Structural and Biophysical Properties of Oligermeric SOD1

由于铜锌超氧化物歧化酶(SO01)突变与家族性肌萎缩侧索硬化症(FALS)之间的联系是 大约10年前首次被描述，世界各地的实验室试图了解 突变使SOD1蛋白对运动神经元产生毒性。越来越多的证据表明，这种有毒物质 来自突变的SOD1蛋白组装成更高顺序结构(可溶低聚物)的能力 和不可溶的聚集体)，以某种方式干扰神经元细胞机制。利用这口井 建立了单晶X射线衍射仪，我们最近观察到了五个不同的fals突变体SOD1 蛋白质可以形成“淀粉样”纤维，这在某种程度上让人想起在其他 神经退行性疾病，如阿尔茨海默氏症和帕金森氏症。致病的SOD1蛋白 能够自我关联，但正常的、未突变的SOD1蛋白不能。这篇文章中概述的实验 项目旨在探索这些异常的致病SOD1-SOD1相互作用，并帮助回答 以下问题：1)我们在X射线研究中观察到的自关联模式是如何 致病SO01蛋白聚集在活细胞中？2)哪些结构元素是毒性的决定因素 在致病SOD1中？3)致病SOD1的氧化修饰在聚集中起作用吗？4) 致病SOD1的解离(单体)形式可能导致聚集吗？回答 这些问题是设计旨在抑制聚集的治疗剂所必需的 进程。

Since the link between mutations in copper-zinc superoxide dismutase (SO01) and familial ALS (FALS) was first described approximately 10 years ago, laboratories worldwide have sought to understand how the mutations render the SOD1 protein toxic to motor neurons. Evidence is accumulating that this toxic property comes from the ability of the mutant SOD1 proteins to assemble into higher order structures (soluble oligomers and insoluble aggregates) that somehow interfere with the neuronal cellular machinery. Using the well established tools of single crystal X-ray diffraction, we recently observed that five different FALS mutant SOD1 proteins can form "amyloid-like" fibers that are somewhat reminiscent of the types of fibers seen in other neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. The pathogenic SOD1 proteins are able to self-associate but the normal, unmutated SOD1 proteins cannot. The experiments outlined in this project are designed to probe these abnormal pathogenic SOD1-SOD1 interactions and to help answer the following questions: 1) Is the mode of self-association we observe in X-ray studies the basis for how the pathogenic SO01 proteins aggregate in living cells? 2) What structural elements are determinants of toxicity in pathogenic SOD1? 3) Does oxidative modification of pathogenic SOD1 play a role in aggregation? 4) Could a dissociated (monomeric) form of pathogenic SOD1 be responsible for aggregation? Answers to questions such as these are required for the design of therapeutic agents aimed inhibiting the aggregation process.