title: Site-specific conformational alteration induced by sialylation of MUC1 tandem repeating glycopeptides at an epitope region for the anti-KL-6 monoclonal antibody.
abstract: Protein O-glycosylation is an essential step for controlling structure and biological functions of glycoproteins involving differentiation, cell adhesion, immune response, inflammation, and tumorigenesis and metastasis. This study provides evidence of site-specific structural alteration induced during multiple sialylation at Ser/Thr residues of the tandem repeats in human MUC1 glycoprotein. Systematic nuclear magnetic resonance (NMR) study revealed that sialylation of the MUC1 tandem repeating glycopeptide, Pro-Pro-Ala-His-Gly-Val-Thr-Ser-Ala-Pro-Asp-Thr-Arg-Pro-Ala-Pro-Gly-Ser-Thr-Ala with core 2-type O-glycans at five potential glycosylation sites, afforded a specific conformational change at one of the most important cancer-relevant epitopes (Pro-Asp-Thr-Arg). This result indicates that disease-relevant epitope structures of human epithelial cell surface mucins can be altered both by the introduction of an inner GalNAc residue and by the distal sialylation in a peptide sequence-dependent manner. These data demonstrate the feasibility of NMR-based structural characterization of glycopeptides synthesized in a chemical and enzymatic manner in examining the conformational impact of the distal glycosylation at multiple O-glycosylation sites of mucin-like domains.
authors.affiliation: Field of Drug Discovery Research, Faculty of Advanced Life Science, Hokkaido University, Sapporo 001-0021, Japan.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Matsushita
authors.forename: Naoki
authors.initials: N
authors.lastname: Ohyabu
authors.forename: Naoki
authors.initials: N
authors.lastname: Fujitani
authors.forename: Kentaro
authors.initials: K
authors.lastname: Naruchi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shimizu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hinou
authors.forename: Shin-Ichiro
authors.initials: S
authors.lastname: Nishimura
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000915:Antibody Affinity; D000939:Epitopes / Q000737:chemistry* / Q000276:immunology*; D006031:Glycosylation; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D018396:Mucin-1 / Q000737:chemistry* / Q000276:immunology*; D019158:N-Acetylneuraminic Acid / Q000737:chemistry / Q000276:immunology; D009369:Neoplasms / Q000737:chemistry / Q000276:immunology; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000737:chemistry / Q000276:immunology; D011487:Protein Conformation
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; C060192:MUC1 protein, human; D018396:Mucin-1; D010455:Peptides; D019158:N-Acetylneuraminic Acid