title: Proton NMR study of the trimannosyl unit in a pentaantennary N-linked decasaccharide structure. Complete assignment of the proton resonances and conformational characterization.
abstract: The chemical shifts of all the ring protons of the three Man residues in a pentaantennary glycan chain have been unambiguously assigned by two-dimensional proton nuclear magnetic resonance (1H-NMR) spectroscopic methods. The study, using chemical shift and J values on the conformation of the trimannosyl unit, revealed that the rotamer about the C5-C6 bond of the alpha 1-->6 linkage in the sequence of Man alpha 1-->6Man beta 1--> is predominantly confined to a gauche-gauche rotamer (omega = 180 degrees, omega = O6-C6-C5-H5) and not to a gauche-trans rotamer (omega = -60 degrees). We do not know of any previous demonstration that the dihedral angle omega (O6-C6-C5-H5) in Man alpha 1-->6Man beta 1--> is preferentially 180 degrees in complex-type N-linked glycans having no bisecting GlcNAc residue.
authors.affiliation: Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Taguchi
authors.forename: K
authors.initials: K
authors.lastname: Kitajima
authors.forename: Y
authors.initials: Y
authors.lastname: Muto
authors.forename: S
authors.initials: S
authors.lastname: Yokoyama
authors.forename: S
authors.initials: S
authors.lastname: Inoue
authors.forename: Y
authors.initials: Y
authors.lastname: Inoue
mesh_terms: D000595:Amino Acid Sequence; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D006020:Glycopeptides / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008358:Mannose / Q000737:chemistry*; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry*; D011487:Protein Conformation; D011522:Protons
chemical_list: D006020:Glycopeptides; D009844:Oligosaccharides; D011522:Protons; D008358:Mannose