Utility of immonium ions for assignment of ε-N-acetyllysine-containing peptides by tandem mass spectrometry
Utility of immonium ions for assignment of ε-N-acetyllysine-containing peptides by tandem mass spectrometry
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DOI：
10.1021/ac800005n
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发表时间：
2008-05-01
影响因子：
7.4
通讯作者：
Jensen, Ole N.
中科院分区：
文献类型：
--
作者：
Trelle, Morten B.;Jensen, Ole N.
串联质谱（MS/MS）是表征后修饰蛋白质（包括含ε-N-乙酰基赖氨酸的物质）的有力工具。以前的报道表明，ε-N-乙酰赖氨酸亚铵离子是含有ε-N-乙酰赖氨酸的肽的有用的标记离子，但这些离子用于通过MS/MS分配赖氨酸乙酰化的特异性和灵敏度尚未详细研究。我们研究了172个ε-N-乙酰赖氨酸胰蛋白酶肽和268个非乙酰化胰蛋白酶肽的MS/MS数据集，以建立ε-N-乙酰赖氨酸亚铵离子用于鉴定和验证乙酰化肽的实用性和可靠性。我们的分析表明，m/z 143处的亚铵离子对赖氨酸乙酰化肽缺乏特异性，而m/z 126处的衍生物具有高度特异性（98.1%）。我们还研究了位置效应的ε-N-乙酰赖氨酸上观察到的乙酰赖氨酸亚胺离子的强度。我们观察到乙酰赖氨酸亚铵离子强度的增加时，乙酰化的赖氨酸是N-末端定位在肽相比，内部位置。基于这些观察结果，我们提出了一个验证方案明确分配的乙酰赖氨酸含肽的MS/MS。我们的分析ε-N-乙酰赖氨酸immonium离子的MS/MS标记离子的特异性和灵敏度，可应用于其他类型的翻译后修饰的研究提供了一个框架的调查。
Tandem mass spectrometry (MS/MS) is a powerful tool for characterization of post-translationally modified proteins, including epsilon-N-acetyllysine-containing species. Previous reports indicate that epsilon-N-acetyllysine immonium ions are useful marker ions for peptides containing epsilon-N-acetyllysine, but the specificity and sensitivity of these ions for assignment of lysine acetylation by MS/MS have not been studied in detail. We investigated MS/MS data sets of 172 epsilon-N-acetyllysine tryptic peptides and 268 non-acetylated tryptic peptides to establish the utility and reliability of epsilon-N-acetyllysine immonium ions for identification and validation of acetylated peptides. Our analysis shows that the immonium ion at m/z 143 lacks specificity for lysine-acetylated peptides, whereas the derivative at m/z 126 is highly specific (98.1%). We also studied the positional effect of the epsilon-N-acetyllysine on the intensity of observed acetyllysine immonium ions. We observed an increase in acetyllysine immonium ion intensities when the acetylated lysine was N-terminally positioned in the peptide as compared to internal positions. Based on these observations we propose a validation scheme for unambiguous assignment of acetyllysine-containing peptides by MS/MS. Our analysis of epsilon-N-acetyllysine immonium ions provide a framework for investigation of MS/MS marker ion specificity and sensitivity that can be applied in studies of other types of post-translational modifications.