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

骨骼、牙齿、耳石、蛋壳、蜗牛和贝壳、珊瑚和植物和动物王国中的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相互作用。这些复合材料具有特殊的性质，和分级组织的超分子组装体，为生物矿化提供了框架。带负电荷的蛋白质可以通过在有机-无机界面与矿物质钙结合来获得调节性化学互补性-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调节晶体生长。我的生物矿化研究计划侧重于调节矿物生长的特定蛋白质/肽（特别是骨桥蛋白）。 有趣的是，氨基酸，肽和全长蛋白质可以被封闭在矿物晶体中。与此相关，生物矿化最初可以通过在受限的、富含蛋白质/肽的反应纳米环境内形成的无定形前体纳米颗粒的组装来进行。在这些纳米颗粒域中，向结晶相的转化可以在不同的长度尺度上发生，使得单晶（通过衍射）实际上可以由对齐的矿物纳米颗粒组成，其融合构建具有封闭的有机物的介晶。这一概念与经典的结晶理论形成鲜明对比，后者假设离子与离子的连接。我的生物矿化研究计划通过探索有机物（氨基酸，相关肽和蛋白质）如何影响生物矿化的基本原理来比较这些情况。 我们将比较在骨桥蛋白/肽/氨基酸存在下生长的两种多晶型碳酸钙晶体（方解石和球霰石）与两种生物矿化结构-鸟类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，将使用各种形态学、生物化学、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、质谱和RosettaSurface能量最小化计算模拟。 有了关于蛋白质和肽如何与晶体结合以调节其生长的这种机械生物矿化信息，我们将能够很好地创建可调矿化事件，以推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。

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.