Biomaterial Database

Substrate specificity of the glycosyl donor for oligosaccharyl transferase. 2001

V W Tai, and B Imperiali

Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.

Oligosaccharyl transferase (OT) catalyzes the co-translational transfer of a dolichol-linked tetradecasaccharide (Dol-PP-GlcNAc(2)Man(9)Glc(3), 1a) to an asparagine side chain of a nascent polypeptide inside the lumen of the endoplasmic reticulum (ER). The glycosyl acceptor requires an Asn-Xaa-Thr/Ser sequon, where Xaa can be any natural amino acid except proline, for N-linked glycosylation to occur. To address the substrate specificity of the glycosyl donor, three unnatural dolichol-linked disaccharide analogues (Dol-PP-GlcNTFA-GlcNAc 1c, Dol-PP-2DFGlc-GlcNAc 1d, and Dol-PP-GlcNAc-Glc 1e) were synthesized and evaluated as substrates or inhibitors for OT from yeast. The synthetic analogue Dol-PP-GlcNAc-Glc 1e, with substitution in the distal sugar, was found to be a substrate (K(m)(app)() = 26 microM) for OT. On the other hand, the analogues Dol-PP-GlcNTFA-GlcNAc 1c (K(i) = 154 microM) and Dol-PP-2DFGlc-GlcNAc 1d (K(i) = 252 microM), with variations in the proximal sugar, were inhibitors for OT. The dolichol-linked monosaccharide Dol-PP-GlcNAc 3 was found to be the minimum unit for glycosylation to occur.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008565	Membrane Proteins	Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.	Cell Membrane Protein,Cell Membrane Proteins,Cell Surface Protein,Cell Surface Proteins,Integral Membrane Proteins,Membrane-Associated Protein,Surface Protein,Surface Proteins,Integral Membrane Protein,Membrane Protein,Membrane-Associated Proteins,Membrane Associated Protein,Membrane Associated Proteins,Membrane Protein, Cell,Membrane Protein, Integral,Membrane Proteins, Integral,Protein, Cell Membrane,Protein, Cell Surface,Protein, Integral Membrane,Protein, Membrane,Protein, Membrane-Associated,Protein, Surface,Proteins, Cell Membrane,Proteins, Cell Surface,Proteins, Integral Membrane,Proteins, Membrane,Proteins, Membrane-Associated,Proteins, Surface,Surface Protein, Cell
D009842	Oligopeptides	Peptides composed of between two and twelve amino acids.	Oligopeptide
D011103	Polyisoprenyl Phosphate Monosaccharides	These compounds function as activated monosaccharide carriers in the biosynthesis of glycoproteins and oligosaccharide phospholipids. Obtained from a nucleoside diphosphate sugar and a polyisoprenyl phosphate.	Isoprenoid Phosphate Monosaccharides,Monosaccharides, Isoprenoid Phosphate,Monosaccharides, Polyisoprenyl Phosphate,Phosphate Monosaccharides, Isoprenoid,Phosphate Monosaccharides, Polyisoprenyl
D004186	Disaccharidases	Enzymes belonging to the class of GLYCOSIDE HYDROLASES which break down DISACCHARIDES into simpler sugars, MONOSACCHARIDES.	Disaccharidase
D004286	Dolichols	A class of polyprenols which contain approximately 20 isoprene residues. Although considered ISOPRENOIDS, they terminate with an alpha-saturated isoprenoid group at the hydroxy end of the molecule.	6,10,14,18,22,26,30,34,38,42,46,50,54,58,62,66,70,74,78-Octacontanonadecaen-1-ol, 3,7,11,15,19,23,27,31,35,39,43,47,51,55,59,63,67,71,75,79-eicosamethyl-,Dolichol,Eicosamethyl Octacontanonadecasen-1-ol,Eicosamethyl Octacontanonadecasen 1 ol,Octacontanonadecasen-1-ol, Eicosamethyl
D006020	Glycopeptides	Proteins which contain carbohydrate groups attached covalently to the polypeptide chain. The protein moiety is the predominant group with the carbohydrate making up only a small percentage of the total weight.	Glycopeptide
D006031	Glycosylation	The synthetic chemistry reaction or enzymatic reaction of adding carbohydrate or glycosyl groups. GLYCOSYLTRANSFERASES carry out the enzymatic glycosylation reactions. The spontaneous, non-enzymatic attachment of reducing sugars to free amino groups in proteins, lipids, or nucleic acids is called GLYCATION (see MAILLARD REACTION).	Protein Glycosylation,Glycosylation, Protein
D006602	Hexosyltransferases	Enzymes that catalyze the transfer of hexose groups. EC 2.4.1.-.
D013379	Substrate Specificity	A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.	Specificities, Substrate,Specificity, Substrate,Substrate Specificities