DEVELOPMENT OF IMPROVED METHODS FOR CARBOHYDRATE SEQUENCING

四极离子陷阱(QIT)质量的电喷雾电离 Analyzer一直被认为是一种改进的工具方法 了解碳水化合物结构的细节。要评估这一点 功能，在BUSM资源处准备了多个样本 带到成功使用LCQ的实验室(芬兰) 保罗离子陷阱。样品，包括GSL、N-和0-连接的多糖 从糖蛋白中提取或释放，并甲基化。广泛性 工作的重点是复杂多糖的内部核心分支，以 确定链接细节。描述这项工作的两篇论文是 接受，出版。在一篇报道中，一种异构体二唾液酸脂 对神经鞘糖脂样品进行了s6序列、分支 和链接信息。得到的结果是定性的 可与三重四极乐器(Qlq2Q3)相媲美 CI-O糖苷破裂的碳水化合物碎片和其他 提供鞘氨醇和N-酰基测定的片段 神经酰胺部分的不均一性。然而，与之形成独特对比的是， QIT通过MS的研究扩展了对碳水化合物的理解 首次提供了定义 糖脂的残基间连接结构。这是通过以下方式实现的 选择次级片段(MS3)，无能量汇 主宰产物离子光谱的易键断裂。隔离和 这些子结构的激活会导致更均匀的 片段的分布，提供了先前的结构洞察 串联质谱学无法获得。在研究复杂和复杂的 支链多糖，MS暴露的结构特征不是 可与串联仪器一起使用，并可从糖蛋白 Fetuin，澄清了三天线分支中存在的一个争议 拓扑学。这项技术似乎提供了重要的一步 朝着了解碳水化合物结构的各个方面的目标前进 在一件乐器里。

Electrospray ionization (ES) with a quadrupole ion trap (qIT) mass analyzer has been considered to be an improved instrumental approach to understand the details of carbohydrate structure. To evaluate this feature, multiple samples were prepared at the BUSM Resource and brought to laboratories that were successfully using a LCQ (Finnigan) Paul ion trap. Samples, including GSL, N-, and 0-linked glycans were extracted or released from glycoproteins, andmethylated. Extensive effort was focused on internal core branching of complex glycans to ascertain linkage detail. Two papers describing this work have been accepted for, publication. In onereport, an isomeric disialyl glycosphingolipid samples was evaluated for s6quence, branching andlinkage information. Results were obtained that were qualitatively comparable with triple quadrupole instruments (Qlq2Q3) with major carbohydrate fragments from CI-O glycosidic rupture and additional fragments that provided a determination of sphingosine and N-acyl heterogeneity of the ceramide moiety. In unique contrast, however, the qIT extended carbohydrate understanding through MS' studies providing for the first time pyran cross-ring cleavages that define inter-residue linkage structure for glycolipids. This was achieved by selecting secondary fragments (MS3), free from the energy sinks of facile bond rupture that dominate product ion spectra. Isolation and activation of these substructures result in a more uniform distribution of fragments, providing structural insights previously inaccessible by tandem mass spectrometry. In studies with complex and branched glycans, the feature of MS' exposed structural features not available with tandem instrumentation, and from the glycoprotein fetuin, clarified an existing controversy in triantennary branching topology. This technology appears to provide a significant step toward the goal of understanding aH aspects of carbohydrate structure in a single instrument.