Methods for the enzymatic synthesis of alpha-sialylated oligosaccharide glycosides
AssigneeAlberta Research Council
InventorsAndre P. Venot, Frank M. Unger, Mohammed A. Kashem, Paul Bird, M. Abdul Mazid
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Abstract
Disclosed are methods for the enzymatic synthesis of alpha-sialylated oligosaccharide glycosides. Specifically, in the disclosed methods, sialyltransferase is activated to transfer an analogue of sialic acid, employed as its CMP-nucleotide derivative, to an oligosaccharide glycoside. The analogue of sialic acid and the oligosaccharide employed in this method are selected to be compatible with the sialyltransferase employed.
Claims17
A method for the enzymatic synthesis of an alpha-sialylated oligosaccharide glycoside containing an analogue of sialic acid which method comprises the steps of:
- a) selecting a sialyltransferase;
- b) selecting a CMP-sialic acid analogue which is compatible with the sialyltransferase selected in, step a) and which is a derivative of a naturally occurring sialic acid;
- c) contacting the selected CMP-sialic acid analogue with an oligosaccharide glycoside acceptor of the formula
- oligosaccharide-Y-R
- in the presence of the selected sialyltransferase under conditions whereby the sialic acid analogue is transferred from the selected CMP-sialic acid analogue to the non-reducing sugar terminus of the oligosaccharide glycoside acceptor so as to form an alpha-sialylated oligosaccharide glycoside containing an analogue of sialic acid wherein R represents an aglycon moiety containing at least one carbon atom with the proviso that R is neither hydrogen, a lipid or a protein, Y is selected from the group consisting of O, NH and S, and oligosaccharide is an oligosaccharide of from 2 to about 10 saccharide units in which the terminal saccharide units at the non-reducing sugar terminus of the oligosaccharide are compatible with the selected sialyltransferase.
A method for the preparation of an antigenic carrier having one or more alpha-sialylated oligosaccharide groups containing an analogue of sialic acid which groups are pendent to said carrier which method comprises the steps of:
- a) selecting a sialyltransferase;
- b) selecting a CMP-sialic acid analogue which is compatible with the sialyltransferase selected in step a) and which is a derivative of a naturally occurring sialic acid;
- c) contacting the selected CMP-sialic acid analogue with an oligosaccharide glycoside acceptor of the formula
- oligosaccharide-Y-R.sub.1
- in the presence of the selected sialyltransferase under conditions whereby the sialic acid analogue is transferred from the selected CMP-sialic acid analogue to the non-reducing sugar terminus of the oligosaccharide glycoside acceptor so as to form an alpha-sialylated oligosaccharide glycoside containing an analogue of sialic acid wherein R.sub.1 represents an aglycon moiety capable of being linked to an antigenic carrier with the proviso that R.sub.1 is neither hydrogen, a lipid nor a protein, Y is selected from the group consisting of O, NH and S, and oligosaccharide is an oligosaccharide of from 2 to about 10 saccharide units in which the terminal saccharide units at the non-reducing terminus of the oligosaccharide are compatible with the selected sialyltransferase;
- d) selecting an antigenic carrier having one or more functionalities capable of linking to the aglycon moiety of the alpha-sialylated oligosaccharide glycoside produced in step c) above;
- e) linking one or more of said alpha-sialylated oligosaccharide glycosides containing an analogue of sialic acid, produced in step c) to the antigenic carrier selected in step d).
A method for the preparation of an antigenic carrier having one or more alpha-sialylated oligosaccharide groups containing an analogue of sialic acid which groups are pendent to said carrier which method comprises the steps of:
- a) selecting a sialyltransferase;
- b) selecting an oligosaccharide glycoside acceptor of the formula
- oligosaccharide-Y-R.sub.1
- wherein R.sub.1 represents an aglycon moiety capable of being linked to an antigenic carrier with the proviso that R.sub.1 is neither hydrogen, a lipid nor a protein, Y is selected from the group consisting of O, NH and S, and oligosaccharide is an oligosaccharide of from 2 to about 10 saccharide units in which the terminal saccharide units at the non-reducing terminus of the oligosaccharide are compatible with the selected sialyltransferase:
- c) selecting an antigenic carrier having one or more functionalities capable of linking to the aglycon moiety of the selected oligosaccharide glycoside acceptor;
- d) linking at least one said oligosaccharide glycoside acceptor to said carrier selected in step c) to form oligosaccharide groups pendant to the antigenic carrier;
- e) selecting a CMP-sialic acid analogue which is compatible with the sialyltransferase selected in step a) and which is a derivative of a naturally occurring sialic acid;
- f) contacting the selected CMP-sialic acid analogue with the antigenic carrier produced in step d) above in the presence of the selected sialyltransferase under conditions whereby the sialic acid analogue is transferred from the selected CMP-sialic acid analogue to the non-reducing sugar terminus of the oligosaccharide group(s) pendant to the antigenic carrier so as to form an antigenic carrier having one or more alpha sialylated oligosaccharide groups containing an analogue of sialic acid pendant to said carrier.
Dependencies are inferred from the claim text.