Development of Sensor System to Analyse and Diagnose the abnormality of Protein Conformation

本研究的目的是建立应激条件下结构异常蛋白质与生物膜动态相互作用的分析方法，特别是关注局部疏水性或结构波动。以淀粉样β蛋白(Aβ)为例，对各种蛋白质的结构异常进行了分析和表征。在过去的两年中，我们开发了蛋白质结构异常传感系统，建立了应激条件下蛋白质结构异常的数据库。2005年，在前人研究成果的基础上，研究了判断蛋白质结构异常的方法。在该数据库的基础上，明确了在应激条件下蛋白质在脂质体表面的构象异常再生的适宜条件(应激条件和脂类组成)，结果表明，膜…的微域结构更多的表面在蛋白质/多肽的构象异常中起着重要作用。此外，还发现通过控制胁迫条件(加热、pH和离子强度)和膜组分(醇、脂肪酸、胆固醇)的修饰，可以适当地控制微域结构。特别是在胆固醇修饰的脂质体中，发现在金属离子铜的存在下，膜上的Aβ与膜的相互作用是受控制的。A-β-Cu络合物还诱导了类金属酶功能(胆固醇和多巴胺的氧化)。Aβ在膜上的上述势能作用与Aβ主链在脂质体内疏水纳米环境中氢键的稳定性密切相关。通过在膜芯片上排列各种应激脂质体，我们发现可以评估蛋白质的结构异常。总结了上述关于蛋白质结构异常的发现，以及Aβ在生物膜上形成淀粉样原纤维的生理作用。较少

The goal of this research project is to establish the analytical method of dynamic interaction between the structurally abnormal protein and biomembrane under the stress condition, especially focusing on the local hydrophobicity (LH) or structural fluctuation. Amyloid beta peptide (Aβ) has been employed as a case study of the system to analyze and characterize the structural abnormality of various proteins. During past two years, we have developed the sensor system of the structural abnormality of protein and have established the database on the protein abnormality under the stress condition. In 2005, the method to judge the structural abnormality of proteins has been investigated based on the previous findings. Based on the database, the suitable conditions (stress condition and lipid compositions) to regenerate the conformational abnormality of protein under the stress condition on the liposome surface have been clarified, resulting that the microdomain-like structure of the membrane … More surface was found to play an important role on the conformational abnormality of proteins/peptides. It was furthermore found that the microdomain-like structure could suitably be controlled by the control of the stress conditions (heating, pH and ionic strength) and the modification of membrane components (alcohols, fatty acids, cholesterol). Especially in the case of the cholesterol-modified liposome, the Aβ-membrane interaction was found to be controlled on the membrane in the presence of metal ion, Cu. The Aβ-Cu complex furthermore induced the metalloenzyme-like function(oxidation of cholesterol and dopamine). The above potential functions of Aβ on the membrane was found to be closely related to the stability of hydrogen-bond of the main chain of the Aβ in the hydrophobic nano environment inside the liposome membrane. By using the membrane chip arraying various stressed-liposomes on the chip, it was found that we could assess the structural abnormality of the protein. The above findings on the structural abnormality of protein were summarized together with the physiological role of amyloid fibril formation of Aβ on the biomembrane. Less