Sialic acids have prominent roles in stabilizing cell membranes, modulating cell interactions with the environment and act as recognition sites. Sialic acids can be found at the terminating branches of N-glycans, O-glycans, and gangliosides with different linkages. The separation of isomeric sialyted N-glycans remains challenging due to similar physic-chemical behaviour of the linkage isomers. Furthermore, in multiantennary N-glycans, the location of sialic acids presented at different antennae can be difficult to determine. Current sialylated N-glycans identification methods using mass spectrometry require permethylation to prevent sialic acids loss during the collision induced dissociation (CID) process.  In this study,  the dissociation patterns of native α-(2,3)- and α-(2,6)- sialylated glycans in sodiated form was studied by low-energy collision induced dissociation (CID) using  a linear ion trap mass spectrometer. The collision induced dissociation mechanism is proposed based on our high-level quantum chemistry calculations. The understanding of the dissociation patterns of sialylated glycans allows unambiguity assignment of the type of linkage and the location of the sialic acids in human serum N-glycans. <br/>

Elucidating native sialylated N-glycans isomers by electrospray ionization tandem mass spectrometry

256th National Meeting (2018)

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