A Hydrodynamic Comparison of Solution and Gas Phase Proteins and Their Complexes
A Hydrodynamic Comparison of Solution and Gas Phase Proteins and Their Complexes
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DOI：
10.1021/jp501950d
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发表时间：
2014-07-24
影响因子：
3.3
通讯作者：
Borysik, Antoni J.
中科院分区：
文献类型：
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作者：
Hewitt, Dominic;Marklund, Erik;Borysik, Antoni J.
从溶液转移到气相时蛋白质结构的保留程度是天然质谱分析的核心问题。在这里，我们将多种不同蛋白质和蛋白质复合物 (15-500 kDa) 的碰撞截面 (Omega) 与其相应的斯托克斯半径 (R-S) 进行比较。使用这些方法，我们发现 Omega 和 R-S 具有良好的相关性，这意味着气相中蛋白质结构的整体保存。考虑到蛋白质水合作用，需要一个缩放项才能使 Omega 和 R-S 达到同等水平。有趣的是，这个缩放项的大小几乎与密立根提出的阻力因子完全一致。然后将 R-S 与从原子坐标中获取的 Omega 的各种不同预测值进行比较。我们发现，许多用于从原子坐标获取 Omega 的方法对溶液中蛋白质的物理尺寸的计算错误高达 20%。因此，从原子坐标估计的 Omega 重新密封似乎适合作为使理论值与溶液中观察到的值一致的通用方法。
The extent to which protein structures are preserved on transfer from solution to gas phase is a central question for native mass spectrometry. Here we compare the collision cross sections (Omega) of a wide range of different proteins and protein complexes (15-500 kDa) with their corresponding Stokes radii (R-S). Using these methods, we find that Omega and R-S are well correlated, implying overall preservation of protein structure in the gas phase. Accounting for protein hydration, a scaling term is required to bring Omega and R-S into parity. Interestingly, the magnitude of this scaling term agrees almost entirely with the drag factor proposed by Millikan. R-S were then compared with various different predicted values of Omega taken from their atomic coordinates. We find that many of the approaches used to obtained Omega from atomic coordinates miscalculate the physical sizes of the proteins in solution by as much as 20%. Resealing of Omega estimated from atomic coordinates may therefore seem appropriate as a general method to bring theoretical values in line with those observed in solution.