提供氧化锰的独特分子水平视图。生物矿化。该项目将扩大最先进的显微技术的使用，主要用于生物医学和材料科学研究，以解决具有地球化学意义的问题。该奖项反映了 NSF 的法定使命，并已被另外通过使用基金会的智力优点和更广泛的影响审查标准进行评估，认为值得支持。