Structural Analysis of Carbohydrates by Mass Spectrometry

<p>Protein glycosylation is a highly frequent post-translational modification. Glycosylation is actively involved in intermolecular and intercellular binding events that are important to a wide range of biological functions such as immunity and fertility. The unique functions of glycans are directly related to their structures. In order to fully characterize the structure of an unknown glycan, 5 levels of structural information is needed: sugar unit identity, anomeric configuration, linkage types, sequence, and branching location. One of the grand challenges limiting the advance of glycosciences is the lack of sensitive tools for detailed glycan structural analysis. Tandem mass spectrometry (MS/MS) is a powerful tool for structural analysis of carbohydrates with its high sensitivity and selectivity. MS2 (two-stage tandem mass spectrometry) is most often adopted due to the wide availability of commercial instruments; however, glycan structural determination typically stops at the level of topology (relative location of sugar unites). The goal of this research is to develop a multiple stage tandem mass spectrometry approach toward a sensitive and full level structural analysis of linear oligosaccharides by obtaining information of individual sugar unit identity, anomeric configuration, linkage types, and sequence. This approach roots in the discovery of diagnostic ions, which are sub-structures of disaccharides and the fragmentation patterns of which can be linked to a specific level of structural information. An MS3 screening method was developed and a new diagnostic ion (Z1) for linkage determination was established for the first time. With the use of another diagnostic ion (non-reducing sugar glycosidically linked to glycolaldehyde, m/z 221) discovered by Bendiak group, identity, anomeric information, and linkage position of the non-reducing sugar within a disaccharide can be determined from MS3 experiments. By utilizing pattern comparison algorithm, spectral similarity score, highly confident structural information can be obtained automatically. The strategy of diagnostic ions was further demonstrated on model linear oligosaccharides using MSn (n =3-5) for full level structural determination.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Year

2013

Author dc:creator

• Konda, Chiharu

Contributors dc:contributor

• Yu Xia
• Peter T. Kissinger
• Nikolai R. Skrynnikov
• Hikka I. Kenttamaa

• carbohydrates
• mass spectrometry
• structural analysis
• Analytical Chemistry

Repository record dc:identifier

https://docs.lib.purdue.edu/open_access_dissertations/141

OAI identifier oai:identifier

oai:docs.lib.purdue.edu:open_access_dissertations-1074