NMR characterization and anticoagulant activity of the oligosaccharides from the fucosylated glycosaminoglycan isolated from Holothuria coluber.

A glycosaminoglycan was isolated from the sea cucumber Holothuria coluber (HcFG). A series of oligosaccharide fragments (dp range 3-11) were prepared from its β-eliminative depolymerized product (dHcFG). Extensive NMR characterization of the oligosaccharides indicated the d-GlcA-β1,3-d-GalNAc _4S6S repeating disaccharide backbone was substituted by monosaccharide branches comprising of Fuc _2S4S , Fuc _3S4S and Fuc _4S , linked to O-3 of d-GlcA. For the prevailing Fuc _3S4S at nonreducing end of dHcFG, the β-eliminative depolymerization process of HcFG was compared with those of the FGs from Actinopyga miliaris (AmFG, branched with Fuc _3S4S ) and Stichopus variegatus (SvFG, branched with Fuc _2S4S ). The result suggested that d-GlcA substituted with Fuc _3S4S was more susceptible to depolymerization than that with Fuc _2S4S . It might be due to the larger steric hindrance effects from Fuc _2S4S on the esterification of GlcA. Biological assays confirmed that the minimum chain length (dp8), regardless of the Fuc branch types, was required for the potent anti-iXase and anticoagulant activities in FG fragments.
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