Distinct growth regimes of α-synuclein amyloid elongation.
Distinct growth regimes of α-synuclein amyloid elongation.
复制标题
α-突触核蛋白淀粉样蛋白伸长的独特生长机制。
DOI：
10.1016/j.bpj.2023.05.009
复制
发表时间：
2023
影响因子：
3.4
通讯作者：
Wittung-Stafshede,Pernilla
中科院分区：
文献类型：
--
作者：
Horvath,Istvan;Welte,Hannah;Schmit,JeremyD;Kovermann,Michael;Wittung-Stafshede,Pernilla
将淀粉样蛋白种子添加到易于聚集的单体中允许淀粉样蛋白纤维生长（伸长），而省略缓慢的成核。在这里，我们结合联合收割机硫磺素T荧光（探测淀粉样蛋白的形成）和溶液状态NMR光谱（探测单体的消失），以评估淀粉样蛋白，α-突触核蛋白的伸长动力学，其中聚集与帕金森氏病。我们发现，这两种光谱检测方法给出了类似的动力学结果，这可以通过应用双指数衰减函数来拟合。当通过数学建模分析两相行为的起源时，平行路径以及走走停停行为被排除作为可能的解释。相反，由以前的理论支持，实验伸长数据揭示不同的动力学制度，取决于瞬时单体浓度。在低单体浓度下（接近实验结束时），淀粉样蛋白生长受到构象变化的限制，导致β链对齐。在较高的单体浓度下（实验的初始时间点），通过掺入未成功完成构象搜索的单体，生长迅速发生。在高单体浓度的快速无序伸长制度的存在下同意粗粒度的模拟和理论，但还没有被检测到实验之前。我们的结果可能与观察到的广泛的淀粉样折叠有关。
Addition of amyloid seeds to aggregation-prone monomers allows for amyloid fiber growth (elongation) omitting slow nucleation. We here combine Thioflavin T fluorescence (probing formation of amyloids) and solution-state NMR spectroscopy (probing disappearance of monomers) to assess elongation kinetics of the amyloidogenic protein, α-synuclein, for which aggregation is linked to Parkinson's disease. We found that both spectroscopic detection methods give similar kinetic results, which can be fitted by applying double exponential decay functions. When the origin of the two-phase behavior was analyzed by mathematical modeling, parallel paths as well as stop-and-go behavior were excluded as possible explanations. Instead, supported by previous theory, the experimental elongation data reveal distinct kinetic regimes that depend on instantaneous monomer concentration. At low monomer concentrations (toward end of experiments), amyloid growth is limited by conformational changes resulting in β-strand alignments. At the higher monomer concentrations (initial time points of experiments), growth occurs rapidly by incorporating monomers that have not successfully completed the conformational search. The presence of a fast disordered elongation regime at high monomer concentrations agrees with coarse-grained simulations and theory but has not been detected experimentally before. Our results may be related to the wide range of amyloid folds observed.