ELECTRON TRANSFER DISSOCIATION OF GLYCANS AND GLYCOCONJUGATES

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 子项目的主要研究者可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 虽然ECD已证明其对蛋白质、肽和碳水化合物的有用性，但其应用受到限制，因为其使用几乎完全限于傅立叶变换离子回旋共振质谱仪。为了使基于电子的方法在FTMS仪器以外的仪器上实用，Hunt等人引入了一种新的解离方法，该方法依赖于负离子化学电离源中产生的负物质（通常是荧蒽阴离子）的电子转移，然后在气相中与ESI产生的多电荷正离子接触并捕获在细胞中。由于我们已经获得了很好的结果，电子捕获和电子衍射的聚糖，我们承担了一个新的项目，探索的实用程序ETD分析聚糖和糖缀合物。由于我们在资源中还没有配备ETD的仪器，因此我们利用布鲁克道尔顿公司的报价开始了我们的研究，他们在位于马萨诸塞州比尔里卡附近的总部有一个适当装备的四极离子阱仪器。我们最初的实验产生的光谱具有丰富的模式，包括糖苷和交叉环裂解。因此，它们与我们已经获得的聚糖的ECD光谱具有很强的相似性，但也显示出额外的片段，因此数据是互补的。2009年4月，布鲁克公司在我们的实验室安装了一台新的离子阱仪器（amaZon ETD），以便我们可以继续进行这些研究，并生成聚糖的参考串联质谱，我们将把这些质谱纳入公共数据库。对于天然化合物以及天然、还原和O-18标记类似物的全甲基化衍生物，通过CID和ETD（单独和组合）获得了一组牛奶聚糖的质谱。这些都被详尽的解释和由此产生的手稿发表在美国质谱学会杂志。进一步分析包括N-连接聚糖和糖肽。此外，正在评估ETD化学试剂和化学电离气体的变化，以优化聚糖的方法。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Although ECD has proven its usefulness for proteins, peptides and carbohydrates, its applications are limited by the fact that its use is almost completely restricted to Fourier transform ion cyclotron resonance mass spectrometers. To make electron-based methods practical on instruments other than FTMS instruments, Hunt et al. introduced a new method for dissociation that relies on electron transfer by negative species (usually fluoranthene anions) that are produced in a negative-ion chemical ionization source and then brought into contact, in the gas phase, with multiply-charged positive ions that have been generated by ESI and trapped in a cell. Because of the excellent results that we had obtained by ECD and EDD of glycans, we undertook a new project to explore the utility of ETD for analysis of glycans and glycoconjugates. Since we did not yet have an instrument equipped for ETD in the Resource, we began our studies by taking advantage of an offer from Bruker Daltonics, Inc., who had an appropriately equipped quadrupole ion trap instrument available at their headquarters in nearby Billerica, MA. Our initial experiments produced spectra that have rich patterns that include both glycosidic and cross-ring cleavages. They therefore bear strong similarities to the ECD spectra of glycans that we have already obtained, but also exhibit additional fragments, and thus the data is complementary. In April 2009, Bruker installed one of their new ion trap instruments (amaZon ETD) in our laboratory, so that we may continue these studies and also generate reference tandem mass spectra for glycans that we will make available for inclusion in public databases. The mass spectra obtained by CID and ETD, alone and in combination, of a set of milk glycans have been obtained, for the native compounds, and for the permethylated derivatives of the native, reduced and O-18 labelled analogs. These were exhaustively interpreted and the resulting manuscript was published in the Journal of the American Society for Mass Spectrometry. Further analyses have included N-linked glycans and glycopeptides. In addition, variation of the chemical reagent for ETD and the chemical ionization gas is being evaluated to optimize the approach for glycans.