title: Decoding of O-Linked Glycosylation by Mass Spectrometry.
abstract: Protein glycosylation (N- and O-linked) plays an important role in many biological processes, including protein structure and function. However, the structural elucidation of glycans, specifically O-linked glycans, remains a major challenge and is often overlooked during protein analysis. Recently, mass spectrometry (MS) has matured as a powerful technology for high-quality analytical characterization of O-linked glycans. This review summarizes the recent developments and insights of MS-based glycomics technologies, with a focus on mucin-type O-glycan analysis. Three main MS-based approaches are outlined: O-glycan profiling (structural analysis of released O-glycan), a "bottom-up" approach (analysis of an O-glycan covalently attached to a glycopeptide), and a "top-down" approach (analysis of a glycan attached to an intact glycoprotein). In addition, the most widely used MS ionization techniques, i.e., matrix-assisted laser desorption ionization and electrospray ionization, as well as ion activation techniques like collision-induced dissociation, electron capture dissociation, and electron transfer dissociation during O-glycan analysis are discussed. The MS technical approaches mentioned above are already major improvements for studying O-linked glycosylation and appear to be valuable for in-depth analysis of the type of O-glycan attached, branching patterns, and the occupancy of O-glycosylation sites.
authors.affiliation: Bioassay Development and Quality, Analytical Sciences, Biopharmaceutical Development, MedImmune , Gaithersburg, Maryland 20878, United States.
authors.forename: SriHariRaju
authors.initials: S
authors.lastname: Mulagapati
authors.affiliation: Bioassay Development and Quality, Analytical Sciences, Biopharmaceutical Development, MedImmune , Gaithersburg, Maryland 20878, United States.
authors.forename: Veerendra
authors.initials: V
authors.lastname: Koppolu
authors.affiliation: Bioassay Development and Quality, Analytical Sciences, Biopharmaceutical Development, MedImmune , Gaithersburg, Maryland 20878, United States.
authors.forename: T Shantha
authors.identifier: http://orcid.org/0000-0002-6698-2508
authors.initials: TS
authors.lastname: Raju
mesh_terms: D000818:Animals; D019295:Computational Biology / Q000379:methods*; D006023:Glycoproteins / Q000737:chemistry / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D010100:Oxygen / Q000378:metabolism*; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism
chemical_list: D006023:Glycoproteins; D011134:Polysaccharides; D010100:Oxygen