Electron Transfer Dissociation Mass Spectrometry of Peptides Containing Free Cysteine Using Group XII Metals as a Charge Carrier
Electron Transfer Dissociation Mass Spectrometry of Peptides Containing Free Cysteine Using Group XII Metals as a Charge Carrier
复制标题
DOI：
10.1021/jp502818u
复制
发表时间：
2014-10-30
影响因子：
3.3
通讯作者：
Wada, Yoshinao
中科院分区：
文献类型：
--
作者：
Asakawa, Daiki;Wada, Yoshinao
电子转移解离 (ETD) 已用于肽测序。由于 ETD 优先产生 c'/z 中心点片段对，因此肽测序通常通过解释一系列连续 c' 和 z 中心点离子之间的质量差异来进行。然而，前体中游离半胱氨酸残基的存在会促进肽键断裂，从而阻碍 ETD 谱的解释。在本研究中，二价第XII族金属，如Zn2+、Cd2+和Hg2+，被用作电荷载体来生产金属-肽复合物。硫醇基团通过与第XII族金属络合而去质子化。使用锌-肽复合物作为前体成功抑制了 b 和 y' 离子的形成，表明 Zn2+ 辅助 ETD 是对含半胱氨酸肽进行测序的有用方法。相比之下，Cd2+和Hg(2+)肽复合物的ETD分别主要导致SH2损失和自由基阳离子形成。这些过程是由金属阳离子和电子之间的复合能介导的。通过碰撞诱导解离的 MS3 分析证实 ETD 产品中存在单价镉和中性汞。
Electron transfer dissociation (ETD) has been used for peptide sequencing. Since ETD preferentially produces the c'/z center dot fragment pair, peptide sequencing is generally performed by interpretation of mass differences between series of consecutive c' and z center dot ions. However, the presence of free cysteine residues in a precursor promotes peptide bond cleavage, hindering interpretation of the ETD spectrum. In the present study, the divalent group XII metals, such as Zn2+, Cd2+ and Hg2+, were used as charge carriers to produce metal-peptide complexes. The thiol group is deprotonated by complexation with the group XII metal. The formation of b and y' ions was successfully suppressed by using the zinc-peptide complex as a precursor, indicating Zn2+-aided ETD to be a useful method for sequencing of cysteine-containing peptides. By contrast, ETD of Cd2+ and Hg(2+)peptide complexes mainly led to SH2 loss and radical cation formation, respectively. These processes were mediated by recombination energy between the metal cation and an electron. The presence of monovalent cadmium and neutral mercury in ETD products was confirmed by MS3 analysis with collision-induced dissociation.