Glycosyltransferase Structure and Function

Glycosyltransferases and their Assays

“…The use of native, unlabelled substrates also provides an opportunity to develop assay formats that are broadly, or even generally, applicable with different GTs. In view of the enormous size of the GT enzyme family, [2,3] assays that are generally applicable with different enzymes are particularly valuable, for example, for the investigation of substrate specificities, for the directed evolution of GTs, and for the selectivity profiling of inhibitor candidates.…”

“…Additional GT fold types, notably a GT-C fold, have recently been predicted on the basis of iterative sequence searches. [2,3] …”

“…Thus, within an individ- Despite the considerable diversity of GT sequence and function, the 3D structures of GTs are remarkably conserved. [2][3][4] From the growing number of X-ray structures that have been solved over the past few years, it appears that most GTs adopt one of two general folds, which are termed GT-A and GT-B [2][3][4] ( Figure 1). The GT-A fold was first identified when the 3D structure of the family 2 enzyme SpsA from B. subtilis was solved in 1999.…”

“…More than 200 GTs have been identified in the human genome, and it has been estimated that GT sequences account for about 1 % of ORFs across all sequenced genomes. [2,3] The large size of the GT family reflects the immense structural variety of complex carGlycosyltransferases (GTs) are a large family of enzymes that are essential in all domains of life for the biosynthesis of complex carbohydrates and glycoconjugates. GTs catalyse the transfer of a sugar from a glycosyl donor to a variety of acceptor molecules, for example, oligosaccharides, peptides, lipids or small molecules.…”

Preliminary joint neutron time-of-flight and X-ray crystallographic study of human ABO(H) blood group A glycosyltransferase

“…The glycosyltransferase GTA transfers the N-acetylgalactosaminyl monosaccharide residue from UDP to Gal O3 of the H antigen [minimal epitope Fuc-(1!2)Gal] with retention of the axial stereochemistry to generate the human blood group A antigen and is a model enzyme for studying the retaining glycosyltransfer mechanism (Alfaro et al, 2008;Lee et al, 2005;Letts et al, 2007;Nguyen et al, 2003;Patenaude et al, 2002;Persson et al, 2007;Schuman et al, 2007Schuman et al, , 2010Seto et al, 1999). Evaluation of hydrogenbonding partners and amino-acid protonation states is critical for understanding the catalytic mechanisms of GTA and indeed of all retaining glycosyltransferases.…”