Leary Julie A, Miller Rebecca L, Wei Wei, Schwörer Ralf, Zubkova Olga V, Tyler Peter C, Turnbull Jeremy E
De partments of Molecular and Cellular Biology and Chemistry, University of California, USA..
Departments of Molecular and Cellular Biology and Chemistry, University of California. Centre for Glycobiology, Institute of Integrative Biology, University of Liverpool, Crown Street, Liverpool, L69 7ZB, UK.
Eur J Mass Spectrom (Chichester). 2015;21(3):245-54. doi: 10.1255/ejms.1337.
Here we report ion mobility mass spectrometry (IMMS) separation and tandem mass spectrometry (MS(2)) sequencing methods used to analyze and differentiate six synthetically produced heparin/heparan sulfate (HS)-like octasaccharide (dp8) isomeric structures. These structures are isomeric with regard to either glucuronic acid (GlcA) or iduronic acid (IdoA) residues at various positions. IMMS analysis showed that a fully GlcA structure exhibited a more compact conformation, whereas the fully IdoA structure was more extended. Interestingly, the change from IdoA to GlcA in specific locations resulted in strong conformational distortions. MS(2) of the six isomers showed very different spectra with unique sets of diagnostic product ions. Analysis of MS(2) product ion spectra suggests that the GlcA group correlated with the formation of a glycosidic product ion under lower energy conditions. This resulted in an earlier product ion formation and more intense product ions. Importantly, this knowledge enabled a complete sequencing of the positions of GlcA and IdoA in each of the four positions located in each unique dp8 structure.
在此，我们报告了离子淌度质谱（IMMS）分离和串联质谱（MS(2)）测序方法，用于分析和区分六种合成制备的肝素/硫酸乙酰肝素（HS）样八糖（dp8）异构体结构。这些结构在不同位置的葡萄糖醛酸（GlcA）或艾杜糖醛酸（IdoA）残基方面是异构的。IMMS分析表明，完全由GlcA构成的结构呈现出更紧凑的构象，而完全由IdoA构成的结构则更为伸展。有趣的是，特定位置从IdoA转变为GlcA会导致强烈的构象扭曲。六种异构体的MS(2)显示出非常不同的光谱，具有独特的诊断产物离子集。对MS(2)产物离子光谱的分析表明，GlcA基团与在较低能量条件下糖苷产物离子的形成相关。这导致了更早的产物离子形成和更强的产物离子。重要的是，这一知识使得能够对每个独特dp8结构中四个位置上的GlcA和IdoA的位置进行完整测序。
