title: [Conformation analysis of modified tetrasaccharide sequences of the N-glycoprotein type--problem of the alpha-(1 to 6)-glycosidic bond].
abstract: The conformational analysis of the recently synthesized tetrasaccharides alpha-D-Manp (1----3)-[alpha-D-Manp-(1----6)]-4-deoxy-beta-D-lyx-hexp+ ++-(1----4)-D-GlcNAc (2) and alpha-D-Manp-(1----3)-[alpha-D-Manp-(1----6)]-beta-D-Talp -(1----4)-D-GlcNAc (3) will be described. The preferred solution conformation of 2 and 3 is a gt-conformation, which is nearly identical with the preferred conformation of the naturally occurring tetrasaccharide alpha-D-Manp-(1----3)-[alpha-D-Manp-(1----6)]-beta-D-Manp -(1----4)-D-GlcNAc (1). The main structural feature is the backfolding of the alpha-(1----6)-linked D-Man to the reducing D-GlcNAc unit. Conformational analysis of the tetrasaccharides alpha-D-Manp-(1----3)-[alpha-D-Manp-(1----6)]-beta-D-Manp -(1----4)-1,6- anhydro-beta-D-GlcNAc (4), alpha-D-Manp-(1----3)-alpha-D-Manp-(1----6)]-4-deoxy-beta-D- lyx-hexp-(1----4)- 1,6-anhydro-beta-D-GlcNAc (5), and alpha-D-Manp-(1----3)-[alpha-D-Manp-(1----6)]-beta-D-Talp -(1----4)- 1,6-anhydro-beta-D-GlcNAc (6) gave additional proof for this backfolding. The substitution of the reducing unit leads to a smaller amount of gt- and a greater amount of gg-conformers. The method used for conformational analysis of 2-6 is a combination of n.m.r.-experiments and HSEA-calculations with the program GESA. Concerning the application of new 2D-techniques, the COLOC-experiment turned out to be extremely useful in sequencing oligosaccharides.
authors: Institut für Organische Chemie der Universität Hamburg, Bundesrepublik Deutschland.
authors: H
authors: H
authors: Paulsen
authors: T
authors: T
authors: Peters
authors: V
authors: V
authors: Sinnwell
authors: B
authors: B
authors: Meyer
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D006023:Glycoproteins / Q000138:chemical synthesis*; D006027:Glycosides; D008958:Models, Molecular; D009844:Oligosaccharides / Q000138:chemical synthesis; D013329:Structure-Activity Relationship
chemical_list: D006023:Glycoproteins; D006027:Glycosides; D009844:Oligosaccharides
vernacular_title: Konformationsanalyse modifizierter Tetrasaccharidsequenzen vom Typ der N-Glycoproteine--zum Problem der alpha-(1----6)-glycosidischen Bindung.