Interplay of α-synuclein binding and conformational switching probed by single-molecule fluorescence
Interplay of α-synuclein binding and conformational switching probed by single-molecule fluorescence
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DOI：
10.1073/pnas.0809232106
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发表时间：
2009-04-07
影响因子：
11.1
通讯作者：
Deniz, Ashok A.
中科院分区：
文献类型：
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作者：
Ferreon, Allan Chris M.;Gambin, Yann;Deniz, Ashok A.
我们研究了α-突触核蛋白的耦合结合和折叠，这是一种与帕金森病相关的内在无序蛋白质。使用单分子荧光共振能量转移和相关方法，我们直接探测蛋白质膜缔合，结构分布和动力学。结果揭示了一个复杂的能量景观上的结合的α-突触核蛋白的两亲性小分子或膜样的合作伙伴调制天然未折叠状态和多个α-螺旋结构之间的构象转变。α-突触核蛋白构象不是连续可调的，而是分成2个主要类别的折叠景观结构最小值。断裂和延伸的螺旋结构之间的切换可以通过改变结合伴侣的浓度或通过改变由脂质模拟SDS组成的胶束或双层所呈现的结合表面的曲率来触发。单分子实验与脂质囊泡的各种组合物表明，低分数的带负电荷的脂质，类似于在生物膜中发现的，是足以驱动α-突触核蛋白的结合和折叠，导致在这里诱导的延伸的螺旋结构。总体而言，我们的研究结果表明，2折叠结构的α-突触核蛋白的氨基酸序列preen编码，并可调的小分子超分子状态和不同的膜性能，提出了新的控制元件的生物和淀粉样蛋白的α-突触核蛋白的调节。
We studied the coupled binding and folding of alpha-synuclein, an intrinsically disordered protein linked with Parkinson's disease. Using single-molecule fluorescence resonance energy transfer and correlation methods, we directly probed protein membrane association, structural distributions, and dynamics. Results revealed an intricate energy landscape on which binding of alpha-synuclein to amphiphilic small molecules or membrane-like partners modulates conformational transitions between a natively unfolded state and multiple alpha-helical structures. alpha-Synuclein conformation is not continuously tunable, but instead partitions into 2 main classes of folding landscape structural minima. The switch between a broken and an extended helical structure can be triggered by changing the concentration of binding partners or by varying the curvature of the binding surfaces presented by micelles or bilayers composed of the lipid-mimetic SDS. Single-molecule experiments with lipid vesicles of various composition showed that a low fraction of negatively charged lipids, similar to that found in biological membranes, was sufficient to drive alpha-synuclein binding and folding, resulting here in the induction of an extended helical structure. Overall, our results imply that the 2 folded structures are preen-coded by the alpha-synuclein amino acid sequence, and are tunable by small-molecule supramolecular states and differing membrane properties, suggesting novel control elements for biological and amyloid regulation of alpha-synuclein.