Proton NMR study of triantennary complex type N-linked glycan chains: assignment of proton chemical shifts of the beta-Man residue in a basic unit of the triantennary glycan chain having a GlcNAc beta 1-->6 Man alpha 1-->6 Man beta-->sequence.
The chemical shifts of ring protons of the beta-Man residue in a triantennary complex type N-linked glycan chain having a GlcNAc beta 1-->6(GlcNAc beta 1-->2)Man alpha 1-->6 Man beta sequence were unambiguously determined by two-dimensional proton nuclear magnetic resonance (1H-NMR) spectroscopic methods. The chemical shift of H4 (3.84 ppm) of the beta-Man residue was for the first time revealed to be different from those (approximately 3.77 ppm) of biantennary and alternative type of triantennary glycans having a GlcNAc beta 1-->2 Man alpha 1-->6 Man beta sequence, but quite close to that (3.86 ppm) of a pentaantennary glycan containing a GlcNAc beta 1-->6 residue on the Man alpha 1-->6 Man beta sequence. Thus, the addition of GlcNAc beta 1-->6 residue on the Man-4' residue, whose formation is catalyzed by GlcNAc transferase V, is considered to cause a down-field shift of beta-Man H4 in the complex-type N-glycan chains. One possible explanation of this phenomenon is that the conformation of Man alpha 1-->6 arm is folded back toward the proximal core region, as is the case with the complex-type N-glycan chains with the bisecting GlcNAc residue.
Taguchi
T
T
Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Japan.
Muto
Y
Y
Kitajima
K
K
Yokoyama
S
S
Inoue
S
S
Inoue
Y
Y
D000117:Acetylglucosamine / Q000737:chemistry*; D000818:Animals; D002240:Carbohydrate Sequence; D009682:Magnetic Resonance Spectroscopy; D008358:Mannose / Q000737:chemistry*; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000737:chemistry*; D011522:Protons; D014337:Trout
D011134:Polysaccharides; D011522:Protons; D008358:Mannose; D000117:Acetylglucosamine