Amyloid protein aggregates of beta-lactoglobulin and their behavior along the process chain

β-乳球蛋白的淀粉样蛋白聚集体及其沿过程链的行为

• 批准号: 315456892
• 负责人: Dr. Julia Keppler
• 金额: --
• 依托单位: Institut für Humanernährung und Lebensmittelkunde
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/315456892?language=en
• 关键词: Amyloid; protein; aggregates; beta; lactoglobulin

Amyloid aggregates occur ubiquitously in nature and are characterized by a stacked β-sheet conformation. Amyloid aggregates from whey protein β-lactoglobulin (BLG) can be specifically produced in order to take advantage of their altered physicochemical properties as a functional substance. The main influencing factors are denaturing conditions induced by high temperatures, interfaces and/or high pressure. At the same time, high stress (shearing, high pressure) and decreasing aW values (drying) also lead to fragmentation of the aggregate. Thus, amyloid aggregates in biotechnological processes can grow unintentionally and lead to unwanted deposits. On the other hand, functional amyloid aggregates can be degraded uncontrollably during processing, whereby their size profile and thus functionality is subject to a certain uncertainty. For process control it is therefore necessary to understand the stability and aggregation behaviour of amyloid BLG aggregates as well as the constructive and destructive forces acting on amyloid structures in biotechnological processes. Based on BLG's self-association process in a homogeneous solution, simplified models will be used to simulate the process from dissolving the BLG to drying. Different morphologies of amyloid aggregates from BLG (fibrils, worm-like, spherical) will be investigated to gain an understanding of their composition, formation and stability. A particular focus is the analysis of the effects of physical and chemical modifications that are relevant in the process chain (e.g. modified interfaces and shear as well as the influence of protein oxidation). The significance of individual amino acid sequences for self-association is to be understood experimentally through targeted mutations of amyloidogenic segments and structure-stabilizing disulphide bridges of BLG. Experimental results will be coupled with numerical simulation in order to gain mechanistical insights. Another focus is the investigation of destabilizing and stabilizing forces during drying and film formation of different amyloid aggregates. In particular, modified interfaces (ice/air), pH changes and concentration of remaining salts are considered relevant. Therefore, the influence on the drying and film formation by various drying processes shall be analyzed. Variances in drying speed and stabilizing additives (cryopreservatives, plasticizers) are relevant parameters that influence amyloid structures from the mesoscale (amyloid aggregate) to the macroscale range (alignment of the amyloid aggregates in the film).

淀粉样蛋白聚集体在自然界中普遍存在，其特征在于堆叠的β-折叠构象。可以特异性地产生来自乳清蛋白β-乳球蛋白（BLG）的淀粉样蛋白聚集体，以利用其改变的物理化学性质作为功能性物质。主要影响因素是高温、界面和/或高压引起的变性条件。同时，高应力（剪切、高压）和aW值降低（干燥）也会导致骨料破碎。因此，生物技术过程中的淀粉样蛋白聚集体可能无意中生长并导致不需要的沉积物。另一方面，功能性淀粉样蛋白聚集体在加工过程中可能不受控制地降解，由此它们的尺寸分布和功能性受到一定的不确定性的影响。因此，对于过程控制，有必要了解淀粉样蛋白BLG聚集体的稳定性和聚集行为，以及在生物技术过程中作用于淀粉样蛋白结构的建设性和破坏性力量。基于BLG在均相溶液中的自缔合过程，采用简化模型模拟BLG从溶解到干燥的过程。将研究来自BLG的淀粉样蛋白聚集体的不同形态（原纤维、蠕虫状、球形），以了解其组成、形成和稳定性。特别关注的是分析与工艺链相关的物理和化学修饰的影响（例如修饰的界面和剪切以及蛋白质氧化的影响）。单个氨基酸序列对自缔合的意义将通过BLG的淀粉样蛋白生成区段和结构稳定二硫桥的靶向突变来实验性地理解。实验结果将与数值模拟相结合，以获得力学见解。另一个重点是研究不同淀粉样蛋白聚集体在干燥和成膜过程中的不稳定力和稳定力。特别是，修改界面（冰/空气），pH值的变化和剩余的盐的浓度被认为是相关的。因此，应分析各种干燥工艺对干燥成膜的影响。干燥速度和稳定添加剂（冷冻保存剂、增塑剂）的差异是影响从中尺度（淀粉样蛋白聚集体）到宏观尺度范围（膜中淀粉样蛋白聚集体的排列）的淀粉样蛋白结构的相关参数。