ECD AND EDD OF NATIVE AND PERMETHYLATED GLYCANS

天然和全甲基化聚糖的 ECD 和 EDD

• 批准号: 8365556
• 负责人: CHI-WEI LIN
• 金额: $ 4.92万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-01 至 2012-08-09
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8365556
• 关键词: Acetylglucosamine; Alkali Metals; Alkalies; Behavior; Biology; Biopolymers; Charge; Diagnostic; Dissociation; Electrons; Funding; Grant; Ions; Isomerism; Mass Spectrum Analysis; Medicine; Metals; Methods; Modeling; Monosaccharides; National Center for Research Resources; Oligosaccharides; Polysaccharides; Principal Investigator; Process; Research; Research Infrastructure; Resources; Site; Source; United States National Institutes of Health; Update; adduct; cost; research study

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. Oligosaccharides are biopolymers composed of multiple monosaccharide units connected through glycosidic bonds. Structural characterization of oligosaccharides requires not only determination of the identity and sequence of each monosaccharide unit, but also differentiation of possible branching, linkage, epimeric and anomeric isomers. It has been shown previously, in our lab and elsewhere, that electron capture dissociation (ECD) and hotECD (hECD) generally provide more extensive cross-ring cleavages than the conventional collisionally activated dissociation (CAD) and infrared multiphoton dissociation (IRMPD) methods. These cross-ring fragments are instrumental in determining the branching and linkage sites. In this study, metal-adducted permethylated linear and branched oligosaccharide ions were subject to ECD at several energies to investigate the effect of metal ion and electron energy on their fragmentation behaviors as well as the general applicability of ECD to isomer differentiation. Update for 2010-2011: Electron capture dissociation (ECD) behavior of oligosaccharides depends on both the electron energy and the type of charge carriers. Lithiated and alkali-earth metal adducted oligosaccharides fragmented effectively under both low and high energy conditions, whereas other alkali metal adducted oligosaccharides fragmented only under the hot-ECD conditions. Here, we carried out a systematic semi-quantitative study on model oligosaccharides to further investigate the effects of varying the electron energy and the charge carriers on the ECD behavior of oligosaccharides. The results of the energy-dependent ECD experiments indicate that, as the electron energy increases, the metal-adducted oligosaccharide ions can undergo three different fragmentation processes: ECD, which dominates when the electron energy is between 0.5 and 6 eV; hot-ECD, as characterized by formation of certain cross-ring cleavages, which occurs when the electron energy is between 6 and 16 eV; and EID, as characterized by the presence of doubly-charged fragment ions, which occurs when the electron energy is above 9 eV. Although the onsets of both the hot-ECD and EID processes were independent of the type of the charge carriers, smaller charge carriers frequently led to a higher degree of EID, whereas larger charge carriers tend to provide more diverse cross-ring cleavages covering a broader range of residues under hot-ECD condition. The potential of ECD for isomer differentiation is being further investigated by performing ECD at various electron energies towards the structural characterization of oligosaccharide linkage isomers. For example, although isomer differentiation between LNT and LNnT could not be achieved using low-energy ECD, hot ECD was able to generate diagnostic ions for each isomer: the presence of 1,3A2 and 2,5A2 fragments in the MS/MS spectra confirmed the 1¿3 linkage on the N-acetylglucosamine residue in LNT, and the 2,4A2 and 3,5A2 fragments confirmed the 1¿4 linkage on this residue in LNnT.

该子项目是利用资源的众多研究子项目之一 由 NIH/NCRR 资助的中心拨款提供 该子项目的主要支持。 并且子项目的主要研究者可能是由其他来源提供的， 包括其他 NIH 来源的子项目可能列出的总成本。 代表子项目使用的中心基础设施的估计数量， NCRR 赠款不直接向子项目或子项目工作人员提供资金。 寡糖是由通过糖苷键连接的多个单糖单元组成的生物聚合物，寡糖的结构表征不仅需要确定每个单糖单元的身份和序列，还需要区分可能的支链、连接、差向异构体和端基异构体。在我们的实验室和其他地方，电子捕获解离 (ECD) 和热 ECD (hECD) 通常提供更广泛的交叉环与传统的碰撞激活解离 (CAD) 和红外多光子解离 (IRMPD) 方法相比，这些交叉环片段有助于确定分支和连接位点。在多种能量下进行 ECD，以研究金属离子和电子能量对其碎裂行为的影响以及 ECD 对异构体分化的一般适用性。 2010-2011 年更新： 寡糖的电子捕获解离 (ECD) 行为取决于电子能量和电荷载体的类型，锂化和碱土金属加合寡糖在低能和高能条件下均能有效裂解，而其他碱金属加合寡糖仅在高能条件下裂解。在这里，我们对模型寡糖进行了系统的半定量研究，以进一步研究改变电子能量和热 ECD 条件的影响。电荷载体对寡糖 ECD 行为的影响。 能量依赖的 ECD 实验结果表明，随着电子能量的增加，金属加合寡糖离子可以经历三种不同的裂解过程：ECD，当电子能量在 0.5 至 6 eV 之间时占主导地位；以形成某些交叉环裂解为特征，当电子能量在 6 至 16 eV 之间时发生；以及 EID，以双电荷片段的存在为特征；尽管热 ECD 和 EID 过程的开始与电荷载流子的类型无关，但较小的电荷载流子通常会导致较高程度的 EID，而较大的电荷则会导致较高程度的 EID。在热 ECD 条件下，载体倾向于提供更多样化的跨环裂解，覆盖更广泛的残基。 通过在不同电子能量下进行 ECD 来研究寡糖连接异构体的结构表征，ECD 在异构体区分方面的潜力正在被研究。能够为每种异构体生成诊断离子：MS/MS 光谱中 1,3A2 和 2,5A2 片段的存在证实了 1¿3 连接LNT 中的 N-乙酰氨基葡萄糖残基，以及 2,4A2 和 3,5A2 片段证实了 LNnT 中该残基上的 1¿4 连接。