title: N.m.r. study on conformation of Ac-Thr(alpha-GalNAc)-Ala-Ala-OMe as a model for mucin type glycoprotein.
abstract: This study report on the results of high resolution 1H n.m.r. investigations on Ac-Thr(alpha-GalNAc)-Ala-Ala-OMe 1 as a mucin type model glycopeptide of antifreeze glycoprotein (AFGP) in both dimethyl sulfoxide (DMSO) and H2O. The temperature dependence of amide proton chemical shifts strongly suggested the presence of the intramolecular hydrogen bond between the amide proton of GalNAc and the carbonyl oxygen of the Thr residues. Due to this bond, the orientation of the sugar residue of 1 appears to be fairly restricted relative to its peptide backbone. Despite the lack of the clear evidence for such intramolecular hydrogen bond in H2O, 1H coupling constant data suggested the structural similarity of 1 in DMSO and H2O, indicating the presence of the intramolecular hydrogen bond even in H2O, which may play an important role in determining the orientation of the sugar moiety with respect to the peptide backbone in glycoprotein.
authors.affiliation: Department of Biomolecular Engineering, Tokyo Institute of Technology, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Mimura
authors.forename: Y
authors.initials: Y
authors.lastname: Inoue
authors.forename: N J
authors.initials: NJ
authors.lastname: Maeji
authors.forename: R
authors.initials: R
authors.lastname: Chûjô
mesh_terms: D000595:Amino Acid Sequence; D021301:Antifreeze Proteins; D006020:Glycopeptides; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009077:Mucins; D011487:Protein Conformation; D013696:Temperature
chemical_list: D021301:Antifreeze Proteins; D006020:Glycopeptides; D009077:Mucins; C062622:3-O-(2-acetamido-2-deoxygalactopyranosyl)-acetyl-threonyl-alanyl-alanine methyl ester