低盐和高盐环境下α-Synuclein构象的^(19)F NMR研究

Salt Content-Dependent Conformational Changes of α-Synuclein Studied by ^(19)F NMR

天然无结构的突触核蛋白α-synuclein(AS)与帕金森病密切相关.最近研究发现低盐与高盐环境下AS纤维化的速率不同,所形成的纤维结构,细胞毒性与传染性也不一样,但盐效应对AS聚集及纤维结构影响的具体分子机制仍不清楚.该文通过生物标记方法在AS的酪氨酸芳香环上引入19F标记的探针,利用19F核磁共振(NMR)方法研究了低盐与高盐环境下AS的构象差异,发现19F NMR对天然无结构蛋白构象变化非常灵敏,AS在低盐中的构象比较紧密,而在高盐下比较松散,这种在溶液中起始的构象差异可能是导致最终AS纤维结构与生物效应不同的原因.

a-synuclein is an intrinsically disordered protein, and is implicated in Parkinson＇s disease. Previous studies have found that the aggregation rate, fibril structure, propagation and cytotoxicity of α-synuclein change markedly with salt concentration. However, the underlying molecular mechanisms remain poorly understood. In this work, 3-fluorotyrosine （3FY） labeling was introduced into α-synuclein, and the conformational changes of the protein under different salt concentrations were studied by 19F NMR. It was found that the protein was more compact at low salt concentration than at high salt concentration; and such conformational changes may account for the fibril morphology diversity and physiological effects of the protein at different salt concentrations. It was also concluded that 19F NMR is a sensitive technique to measure conformational change of intrinsically disordered protein.