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

本课题旨在建立应力条件下结构异常蛋白与生物膜动态相互作用的分析方法，尤其关注局部疏水性（LH）或结构波动。以淀粉样β肽（a β）为例，分析和表征了各种蛋白质的结构异常。在过去的两年中，我们开发了蛋白质结构异常的传感器系统，并建立了应激条件下蛋白质异常的数据库。2005年，在前人研究的基础上，研究了判断蛋白质结构异常的方法。在此基础上，明确了在应激条件下脂质体表面再生蛋白质构象异常的适宜条件（应激条件和脂质组成），发现膜的微结构域样结构对蛋白质/多肽的构象异常起重要作用。此外，通过控制应力条件（加热、pH和离子强度）和膜组分（醇类、脂肪酸、胆固醇）的修饰可以适当地控制微畴结构。特别是在胆固醇修饰脂质体中，发现在金属离子Cu存在的情况下，a β与膜的相互作用在膜上受到控制。a - β- cu复合物进一步诱导类似金属酶的功能（胆固醇和多巴胺的氧化）。研究发现，Aβ在膜上的上述潜在功能与脂质体膜内疏水纳米环境中Aβ主链氢键的稳定性密切相关。通过在薄膜芯片上排列各种应力脂质体，我们发现我们可以评估蛋白质的结构异常。以上关于蛋白结构异常的发现，以及Aβ淀粉样纤维形成对生物膜的生理作用进行了综述。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