In this study, we describe a chemometric data analysis approach to assist in the interpretation of the complex datasets from the analysis of high-molecular mass oligomeric proteins by ion mobility mass spectrometry (IM-MS). The homotetrameric protein transthyretin (TTR) is involved in familial amyloidotic polyneuropathy type I (FAP-I). FAP-I is associated with a specific TTR mutant variant (TTR(Met30)) that can be easily detected analyzing the monomeric forms of the mutant protein. However, the mechanism of protein misfolding and aggregation onset, which could be triggered by structural changes in the native tetrameric protein, remains under investigation. Serum TTR from healthy controls and FAP-I patients was purified under non-denaturing conditions by conventional immunoprecipitation in solution and analyzed by IM-MS. IM-MS allowed separation and characterization of several tetrameric, trimeric and dimeric TTR gas ions due to their differential drift time. After an appropriate data pre-processing, multivariate curve resolution alternating least squares (MCR-ALS) was applied to the complex datasets. A group of seven independent components being characterized by their ion mobility profiles and mass spectra were resolved to explain the observed data variance in control and patient samples. Then, principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were considered for exploration and classification. Only four out of the seven resolved components were enough for an accurate differentiation. Furthermore, the specific TTR ions identified in the mass spectra of these components and the resolved ion mobility profiles provided a straightforward insight into the most relevant oligomeric TTR proteoforms for the disease.

在这项研究中，我们描述了一种化学计量学数据分析方法，可帮助通过离子迁移质谱（IM-MS）对高分子质量寡聚蛋白进行分析来解释复杂的数据集。同型四聚体蛋白甲状腺素蛋白（TTR）参与家族性I型淀粉样变性多发性神经病（FAP-1）。FAP-1与特定的TTR突变体变体（TTR（Met30））相关，通过分析突变体蛋白的单体形式可以很容易地检测到它。然而，可能由天然四聚体蛋白质的结构变化触发的蛋白质错误折叠和聚集开始的机制仍在研究中。通过在溶液中进行常规免疫沉淀，在非变性条件下纯化健康对照组和FAP-1患者的血清TTR，并通过IM-MS进行分析。IM-MS由于其不同的漂移时间而允许分离和表征几种四聚，三聚和二聚TTR气体离子。经过适当的数据预处理后，将多元曲线分辨率交替最小二乘（MCR-ALS）应用于复杂数据集。解析了由其离子迁移谱和质谱表征的一组七个独立组分，以解释对照样品和患者样品中观察到的数据差异。然后，考虑进行主成分分析（PCA）和偏最小二乘判别分析（PLS-DA）进行探索和分类。在七个已解析的组件中，只有四个足以进行精确区分。此外，