Poster: Cyclic Ion Mobility Mass Spectrometry Distinguishes Anomers and Open-Ring Forms of Pentasaccharides
31. Cyclic Ion Mobility Mass Spectrometry Distinguishes
Anomers and Open-Ring Forms of Pentasaccharides
Authors: Jakub Ujma - Waters,David Ropartz - INRA, UR1268 Biopolymers
Interactions Assemblies,Kevin Giles - Waters,Keith Richardson - Waters,David
Langridge - Waters,Jason Wildgoose - Waters,Martin Green - Waters,Steven
Pringle - Waters,
Aims
There is increasing biopharmaceutical interest in oligosaccharides and
glycosylation. A key requirement for these sample types is the ability to
characterize the chain length, branching, type of monomers and importantly
stereochemistry and anomeric configuration. MS methods provide key
advantages in analysis of saccharides. Nevertheless, determination of the
anomeric configuration of the linkage between subunits is a major challenge.
Herein, we showcase a study of three isomeric pentasaccharides using a cyclic
ion mobility (cIM) separator embedded in a Q-ToF mass spectrometer (Q-cIMToF
MS).
Results
The instrument is based on a Waters SYNAPT G2-Si IM-MS platform,
with the IM separation region modified to accept a cyclic ion mobility (cIM)
device. In addition to single and multi-pass separations around the cIM, providing
selectable mobility resolution, the instrument design and control software enable
a range of ‘multi-function’ experiments such as: mobility selection, activation,
storage, IMS^n and importantly, custom combinations of these functions. Using
high cIM resolution we demonstrate the separation of three isomeric
pentasaccharides and, moreover, that three components are present for each
compound. Using IMS^n we show that structural differences between product
ions reflect the precursor differences in some cases but not others. These
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findings are corroborated by a heavy oxygen labelling approach. Using this
methodology, the identity of fragment ions may be assigned.
Conclusions
The IMSˆn approach proved extremely flexible and valuable in
unravelling new information regarding the fragmentation of oligosaccharides. We
show that the performance of the instrument is sufficient to resolve three
components of three isomeric pentasaccharides. With the aid of isotopic
labelling, we were able to correlate the assignments of features resolved in
IMS^n experiments. Collectively, the results enable us to postulate that the two
main components observed for each pentasaccharide are anomeric forms. The
remaining low abundance component is assigned as an open-chain form.