Saraiva Marco A
Centro de Química Estrutural, Institute of Molecular Sciences, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, Campus Alameda, 1049-001, Lisbon, Portugal.
Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal.
Eur Biophys J. 2025 May;54(3-4):109-122. doi: 10.1007/s00249-025-01737-z. Epub 2025 Mar 3.
Currently, there is an increased interest in identifying the characteristics of amyloid aggregates in the initial stages of amyloid formation. The aggregation mechanism of the α-synuclein (Syn) amyloid protein, which has been extensively studied, is still not fully understood. I show that with conventional dynamic light scattering (DLS) technique, the measurements of the dimensions of Syn amyloid precursor forms can be done early in the protein incubation. Additionally, the early aggregation of the Syn protein was initially studied by analyzing autocorrelation functions from fit distributions up to 10 µs in the initial DLS measurements, specifically within the first 21 min. Investigation was conducted on the variation in the pH of the Syn solution throughout time. Based on DLS data, large Syn aggregated species formed from the monomer protein species. Afterward, I generated the autocorrelation functions based on the original DLS data, extending the fit distributions up to 10 µs and noticed the existence of elongated Syn amyloid precursor forms in the protein solutions. Because the length of the elongated Syn amyloid precursor forms closely matches the wavelength of the incident light, the combination of translational diffusion Dt and rotational diffusion Dr in the decay rates enabled the measurement of their geometric dimensions through DLS. The improved precision of the fitted distributions I offered resulted in a new interpretation for the Syn protein aggregation in the initial stages. Overall, the methodology used in this study could be an effective strategy for examining how Syn amyloid precursor forms develop over time.
目前，人们对确定淀粉样蛋白形成初始阶段淀粉样聚集体的特征越来越感兴趣。已被广泛研究的α-突触核蛋白（Syn）淀粉样蛋白的聚集机制仍未完全了解。我表明，使用传统的动态光散射（DLS）技术，可以在蛋白质孵育早期对Syn淀粉样前体形式的尺寸进行测量。此外，通过分析初始DLS测量中长达10微秒的拟合分布的自相关函数，特别是在最初的21分钟内，对Syn蛋白的早期聚集进行了初步研究。对Syn溶液在整个时间段内的pH变化进行了研究。基于DLS数据，单体蛋白物种形成了大型的Syn聚集物种。之后，我根据原始DLS数据生成自相关函数，将拟合分布扩展到10微秒，并注意到蛋白质溶液中存在拉长的Syn淀粉样前体形式。由于拉长的Syn淀粉样前体形式的长度与入射光的波长密切匹配，衰减率中的平动扩散Dt和转动扩散Dr的组合使得能够通过DLS测量它们的几何尺寸。我提供的拟合分布的更高精度为Syn蛋白在初始阶段的聚集带来了新的解释。总体而言，本研究中使用的方法可能是一种有效的策略，用于研究Syn淀粉样前体形式如何随时间发展。
