Schistosoma mansoni: Characterization of an α1-3 fucosyltransferase in adult parasites

We report that extracts of Schistosoma mansoni contain a GDPFuc:Galβ1-4GlcNac (Fuc to GlcNAc) α1-3 fucosyltransferase (α1,3FT) capable of synthesizing the antigenic determinant known as Lewis x (Le(x), Galβ1-4[Fucα1-3]GlcNAcβ1-R). When the acceptor lacto-N-neotetraose (LNnt, Galβ1-4GlcNAcβ1-3Galβ1-4Glc) was incubated with extracts of S. manosoni in the presence of GDPFuc and Mn^2, Fuc was transferred to generate the pentasaccharide lacto-N-fucopentaose III (LNFPIII, Galβ1-4[Fucα1-3Galβ1-4Glc). The enzyme did not transfer efficiently to the isomeric oligosaccharide lacto-N-tetraose (LNT, Galβ1-3GlcNAcβ1-3Galβ1-4Glc. The activity of the schistosome α1,3FT toward LNnT was dependent upon time, protein, and GDPFuc. Interestingly, the schistosome α1,3FT was also able to transfer Fuc to a sialic acid-containing trisaccharide NeuAcα2-3Galβ1-4GlcNAc to produce the tetrasaccharide sialyl Lewis x (2,3 sLe(x), NeuAcα2-3Galβ1-4[Fuc1-3]GlcNAc, although the rate of reaction with the sialylated acceptor was <5% of the rate obtained toward nonsialylated acceptor. The schistosome α1,3FT was relatively resistant to inhibition by N-ethylmaleimide. The enzymatic properties of the schistosome α1,3FT resemble those of the human myeloid fucosyltransferase FTIV and not those of other known human focosyltransferases.