Department of Chemistry, University of Washington , Box 351700, Seattle, Washington 98195, United States.
Acc Chem Res. 2013 Sep 17;46(9):2136-44. doi: 10.1021/ar300321e. Epub 2013 Aug 9.
Nature has evolved sophisticated strategies for engineering hard tissues through the interaction of proteins, and ultimately cells, with inorganic mineral phases. This process, called biomineralization, is how living organisms transform inorganic materials such as hydroxyapatite, calcite, and silica into highly intricate and organized structures. The remarkable material properties of shell, bone, and teeth come from the activities of proteins that function at the organic-inorganic interface. A better understanding of the biomolecular mechanisms used to promote or retard the formation of mineral-based structures could provide important design principles for the development of calcification inhibitors and promoters in orthopedics, cardiology, urology, and dentistry. With the knowledge of the structural basis for control of hard tissue growth by proteins, scientists could potentially develop materials using biomimetic principles with applications in catalysis, biosensors, electronic devices, and chromatographic separations, to name a few. Additionally, biomineralization also has potential applications in electronics, catalysis, magnetism, sensory devices, and mechanical design. Where man-made hard materials require the use of extreme temperatures, high pressure, and pH, biological organisms can accomplish these feats at ambient temperature and at physiological pH. Despite the fact that many researchers want to identify and control the structure of proteins at material and biomineral interfaces, there is a decided lack of molecular-level structure information available for proteins at biomaterial interfaces in general. In particular, this holds for mammalian proteins that directly control calcification processes in hard tissue. The most fundamental questions regarding the secondary and tertiary structures of proteins adsorbed to material surfaces, how proteins catalyze the formation of biomineral composites, or how proteins interact at biomaterial interfaces remain unanswered. This is largely due to a lack of methods capable of providing high-resolution structural information for proteins adsorbed to material surfaces under physiologically relevant conditions. In this Account, we highlight recent work that is providing insight into the structure and crystal recognition mechanisms of a salivary protein model system, as well as the structure and interactions of a peptide that catalyzes the formation of biosilica composites. To develop a better understanding of the structure and interactions of proteins in biomaterials, we have used solid-state NMR techniques to determine the molecular structure and dynamics of proteins and peptides adsorbed onto inorganic crystal surfaces and embedded within biomineral composites. This work adds to the understanding of the structure and crystal recognition mechanisms of an acidic human salivary phosphoprotein, statherin.
大自然通过蛋白质与无机矿物相的相互作用，进化出了精巧的方法来构建硬组织。这个过程被称为生物矿化，它是生物将羟磷灰石、方解石和二氧化硅等无机材料转化为高度复杂和有组织的结构的方式。壳、骨和牙齿的优异材料特性源于在有机-无机界面起作用的蛋白质的活动。更好地了解促进或抑制基于矿物质的结构形成的生物分子机制，可以为骨科、心脏病学、泌尿科和牙科领域的钙化抑制剂和促进剂的开发提供重要的设计原则。通过了解蛋白质控制硬组织生长的结构基础，科学家们有可能利用仿生原理开发材料，应用于催化、生物传感器、电子设备和色谱分离等领域。此外，生物矿化在电子、催化、磁性、感测装置和机械设计方面也具有潜在的应用。人造硬材料需要使用极端温度、高压和 pH 值，而生物有机体则可以在环境温度和生理 pH 值下完成这些壮举。尽管许多研究人员希望识别和控制材料和生物矿化界面处的蛋白质结构，但总的来说，一般来说，关于吸附在生物材料界面上的蛋白质的分子水平结构信息存在明显的缺乏。特别是对于直接控制硬组织钙化过程的哺乳动物蛋白质。关于吸附在材料表面的蛋白质的二级和三级结构、蛋白质如何催化生物矿化复合材料的形成，以及蛋白质如何在生物材料界面相互作用的最基本问题仍未得到解答。这主要是由于缺乏能够在生理相关条件下为吸附在材料表面的蛋白质提供高分辨率结构信息的方法。在本述评中，我们重点介绍了最近的工作，这些工作提供了对唾液蛋白模型系统的结构和晶体识别机制的深入了解，以及对催化生物硅复合材料形成的肽的结构和相互作用的了解。为了更好地了解生物材料中蛋白质的结构和相互作用，我们使用固态 NMR 技术来确定吸附在无机晶体表面和嵌入生物矿化复合材料中的蛋白质和肽的分子结构和动力学。这项工作增加了对酸性人唾液磷蛋白 statherin 的结构和晶体识别机制的理解。
