Estimation of Peptide N-Cα Bond Cleavage Efficiency during MALDI-ISD Using a Cyclic Peptide
Estimation of Peptide N-Cα Bond Cleavage Efficiency during MALDI-ISD Using a Cyclic Peptide
复制标题
使用环状肽估计 MALDI-ISD 期间肽 N-Cα 键裂解效率
DOI：
10.1002/jms.3748
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发表时间：
2016
影响因子：
2.3
通讯作者：
E. De Pauw
中科院分区：
文献类型：
--
作者：
D. Asakawa;N. Smargiasso;E. De Pauw
基质辅助激光解吸电离源内衰变（MALDI-ISD）通过从基质到肽骨架的氢转移诱导N-Cα键裂解，从而产生ac′/z·片段对。随后，由于thez·的低稳定性，thez·通过进一步的自由基反应生成z ′和[z+ matrix]片段。在本研究中，我们研究了环肽的MALDI-ISD。通过MALDI-ISD切割环肽中的N-Cα键产生富含氢的肽自由基[M +2 H]+·，其在α-碳原子上具有自由基位点，然后与基质反应，得到[M +3 H]+和[M + H +基质]+。对于具有Z片段的1，5-二氨基萘（1，5-DAN）加合物，由环肽产生的[M + H +1，5-DAN]+的源后衰变显示具有1，5-DAN的氨基酸的主要损失。此外，MALDI-ISD与傅里叶变换离子回旋共振质谱法允许检测两个13 C原子的[M +3 H]+和[M + H]+。这些结果有力地表明[M +3 H]+和[M + H +1，5-DAN]+是通过N-Cα键断裂并进一步自由基反应形成的。因此，MALDI-ISD过程中N-Cα键的裂解效率可以通过傅立叶变换离子回旋共振光谱中[M + H]+和[M +3 H]+的强度比来估计。由于环状肽环（Arg-Gly-Asp-D-Phe-瓦尔）基质的还原效率与其切割线性肽中N-Cα键的趋势相关，因此本方法可用于评价MALDI基质开发的N-Cα键切割效率。版权所有© 2016约翰威利父子有限公司.
Matrix‐assisted laser desorption/ionization in‐source decay (MALDI‐ISD) induces N–Cαbond cleavage via hydrogen transfer from the matrix to the peptide backbone, which produces ac′/z• fragment pair. Subsequently, thez• generatesz′ and [z+ matrix] fragments via further radical reactions because of the low stability of thez•. In the present study, we investigated MALDI‐ISD of a cyclic peptide. The N–Cαbond cleavage in the cyclic peptide by MALDI‐ISD produced the hydrogen‐abundant peptide radical [M + 2H]+• with a radical site on the α‐carbon atom, which then reacted with the matrix to give [M + 3H]+and [M + H + matrix]+. For 1,5‐diaminonaphthalene (1,5‐DAN) adducts withzfragments, post‐source decay of [M + H + 1,5‐DAN]+generated from the cyclic peptide showed predominant loss of an amino acid with 1,5‐DAN. Additionally, MALDI‐ISD with Fourier transform‐ion cyclotron resonance mass spectrometry allowed for the detection of both [M + 3H]+and [M + H]+with two13C atoms. These results strongly suggested that [M + 3H]+and [M + H + 1,5‐DAN]+were formed by N–Cαbond cleavage with further radical reactions. As a consequence, the cleavage efficiency of the N–Cαbond during MALDI‐ISD could be estimated by the ratio of the intensity of [M + H]+and [M + 3H]+in the Fourier transform‐ion cyclotron resonance spectrum. Because the reduction efficiency of a matrix for the cyclic peptide cyclo(Arg‐Gly‐Asp‐D‐Phe‐Val) was correlated to its tendency to cleave the N–Cαbond in linear peptides, the present method could allow the evaluation of the efficiency of N–Cαbond cleavage for MALDI matrix development. Copyright © 2016 John Wiley & Sons, Ltd.