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Zähringer, Raphael

doi:10.1515/9783110535853

Cited by 6 publications

(2 citation statements)

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“…17 NMR and mass spectrometry have revealed the saccharide composition and connectivity of each of these core types of LPS. 18,19 An array of MS/MS approaches 20,21 have been used to analyze the lipid A portion (the most widely studied of all the domains), [22][23][24][25][26][27] rough type LOS (LPS molecules without the highly repetitive O-antigen portion), [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] smooth type LPS (LPS molecules containing the Oantigen portion), 20,[43][44][45][46] and to a lesser extent the oligosaccharide core. [32][33][34]47,48 Characterization of intact LPS and LOS are the most demanding endeavors because of their amphiphilic structures, and the most effective strategies have combined multiple ion activation methods and multi-stage MS n strategies to maximize the information obtained from the complex structures.…”

Section: Introductionmentioning

confidence: 99%

“…[32][33][34]47,48 Characterization of intact LPS and LOS are the most demanding endeavors because of their amphiphilic structures, and the most effective strategies have combined multiple ion activation methods and multi-stage MS n strategies to maximize the information obtained from the complex structures. [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] Conventional CID typically allows localization of glycylation, phosphorylation, and acylation of the lipid A portion of LPS and LOS, but has been less successful for oligosaccharide connectivity information owing to insufficient production of X-and A-type ions, cross-ring cleavage products typically used for characterizing branching patterns of oligosaccharides. 42 Top-down methods have gained attention owing to the compelling goal of characterizing the lipopolysaccharides as intact species, 28 thus alleviating the need for hydrolysis and deacylation methods that simplify the molecules at the expense of degradation of important structural features.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Antigenic Oligosaccharides from Gram-Negative Bacteria via Activated Electron Photodetachment Mass Spectrometry

et al. 2019

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Lipooligosaccharides (LPS), composed of hydrophilic oligosaccharides and hydrophilic lipid A domains, are found on the outer membranes of Gram-negative bacteria. Here we report the characterization of core oligosaccharides of LPS by activated-electron photodetachment mass spectrometry. Collision induced dissociation (CID) of these phosphorylated oligosaccharides produces simple MS/MS spectra with most fragment ions arising from cleavages near the reducing end of the molecule where the phosphate groups are located. In contrast, 193 nm ultraviolet photodissociation (UVPD) generates a wide array of product ions throughout the oligosaccharide including cross-ring fragments that illuminate the branching patterns. However, there are also product ions that are redundant or uninformative, resulting in more congested spectra that complicate interpretation. In this work, a hybrid UVPD-CID approach known as activated-electron photodetachment (a-EPD) affords less congested spectra than UVPD alone and richer fragmentation patterns than CID alone. a-EPD combines UVPD of negatively charged oligosaccharides to yield abundant charge-reduced radical ions which are subsequently interrogated by collisional activation. CID of the charge-reduced precursors results in extensive fragmentation throughout the backbone of the oligosaccharide. This hybridized a-EPD approach was employed to characterize the structure and branching pattern of core oligosaccharides from lipopolysaccharides of E. coli.

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