Electron Transfer Dissociation: Effects of Cation Charge State on Product Partitioning in Ion/Ion Electron Transfer to Multiply Protonated Polypeptides.
Electron Transfer Dissociation: Effects of Cation Charge State on Product Partitioning in Ion/Ion Electron Transfer to Multiply Protonated Polypeptides.
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DOI：
10.1016/j.ijms.2012.07.013
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发表时间：
2012-12-15
影响因子：
1.8
通讯作者：
McLuckey SA
中科院分区：
文献类型：
--
作者：
Liu J;McLuckey SA
考察了多质子化胰多肽、模型多肽和相对较大的多肽与单电荷基阴离子在气相离子/离子电子转移反应中，阳离子荷态对产物分配的影响。特别是，分配到各种相互竞争的通道中，例如质子转移(PT)和电子转移(ET)，随后解离的电子转移(ETD)和没有解离的电子转移(ET，NOD)，以及主干键的断裂和侧链的断裂，作为多肽电荷状态的函数被定量测量，以使人们能够深入了解导致ETD的离子/离子反应的基本方面。随着阳离子电荷态的增加，ET通道相对于PT通道增加，ETD相对于ET、NOD增加，主链断裂相对于侧链断裂增加。ET与PT随电荷态的增加符合基于Landau-Zener的曲线交叉模型。用基态-基态反应模型预测了电子转移的最佳荷电状态。然而，当考虑激发产物离子态的布居时，由于可能存在产物的激发电子态布居，电子转移效率不可能随着电荷态的增加而降低。有几个因素可以导致ETD相对于ET、NOD和主干裂解相对于侧链损失的增加。这些因素包括反应放热的增加和前驱体和产物离子结构、稳定性和质子化位置的电荷状态依赖的差异。
The effect of cation charge state on product partitioning in the gas-phase ion/ion electron transfer reactions of multiply protonated tryptic peptides, model peptides, and relatively large peptides with singly charged radical anions has been examined. In particular, partitioning into various competing channels, such as proton transfer (PT) versus electron transfer (ET), electron transfer with subsequent dissociation (ETD) versus electron transfer with no dissociation (ET,noD), and fragmentation of backbone bonds versus fragmentation of side chains, was measured quantitatively as a function of peptide charge state to allow insights to be drawn about the fundamental aspects of ion/ion reactions that lead to ETD. The ET channel increases relative to the PT channel, ETD increases relative to ET,noD, and fragmentation at backbone bonds increases relative to side-chain cleavages as cation charge state increases. The increase in ET versus PT with charge state is consistent with a Landau-Zener based curve-crossing model. An optimum charge state for ET is predicted by the model for the ground state-to-ground state reaction. However, when the population of excited product ion states is considered, it is possible that a decrease in ET efficiency as charge state increases will not be observed due to the possibility of the population of excited electronic states of the products. Several factors can contribute to the increase in ETD versus ET,noD and backbone cleavage versus side-chain losses. These factors include an increase in reaction exothermicity and charge state dependent differences in precursor and product ion structures, stabilities, and sites of protonation.
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影响因子：
2
作者：
Misharin, AS;Silivra, OA;Zubarev, RA
通讯作者：
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影响因子：
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