Protein-mineral interactions at the organic-inorganic interface in biominerals

生物矿物质中有机-无机界面的蛋白质-矿物质相互作用

• 批准号: RGPIN-2016-05031
• 负责人: McKee, Marc
• 金额: $ 2.4万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=615454
• 关键词: Protein; mineral; interactions; organic; inorganic

Bones, teeth, otoconia, eggshells, snail and sea shells, corals and many other biomineralized structures in the plant and animal kingdoms arise from synergistic interactions between co-existing organic (usually proteins) and inorganic mineral phases. These composites have specialized properties, and hierarchically organized supramolecular assemblies that provide a framework for biomineralization. Negatively charged proteins may attain regulatory chemical complementarity by binding to mineral calcium at the organic-inorganic interface − a mechanism to influence crystal growth processes. It is hypothesized that the molecular precision of such organic-inorganic interfacial interactions regulates crystal growth. My biomineralization research program focuses on specific proteins/peptides (notably osteopontin) that regulate mineral growth. Intriguingly, amino acids, peptides and full-length proteins can be occluded within mineral crystals. Related to this, biomineralization can proceed initially through assembly of amorphous precursor nanoparticles forming within a confined, protein/peptide-rich reaction nanoenvironment. Within these nanoparticle domains, transformation towards a crystalline phase may occur over different length scales such that single crystals (by diffraction) can actually consist of aligned mineral nanoparticles, the fusion of which builds mesocrystals having occluded organics. This notion is in stark contrast to classical crystallization theory which postulates ion-by-ion attachment. My biomineralization research program compares these scenarios by exploring fundamental principles of how organics (amino acids, and relevant peptides and proteins) influence biomineralization. We will compare two polymorphs of calcium carbonate crystals (calcite and vaterite) grown in the presence of osteopontin protein/peptides/amino acids to two biomineralized structures − avian eggshell and mouse inner ear otoconia. To study the growth of calcium carbonate crystals in the presence of these organics, a variety of morphological, biochemical, immunochemical, cell biological/molecular, and characterization techniques will be used including: electron microscopy, atomic force microscopy, confocal microscopy, X-ray and electron diffraction, Canadian Light Source synchrotron analyses, Raman spectroscopy, immunocytochemistry on mouse otoconia, in vitro cell culture and crystal growth systems, mass spectroscopy, and RosettaSurface energy-minimization computational simulations. With this mechanistic biomineralization information on how proteins and peptides bind to crystals to regulate their growth, we will be well-positioned to create tunable mineralization events that advance biomaterials and tissue engineering applications to the benefit of Canadians and citizens worldwide.

在动植物王国中，骨骼、牙齿、耳石、蛋壳、蜗牛和海贝、珊瑚和许多其他生物矿化结构来自共存的有机(通常是蛋白质)和无机矿物相之间的协同作用。这些复合材料具有特殊的性质，并有层次地组织超分子组装，为生物矿化提供了一个框架。带负电荷的蛋白质可能通过与有机-无机界面上的矿物质钙结合来实现调节化学互补，这是一种影响晶体生长过程的机制。据推测，这种有机-无机界面相互作用的分子精度决定了晶体的生长。我的生物矿化研究项目专注于调节矿物质生长的特定蛋白质/多肽(特别是骨桥蛋白)。 有趣的是，氨基酸、多肽和全长蛋白质可以被包裹在矿物晶体中。与此相关，生物矿化最初可以通过在受限的富含蛋白质/肽的反应纳米环境中形成的无定形前驱体纳米颗粒的组装来进行。在这些纳米粒子域中，向晶相的转变可能发生在不同的长度尺度上，使得单晶(通过衍射)实际上可以由排列的矿物纳米颗粒组成，它们的融合形成具有闭塞有机物的介晶。这一概念与经典结晶理论形成鲜明对比，经典结晶理论假定离子与离子之间存在相互作用。我的生物矿化研究项目通过探索有机物(氨基酸、相关多肽和蛋白质)如何影响生物矿化的基本原理来比较这些情景。 我们将比较在骨桥蛋白/多肽/氨基酸存在下生长的两种多晶型碳酸钙晶体(方解石和球形石)与两种生物矿化结构−禽蛋壳和小鼠内耳耳石。为了研究碳酸钙晶体在这些有机物存在下的生长，将使用各种形态、生化、免疫化学、细胞生物学/分子和表征技术，包括：电子显微镜、原子力显微镜、共聚焦显微镜、X射线和电子衍射、加拿大光源同步加速器分析、拉曼光谱、小鼠耳石的免疫细胞化学、体外细胞培养和晶体生长系统、质谱学和Rosetta表面能量最小化计算模拟。 有了这种关于蛋白质和多肽如何与晶体结合以调节其生长的机械生物矿化信息，我们将能够很好地创建可调矿化事件，促进生物材料和组织工程应用，造福加拿大人和世界各地的公民。