Analysis of conformationally restricted models for the (1----6)-branch of asparagine-linked oligosaccharides by n.m.r.-spectroscopy and HSEA calculation.
The conformational preferences of the trisaccharide, beta-D-GlcpNAc-(1----2)-alpha-D-Manp-(1----6)-beta-D-GlcpOR (1) have been investigated by n.m.r.-spectroscopy and HSEA calculation. The fixed omega-angle bicyclic analogs 2 and 3, models for the gt and gg rotamers, respectively, of 1, were furthermore examined with the same techniques in an attempt to deduce which of the conformations accessible to 1 was recognized and glycosylated by the enzyme GlcNAc-transferase-V, which acts on a component of the (1----6)-arm of glycoproteins. Only the gg bicyclic 3 was found to be reactive with the enzyme and this study concludes, based on conformational analysis, that 1 as well as the natural Asn-linked oligosaccharide are recognized by GlcNAc-transferase-V in only one of the two local minimum energy conformations energetically accessible to these molecules in their gg rotamer.
Bock
K
K
Department of Chemistry, Carlsberg Laboratory, Valby, Denmark.
Duus
J O
JO
Hindsgaul
O
O
Lindh
I
I
D001216:Asparagine / Q000737:chemistry; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D006023:Glycoproteins / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008432:Mathematical Computing; D008956:Models, Chemical; D008969:Molecular Sequence Data; D014312:Trisaccharides / Q000737:chemistry* / Q000378:metabolism
D006023:Glycoproteins; D014312:Trisaccharides; D001216:Asparagine