Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford, OX3 7FZ, UK.
Anal Bioanal Chem. 2021 Dec;413(29):7277-7294. doi: 10.1007/s00216-021-03480-8. Epub 2021 Aug 3.
Structural determination of N-glycans by mass spectrometry is ideally performed by negative ion collision-induced dissociation because the spectra are dominated by cross-ring fragments leading to ions that reveal structural details not available by many other methods. Most glycans form [M - H] or [M + adduct] ions but larger ones (above approx. m/z 2000) typically form doubly charged ions. Differences have been reported between the fragmentation of singly and doubly charged ions but a detailed comparison does not appear to have been reported. In addition to [M + adduct] ions (this paper uses phosphate as the adduct) other doubly, triply, and quadruply charged ions of composition [M + (HPO)] have been observed in mixtures of N-glycans released from viral and other glycoproteins. This paper explores the formation and fragmentation of these different types of multiply charged ions with particular reference to the presence of diagnostic fragments in the CID spectra and comments on how these ions can be used to characterize these glycans.
通过质谱法对 N-糖链进行结构测定，最理想的方法是采用负离子碰撞诱导解离，因为谱图主要由交联片段主导，产生的离子可以提供许多其他方法无法获得的结构细节。大多数糖链形成 [M - H] 或 [M + 加合物] 离子，但较大的糖链（约 m/z 2000 以上）通常形成双电荷离子。已有报道称单电荷和双电荷离子的碎裂存在差异，但似乎尚未有详细的比较报道。除了 [M + 加合物] 离子（本文使用磷酸盐作为加合物）之外，在从病毒和其他糖蛋白中释放的 N-糖链混合物中还观察到其他双电荷、三电荷和四电荷离子，组成 [M + (HPO)]。本文特别探讨了这些不同类型的多电荷离子的形成和碎裂，重点介绍了 CID 谱中存在的诊断片段，并评论了如何利用这些离子来表征这些糖链。
