Interaction of Alpha-Synuclein and Its Mutants with Rigid Lipid Vesicle Mimics of Varying Surface Curvature
Interaction of Alpha-Synuclein and Its Mutants with Rigid Lipid Vesicle Mimics of Varying Surface Curvature
复制标题
DOI：
10.1021/acsnano.0c03420
复制
发表时间：
2020-08-25
期刊：
影响因子：
17.1
通讯作者：
Murphy, Catherine J.
中科院分区：
文献类型：
--
作者：
McClain, Sophia M.;Ojoaw, Adedolapo M.;Murphy, Catherine J.
α -突触核蛋白（α -syn）是一种内在紊乱的神经元蛋白，其异常聚集与帕金森病的发展密切相关。更好地了解α -syn的天然功能及其在神经退行性疾病中的致病作用的努力表明，该蛋白通过采用两亲α -螺旋结构与阴离子脂质囊泡相互作用；然而，α -syn重塑脂质膜的能力使得破译囊泡表面曲率在蛋白质结合行为中的作用变得困难。在这项研究中，合成了十二烷基硫酸钠（SDS）包覆的金纳米颗粒（AuNPs），模拟双层囊泡结构，以便系统地研究α -syn及其两个突变体（A30P和E46K）与具有定义表面曲率的刚性脂质囊泡的结合相互作用。通过加入刚性AuNP核心（类似于10-100 nm）， α -syn重塑囊泡模拟物的能力被去除，它们的表面曲率可以固定。蛋白质组学研究表明，游离α -syn结合到SDS-AuNPs表面后，α -syn的n端变得不易被溶剂接触，而其c端变得更易被溶剂接触。有趣的是，α -syn的非淀粉样β成分（NAC）区域也表现出更高的溶剂亲和性，这表明与刚性囊泡样结构结合的α -syn可能具有更高的聚集倾向，因此具有致病性。此外，发现A30P和E46K突变在模拟物表面采用不同的结合模式。与之前的报道相反，我们观察到WT、A30P和E46K α -syn对各种大小的SDS-AuNPs具有相似的结合亲和力，这表明囊泡可变形性在决定α -syn结合行为方面具有潜在的重要性。
Abnormal aggregation of alpha-synuclein (alpha-syn), an intrinsically disordered neuronal protein, is strongly implicated in the development of Parkinson's disease. Efforts to better understand alpha-syn's native function and its pathogenic role in neurodegeneration have revealed that the protein interacts with anionic lipid vesicles via adoption of an amphipathic alpha-helical structure; however, the ability of alpha-syn to remodel lipid membranes has made it difficult to decipher the role of vesicle surface curvature in protein binding behavior. In this study, sodium dodecyl sulfate (SDS)-coated gold nanoparticles (AuNPs), which mimic bilayer vesicle architecture, were synthesized in order to conduct a systematic investigation into the binding interaction of alpha-syn and two of its mutants (A30P and E46K) with rigid lipid vesicle mimics of defined surface curvature. By incorporating a rigid AuNP core (similar to 10-100 nm), the ability of alpha-syn to remodel the vesicle mimics was removed and their surface curvature could be fixed. Proteomics studies showed that, upon binding of free alpha-syn to the surface of SDS-AuNPs, the N-terminus of alpha-syn became less solvent accessible, whereas its C-terminus became more accessible. Interestingly, alpha-syn's non-amyloid-beta component (NAC) region also exhibited increased solvent accessibility, suggesting that alpha-syn bound to rigid vesicle-like structures could possess heightened aggregation propensity and therefore pathogenicity. Additionally, both the A30P and E46K mutations were found to adopt distinct binding modes on the mimics' surface. In contrast with previous reports, similar binding affinities were observed for WT, A30P, and E46K alpha-syn toward SDS-AuNPs of all sizes, indicating the potential importance of vesicle deformability in determining alpha-syn binding behavior.