Glycosyltransferases for biosynthesis of oligosaccharides, and genes encoding them

A method for preparing an oligosaccharide having the structure GalNA.beta.1.fwdarw.3Gal.beta.1.fwdarw.4GlcNAc.beta.1.fwdarw.3Gal.beta.1.f wdarw.4Glc, which comprises sequentially performing the steps of:

• a) contacting a reaction mixture comprising an activated Gal to an acceptor moiety comprising a Glc residue in the presence of a glycosyltransferase having an amino acid sequence of SEQ ID NO:6;
• b) contacting a reaction mixture comprising an activated GlcNAc to the acceptor moiety comprising a Gal.beta.1.fwdarw.4Glc residue in the presence of a glycosyltransferase having an amino acid sequence of SEQ ID NO:3 or SEQ ID NO:11;
• c) contacting a reaction mixture comprising an activated Gal to the acceptor moiety comprising a GlcNAc.beta.1.fwdarw.3Gal.beta.1.fwdarw.4Glc residue in the presence of a glycosyltransferase having an amino acid of SEQ ID NO:8;
• and
• d) contacting a reaction mixture comprising an activated GalNAc to the acceptor moiety comprising a Gal.beta.1.fwdarw.4GlcNAc.beta.1.fwdarw.3Gal.beta.1.fwdarw.4Glc residue in the presence of a glycosyltransferase having an amino acid sequence of SEQ ID NO:5 or SEQ ID NO:12.

A method for preparing an oligosaccharide having the structure Gal.beta.1.fwdarw.4GlcNAc.beta.1.fwdarw.3Gal.beta.1.fwdarw.4Glc, which comprises sequentially performing the steps of:

• a) contacting a reaction mixture comprising an activated Gal to an acceptor moiety comprising a Glc residue in the presence of a glycosyltransferase having an amino acid sequence of SEQ ID NO:6;
• b) contacting a reaction mixture comprising an activated GlcNAc to the acceptor moiety comprising a Gal.beta.1.fwdarw.4Glc residue in the presence of a glycosyltransferase having an amino acid sequence of SEQ ID NO:3 or SEQ ID NO:11;
• and
• c) contacting a reaction mixture comprising an activated Gal to the acceptor moiety comprising a GlcNAc.beta.1.fwdarw.3Gal.beta.1.fwdarw.4Glc residue in the presence of a glycosyltransferase having an amino acid of SEQ ID NO:8.