Structural characterization of intrinsically disordered proteins (IDPs) has been a major challenge in the field of protein science due to limited capabilities to obtain full-length high-resolution structures. Native ESI-MS with top-down MS was utilized to obtain structural features of protein-ligand binding for the Parkinson’s disease-related protein, α-synuclein (αSyn), which is natively unstructured. Binding of heavy metals has been implicated in the accelerated formation of αSyn aggregation. Using high-resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry, native top-down MS with various fragmentation methods, including electron capture dissociation (ECD), collisional activated dissociation (CAD), and multistage tandem MS (MS³), deduced the binding sites of cobalt and manganese to the C-terminal region of the protein. Ion mobility MS (IM-MS) revealed a collapse toward compacted states of αSyn upon metal binding. The combination of native top-down MS and IM-MS provides structural information of protein-ligand interactions for intrinsically disordered proteins.

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由于获得全长高分辨率结构的能力有限，固有无序蛋白（IDP）的结构表征一直是蛋白科学领域的主要挑战。利用具有自上而下的MS的天然ESI-MS获得与自然无关的帕金森氏病相关蛋白α-突触核蛋白（αSyn）的蛋白质-配体结合的结构特征。重金属的结合与αSyn聚集体的加速形成有关。使用高分辨率傅里叶变换离子回旋共振（FT-ICR）质谱技术，采用各种碎片化方法（包括电子俘获解离（ECD），碰撞活化解离（CAD）和多级串联质谱（MS ³））进行自然自上而下的MS），推导了钴和锰与蛋白质C末端区域的结合位点。离子迁移率质谱（IM-MS）显示，金属结合后，αSyn的压缩状态崩溃。天然的自上而下MS和IM-MS的结合提供了固有紊乱蛋白质的蛋白质-配体相互作用的结构信息。

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