The LEC11 Chinese hamster ovary mutant synthesizes N-linked carbohydrates containing sialylated, fucosylated lactosamine units. Analysis by one- and two-dimensional ¹H NMR spectroscopy

Glycoproteins synthesized by the Chinese hamster ovary cell mutants LEC11 and LEC12 carry the Le(x) determinant (Galβ1,4(Fucα1,3)GlcNAc), while those synthesized by LEC11 cells also carry the sialyl-Le(x) determinant (NeuAcα2,3Galβ1,4(Fucα1,3)GlcNAc), and both mutants have been shown to possess a distinct α(1,3)-fucosyltransferase of the appropriate specificity to synthesize these determinants (Campbell, C., and Stanley, P. (1983) Cell 35, 303-309; Campbell, C., and Stanley, P. (1984), J. Biol. Chem. 259, 11208-11214; Howard, D. R., Fukuda, M., Fukuda, M. N., and Stanley, P. (1987) J. Biol. Chem. 262, 16830-16837). The LEC11 cells therefore provide a source of carbohydrates terminating in sialylated, fucosylated lactosamine, a relatively rare structure not previously characterized by ¹H NMR spectroscopy when in association with an N-linked carbohydrate. In this paper we use a monoclonal antibody specific for Le(x) to show that the G glycoprotein of vesicular stomatitis virus (VSV) grown in LEC11 and LEC12 cells possesses the Le(x) determinant and that G from LEC11/VSV also possesses sialylated Le(x). Biantennary carbohydrates purified from LEC11/VSV and LEC12/VSV were therefore used to examine the effects on the ¹H NMR spectrum of the presence of α(1,3)-fucose residues on sialylated and unsialylated lactosamine units. Comparisons of one-dimensional spectra obtained at 500 MHz from LEC11/VSV and LEC12/VSV glycopeptides before and after neuraminidase treatment with spectra of biantennary carbohydrates lacking α(1,3)-fucose allowed the assignment of several new resonances. Resolution of certain signals and determinations of coupling constants were achieved by two-dimensional correlation spectroscopy (COSY) at 400 MHz and allowed the assignment of several more resonances in the one-dimensional spectrum.