Difference of Electron Capture and Transfer Dissociation Mass Spectrometry on Ni2+-, Cu2+-, and Zn2+-Polyhistidine Complexes in the Absence of Remote Protons
Difference of Electron Capture and Transfer Dissociation Mass Spectrometry on Ni2+-, Cu2+-, and Zn2+-Polyhistidine Complexes in the Absence of Remote Protons
复制标题
DOI：
10.1007/s13361-016-1395-z
复制
发表时间：
2016-07-01
影响因子：
3.2
通讯作者：
De Pauw, Edwin
中科院分区：
文献类型：
--
作者：
Asakawa, Daiki;De Pauw, Edwin
金属-多肽络合物中的电子俘获解离(ECD)和电子转移解离(ETD)与金属阳离子有关。由于二价过渡金属Ni2+、Cu2+和Zn2+与多肽中的中性组氨酸残基结合很强，因此可以在没有远程质子的情况下作为载流子生成金属-多组氨酸络合物。在Cu2+-多组氨酸络合物的ECD和ETD的情况下，络合物中的金属阳离子被还原，复合能在肽中重新分配，形成具有质子化的组氨酸残基和去质子化的酰胺氮的两性离子多肽。两性离子随后发生肽键断裂，产生a和b片段离子。相反，ECD和ETD在锌-多组氨酸复合体中诱导不同的裂解过程。尽管锌-多组氨酸络合物中的N-C-α键被ETD断裂，但锌-多组氨酸的ECD导致肽键断裂并伴随着氢原子的释放。ECD和ETD的不同碎裂模式源于这些过程产生的电荷还原络合物的不同电子态。用密度泛函理论对碎裂过程进行了详细的研究。
Electron capture dissociation (ECD) and electron transfer dissociation (ETD) in metal-peptide complexes are dependent on the metal cation in the complex. The divalent transition metals Ni2+, Cu2+, and Zn2+ were used as charge carriers to produce metal-polyhistidine complexes in the absence of remote protons, since these metal cations strongly bind to neutral histidine residues in peptides. In the case of the ECD and ETD of Cu2+-polyhistidine complexes, the metal cation in the complex was reduced and the recombination energy was redistributed throughout the peptide to lead a zwitterionic peptide form having a protonated histidine residue and a deprotonated amide nitrogen. The zwitterion then underwent peptide bond cleavage, producing a and b fragment ions. In contrast, ECD and ETD induced different fragmentation processes in Zn2+-polyhistidine complexes. Although the N-C-alpha bond in the Zn2+-polyhistidine complex was cleaved by ETD, ECD of Zn2+-polyhistidine induced peptide bond cleavage accompanied with hydrogen atom release. The different fragmentation modes by ECD and ETD originated from the different electronic states of the charge-reduced complexes resulting from these processes. The details of the fragmentation processes were investigated by density functional theory.