Effects of Parkinson's disease-linked mutations on the structure of lipid-associated α-synuclein
Effects of Parkinson's disease-linked mutations on the structure of lipid-associated α-synuclein
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DOI：
10.1021/bi036135
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发表时间：
2004-04-27
期刊：
影响因子：
2.9
通讯作者：
Eliezer, D
中科院分区：
文献类型：
--
作者：
Bussell, R;Eliezer, D
α-突触核蛋白（α S）是一种功能未知的脂质结合突触蛋白，其在神经元内路易体沉积物中以聚集的淀粉样原纤维形式存在，所述路易体沉积物是帕金森病（PD）的定义特征。虽然在溶液中游离时本质上是非结构化的，但aS采用与脂质膜或膜模拟洗涤剂胶束相关联的高度螺旋构象。在aS基因的两个突变已被链接到早发性常染色体显性遗传形式的PD，并已被证明会影响蛋白质在体外的聚集动力学。我们已经使用了高分辨率NMR光谱，圆二色性，和有限的蛋白水解，以调查这些PD连锁突变的螺旋结构上所采用的aS在脂质或洗涤剂胶束结合的形式的影响。我们发现，无论是A53 T，也不是A30 P突变有一个显着的折叠蛋白质的结构上的影响，虽然A30 P突变可能会导致轻微的扰动，在螺旋结构周围的突变位点。A30 P，但不是A53 T，突变似乎也降低了蛋白质对脂质表面的亲和力，可能是通过扰乱游离蛋白质的新生螺旋结构。这些结果的作用，即在PD的潜在影响进行了讨论。
alpha-Synuclein (alphaS) is a lipid-binding synaptic protein of unknown function that is found in an aggregated amyloid fibril form in the intraneuronal Lewy body deposits that are a defining characteristic of Parkinson's disease (PD). Although intrinsically unstructured when free in solution, aS adopts a highly helical conformation in association with lipid membranes or membrane mimetic detergent micelles. Two mutations in the aS gene have been linked to early onset autosomal dominant hereditary forms of PD, and have been shown to affect the aggregation kinetics of the protein in vitro. We have used high-resolution NMR spectroscopy, circular dichroism, and limited proteolysis to investigate the effects of these PD-linked mutations on the helical structure adopted by aS in the lipid or detergent micelle-bound form. We show that neither the A53T nor the A30P mutation has a significant effect on the structure of the folded protein, although the A30P mutation may cause a minor perturbation in the helical structure around the site of the mutation. The A30P, but not the A53T, mutation also appears to decrease the affinity of the protein for lipid surfaces, possibly by perturbing the nascent helical structure of the free protein. The potential implications of these results for the role of aS in PD are discussed.