title: Chemoenzymatic synthesis of a MUC1 glycopeptide carrying non-natural sialyl TF-beta O-glycan.
abstract: A MUC1 type of glycopeptide was synthesized by the 9-fluorenylmethoxycarbonyl (Fmoc) solid-phase peptide synthesis (SPPS) protocol using benzyl and benzylidene-protected beta-D-Gal-(1-->3)-beta-D-GalNAc-Ser/Thr (TF-beta: a stereoisomer of the Thomsen-Friedenreich antigen). The synthetic glycopeptide was released from the resin with reagent K, and the resulting benzylated glycopeptide was deprotected under conditions of low-acidity trifluoromethanesulfonic acid (TfOH). The glycopeptide carrying duplicate non-natural O-glycans was dominant in the products, but was accompanied by a considerable amount of the glycopeptide missing one of the O-glycans. In contrast, the native alpha-glycoside was relatively stable under the acidic debenzylation conditions as shown by a parallel experiment with the glycopeptide involving alpha-D-GalNAc-Ser/Thr linkage. Enzymatic glycosylation with CMP-NeuAc was successful with both natural and non-natural O-glycans of the synthetic glycopeptide.
authors.affiliation: Department of Applied Biochemistry, Institute of Glycotechnology, Tokai University, Japan.
authors.forename: Eriko
authors.initials: E
authors.lastname: Tanaka
authors.forename: Yuko
authors.initials: Y
authors.lastname: Nakahara
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kuroda
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takano
authors.forename: Naoya
authors.initials: N
authors.lastname: Kojima
authors.forename: Hironobu
authors.initials: H
authors.lastname: Hojo
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Nakahara
mesh_terms: D000951:Antigens, Neoplasm; D020650:Combinatorial Chemistry Techniques; D006020:Glycopeptides / Q000138:chemical synthesis; D006031:Glycosylation; D006801:Humans; D018396:Mucin-1; D009077:Mucins / Q000138:chemical synthesis*; D011134:Polysaccharides / Q000737:chemistry*; D015202:Protein Engineering / Q000379:methods*; D052116:Sialomucins / Q000138:chemical synthesis; D012799:Sialyltransferases / Q000378:metabolism
chemical_list: D000951:Antigens, Neoplasm; D006020:Glycopeptides; C060192:MUC1 protein, human; D018396:Mucin-1; D009077:Mucins; D011134:Polysaccharides; D052116:Sialomucins; D012799:Sialyltransferases