University of the Chinese Academy of Sciences, Beijing 100039, China.
Anal Chem. 2016 Dec 6;88(23):11720-11726. doi: 10.1021/acs.analchem.6b03359. Epub 2016 Nov 14.
Misfolding and aggregation of Cu, Zn superoxide dismutase (SOD1) is implicated in the etiology of amyotrophic lateral sclerosis (ALS). The use of small molecules may stabilize the spatial structure of SOD1 dimer, thus, preventing its dissociation and aggregation. In this study, "native" mass spectrometry (MS) was used to study the noncovalent interactions between SOD1 and flavonoid compounds. MS experiments were performed on a quadruple time-of-flight (Q-ToF) mass spectrometer with an electrospray ionization (ESI) source and T-wave ion mobility. ESI-MS was used to detect the SOD1-flavonoid complexes and compare their relative binding strengths. The complement of ion mobility separation allowed comparison in the binding affinities between flavonoid isomers and provided information on the conformational changes. Molecular docking together with molecular dynamics simulations and MM/PBSA methods were applied to gain insights into the binding modes and free energies of SOD1-flavonoid complexes at the molecule level. Among all the flavonoids investigated, flavonoid glycosides preferentially bind to SOD1 than their aglycone counterparts. Naringin, one of the compounds that has the strongest binding affinity to SOD1, was subjected to further characterization. Experiment results show that the binding of naringin can stabilize SOD1 dimer and inhibit the aggregation of SOD1. Molecular simulation results suggest that naringin could reduce the dissociation of SOD1 dimers through direct interaction with the dimer interface. This developed analytical strategy could also be applied to study the interactions between SOD1 and other drug-like molecules, which may have the effect to reduce the aggregation.
错误折叠和聚集的铜锌超氧化物歧化酶（SOD1）与肌萎缩侧索硬化症（ALS）的病因有关。使用小分子可能会稳定 SOD1 二聚体的空间结构，从而防止其解离和聚集。在这项研究中，“天然”质谱（MS）被用于研究 SOD1 与类黄酮化合物之间的非共价相互作用。MS 实验在带有电喷雾电离（ESI）源和 T 波离子淌度的四重飞行时间（Q-ToF）质谱仪上进行。ESI-MS 用于检测 SOD1-类黄酮复合物，并比较它们的相对结合强度。离子淌度分离的补充允许比较类黄酮异构体之间的结合亲和力，并提供有关构象变化的信息。分子对接以及分子动力学模拟和 MM/PBSA 方法被应用于深入了解 SOD1-类黄酮复合物在分子水平上的结合模式和自由能。在所研究的所有类黄酮中，类黄酮糖苷比它们的糖苷配基更优先与 SOD1 结合。柚皮苷是与 SOD1 结合亲和力最强的化合物之一，对其进行了进一步表征。实验结果表明，柚皮苷的结合可以稳定 SOD1 二聚体并抑制 SOD1 的聚集。分子模拟结果表明，柚皮苷可以通过与二聚体界面的直接相互作用减少 SOD1 二聚体的解离。这种开发的分析策略也可以应用于研究 SOD1 与其他类似药物的分子之间的相互作用，这可能有助于减少聚集。
