GNT1 is a fungal enzyme that belongs to the GT 8 family. N-acetylglucosaminyltransferase is a fungal enzyme that catalyzes the addition of N-acetyl-D-glucosamine to mannotetraose side chains by an alpha 1-2 linkage during the synthesis of mannan. The N-acetyl-D-glucosamine moiety in mannan plays a role in the attachment of mannan to asparagine residues in proteins. The mannotetraose and its N-acetyl-D-glucosamine derivative side chains of mannan are the principle immunochemical determinants on the cell surface. N-acetylglucosaminyltransferase is a member of glycosyltransferase family 8, which are, based on the relative anomeric stereochemistry of the substrate and product in the reaction catalyzed, retaining glycosyltransferases.
Glycogenin belongs the GT 8 family and initiates the biosynthesis of glycogen. Glycogenin initiates the biosynthesis of glycogen by incorporating glucose residues through a self-glucosylation reaction at a Tyr residue, and then acts as substrate for chain elongation by glycogen synthase and branching enzyme. It contains a conserved DxD motif and an N-terminal beta-alpha-beta Rossmann-like fold that are common to the nucleotide-binding domains of most glycosyltransferases. The DxD motif is essential for coordination of the catalytic divalent cation, most commonly Mn2+. Glycogenin can be classified as a retaining glycosyltransferase, based on the relative anomeric stereochemistry of the substrate and product in the reaction catalyzed. It is placed in glycosyltransferase family 8 which includes lipopolysaccharide glucose and galactose transferases and galactinol synthases.
Members of glycosyltransferase family 8 (GT-8) are involved in lipopolysaccharide biosynthesis and glycogen synthesis. Members of this family are involved in lipopolysaccharide biosynthesis and glycogen synthesis. GT-8 comprises enzymes with a number of known activities: lipopolysaccharide galactosyltransferase, lipopolysaccharide glucosyltransferase 1, glycogenin glucosyltransferase, and N-acetylglucosaminyltransferase. GT-8 enzymes contains a conserved DXD motif which is essential in the coordination of a catalytic divalent cation, most commonly Mn2+.
