Quantification of α-synuclein binding to lipid vesicles using fluorescence correlation spectroscopy
Quantification of α-synuclein binding to lipid vesicles using fluorescence correlation spectroscopy
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DOI：
10.1529/biophysj.105.079251
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发表时间：
2006-06-01
影响因子：
3.4
通讯作者：
Eliezer, David
中科院分区：
文献类型：
--
作者：
Rhoades, Elizabeth;Ramlall, Trudy F.;Eliezer, David
α-突触核蛋白 (α S) 是一种可溶性突触蛋白，是不溶性纤维状路易体沉积物的主要蛋白质成分，而路易体沉积物是帕金森病的标志。 aS 与突触小泡的相互作用被认为对其正常功能及其在帕金森病中的病理作用至关重要。我们展示了荧光相关光谱作为快速定量分析 α S 与各种脂质成分的大单层囊泡结合的工具的用途。我们发现 aS 优先与含有酸性脂质的囊泡结合，并且可以通过增加溶液中 NaCl 的浓度来阻断这种相互作用。负电荷并不是决定结合的唯一因素，因为我们清楚地观察到与完全由两性离子脂质组成的囊泡的结合。此外，我们发现头基体积较小，与脂质的结合增强。量。结合不同脂质成分所需的蛋白质与脂质比率的阳离子，结合文献中的其他数据，得出结合每个单独的 aS 分子所需的脂质分子数量的上限估计值。我们的结果表明，荧光相关光谱为 α S-脂质相互作用的定量表征提供了强大的工具。
alpha-Synuclein (alpha S) is a soluble synaptic protein that is the major proteinaceous component of insoluble fibrillar Lewy body deposits that are the hallmark of Parkinson's disease. The interaction of aS with synaptic vesicles is thought to be critical both to its normal function as well as to its pathological role in Parkinson's disease. We demonstrate the use of fluorescence correlation spectroscopy as a tool for rapid and quantitative analysis of the binding of alpha S to large unilamellar vesicles of various lipid compositions. We find that aS binds preferentially to vesicles containing acidic lipids, and that this interaction can be blocked by increasing the concentration of NaCl in solution. Negative charge is not the only factor determining binding, as we clearly observe binding to vesicles composed entirely of zwitterionic lipids. Additionally, we find enhanced binding to lipids with less bulky headgroups. Quanti. cation of the protein-to-lipid ratio required for binding to different lipid compositions, combined with other data in the literature, yields an upper bound estimate for the number of lipid molecules required to bind each individual molecule of aS. Our results demonstrate that fluorescence correlation spectroscopy provides a powerful tool for the quantitative characterization of alpha S-lipid interactions.