Electron Transfer Dissociation (ETD) of Peptides Containing Intrachain Disulfide Bonds
Electron Transfer Dissociation (ETD) of Peptides Containing Intrachain Disulfide Bonds
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DOI：
10.1007/s13361-011-0300-z
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发表时间：
2012-02-01
影响因子：
3.2
通讯作者：
Xia, Yu
中科院分区：
文献类型：
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作者：
Cole, Scott R.;Ma, Xiaoxiao;Xia, Yu
在电子转移解离（ETD）条件下研究了含有链内二硫键的肽段的断裂化学。由于链内二硫键形成，观察到肽骨架的环状区域内的片段，包括：c（奇电子）、z（偶电子）、c-33 Da、z+33 Da、c+32 Da和z-32 Da类型的离子。这些离子的存在表明在二硫键和N-C α骨架处均发生了来自单个电子转移事件的裂解。机理研究支持N-C α键首先裂解的机制，并且自由基驱动的反应在半胱氨酰残基内的S-S键或S-C键处引起裂解。还观察到二硫键处的直接ETD，这与电荷减少的肽离子的33 Da（SH）的特征丢失相关。研究发现，在较低电荷状态的肽离子中，二硫键处的初始ETD切割得到促进，而在较高电荷状态的肽离子中，骨架断裂更加丰富。从ETD诱导骨架和二硫键裂解的能力对于测序含有完整链内二硫键的肽可能特别有用。本文研究的13种肽的ETD都显示出相当大的序列覆盖率，占可能的骨架片段的75%-100%。
The fragmentation chemistry of peptides containing intrachain disulfide bonds was investigated under electron transfer dissociation (ETD) conditions. Fragments within the cyclic region of the peptide backbone due to intrachain disulfide bond formation were observed, including: c (odd electron), z (even electron), c-33 Da, z+33 Da, c+32 Da, and z-32 Da types of ions. The presence of these ions indicated cleavages both at the disulfide bond and the N-C alpha backbone from a single electron transfer event. Mechanistic studies supported a mechanism whereby the N-C alpha bond was cleaved first, and radical-driven reactions caused cleavage at either an S-S bond or an S-C bond within cysteinyl residues. Direct ETD at the disulfide linkage was also observed, correlating with signature loss of 33 Da (SH) from the charge-reduced peptide ions. Initial ETD cleavage at the disulfide bond was found to be promoted amongst peptides ions of lower charge states, while backbone fragmentation was more abundant for higher charge states. The capability of inducing both backbone and disulfide bond cleavages from ETD could be particularly useful for sequencing peptides containing intact intrachain disulfide bonds. ETD of the 13 peptides studied herein all showed substantial sequence coverage, accounting for 75%-100% of possible backbone fragmentation.