Hydrogen atom attachment to histidine and tryptophan containing peptides in the gas phase
Hydrogen atom attachment to histidine and tryptophan containing peptides in the gas phase
复制标题
DOI：
10.1039/c9cp00083f
复制
发表时间：
2019-06-14
影响因子：
3.3
通讯作者：
Tanaka, Koichi
中科院分区：
文献类型：
--
作者：
Asakawa, Daiki;Takahashi, Hidenori;Tanaka, Koichi
在这项研究中，我们结合使用串联质谱和氢自由基介导的断裂技术来分析肽序列。我们重点关注气相中发生的肽中组氨酸和色氨酸残基侧链上氢原子附着引起的断裂。氢原子分别连接到组氨酸和色氨酸残基中的咪唑和吲哚环上，所得中间体经历C-α-C-β键断裂。使用密度泛函理论通过计算分析研究了详细的碎片机制。结果表明，氢附着发生在组氨酸的C-5位和色氨酸的C-2位，与其他位置相比，其活化能较低，并且产生的中间自由基由于C-α-C-β键断裂而产生片段。对于含有组氨酸和色氨酸残基的肽，C-α-C-β 和 N-C-α 键的裂解独立发生。因此，本研究中提出的方法适用于分析含有组氨酸和色氨酸残基的肽。
In this study, we use a combination of tandem mass spectrometry and hydrogen radical-mediated fragmentation techniques to analyze the sequence of peptides. We focus on fragmentation induced by the attachment of hydrogen atoms to the histidine and tryptophan residue side-chains in the peptide that occurs in the gas-phase. The hydrogen atom attached to the imidazole and indole rings in the histidine and tryptophan residues, respectively, and the resulting intermediate experienced C-alpha-C-beta bond cleavage. The detailed fragmentation mechanism is investigated by computational analysis using density functional theory. According to the results, hydrogen attachment occurs at the C-5 position in histidine and at the C-2 position in the tryptophan, which has a lower activation energy compared with the other positions and the resulting intermediate radicals yielded fragments due to C-alpha-C-beta bond cleavage. For the peptides that contain the histidine and tryptophan residues, cleavages in the C-alpha-C-beta and N-C-alpha bonds occurred independently. Therefore, the method presented in this study is applicable when analyzing peptides that contain histidine and tryptophan residues.