Human α3-fucosyltransferases convert chitin oligosaccharides to products containing a GlcNAcβ1-4(Fucα1-3)GlcNAcβ1-4R determinant at the nonreducing terminus

Human alpha3-fucosyltransferases (Fuc-Ts) are known to convert N-acetyllactosamine to Gal beta1-4(Fuc alpha1-3)GlcNAc (Lewis x antigen); some of them transfer fucose also to GalNAc beta1-4GlcNAc, generating GalNAc beta1-4(Fuc alpha1-3)GlcNAc determinants. Here, we report that recombinant forms of Fuc-TV and Fuc-TVI as well as Fuc-Ts of human milk converted chitin oligosaccharides of 2-4 GlcNAc units efficiently to products containing a GlcNAc beta1-4(Fuc alpha1-3)GlcNAc beta1-4R determinant at the nonreducing terminus. The product structures were identified by mass spectrometry and nuclear magnetic resonance experiments; rotating frame nuclear Overhauser spectroscopy data suggested that the fucose and the distal N-acetylglucosamine are stacked in the same way as the fucose and the distal galactose of the Lewis x determinant. The products closely resembled a nodulation factor of Mesorhizobium loti but were distinct from nodulation signals generated by NodZ-enzyme.