title: Inhibition of reverse transcriptase activity of HIV by polysaccharides of brown algae.
abstract: Brown algae have two kinds of acid polysaccharides present in the extracellular matrix: sulfated fucan and alginic acid. We have previously isolated and characterized fucans from several species of brown seaweed. The characterized fucans from Dictyotaceae are heterofucans containing mainly fucose, galactose, glucose, xylose, and/or uronic acid. The fucan from Fucus vesiculosus is a homofucan containing only sulfated fucose. We assessed the activity of these fucans as inhibitors of HIV from reverse transcriptase (RT). Using activated DNA and template primers poly(rA)-oligo(dT), we found that fucans at a concentration of 0.5-1.0 microg/mL had a pronounced inhibitory effect in vitro on the avian reverse transcriptase, with the exception of xylogalactofucan isolated from Spatoglossum schröederi, which had no inhibitory activity. The alginic acid (1.0 microg/mL) inhibited the reverse transcriptase activity by 51.1% using activated DNA. The inhibitory effect of fucans was eliminated by their desulfation. Furthermore, only xylofucoglucuronan from S. schröederi lost its activity after carboxyreduction. We suggest that fucan activity is not only dependent on the ionic changes but also on the sugar rings that act to spatially orientate the charges in a configuration that recognizes the enzyme, thus determining the specificity of the binding.
authors.affiliation: Laboratório de Glicobiologia, Departamento de Bioquímica, Universidade Federal de Rio Grande do Norte-UFRN, Av. Senador Salgado Filho, 3000, Campus Universitário, Centro de Biociências, Bairro Lagoa Nova. CEP 59072-970, Natal-RN, Brazil.
authors.forename: K C S
authors.initials: KC
authors.lastname: Queiroz
authors.forename: V P
authors.initials: VP
authors.lastname: Medeiros
authors.forename: L S
authors.initials: LS
authors.lastname: Queiroz
authors.forename: L R D
authors.initials: LR
authors.lastname: Abreu
authors.forename: H A O
authors.initials: HA
authors.lastname: Rocha
authors.forename: C V
authors.initials: CV
authors.lastname: Ferreira
authors.forename: M B
authors.initials: MB
authors.lastname: Jucá
authors.forename: H
authors.initials: H
authors.lastname: Aoyama
authors.forename: E L
authors.initials: EL
authors.lastname: Leite
mesh_terms: D019380:Anti-HIV Agents / Q000737:chemistry*; D054303:HIV Reverse Transcriptase / Q000037:antagonists & inhibitors* / Q000737:chemistry; D000459:Phaeophyceae / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*; D018894:Reverse Transcriptase Inhibitors / Q000737:chemistry*; D013329:Structure-Activity Relationship
chemical_list: D019380:Anti-HIV Agents; D011134:Polysaccharides; D018894:Reverse Transcriptase Inhibitors; C007789:fucoidan; C514824:reverse transcriptase, Human immunodeficiency virus 1; D054303:HIV Reverse Transcriptase