Glycosyltransferases involved in type 1 chain and Lewis antigen biosynthesis exhibit glycan and core chain specificity.

Abstract

Sialyl Lewis A (SLe(a)), Lewis A (Le(a)), and Lewis B (Le(b)) have been studied in many different biological contexts, for example in microbial adhesion and cancer. Their biosynthesis is complex and involves beta1,3-galactosyltransferases (beta3Gal-Ts) and a combined action of alpha2- and/or alpha4-fucosyltransferases (Fuc-Ts). Further, O-glycans with different core structures have been identified, and the ability of beta3Gal-Ts and Fuc-Ts to use these as substrates has not been resolved. Therefore, to examine the in vivo specificity of enzymes involved in SLe(a), Le(a), and Le(b) synthesis, we have transiently transfected CHO-K1 cells with relevant human glycosyltransferases and, on secreted reporter proteins, detected the resulting Lewis antigens on N- and O-linked glycans using western blotting and Le-specific antibodies. beta3Gal-T1, -T2, and -T5 could synthesize type 1 chains on N-linked glycans, but only beta3Gal-T5 worked on O-linked glycans. The latter enzyme could use both core 2 and core 3 precursor structures. Furthermore, the specificity of FUT5 and FUT3 in Le(a) and Le(b) synthesis was different, with FUT5 fucosylating H type 1 only on core 2, but FUT3 fucosylating H type 1 much more efficient on core 3 than on core 2. Finally, FUT1 and FUT2 were both found to direct alpha2-fucosylation on type 1 chains on both N- and O-linked structures. This knowledge enables us to engineer recombinant glycoproteins with glycan- and core chain-specific Lewis antigen substitution. Such tools will be important for investigations on the fine carbohydrate specificity of Le(b)-binding lectins, such as Helicobacter pylori adhesins and DC-SIGN, and may also prove useful as therapeutics.

• Authors: Jan Holgersson, Jonas Löfling
• Journal: Glycobiology (Glycobiology) Vol. 16 Issue 7 Pg. 584-93 (Jul 2006) ISSN: 0959-6658 [Print] England
• PMID: 16484342 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• 3-aminopropyl fucopyranosyl-1-2-galactopyranosyl-1-3-(fucopyranosyl-1-4)-2-acetamido-2-deoxyglucopyranosyl-1-3-galactopyranosyl-1-4-glucopyranoside
• Antibodies, Monoclonal
• Antigens, Neoplasm
• DU-PAN-2 antigen, human
• Glycoproteins
• Lewis Blood Group Antigens
• Lewis a oligosaccharide
• Oligosaccharides
• Polysaccharides
• Serum Albumin
• Glycosyltransferases
• B3GALT5 protein, human
• Fucosyltransferases
• Galactosyltransferases
• galactoside 2-alpha-L-fucosyltransferase

Topics

• Animals
• Antibodies, Monoclonal (immunology)
• Antigens, Neoplasm (analysis, biosynthesis, immunology)
• CHO Cells
• Cricetinae
• Cricetulus
• Fucosyltransferases (genetics, metabolism)
• Galactosyltransferases (genetics, metabolism)
• Glycoproteins (chemistry)
• Glycosyltransferases (genetics, metabolism)
• Humans
• Lewis Blood Group Antigens
• Mice
• Oligosaccharides (analysis, biosynthesis, immunology)
• Polysaccharides (metabolism)
• Serum Albumin (chemistry)
• Substrate Specificity