Structural Dynamics of Native-Like Ions in the Gas Phase: Results from Tandem Ion Mobility of Cytochrome c
Structural Dynamics of Native-Like Ions in the Gas Phase: Results from Tandem Ion Mobility of Cytochrome c
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DOI：
10.1021/acs.analchem.7b01234
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发表时间：
2017-07-18
影响因子：
7.4
通讯作者：
Bush, Matthew F.
中科院分区：
文献类型：
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作者：
Allen, Samuel J.;Eaton, Rachel M.;Bush, Matthew F.
离子迁移率（IM）是一种气相分离技术，用于确定蛋白质和蛋白质复合物的类天然离子的碰撞截面，这反过来又被用作模拟溶液中这些分析物结构的约束。在这里，我们评估的稳定性的本地样离子使用串联IM实验实现无损离子操作（SLIM）的结构。在串联IM的该实施方式中，离子经历IM的第一维度直到用于选择性地传输期望迁移率的离子的开关。选定的离子在阱中积累，然后在延迟后释放，以启动IM的第二维。对于16至33 231 ms的延迟范围，类天然7+细胞色素c离子的碰撞截面从15.1 nm单调增加至17.1 nm（2）。在这些实验中，在接近环境温度下形成的最大产物仍然远小于在能量依赖实验中形成的产物（类似于21 nm（2））。然而，碰撞截面增加了类似的延迟时间16和211毫秒之间的2%，这可能会影响其他IM实验在这些时间尺度上。最后，从整个群体中选择两个亚群体，每个亚群体的移动性作为延迟时间的函数进行分析，表明这三个群体可以区分至少1 s。总之，这些结果表明，本机样结构的元素可以有很长的寿命在近环境温度下的气相，但气相动力学解释IM的结果时，应考虑。
Ion mobility (IM) is a gas-phase separation technique that is used to determine the collision cross sections of native-like ions of proteins and protein complexes, which are in turn used as restraints for modeling the structures of those analytes in solution. Here, we evaluate the stability of native-like ions using tandem IM experiments implemented using structures for lossless ion manipulations (SLIM). In this implementation of tandem IM, ions undergo a first dimension of IM up to a switch that is used to selectively transmit ions of a desired mobility. Selected ions are accumulated in a trap and then released after a delay to initiate the second dimension of IM. For delays ranging from 16 to 33 231 ms, the collision cross sections of native-like, 7+ cytochrome c ions increase monotonically from 15.1 to 17.1 nm(2). The largest products formed in these experiments at near-ambient temperature are still far smaller than those formed in energy-dependent experiments (similar to 21 nm(2)). However, the collision cross section increases by similar to 2% between delay times of 16 and 211 ms, which may have implications for other IM experiments on these time scales. Finally, two subpopulations from the full population were each mobility selected and analyzed as a function of delay time, showing that the three populations can be differentiated for at least 1 s. Together, these results suggest that elements of native-like structure can have long lifetimes at near-ambient temperature in the gas phase but that gas-phase dynamics should be considered when interpreting results from IM.