Differentiation of the fucoidan sulfated l-fucose isomers constituents by CE-ESIMS and molecular modeling

Abstract

Alpha-L-fucose, the monosaccharide component of fucoidan, is found in the polysaccharide mainly as its sulfated form where sulfate groups are in position 2 and/or 4 and/or 3. The correlation between biological activities and structure of fucoidan requires the determination of the sulfation pattern of the fucose residues. Therefore, it is of importance to discriminate between the isobaric sulfated fucose isomers. For this purpose, the three isomers 2-O-, 3-O-, and 4-O-sulfated fucose have been analyzed using electrospray ion trap mass spectrometry and capillary electrophoresis. The results reported herein show that it is possible to differentiate between these three positional isomers of sulfated fucose based on their fragmentation pattern upon MS/MS experiments. 3-O-Sulfated fucose was characterized by the loss of the hydrogenosulfate anion HSO4- as the main fragmentation product, while the two other isomers 2-O-, and 4-O-sulfated fucose exhibited cross-ring fragmentation yielding to distinctive (0,2)X and (0,2)A daughter ion, respectively. A computational study of the conformation of the sulfated fucose isomers was carried out providing an understanding of the fragmentation pattern with respect to the position of the sulfate group.

Structural analysis of a highly sulfated fucan from the brown alga Laminaria cichorioides by tandem MALDI and ESI mass spectrometry

“…It must be noted that the MS/MS spectrum did not contain fragment ions at m/z 168.9, which would have suggested 3-sulfation of the a-L-Fucp residue. 21 But the MALDI MS/ MS spectrum (not shown) contained an abundant fragment ion of 0,2 A at m/z 182.9, while the intensity of the 0,2 X fragment ion at m/z 138.9 was much lower.…”

B3LYP/6-311++G∗∗ study of structure and spin–spin coupling constant in heparin disaccharide

“…[19][20][21][22] Well-refined structures are essential for calculations of other theoretical data, such as NMR parameters. Calculations on structurally similar compounds, 23-25 obtained using the B3LYP/6-311++G ** and B3LYP/6-31+G * basis sets, enabled calculations of geometries, energies and NMR parameters.…”

Structure and anticancer activity in vitro of sulfated galactofucan from brown alga Alaria angusta

“…2) was observed. The presence of 0,3 A-type ions from the crossring cleavage of the non-reducing (and even internal) Gal residue also, probably, indicated sulfation at C3 (Tissot, Salpin, Martinez, Gaigeot, & Daniel, 2006).…”