Carbohydrate structural isomers analyzed by sequential mass spectrometry
Carbohydrate structural isomers analyzed by sequential mass spectrometry
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DOI：
10.1021/ac062383a
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发表时间：
2007-05-15
影响因子：
7.4
通讯作者：
Reinhold, Vernon N.
中科院分区：
文献类型：
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作者：
Ashline, David J.;Lapadula, Anthony J.;Reinhold, Vernon N.
与全面碳水化合物测序策略的目标一致，我们扩展了早期报告以包括结构（组成）异构体的表征。协议是围绕提供顺序质谱 (MSn) 的离子阱仪器开发的，并得到自动化和相关计算工具的支持。这些策略建立在这样的原则上：对于单一结构，顺序裂解后的所有产物光谱都是可再现的，并且每个阶段代表其前体的合理光谱；即，应考虑所有主要碎片。任何阶段的异常离子都是表明结构异构体存在的线索。此类离子的气相分离和随后的碎裂提供了专门解析所选结构以进行详细表征的机会。重要的是，一些异构体在 MS2 后未检测到，需要多个 (MSn > 2) 阶段进行表征。衍生化对于在聚糖阵列中定位子结构仍然至关重要，因为产物离子在整个 MSn 树中携带碎片“疤痕”。同样重要的是每个阶段之间的通路关系以及使用较少数量的振荡器获得更高的片段产量。应用针对卵清蛋白和 IgG 的结构异构体，在后一种情况下，检测到了几种先前未报道的聚糖。程序得到生物信息学工具的支持，用于从 MSn 数据集中吸收结构。
Consistent with the goals of a comprehensive carbohydrate sequencing strategy, we extend earlier reports to include the characterization of structural (constitutional) isomers. Protocols were developed around ion trap instrumentation providing sequential mass spectrometry (MSn) and supported with automation and related computational tools. These strategies have been built on the principle that for a single structure all product spectra upon sequential fragmentation are reproducible and each stage represents a rational spectrum of its precursor; i.e., all major fragments should be accounted for. Anomalous ions at any stage are clues indicating the presence of structural isomers. Gas-phase isolation and subsequent fragmentation of such ions provide an opportunity to specifically resolve selected structures for their detailed characterization. Importantly, some isomers were not detected following MS2 and required multiple (MSn > 2) stages for their characterization. Derivatization remains critical to position substructures in a glycan array since product ions carry fragmentation "scars" throughout the MSn tree. Equally as important are the pathway relationships between each stage and the greater yield of fragments with the smaller number of oscillators. Applications were directed to the structural isomers in ovalbumin and IgG, where, in the latter case, several previously unreported glycans were detected. Procedures were supported with bioinformatics tools for assimilating structure from the MSn data sets.