Crystallization and preliminary X-ray crystallographic studies of a lectin from the mushroom Marasmius oreades

The Marasmius oreades agglutinin (MOA) recognizes blood group B oligosaccharides. This mushroom lectin belongs to the ricin superfamily and is currently the only lectin known with exclusive specificity for Galalpha1,3Gal-structures, as occur in the subterminally fucosylated blood group B epitope Galalpha1,3(Fucalpha1,2)Galbeta1,4GlcNAc (MOA's preferred ligand) or without fucosylation in the xenotransplantation epitope. MOA has been co-crystallized with the linear blood group B trisaccharide Galalpha1,3Galbeta1,4GlcNAc using the hanging-drop vapour-diffusion technique at room temperature. MOA crystals were grown in the presence of ammonium formate and HEPES buffer. A 3.0 A data set has been collected. Preliminary analysis of the X-ray data is consistent with space group P3(1) or P3(2) and unit-cell parameters a = b = 105, c = 113 A, with two dimers per asymmetric unit.