title: A lectin recognizes differential arrangements of O-glycans on mucin repeats.
abstract: Interaction of Vicia villosa agglutinin-B4 (VVA-B4) to glycopeptides with O-linked GalNAc residues was investigated by surface plasmon resonance. The affinity was shown to be influenced by the arrangement of O-glycosylation sites on a peptide, PTTTPITTTTK, representing the tandem repeat of MUC2. The association rate constant was relatively high with a particular category of GalNAc-peptides in which more than three amino acid residues were placed between GalNAc-Thr residues. PTT( *)T( *)PITT( *)T( *)TK (T( *) indicates GalNAc-Thr) had the highest association rate constant among the glycopeptides tested. The dissociation rate constant was low in the peptides containing consecutive GalNAc residues and PT( *)TTPIT( *)T( *)T( *)TK was the lowest of the glycopeptides tested. Dissociation constant (K(D)), calculated as k(d)/k(a) was the lowest with PTT( *)T( *)PITT( *)T( *)TK. Therefore, the arrangement but not the quantity of GalNAc residues apparently determines the affinity between VVA-B4 and peptides with attached GalNAc residues.
authors.affiliation: Laboratory of Cancer Biology and Molecular Immunology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kato
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Takao
authors.initials: T
authors.lastname: Ohki
authors.forename: Michihiko
authors.initials: M
authors.lastname: Waki
authors.forename: Katsuaki
authors.initials: K
authors.lastname: Usami
authors.forename: Helle
authors.initials: H
authors.lastname: Hassan
authors.forename: Henrik
authors.initials: H
authors.lastname: Clausen
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Irimura
mesh_terms: D000116:Acetylgalactosamine / Q000737:chemistry*; D000595:Amino Acid Sequence; D006020:Glycopeptides / Q000737:chemistry; D006801:Humans; D008969:Molecular Sequence Data; D055262:Mucin-2; D009077:Mucins / Q000737:chemistry*; D037121:Plant Lectins / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*; D020449:Repetitive Sequences, Amino Acid; D020349:Surface Plasmon Resonance
chemical_list: D006020:Glycopeptides; C524625:MUC2 protein, human; D055262:Mucin-2; D009077:Mucins; D037121:Plant Lectins; D011134:Polysaccharides; C042242:Vicia lectins; D000116:Acetylgalactosamine