De Vleeschouwer Matthias, Pradhan Brajabandhu, Rousseau Frederic, Schymkowitz Joost
Switch Laboratory, VIB Center for Brain and Disease Research, Leuven, Belgium.
Department for Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.
J Pept Sci. 2025 Aug;31(8):e70041. doi: 10.1002/psc.70041.
Medin, a 50-amino acid fragment derived from the protein MFG-E8 (lactadherin), is the most prevalent amyloid found in humans, present in the vasculature of nearly all individuals over the age of 50. Its biological relevance is highlighted by its co-localization with amyloid-β (Aβ) deposits in both Alzheimer's disease patients and transgenic mice models. Notably, Medin promotes amyloid-β aggregation, forming mixed fibrils with Aβ and enhancing its deposition in blood vessels. Here we report a new and efficient strategy to chemically access this compound. Our approach employs a solubilizing linker that not only ensures high solubility but also suppresses aggregation, allowing efficient purification of the product. The linker can be removed without a trace, after which the product behaves identically to wild-type Medin and forms amyloid fibrils. The synthesis route allows opening up a new chemical space, including nonnatural modifications like biotinylation. Together with the control over the aggregation properties, this is a powerful tool for amyloid protein studies.
Medin是一种源自蛋白质MFG-E8(乳粘连蛋白)的由50个氨基酸组成的片段,是人类中最普遍存在的淀粉样蛋白,存在于几乎所有50岁以上个体的脉管系统中。它与阿尔茨海默病患者和转基因小鼠模型中的淀粉样β蛋白(Aβ)沉积物共定位,凸显了其生物学相关性。值得注意的是,Medin促进淀粉样β蛋白聚集,与Aβ形成混合纤维并增强其在血管中的沉积。在此,我们报告一种化学合成该化合物的新的高效策略。我们的方法采用一种增溶连接子,它不仅确保高溶解度,还抑制聚集,从而实现产物的高效纯化。该连接子可以完全去除,之后产物的行为与野生型Medin相同并形成淀粉样纤维。该合成路线能够开拓新的化学空间,包括生物素化等非天然修饰。连同对聚集特性的控制,这是淀粉样蛋白研究的一个强大工具。