Fucose Migration Pathways Identified Using Infrared Spectroscopy**

Abstract

Fucose is a ubiquitous monosaccharide associated to major classes of glycans. A main obstacle to the sequencing of fucosylated glycans is the migration of fucose, which leads to misinterpretations in mass spectrometry analysis. Here, using ion vibrational spectroscopy, we resolve the structure of fucosylated fragments of Lewis and blood group H antigen trisaccharides and we unveil the position and linkage of the fucose after migration. Our findings demonstrate that the structure of fragment ions resulting from fucose migration can be characterized. Additionally, we report a new type of fucose migration, which does not feature any change of mass and therefore had not been previously reported: it consists of a local migration where the fucose changes its position remaining on the initial residue. Our approach allows the characterization of glycans, an essential step to interpret glycomics data, as well as to understand underlying processes at play in mass spectrometry.

Reinvestigation of the internal glycan rearrangement of Lewis a and blood group type H1 epitopes

“…In recent work, Moge et al reported 33 the rearrangement product of fucose-containing disaccharides that carried a fucose attached by an α(1 → 6) bond to GlcNAc. The rearrangement product that features a similar glycosidic linkage, [an16 + H] + , is among the most stable isomers and is more stable by 2.0 and 3.9 kcal mol −1 than, respectively, the α and β-anomers of Le a .…”

“…Products of fucose migration in (B) T2-derived antigens 32 and in (C) a series of Fuc -GlcNAc disaccharides. 33 the theoretical calculations, inconclusive. In the study of Mucha et al, the IR spectra of the two ions showed enough difference to conclude that the fucose rearrangement is rather unlikely.…”

“…[20][21][22][23][24] However, it has been observed that -in a process similar to peptide scrambling 25 electrospray ionization (ESI) or collision-induced dissociation (CID) can alter the glycan sequence which results in additional non-native fragments being recorded in the mass spectrum. [26][27][28][29][30][31][32][33] Although the phenomenon is associated mostly with fucose-containing protonated glycans -hence it is often called fucose migration 28,[34][35][36][37] -similar rearrangements have been observed for rhamnose, 38 mannose, 39 and xylose. 40 The structural motifs that trigger this rearrangement, as well as its mechanism and likelihood of occurrence, remain unknown after more than 40 years since their first observation.…”

“…1C). 33 In this work, we aim to deepen our understanding of the structural motifs that drive the fucose migration by interrogating whether a similar phenomenon occurs in the T1-derived antigens. By comparing the likelihood of the migration and its tentative products in these two model systems, i.e.…”

The Structure Determination of Organic Molecules by Co-crystallization of Anthracene-Based Crystallization Chaperone

“…Whether the organic compounds are natural products − or synthesized by chemists, it is extremely important to determine their structures and absolute conformations at the atomic level. Over the past few decades, numerous researchers have developed and refined many methods for the structural identification of organic molecules, such as nuclear magnetic resonance ( NMR ), − infrared spectroscopy ( IR ), − mass spectrometry ( MS ), − single crystal X-ray diffraction ( X-ray SCD ), − etc. Among them, X-ray SCD can provide direct and accurate structural information and is globally recognized as a fairly reliable method for the structural identification of organic compounds, including their stereochemical conformation.…”