Molecular mechanisms of transthyretin amyloidosis

许多使人类衰弱的疾病与细胞外的错误折叠和聚集有关 形成富含β-Sheet的纤维状沉积物。有相当多的证据 这一过程是由本地结构的局部展开来形成易于聚集的 淀粉样变性中间体。然后，聚集通过成核-增长或下坡进行 聚合机理。尽管它们在淀粉样蛋白发生中起关键作用，但影响动力学 在聚集和折叠通路之间进行划分，对其结构知之甚少 淀粉样变性中间体，因为它们有很强的聚集倾向。世界银行的目标是 目前的建议是应用最先进的核磁共振方法来阐明基本分子 转甲状腺素淀粉样变性的相关事件。转甲状腺素淀粉样变性与许多 神经退行性疾病和心肌病。反式甲状腺激素的错误折叠和聚集 导致周围神经和心脏中的纤维沉积。野生型蛋白的沉积是年龄 相关，而家族性疾病与基因突变有关，这些突变破坏了 第四系和/或三级结构起得早。拟议的研究将提供新的 对野生型转甲状腺素聚集的基本分子机制的洞察 通过哪些家族突变破坏了天然的转甲状腺素四聚体的稳定性，并推动了 聚合级联。实时~(19)F-核磁共振将被用来绘制动力学聚集图景 野生型和致病变异型反式甲状腺激素，表征和量化 聚集在聚集途径上的中间产物，并检查抑制机制 由小分子和多肽组成。多维核磁共振实验将被用来阐明 促进四聚体解离的交替构象状态的结构和动力学， 以及在聚集途径上形成的细胞毒性单体和寡聚中间体， 促进聚集和原纤维生长。这项研究将促进我们对 启动四聚体解离并促进进入和 两个野生型人类都沿着导致淀粉样蛋白形成的聚集级联进行 转甲状腺激素和致病变异体。

Many debilitating human diseases are associated with the extracellular misfolding and aggregation of globular proteins to form fibrillar deposits that are rich in β-sheet. There is considerable evidence that the process is initiated by local unfolding of the native structure to form aggregation-prone amyloidogenic intermediates. Aggregation then proceeds via nucleation-growth or downhill polymerization mechanisms. Despite their key role in amyloidogenesis, influencing the kinetic partitioning between aggregation and refolding pathways, very little is known about the structure of amyloidogenic intermediates because of their strong propensity to aggregate. The goals of the present proposal are to apply state-of-the-art NMR methods to elucidate the fundamental molecular events involved in transthyretin amyloidosis. Transthyretin amyloidosis is associated with numerous neurodegenerative diseases and cardiomyopathies. Misfolding and aggregation of transthyretin leads to fibrous deposits in the peripheral nerves and heart. Deposition of wild type protein is age related, whereas the familial diseases associated with genetic mutations that destabilize the quaternary and/or tertiary structure are early onset. The proposed research will provide novel insights into the fundamental molecular mechanisms by which wild type transthyretin aggregates and by which familial mutations destabilize the native transthyretin tetramer and drive the aggregation cascade. Real-time 19F NMR will be used to map the kinetic aggregation landscape of wild type and pathogenic variant transthyretin, characterize and quantify the population of intermediates that accumulate on the aggregation pathway, and examine mechanisms of inhibition by small molecules and peptides. Multidimensional NMR experiments will be utilized to elucidate the structure and dynamics of an alternate conformational state that promotes tetramer dissociation, and of cytotoxic monomeric and oligomeric intermediates, formed on the aggregation pathway, that promote aggregation and fibril growth. This research will advance our understanding of the underlying molecular events that initiate tetramer dissociation and promote entry into and progression down the aggregation cascade that leads to amyloid formation by both wild type human transthyretin and pathogenic variants.