Studies of Peptide a- and b-Type Fragment Ions Using Stable Isotope Labeling and Integrated Ion Mobility/Tandem Mass Spectrometry
Studies of Peptide a- and b-Type Fragment Ions Using Stable Isotope Labeling and Integrated Ion Mobility/Tandem Mass Spectrometry
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DOI：
10.1016/j.jasms.2008.09.024
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发表时间：
2008-12-01
影响因子：
3.2
通讯作者：
Gaskell, Simon J.
中科院分区：
文献类型：
--
作者：
Garcia, Isabel Riba;Giles, Kevin;Gaskell, Simon J.
肽a-和b-型碎片离子的结构进行了研究，使用合成肽，包括一组异构肽，不同的序列位置的丙氨酸残基标记的N-15和均匀的C-13。通过a（n）和B（n）离子（其中n = 4或5）衍生的第二代碎片离子的同位素标记模式表明，这些中间体部分以大环结构形式存在，其中替代的开环位点产生不同的线性形式，其简单的切割可能会产生观察到的最终产物。类似的结论来自组合离子迁移率/串联MS分析，其中观察到不同的碎片模式的异构体a-或b-型离子，显示不同的离子迁移率。这些分析促进了一种新的方法来处理离子迁移率/串联MS数据，从不同的和单独的产品离子光谱来自不完全分离的离子迁移率的离子。最后，提供了一个例子的证据为大环结构的B（n）离子，其中n = 8或9。（J Am Soc Mass Spectrom 2008，19，1781-1787）（c）Elsevier Inc.美国质谱学会American Society for Mass Spectrometry
The structures of peptide a- and b-type fragment ions were studied using synthetic peptides including a set of isomeric peptides, differing in the sequence location of an alanine residue labeled with N-15 and uniformly with C-13. The pattern of isotope labeling of second-generation fragment ions derived via a(n) and b(n) ions (where n = 4 or 5) suggested that these intermediates existed in part as macrocyclic structures, where alternative sites of ring opening gave rise to different linear forms whose simple cleavage might give rise to the observed final products. Similar conclusions were derived from combined ion mobility/tandem MS analyses where different fragmentation patterns were observed for isomeric a- or b-type ions that display different ion mobilities. These analyses were facilitated by a new approach to the processing of ion mobility/tandem MS data, from which distinct and separate product ion spectra are derived from ions that are incompletely separated by ion mobility. Finally, an example is provided of evidence for a macrocyclic structure for b(n) ions where n = 8 or 9. (J Am Soc Mass Spectrom 2008, 19, 1781-1787) (c) 2608 Published by Elsevier Inc. on behalf of American Society for Mass Spectrometry