The Structure of Sulfated Polysaccharides from the Sea Cucumber Holothuria (Stauropora) fuscocinerea

Fucosylated chondroitin sulfate FCS-Hf and preparations of fucan sulfates Hf-Fuc1 and Hf-Fuc2 were isolated from the Vietnamese sea cucumber Holothuria (Stauropora) fuscocinerea. Separation of the polysaccharides was carried out using anion-exchange chromatography on DEAE-Sephacel. The structure of polysaccharides was established by determinations of the content of monosaccharides and sulfate, as well as by NMR spectra. It was shown that FCS-Hf was built of the repeating trisaccharide fragments, with alternating 3-linked N-acetyl-β-D-galactosamine and 4-linked β-D-glucuronic acid residues forming the main polymer chain, which carries α-L-fucose residues as side branches attached to O3 of glucuronic acid. The regular structure of the polymer is masked by an uneven distribution of sulfate groups attached to fucose residues (2,4-disulfate, 3,4-disulfate and 4-monosulfate in a ratio of 2 : 2 : 1) and galactosamine residues (4,6-disulfate and 4-monosulfate in a ratio of 3 : 1). It was also shown that fucan sulfate Hf-Fuc1 contained predominantly linear molecules built of 4-linked α-L-fucose 3-sulfate residues, while Hf-Fuc2 appeared to be a mixture of several related linear and branched fucan sulfates containing 3-linked and 4-linked α-L-Fuc residues sulfated at different positions.