The hydrogen/deuterium exchange (HDX) is a reliable method to survey the dynamic behavior of proteins and epitope mapping. Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) is a quantifying tool to assay for HDX in the protein of interest. We combined HDX-MALDI-TOF MS and molecular docking/MD simulation to identify accessible amino acids and analyze their contribution into the structural changes of profilin-1 (PFN-1). The molecular docking/MD simulations are computational tools for enabling the analysis of the type of amino acids that may be involved via HDX identified under the lowest binding energy condition. Glycine to valine amino acid (G117V) substitution mutation is linked to amyotrophic lateral sclerosis (ALS). This mutation is found to be in the actin-binding site of PFN-1 and prevents the dimerization/polymerization of actin and invokes a pathologic toxicity that leads to ALS. In this study, we sought to understand the PFN-1 protein dynamic behavior using purified wild type and mutant PFN-1 proteins. The data obtained from HDX-MALDI-TOF MS for PFN-1WT and PFN-1G117V at various time intervals, from seconds to hours, revealed multiple peaks corresponding to molecular weights from monomers to multimers. PFN-1/Benzaldehyde complexes identified 20 accessible amino acids to HDX that participate in the docking simulation in the surface of WT and mutant PFN-1. Consistent results from HDX-MALDI-TOF MS and docking simulation predict candidate amino acid(s) involved in the dimerization/polymerization of PFNG117V. This information may shed critical light on the structural and conformational changes with details of amino acid epitopes for mutant PFN-1s' dimerization, oligomerization, and aggregation.

中文翻译：

---

用氢/氘交换质谱和生物信息学技术检测导致 ALS 的突变型 profilin-1 的结构和构象变化。

氢/氘交换 (HDX) 是一种可靠的方法来调查蛋白质的动态行为和表位作图。基质辅助激光解吸电离-飞行时间质谱 (MALDI-TOF MS) 是一种量化工具，可用于检测目标蛋白质中的 HDX。我们结合 HDX-MALDI-TOF MS 和分子对接/MD 模拟来识别可接近的氨基酸并分析它们对 profilin-1 (PFN-1) 结构变化的贡献。分子对接/MD 模拟是一种计算工具，用于分析在最低结合能条件下通过 HDX 鉴定的可能涉及的氨基酸类型。甘氨酸到缬氨酸（G117V）取代突变与肌萎缩侧索硬化症（ALS）有关。发现这种突变位于 PFN-1 的肌动蛋白结合位点，并阻止肌动蛋白的二聚化/聚合，并引发导致 ALS 的病理毒性。在这项研究中，我们试图使用纯化的野生型和突变型 PFN-1 蛋白来了解 PFN-1 蛋白的动态行为。从 HDX-MALDI-TOF MS 获得的 PFN-1WT 和 PFN-1G117V 在不同时间间隔（从几秒到几小时）的数据揭示了对应于从单体到多聚体的分子量的多个峰。PFN-1/苯甲醛复合物鉴定了 20 个 HDX 可接近的氨基酸，它们参与了 WT 和突变体 PFN-1 表面的对接模拟。HDX-MALDI-TOF MS 和对接模拟的一致结果预测了参与 PFNG117V 二聚/聚合的候选氨基酸。