The mechanism of a multi-chaperone system for promoting protein disaggregation

多伴侣系统促进蛋白质解聚的机制

• 批准号: BB/G01468X/1
• 负责人: Steven Burston
• 金额: $ 38.76万
• 依托单位: University of Bristol
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FG01468X%2F1
• 关键词: mechanism; multi; chaperone; system; promoting

Proteins are the work-horses of the cell performing or catalysing many of the processes that are essential for life. In order to perform their appropriate function proteins, which are composed of a linear chain of amino acids, must fold up into the correct three-dimensional structure in the correct place within the cell, or be targeted for destruction when damaged. To achieve this a set of proteins have evolved, known as molecular chaperones, whose function is essentially one of protein quality control, ensuring proteins fold correctly or are unfolded and targeted for degradation. One particularly acute problem is when the cell is exposed to harsh environmental conditions, such as heat, cold or chemical insult. This causes proteins to misfold and self-associate to form insoluble aggregates. These aggregates can cause cell-death and in some cases disease e.g. CJD, Alzheimer's disease. The protein to be studied in this project, ClpB, is a bacterial ATP-driven motor protein (part of the so-called AAA ATPase family) which is able to rescue proteins which have previously aggregated, thus helping the cell to recover. It adopts a ring structure and rescues proteins by translocating them through its central pore in a process dependent on the energy provided by ATP turnover. The mechanism is also analogous to that seen in similar AAA ATPase proteins which are involved in a diverse set of cellular functions. The aims of the proposed work is to investigate exactly how the energy derived from ATP is coupled to protein translocation through the ClpB protein complex. This involves measuring the nucleotide binding and hydrolysis characteristics in the two ATP binding sites on each polypeptide and evaluating how these two sites communicate with each other. The kinetics of the structural changes in the protein induced by the binding and hydrolysis of ATP, as well as those of the protein substrate being translocated will determined and compared. We are also going to examine the aggregation and amyloidogenesis processes at the level of single molecules (or single particles) to determine exactly which aggregates can be dissolved by molecular chaperones, and exactly how this is achieved.

蛋白质是细胞的工作马匹，执行或催化生命所必需的许多过程。蛋白质由一条线性氨基酸链组成，为了执行其适当的功能，必须在细胞内的正确位置折叠成正确的三维结构，或者在受损时成为破坏的目标。为了实现这一点，进化出了一系列蛋白质，称为分子伴侣，其功能本质上是蛋白质质量控制之一，确保蛋白质正确折叠或展开并针对降解。一个特别严重的问题是当细胞暴露在恶劣的环境条件下，如热、冷或化学侮辱。这会导致蛋白质错误折叠和自我结合，形成不可溶的聚集体。这些聚集体可以导致细胞死亡，在某些情况下还会导致CJD、阿尔茨海默病等疾病。这个项目中要研究的蛋白质ClpB是一种细菌ATP驱动的马达蛋白(所谓的AAA ATPase家族的一部分)，它能够挽救先前聚集的蛋白质，从而帮助细胞恢复。它采用环形结构，通过中央毛孔转移蛋白质来拯救蛋白质，这一过程依赖于ATP周转提供的能量。这种机制也类似于类似的AAA ATPase蛋白，它们参与了一系列不同的细胞功能。这项拟议工作的目的是确切地研究来自ATP的能量是如何通过ClpB蛋白质复合体耦合到蛋白质转运的。这包括测量每个多肽上两个ATP结合位点的核苷酸结合和水解特性，并评估这两个位点如何相互通信。将测定和比较由ATP结合和水解引起的蛋白质结构变化以及蛋白质底物移位引起的结构变化的动力学。我们还将在单分子(或单颗粒)的水平上研究聚集和淀粉样蛋白的形成过程，以准确地确定哪些聚集体可以被分子伴侣溶解，以及这是如何实现的。