Structural Characterization of Gangliosides and Glycolipids via Ultraviolet Photodissociation Mass Spectrometry

Abstract

Ultraviolet photodissociation (UVPD) mass spectrometry was used to characterize the structures of amphiphilic glycosphingolipids and gangliosides in comparison to collision induced dissociation (CID) and higher energy collision dissociation (HCD) in a high performance Orbitrap mass spectrometer. UVPD produced the widest array of fragment ions diagnostic for both the ceramide base and oligosaccharide moieties. CID and HCD generated mainly glycosidic B/Y and C/Z cleavages of the oligosaccharides moieties and very few informative fragments related to the hydrophobic ceramide base. Several unique cleavages at the sphingoid base and the fatty acid chain occurred upon UVPD, as well as a wider variety of cross ring cleavages (A/X ions), thus affording differentiation of isobaric gangliosides. An LC-UVPD-MS strategy allowed the elucidation of 27 gangliosides among five different classes.

A monophasic extraction strategy for the simultaneous lipidome analysis of polar and nonpolar retina lipids

“…Other ganglioside lipid classes, including GM1, GM2, GD2, GT2, and GP, were not observed in this study above the limits of detection using either retina tissue extraction method. In order to confi rm the putative retina ganglioside species identifi ed by accurate mass measurements, negative ionization mode HCD-MS/MS was utilized to detect the presence of characteristic ganglioside product ions in both the modifi ed Svennerholm upper phase and monophasic retina lipid extracts, as previously described ( 56 ), and by comparison to HCD-MS/MS results obtained from commercially available ganglioside standards. As shown in Fig.…”

Top-down strategies for the structural elucidation of intact gram-negative bacterial endotoxins

“…44,46 We have explored UVPD at 193 nm for characterization of glycolipids, including lipid A, and found that UV photoexcitation promotes extensive C-C, C-N, C-O, glycosidic and cross-ring cleavages which contribute to the highly informative fragmentation patterns observed upon UVPD. 41,61–66 UVPD has allowed unusual modifications to be accurately pinpointed and isobaric species to be differentiated. 41,61–66 …”

Challenges in Separations of Proteins and Small Biomolecules and the Role of Modern Mass Spectroscopy Tools for Solving Them, as Well as Bypassing Them, in Structural Analytical Studies of Complex Biomolecular Mixtures

“…Also, in order to identify structural isomers cleavage of "inert" C-C and C-N bonds in the lipid part are highly desirable. A novel MS/MS fragmentation technique, UVPD (ultraviolet photodissociation) excels in both these aspects [55,[57][58][59].…”

“…Phospholipids and glycolipids represent a diverse class of lipids, and have been studied the most amongst lipids using various MS techniques over the last decade [3,4,[55][56][57][58][59]. MALDI MS/MS approach, using diagnostic precursor ion and neutral loss scans was shown to be highly efficient for analysis of biological lipid mixtures [3].…”

“…Structural isomerism of biomolecules represents a challenge in MS analyses. Sometimes this problem can be solved using alternate MS/MS techniques, such as electronic excitation dissociation (EED [86] or electron transfer dissociation (ETD) [87]) for glycans, or ultraviolet photodissociation (UVPD) for lipids [55,59]. However, most of the time LC separation prior to MS analysis represents the method of choice for dealing with structural isomerism of biomolecules.…”