InterPro domain: IPR001503

The biosynthesis of disaccharides, oligosaccharides and polysaccharides involves the action of hundreds of different glycosyltransferases. These enzymes catalyse the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. A classification of glycosyltransferases using nucleotide diphospho-sugar, nucleotide monophospho-sugar and sugar phosphates ([intenz:2.4.1.-]) and related proteins into distinct sequence based families has been described [ 1 ]. This classification is available on the CAZy (CArbohydrate-Active EnZymes) web site. The same three-dimensional fold is expected to occur within each of the families. Because 3-D structures are better conserved than sequences, several of the families defined on the basis of sequence similarities may have similar 3-D structures and therefore form 'clans'.

Glycosyltransferase family 10 ( GT10 ) comprises enzymes with two known activities; galactoside 3(4)-L-fucosyltransferase ( 2.4.1.65 ) and galactoside 3-fucosyltransferase ( 2.4.1.152 ).

The galactoside 3-fucosyltransferases display similarities with the alpha-2 and alpha-6-fucosyltranferases [ 2 ]. The biosynthesis of the carbohydrate antigen sialyl Lewis X (sLe(x)) is dependent on the activity of an galactoside 3-fucosyltransferase. This enzyme catalyses the transfer of fucose from GDP-beta-fucose to the 3-OH of N-acetylglucosamine present in lactosamine acceptors [ 3 ].

Some of the proteins in this group are responsible for the molecular basis of the blood group antigens, surface markers on the outside of the red blood cell membrane. Most of these markers are proteins, but some are carbohydrates attached to lipids or proteins [Reid M.E., Lomas-Francis C. The Blood Group Antigen FactsBook Academic Press, London / San Diego, (1997)]. Galactoside 3(4)-L-fucosyltransferase ( 2.4.1.65 ) belongs to the Lewis blood group system and is associated with Le(a/b) antigen.

1. A classification of nucleotide-diphospho-sugar glycosyltransferases based on amino acid sequence similarities. Biochem. J. 326 ( Pt 3), 929-39
2. Conserved structural features in eukaryotic and prokaryotic fucosyltransferases. Glycobiology 8, 87-94
3. Chemical modification of an alpha 3-fucosyltransferase; definition of amino acid residues essential for enzyme activity. Biochim. Biophys. Acta 1334, 57-64