Influence of Metal-Peptide Complexation on Fragmentation and Inter-Fragment Hydrogen Migration in Electron Transfer Dissociation
Influence of Metal-Peptide Complexation on Fragmentation and Inter-Fragment Hydrogen Migration in Electron Transfer Dissociation
复制标题
金属-肽络合对电子转移解离中断裂和片段间氢迁移的影响
DOI：
10.1007/s13361-014-0855-6
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Y. Wada
中科院分区：
文献类型：
--
作者：
D. Asakawa;T. Takeuchi;A. Yamashita;Y. Wada
在肽的电喷雾电离 (ESI) 中使用金属盐会增加肽离子的电荷状态，从而促进串联质谱中的电子转移解离 (ETD)。在本研究中，K+和Ca2+被用作电荷载体，形成多电荷金属-肽复合物。钾或钙肽复合物的 ETD 是通过将电子转移到远离金属阳离子的质子而引发的，并形成 ac'-z• 片段复合物，其中 c' 和 z• 片段通过与几个氨基酸残基配位的金属阳离子连接在一起。 ETD前体中金属阳离子的存在增加了c'-z•片段复合物的寿命，最终通过片段间氢迁移产生c•和z'片段。氢迁移的程度取决于金属-肽复合物中金属阳离子的位置，但与分子力学模拟获得的前体离子的构象不一致。相反，ETD 光谱表明中间体中金属阳离子的位置与“质子去除”前体的构象一致，表明 ETD 导致前体离子的电荷减少在碎裂过程中引起构象重排。
The use of metal salts in electrospray ionization (ESI) of peptides increases the charge state of peptide ions, facilitating electron transfer dissociation (ETD) in tandem mass spectrometry. In the present study, K+and Ca2+were used as charge carriers to form multiply-charged metal–peptide complexes. ETD of the potassium- or calcium-peptide complex was initiated by transfer of an electron to a proton remote from the metal cation, and ac'-z• fragment complex, in which thec'andz• fragments were linked together via a metal cation coordinating with several amino acid residues, was formed. The presence of a metal cation in the precursor for ETD increased the lifetime of thec'-z• fragment complex, eventually generatingc• andz'fragments through inter-fragment hydrogen migration. The degree of hydrogen migration was dependent on the location of the metal cation in the metal-peptide complex, but was not reconciled with conformation of the precursor ion obtained by molecular mechanics simulation. In contrast, the location of the metal cation in the intermediate suggested by the ETD spectrum was in agreement with the conformation of “proton-removed” precursors, indicating that the charge reduction of precursor ions by ETD induces conformational rearrangement during the fragmentation process.