title: Chemical and enzymatic synthesis of multivalent sialoglycopeptides.
abstract: Linear and branched glycopeptides containing multiple sialyl-N-acetyllactosamine side chains have been synthesized using a combined chemical and enzymatic approach. Peptide backbones in which beta-GlcNAc-Asn residues were incorporated were obtained in good yields by optimized solid-phase synthesis following the Boc strategy. The resulting multivalent glycopeptides were galactosylated in near-quantitative yields using bovine galactosyltransferase, UDP-galactose, and calf alkaline phosphatase that destroys the inhibiting side product UDP. Subsequent enzymatic sialylation yielded the desired glycopeptides containing asparagine-linked sialyl-N-acetyllactosamine side chains. The compounds were characterized by 1H NMR and FABMS. Recombinant sialyltransferase and CMP-sialate synthetase were used for the enzymatic synthesis of sialosides on a preparative scale. The synthetic glycopeptides were tested as inhibitors of influenza virus to cells, revealing that most of the multivalent sialoglycopeptides exhibit increased binding that depends on the spacing when compared to monovalent compounds. A possible mechanism for increased binding is proposed.
authors.affiliation: Department of Biological Chemistry, UCLA School of Medicine 90024-1737.
authors.forename: C
authors.initials: C
authors.lastname: Unverzagt
authors.forename: S
authors.initials: S
authors.lastname: Kelm
authors.forename: J C
authors.initials: JC
authors.lastname: Paulson
mesh_terms: D000595:Amino Acid Sequence; D000606:Amino Sugars / Q000737:chemistry; D000998:Antiviral Agents / Q000138:chemical synthesis / Q000494:pharmacology; D002240:Carbohydrate Sequence; D003569:Cytidine Monophosphate N-Acetylneuraminic Acid / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism; D005700:Galactosyltransferases / Q000378:metabolism; D006031:Glycosylation; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral / Q000378:metabolism; D008969:Molecular Sequence Data; D000216:N-Acylneuraminate Cytidylyltransferase / Q000378:metabolism; D009975:Orthomyxoviridae / Q000187:drug effects*; D012795:Sialoglycoproteins / Q000096:biosynthesis / Q000138:chemical synthesis / Q000494:pharmacology; D012799:Sialyltransferases / Q000378:metabolism
chemical_list: D000606:Amino Sugars; D000998:Antiviral Agents; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral; D012795:Sialoglycoproteins; C032269:sialyl-N-acetyllactosamine; D003569:Cytidine Monophosphate N-Acetylneuraminic Acid; D005700:Galactosyltransferases; D012799:Sialyltransferases; D000216:N-Acylneuraminate Cytidylyltransferase