The role of the N-acetyl group in determining the conformation of 2-acetamido-2-deoxy-d-galactopyranosyl-threonine-containing peptides

✍ Scribed by N.Joe Maeji; Yoshio Inoue; Riichiro Chûjô

• Publisher: Elsevier Science
• Year: 1987
• Tongue: English
• Weight: 351 KB
• Volume: 162
• Category: Article
• ISSN: 0008-6215
• DOI: 10.1016/0008-6215(87)80232-x

✦ Synopsis

The complex oligosaccharide moieties in glycoproteins may play an important role in biological systems1**, for example, in recognition signals in which conformation is thought be important-.

x4 The glycan moieties.may be visualisedj as antennae attached to the protein, but the conformations of the carbohydrate-peptide linkages have not been determined.

Although early studieP suggested that glycosylation played only a minor role in the conformation of the protein backbone, recent data obtained using light-scattering', electron microscopy, and ultracentrifugation* on "mucin"-type 0-glycoproteins indicated the importance of the conformation of the carbohydrate units near to the carbohydrate-peptide linkage. Removal of the GalNAc residue from ovine submaxillary mucin caused the extended filament to collapse to a globular forms.

Recently, we presented evidence9 that "mucin" -type, glycosylated threoninecontaining dipeptides formed an intramolecular hydrogen bond between the Thr NH group and the GalNAc CO group (Fig. 1), the strength of which was influenced by neighbouring amino acids.

We now report rH-n.m.r.