title: Is there a correlation between structure and anticoagulant action of sulfated galactans and sulfated fucans?
abstract: We attempted to identify the specific structural features in sulfated galactans and sulfated fucans that confer anticoagulant activity. For this study we employed a variety of invertebrate polysaccharides with simple structures composed of well-defined units of oligosaccharides. Our results indicate that a 2-O-sulfated, 3-linked alpha-L-galactan, but not a alpha-L-fucan with a similar molecular size, is a potent thrombin inhibitor mediated by antithrombin or heparin cofactor II. The difference between the activities of these two polysaccharides is not very pronounced when factor Xa replaced thrombin. The occurrence of 2,4-di-O-sulfated units is an amplifying motif for 3-linked alpha-fucan-enhanced thrombin inhibition by antithrombin. If we replace antithrombin by heparin cofactor II, then the major structural requirement for the activity becomes single 4-O-sulfated fucose units. The presence of 2-O-sulfated fucose residues always had a deleterious effect on anticoagulant activity. Overall, our results indicate that the structural requirements for interaction of sulfated galactans and sulfated fucans with coagulation cofactors and their target proteases are stereospecific and not merely a consequence of their charge density and sulfate content.
authors.affiliation: Laboratório de Tecido Conjuntivo, Hospital Universitário Clementino Fraga Filho and Departamento de Bioquímica Médica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Caixa Postal 68041, Rio de Janeiro, RJ, 21941-590, Brazil.
authors.forename: Mariana S
authors.initials: MS
authors.lastname: Pereira
authors.forename: Fábio R
authors.initials: FR
authors.lastname: Melo
authors.forename: Paulo A S
authors.initials: PA
authors.lastname: Mourão
mesh_terms: D000925:Anticoagulants / Q000737:chemistry* / Q000494:pharmacology*; D002240:Carbohydrate Sequence; D002850:Chromatography, Gel; D005685:Galactans / Q000737:chemistry* / Q000494:pharmacology*; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000737:chemistry* / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D000925:Anticoagulants; D005685:Galactans; D011134:Polysaccharides; C007789:fucoidan