Botryosphaeran, a (1 -> 3;1 -> 6)-beta-D-glucan produced by Botryosphaeria rhodina MAMB-05, was found to be present in a triple helix conformation from helix-coil transition studies using Congo Red. The triple helix conformation was disrupted at increasing alkali concentrations. Conformational changes were also observed using phenanthrene as a fluorescent probe, and the fluorescence intensity decreased 80% in the presence of dimethyl sulfoxide. The results confirmed the triple helix conformation of botryosphaeran, an important property manifesting biological response modifying activity. (C) 2008 Elsevier Ltd. All rights reserved.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)