Content area
Abstract
Tandem mass spectrometry (MS/MS) is among one of the most powerful tools in glycoconjugate and carbohydrate analysis. With a need for further structural characterization of such analytes, there is a rising demand for enhancing the information content of MS/MS spectra. Therefore, in recent years, there have been many efforts to increase glycoprotein sequence coverages and in turn provide more structural and bioanalytical insights toward the functions and bioactivities of glycoproteins. A variety of ion activation and dissociation techniques have been implemented to achieve this goal, though some are subjected to limitations arising from the fragmentation pathways available in the ion activation process. A comprehensive understanding of the key parameters that govern fragmentation channels can allow for prediction of the product ions formed in gas-phase activation routes. This dissertation centers on the development of experimental designs that allow for the investigation into fundamentals of glycopeptide dissociation and major factors that influence the dissociation mechanisms. Chapter I is an overview on MS/MS strategies that are utilized to obtain vast information on peptide composition, attached glycan structure, and the glycosylation site of a glycoprotein. Chapter II describes a study on the effect of glycopeptide charge carrier on vibrational activation / dissociation characteristics of N-linked high mannose glycopeptides. Chapter III illustrates the impact of glycan size on the fragmentation pattern of high mannose N-linked glycopeptides via low energy collision-induced dissociation (CID). Chapter IV discusses the incorporation of surface-induced dissociation (SID) inside Synapt G2-S HDMS quadrupole time-of-flight (Q-TOF) instrument. The resulting comparison of the energy deposition processes in multi-collision (CID) and single event (SID) activation confirms the involvement of diverse energy deposition channels in each method. Chapter V describes the use of energy-sudden activation dissociation to circumvent the limitations of CID in carbohydrate sequencing. Overall, this dissertation works to address some of the ambiguity in glycopeptide and carbohydrate fragmentation processes.
