A Semi-Empirical Framework for Interpreting Traveling Wave Ion Mobility Arrival Time Distributions
A Semi-Empirical Framework for Interpreting Traveling Wave Ion Mobility Arrival Time Distributions
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DOI：
10.1007/s13361-019-02133-6
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发表时间：
2019-06-01
影响因子：
3.2
通讯作者：
Ruotolo, Brandon T.
中科院分区：
文献类型：
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作者：
Dixit, Sugyan M.;Ruotolo, Brandon T.
生物分子固有的结构异质性是一个重要的生物物理性质，是必不可少的功能，但具有挑战性的实验表征。我们提出了一个工作流程，快速和定量评估的构象异构性的肽和蛋白质在气相中使用行波离子迁移率（TWIM）到达时间分布（ATDs）。我们已经建立了一组半经验方程，该方程在宽范围的波振幅（V）和波速度（V）上对TWIM ATD峰宽和分辨率进行建模。此外，可以从该分析中提取构象加宽参数，其报告了在离子迁移率分离期间构象异质性对TWIM ATD峰宽加宽的贡献。我们用这个值来评估一组螺旋肽的构象异质性，我们的分析与以前的峰宽观察报告这些离子。此外，我们使用分子动力学模拟独立调查的一般灵活性，这些肽在气相中，并产生类似的趋势，发现在实验TWIM数据。最后，我们扩展了我们的分析，抗生物素蛋白，64 kDa的同源四聚体，并量化的结构异质性，这个完整的复合物使用TWIM ATD数据作为交联的函数。我们观察到作为交联剂浓度的函数的值的初始减少，证明了我们的值分析对组装的灵活性变化的敏感性。
The inherent structural heterogeneity of biomolecules is an important biophysical property that is essential to their function, but is challenging to characterize experimentally. We present a workflow that rapidly and quantitatively assesses the conformational heterogeneity of peptides and proteins in the gas phase using traveling wave ion mobility (TWIM) arrival time distributions (ATDs). We have established a set of semi-empirical equations that model the TWIM ATD peak width and resolution across a wide range of wave amplitudes (V) and wave velocities (v). In addition, a conformational broadening parameter, , can be extracted from this analysis that reports on the contribution of conformational heterogeneity to the broadening of TWIM ATD peak width during ion mobility separation. We use this value to evaluate the conformational heterogeneity of a set of helical peptides, and our analysis correlates well with previous peak width observations reported for these ions. Furthermore, we use molecular dynamics simulations to independently investigate the general flexibility of these peptides in the gas phase, and generate similar trends found in experimental TWIM data. Finally, we extended our analysis to Avidin, a 64-kDa homotetramer, and quantify the structural heterogeneity of this intact complex using TWIM ATD data as a function of cross-linking. We observe an initial reduction in values as a function of cross-linker concentration, demonstrating the sensitivity of our value analysis to changes in flexibility of the assembly.