Multistage LC-MSn for automated glycan isomer assignment of glycopeptides

N- and O-linked glycosylation are some of the most common, abundant, and biologically important posttranslational modifications of proteins, yet they are also some of the most difficult to study. The dominant analytical platform for the study of glycosylation is mass spectrometry, yet this platform on its own is incomplete, because it cannot elucidate glycan topology and linkage stereochemistry. This project will advance the use of mass spectrometry for glycan structure determination, especially for the case of O-linked glycans, by studying the ion propensities of various structural motifs in multi-stage ion trap mass spectrometry, and by building new software for structure inference from such mass spectra.NARRATIVE A milieu of complex sugar structures cover the cells of higher organisms and play critical roles in biology including regulation of host-pathogen interactions and modulation of the immune system. Understanding the detailed structures of the sugars that are associated with disease onset can identify ways of preventing pathogens from infecting cells and provide better ways to detect and target cancer cells. This project aims to implement recent developments in sugar analysis by mass spectrometry into a software platform to provide a much- needed tool to study the biological roles of structural sugars, including regulation of the immune response and tumor progression.