Structure, assembly, and biological activity of amyloid peptides and proteins.

淀粉样肽和蛋白质的结构、组装和生物活性。

• 批准号: 342069-2013
• 负责人: Sharpe, Simon
• 金额: $ 3.13万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=630000
• 关键词: Structure; assembly; biological; activity; amyloid

Amyloid fibrils are highly ordered filamentous structures formed by a wide range of different proteins and peptides. These assemblies were originally described as potential mediators of cytotoxicity in amyloidosis, and are linked to infectivity in prion diseases. More recently, amyloids been shown to play important functional roles in diverse biological processes ranging from assembly of the skin pigment melanin, genetic diversification of fungi and yeast and adhesion of bacteria and yeast to surfaces during biofilm formation. Despite their biological importance, the ability of diverse proteins to self-assemble into closely related structures having highly divergent function remains poorly understood. Similarly, it is not known how some of these assemblies can be potently cytotoxic while others avoid toxicity to perform biological tasks. This chemical and functional diversity, built on an ordered scaffold, is also a desirable feature in the development of novel biomaterials. Understanding the roles of amyloid proteins in biology, and exploiting their materials potential, both require detailed knowledge of the molecular basis for fibril formation, and the ability to link sequence with the structure and function of the fibrillar state. We will use solid-state nuclear magnetic resonance to determine the molecular structures of amyloid fibrils formed by peptides and proteins with varied sequence and functionality. This method has emerged as a powerful tool for structural biology of otherwise intractable systems, and allows us to obtain atomic resolution structures of fibrillar protein assemblies. We will focus on three distinct systems, providing an opportunity to elucidate the molecular basis for structural variation in amyloids, and to distinguish between toxic and functional assemblies. Specifically we will: 1) Determine the mechanism through which cytotoxic oligomers formed by model amyloid peptides kill cells; 2) Define the basis for the unique structural polymorphism seen in fibrils formed by the serum amyloid A protein; and 3) Determine how amyloid fibril forming domains mediate cell-cell and cell-surface adhesion in fungal biofilms.

淀粉样蛋白原纤维是由多种不同蛋白质和肽形成的高度有序的丝状结构。这些组件最初被描述为淀粉样变性中细胞毒性的潜在介体，并与病毒疾病的感染性有关。最近，淀粉样蛋白在多种生物学过程中起着重要的功能作用，包括皮肤色素黑色素的组装，真菌和酵母的遗传多样化以及在生物膜形成期间细菌和酵母的粘附到表面。尽管具有生物学的重要性，但各种蛋白质自我组装成具有高度不同功能的紧密相关结构的能力仍然很差。同样，这些组件中的某些人如何有效地细胞毒性，而另一些则避免毒性执行生物学任务。这种基于有序脚手架的化学和功能多样性也是新型生物材料发展的理想特征。了解淀粉样蛋白在生物学中的作用，并利用其材料潜力，均需要详细了解原纤维形成的分子基础，以及将序列与原纤维状态的结构和功能联系起来的能力。我们将使用固态核磁共振来确定由肽和蛋白质形成的具有变化序列和功能的蛋白质的淀粉样蛋白原纤维的分子结构。该方法已成为原本棘手系统的结构生物学的强大工具，并使我们能够获得纤维蛋白组件的原子分辨率结构。我们将重点关注三个不同的系统，为阐明淀粉样蛋白结构变化的分子基础提供机会，并区分有毒和功能组件。具体而言，我们将：1）确定模型淀粉样蛋白肽杀死细胞的细胞毒性低聚物的机制； 2）定义在血清淀粉样蛋白A蛋白质形成的原纤维中看到的独特结构多态性的基础； 3）确定淀粉样纤维形成结构域如何介导真菌生物膜中的细胞细胞和细胞表面粘附。