Collaborative Research: Using Single-Molecule Force and Fluorescence Microscopy to Elucidate the Molecular Mechanism of Bioinspired Magnetite Synthesis in Magnetotactic Bacteria

合作研究：利用单分子力和荧光显微镜阐明趋磁细菌中仿生磁铁矿合成的分子机制

• 批准号: 0920718
• 负责人: Dennis Bazylinski
• 金额: $ 14.63万
• 依托单位: University of Nevada Las Vegas
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0920718&HistoricalAwards=false
• 关键词: Collaborative; Research; Using; Single; Molecule

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Microorganisms are the oldest living inhabitants of planet Earth, spanning some 3.5 billion years, and their importance in shaping the Earth?s soils, oceans, and atmosphere has long been accepted. The biosynthesis of magnetite (Fe3O4) by magnetotactic bacteria is an interesting example that has generated a great deal of interest because of its importance in applications such as catalysis, electronics, nanotechnology, and biomedical sciences, its philosophical implications concerning the origin and evolution of life on Earth, and its potential to participate in the biogeochemical cycling of iron, nitrogen, sulfur, and carbon in natural environments. Furthermore, the biogeochemical cycling of iron by microorganisms (e.g., the accumulation and conversion of iron into Fe3O4 by magnetotactic bacteria) is of particular importance because iron is a ubiquitous and very reactive constituent of surface and subsurface environments and, as a result, impacts regional and global scale climatic and ecological phenomena. In addition, despite its ubiquity and because of it reactivity, iron is often a limiting factor for growth of organisms, for example, in some parts of the world?s oceans. From the point of view of mineralization, biological control over nucleation and directed growth of nanominerals is an elegant example of self-organization in complex molecular systems.Despite the discovery of magnetotactic bacteria over 30 years ago, the mechanism for Fe3O4 biomineralization in these microorganisms remains unknown. The objective of this research is to use single-molecule techniques of atomic force (single-molecule antibody recognition force microscopy) and fluorescence microscopy/spectroscopy (time-resolved fluorescence anisotropy and fluorescence resonance energy transfer) to determine the molecular mechanism for the biomineralization of nanomagnetite crystals in magnetotactic bacteria. Investigators will identify the function(s) of the individual protein molecules involved in the biomineralization process and determine how they control crystal nucleation, growth and morphology, examine the organization of the protein molecules within a bacterial membrane and with respect to nascent Fe3O4 nanoparticles, identify the amino acid sequences within these molecules required for crystal nucleation and growth, and uncover functional protein complexes required for Fe3O4 biomineralization.The broader impacts resulting from the proposed activity ? Understanding the molecular mechanism by which bacteria direct the synthesis of Fe3O4 nanoparticles represents an important paradigm for bioinspired materials synthesis that would provide enormous insight into the strategies of controlled crystal synthesis used by other organisms, including multi-cellular organisms. By understanding the biomineralization process of Fe3O4 in magnetotactic bacteria, we might learn how to determine whether Fe3O4 grains in the environment are biogenic in origin, which, in turn, might provide evidence of reliability for the use of Fe3O4 crystals found in the environment to be used as biomarkers for past life on Earth. Furthermore, because technological progress often relies on a detailed understanding of the material properties of single crystals, composites, interfaces, and nanocrystals, and because the mineralization process in microorganisms is inherently controlled by nanoscale structures (e.g., proteins), this knowledge will become the basis for bio-controlled approaches to synthesize tailor-made inorganic nanostructures for applications across a diverse span of technologies. Finally, investigators believe that the novel imaging techniques developed as a result of this project will emerge as powerful tools that can be used for studies in other geobiological or biological systems.The proposed research will support a new collaboration between the two PIs and two Ph.D. graduate students (one student from each laboratory) who will play an integral role in this research and be encouraged to present their findings at international and national conferences and local seminars at each university. One PI is an early-career faculty member who has helped pioneer efforts to develop imaging techniques to study geobiological processes on a molecular level and the second PI is a senior faculty member who is a world-renowned authority in magnetite biomineralization and has authored over 150 publications in this field. This proposal will also fund 1 female PhD student who works in the Lead- PI?s laboratory. The results of this research will be integrated into the undergraduate and graduate courses currently taught and being developed by the PIs. Furthermore, this proposal will support efforts to educate elementary, middle-, and high school age students about the burgeoning yet often overlooked fields of nanogeoscience and biogeochemistry through hands-on demonstrations and presentations. These efforts will be geared to encourage pre-college students to pursue careers in biogeochemistry and/or become responsible stewardesses of the environment.

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。微生物是地球上最古老的居住者，跨越约35亿年，它们在塑造地球方面的重要性？地球的土壤、海洋和大气早已被人们所接受。由趋磁细菌生物合成磁铁矿（Fe 3 O 4）是一个有趣的例子，由于其在催化，电子，纳米技术和生物医学科学等应用中的重要性，其关于地球上生命起源和进化的哲学含义，以及其参与铁，氮，硫，和碳元素。此外，铁通过微生物（例如，铁的积累和由趋磁细菌转化为Fe 3 O 4）是特别重要的，因为铁是地表和地下环境中普遍存在的和非常活跃的成分，因此影响区域和全球尺度的气候和生态现象。此外，尽管它的普遍存在，因为它的反应性，铁往往是一个限制因素的生长的生物体，例如，在世界的某些地区？的海洋。从矿化的角度来看，生物控制纳米矿物的成核和定向生长是复杂分子系统自组织的一个极好例子。尽管趋磁细菌的发现已有30多年的历史，但这些微生物中Fe 3 O 4的生物矿化机制仍不清楚。本研究的目的是使用原子力（单分子抗体识别力显微镜）和荧光显微镜/光谱（时间分辨荧光各向异性和荧光共振能量转移）的单分子技术，以确定在趋磁细菌的纳米磁铁矿晶体的生物矿化的分子机制。研究人员将确定参与生物矿化过程的单个蛋白质分子的功能，并确定它们如何控制晶体成核，生长和形态，检查细菌膜内蛋白质分子的组织以及新生Fe 3 O 4纳米颗粒，确定晶体成核和生长所需的这些分子内的氨基酸序列，并揭示功能蛋白质复合物所需的Fe 3 O 4生物矿化。更广泛的影响所产生的拟议活动？了解细菌指导Fe 3 O 4纳米颗粒合成的分子机制代表了生物启发材料合成的重要范例，这将为其他生物体（包括多细胞生物体）使用的受控晶体合成策略提供巨大的洞察力。通过了解Fe 3 O 4在趋磁细菌中的生物矿化过程，我们可以了解如何确定环境中的Fe 3 O 4颗粒是否是生物起源的，这反过来可能为使用环境中发现的Fe 3 O 4晶体作为地球上过去生命的生物标志物提供可靠的证据。此外，由于技术进步通常依赖于对单晶、复合材料、界面和纳米晶体的材料性质的详细理解，并且由于微生物中的矿化过程固有地由纳米级结构控制（例如，蛋白质），这一知识将成为生物控制方法的基础，以合成定制的无机纳米结构，用于各种技术的应用。最后，研究人员认为，作为该项目的结果开发的新的成像技术将成为强大的工具，可用于其他地球生物学或生物系统的研究。拟议的研究将支持两个PI和两个博士之间的新的合作。研究生（每个实验室一名学生），他们将在这项研究中发挥不可或缺的作用，并被鼓励在国际和国家会议以及每个大学的地方研讨会上介绍他们的研究结果。一个PI是一个早期的职业教师，他帮助开拓了开发成像技术以在分子水平上研究地球生物学过程的努力，第二个PI是一个高级教师，他是磁铁矿生物矿化的世界知名权威，并在该领域发表了150多篇论文。该提案还将资助1名在首席研究员工作的女博士生？的实验室。这项研究的结果将被整合到目前教授的本科和研究生课程，并由PI开发。此外，该提案将支持努力教育小学，初中和高中年龄的学生关于新兴但往往被忽视的纳米地球科学和纳米地球化学领域，通过动手演示和演示。这些努力将旨在鼓励大学预科学生追求地球化学事业和/或成为环境的负责任的管家。