Distinctive MS/MS Fragmentation Pathways of Glycopeptide-Generated Oxonium Ions Provide Evidence of the Glycan Structure.
Distinctive MS/MS Fragmentation Pathways of Glycopeptide-Generated Oxonium Ions Provide Evidence of the Glycan Structure.
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DOI：
10.1002/chem.201503659
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发表时间：
2016-01
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通讯作者：
Jin Yu;Manuel Schorlemer;Alejandro Gómez Toledo;Christian Pett;C. Sihlbom;G. Larson;Ulrika Westerlind;J. Nilsson
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文献类型：
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作者：
Jin Yu;Manuel Schorlemer;Alejandro Gómez Toledo;Christian Pett;C. Sihlbom;G. Larson;Ulrika Westerlind;J. Nilsson
蛋白质的翻译后糖基化在细胞过程中起着关键作用，聚糖结构的位点特异性表征对于理解这些事件至关重要。鉴于鉴定聚糖异构体的挑战，糖蛋白组学研究通常依赖于保守的生物合成途径的假设。然而，在最近的一项研究中，我们发现了依赖于聚糖结构的特征性不同的HexNAc氧鎓离子碎片模式。这种模式可用于区分糖肽结构异构体。为了获得一个机制的见解，氘标记的糖肽的制备和分析。我们发现，HexNAc衍生的m/z 126和144氧离子，H2 O质量不同，具有完全不同的结构，高甘露糖N-糖肽产生丰富的Hex衍生的氧离子。我们描述了氧离子的分解机制和氧离子的相对丰度作为碰撞能量的函数的一些定义明确的聚糖结构，这为未来的糖蛋白质组学研究提供了重要的信息。
Post-translational glycosylation of proteins play key roles in cellular processes and the site-specific characterisation of glycan structures is critical to understanding these events. Given the challenges regarding identification of glycan isomers, glycoproteomic studies generally rely on the assumption of conserved biosynthetic pathways. However, in a recent study, we found characteristically different HexNAc oxonium ion fragmentation patterns that depend on glycan structure. Such patterns could be used to distinguish between glycopeptide structural isomers. To acquire a mechanistic insight, deuterium-labelled glycopeptides were prepared and analysed. We found that the HexNAc-derived m/z 126 and 144 oxonium ions, differing in mass by H2 O, had completely different structures and that high-mannose N-glycopeptides generated abundant Hex-derived oxonium ions. We describe the oxonium ion decomposition mechanisms and the relative abundance of oxonium ions as a function of collision energy for a number of well-defined glycan structures, which provide important information for future glycoproteomic studies.