Fucosylation of complex glycosphingolipids by recombinant fucosyltransferase-VII.
Fucosyltransferase VII (FucT-VII) is one of five known alpha 1-->3fucosyltransferases capable of transferring fucose to the C-3 position of N-acetylglucosamine residues found in lactosamine based glycans. Previous studies have indicated that FucT-VII has a very restricted specificity, capable of fucosylating only terminally alpha 2-->3sialylated carbohydrate substrates, resulting in the synthesis of the sialyl Lewis x (sLe(x)) epitope. Although FucT-VII is expressed in cells of myeloid origin, the monosialylganglioside fraction of HL60 cells contains only internally and/or multiply fucosylated polylactosamine structures; no monofucosylated sLe(x) derivatives are detected. We now report that the structure of the final product formed by the action of FucT-VII on sialynorhexaosylceramide (a glycosphingolipid substrate having multiple fucosylation sites) is extended monofucosyl sLe(x) and fucosylation is restricted to the terminal GlcNAc-V. This indicates that the biosynthesis of all fucosylated monosialylated gangliosides found in HL60 cells (including the E-selectin binding fractions) involves at least one additional alpha 1-->3fucosyltransferase.
Stroud
M R
MR
Department of Cell Surface Biochemistry, Northwest Hospital, Seattle, Washington 98125, USA.
Holmes
E H
EH
D002240:Carbohydrate Sequence; D002250:Carbon Radioisotopes; D002518:Ceramides / Q000737:chemistry / Q000378:metabolism; D005643:Fucose / Q000378:metabolism*; D005647:Fucosyltransferases / Q000235:genetics / Q000378:metabolism*; D005732:Gangliosides / Q000737:chemistry / Q000378:metabolism; D006028:Glycosphingolipids / Q000737:chemistry / Q000378:metabolism*; D006154:Guanosine Diphosphate Fucose / Q000378:metabolism; D018922:HL-60 Cells; D006801:Humans; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism*; D013379:Substrate Specificity
D002250:Carbon Radioisotopes; D002518:Ceramides; D005732:Gangliosides; D006028:Glycosphingolipids; D009844:Oligosaccharides; D011994:Recombinant Proteins; C025447:sialogangliosides; D006154:Guanosine Diphosphate Fucose; D005643:Fucose; D005647:Fucosyltransferases