Energy-Dependent Electron Activated Dissociation of Metal-Adducted Permethylated Oligosaccharides

Abstract

The effects of varying the electron energy and cationizing agents on electron activated dissociation (ExD) of metal-adducted oligosaccharides were explored, using permethylated maltoheptaose as the model system. Across the examined range of electron energy, the metal-adducted oligosaccharide exhibited several fragmentation processes, including electron capture dissociation (ECD) at low energies, hot-ECD at intermediate energies, and electronic excitation dissociation (EED) at high energies. The dissociation threshold depended on the metal charge carrier(s), whereas the types and sequence spans of product ions were influenced by the metal-oligosaccharide binding pattern. Theoretical modeling contributed insight into the metal-dependent behavior of carbohydrates during low-energy ECD. When ExD was applied to a permethylated high mannose N-linked glycan, EED provided more structural information than either collision-induced dissociation (CID) or low-energy ECD, thus demonstrating its potential for oligosaccharide linkage analysis.

GlycoDeNovo – an Efficient Algorithm for Accurate de novo Glycan Topology Reconstruction from Tandem Mass Spectra

“…Lately, a number of radical-induced dissociation methods have been applied to structural analysis of glycans, many of which were capable of producing more extensive sequence information than CID [33–43]. Among them, the recently developed EED is a particularly powerful method, as it can generate rich structural information for glycan characterization, including linkage differentiation, for a wide variety of glycans, with or without derivatization [40–41,44–45]. Figure 3 shows the CID and EED spectra and cleavage maps of deutero-reduced and permethylated LNFP II, [M+Na] + , with all assigned peaks listed in Supporting Table S1.…”

Radical mediated dissection of oligosaccharides

“…The advantage of cleavage at glycosidic bonds is that the generic monomeric substructure is revealed; however, linkage site information is often lost. In contrast, cross-ring cleavage is frequently observed in many activated ion dissociation methods including electron capture dissociation (ECD) [7,8], electronic excitation dissociation (EED) [9], electron transfer dissociation (ETD) [10,11], electron detachment dissociation (EDD) [12] and high energy photodissociation [13][14][15]. Odd-electron radical species and fragments are generated in most of these methods, which facilitate homolytic bond cleavage and ring-opening.…”

Populations of Metal-Glycan Structures Influence MS Fragmentation Patterns

“…11–15 Several papers have compared ionization efficiencies of underivatized glycans in the presence of various metals and demonstrated that individual metals could induce distinct fragmentation patterns during collision-induced dissociation (CID) and electron activated dissociation. 16–20 However, much less is known about the structures of carbohydrate complexes associated with different charge carriers, such as transition metals.…”