ABSTRACT
A series of D- and L-glycopyranuronic acids are coupled to glucosamines to give saccharopeptides. These 'disaccharides', in which the acetyl moiety of the natural N-acetyl-glucosamine is replaced by various sugar acids, turned out to be surprisingly good substrates for beta(1-4)-galactosyl-transferase and alpha(1-3)-galactosyl-transferase. The enzymes transfer successively two galactose units from the donor UDP-galactose onto these acceptor substrates, despite the far reaching alterations, regio- and stereospecifically in the expected manner to give linear-B saccharopeptides.
Subject(s)
Amides/chemistry , Carbohydrates/chemical synthesis , Galactose/chemistry , Galactosyltransferases/chemistry , N-Acetyllactosamine Synthase/chemistry , Peptides/chemical synthesis , Carbohydrates/chemistry , Magnetic Resonance Spectroscopy , Mass Spectrometry , Peptides/chemistryABSTRACT
A series of glycohexopyranuronic acids are coupled to glucosamines to give 'disaccharides' which have the natural N-acetyl group of the glcNAc-moiety replaced by various sugar acids (-->saccharopeptides). These saccharopeptides are surprisingly good substrates for beta(1-4)galactosyl-transferase, alpha(2-3)sialyl-transferase, and fucosyl-transferase VI. The enzymes transfer successively galactose, sialic acid, and fucose from the corresponding donors onto these acceptor substrates--despite the far reaching alterations--regio- and stereospecifically in the expected manner to yield a new class of compounds, the sialyl-Lewis(x)-saccharopeptides.
Subject(s)
N-Acetyllactosamine Synthase/metabolism , Peptides/chemistry , Polysaccharides/chemistry , Polysaccharides/metabolism , Fucose , Fucosyltransferases/chemistry , Fucosyltransferases/metabolism , Glycosylation , Magnetic Resonance Spectroscopy , N-Acetyllactosamine Synthase/chemistry , Oligosaccharides/chemical synthesis , Oligosaccharides/chemistry , Oligosaccharides/metabolism , Peptides/metabolism , Sialyl Lewis X Antigen , Sialyltransferases/chemistry , Sialyltransferases/metabolism , Structure-Activity Relationship , Substrate Specificity , beta-Galactoside alpha-2,3-SialyltransferaseABSTRACT
A series of methyl hexopyranosiduronic acids are coupled to type I disaccharide amines to give 'trisaccharides' which have the natural N-acetyl group of the type I disaccharides replaced by uronic acids (-->saccharopeptides). These saccharopeptides are surprisingly good substrates for alpha-2,3,-sialyltransferase and fucosyltransferase III. The enzymes transfer N-acetylneuraminic acid and fucose, respectively, onto these acceptor substrates, despite the far reaching alterations, regio- and stereospecifically in the expected manner to yield sialyl-Lewis(a)-saccharopeptides.
Subject(s)
Gangliosides/metabolism , Glycosyltransferases/metabolism , Lewis Blood Group Antigens/metabolism , Oligopeptides/metabolism , CA-19-9 Antigen , Carbohydrate Sequence , Catalysis , Humans , Magnetic Resonance Spectroscopy , Molecular Sequence Data , Oligosaccharides/metabolism , Sialyl Lewis X Antigen , Uronic Acids/metabolismABSTRACT
A number of non-natural N-acyl derivatives of glucosamine is incubated with a recombinant beta(1-3)galactosyl-transferase and UDP-galactose. Surprisingly, the enzyme recognizes the non-natural acceptors as substrates and transfers galactose onto the 3-OH group in a beta-mode to give a series of Lewis(c)-(type 1) disaccharides.
Subject(s)
Disaccharides/chemical synthesis , Galactosyltransferases/metabolism , Carbohydrate Conformation , Disaccharides/chemistry , Galactose , Glucosamine/analogs & derivatives , Indicators and Reagents , Magnetic Resonance Spectroscopy , Models, Molecular , Recombinant Proteins/metabolism , Substrate Specificity , Uridine Diphosphate GalactoseABSTRACT
A series of sialylated type-I sugars, which have the natural N-acetyl group of the glucosamine moiety replaced by a wide range of amides, is incubated with recombinant fucosyl-transferase III and non-natural guanosine-diphosphate activated donor-sugars. Surprisingly, the enzyme tolerates the simultaneous alterations on the donor and acceptor to form a wide array of sialyl-Lewis(a)-analogues.
Subject(s)
Fucosyltransferases/metabolism , Gangliosides/chemical synthesis , Oligosaccharides/chemical synthesis , Amides , Carbohydrate Conformation , Carbohydrate Sequence , Databases as Topic , Gangliosides/chemistry , Glucosamine/metabolism , Guanosine Diphosphate Sugars , Models, Molecular , Molecular Sequence Data , Monosaccharides/chemistry , Monosaccharides/metabolism , Oligosaccharides/chemistry , Recombinant Proteins/metabolism , Structure-Activity Relationship , Substrate SpecificityABSTRACT
Recombinant alpha(2-3)sialyl-transferase from rat liver is used to sialylate a series of type-I (Lewisc) disaccharides on a preparative scale. The enzyme tolerates a broad array of N-acetyl replacements of the N-glucosamine subunit ranging from small and large lipophilic groups to charged and heterocyclic amides.
Subject(s)
Disaccharides/chemistry , N-Acetylneuraminic Acid/chemistry , Sialyltransferases/chemistry , Animals , Carbohydrate Sequence , Liver/enzymology , Rats , Recombinant Proteins/chemistryABSTRACT
Recombinant fucosyl-transferase-III (Lewis type enzyme) is used to prepare a series of non-natural sialyl-Lewis derivatives on a preparative scale. The enzyme tolerates a wide range of acceptors which have the natural N-acetyl group of the glucosamine moiety replaced by substituted aromatic and heteroaromatic amides.
Subject(s)
Fucosyltransferases/chemistry , N-Acetylneuraminic Acid/chemistry , Oligosaccharides/chemistry , Carbohydrate Sequence , Molecular Sequence Data , Recombinant Proteins/chemistryABSTRACT
A series of non-natural N-acyl derivatives of lactosamine is incubated with recombinant alpha(1-3)galactosyl-transferase and UDP-galactose. The enzyme shows a high promiscuity towards the non-natural acceptors. It selectively transfers a galactose unit onto the 3-OH group of the terminal beta-linked galactose in an alpha-mode to give an array of linear-B trisaccharides.
Subject(s)
Galactosyltransferases/metabolism , Animals , Glycosylation , Magnetic Resonance Spectroscopy , Recombinant Proteins/metabolism , SwineABSTRACT
A series of peracetylated beta-sugar-1-phosphates with L-fuco configuration are efficiently prepared chemically and coupled in high yields to purine monophosphate bases via imidazolide activation. The resulting purine diphosphate sugars are deacetylated completely by a mild treatment with commercial acetylesterase (EC 3.1.1.6) to give donor-substrates for fucosyl-transferases.
