The Peptide Can Influence Sugar Conformation in Small Asn Glycopeptides

Abstract

The Asn glycopeptide 1, when compared to analogs Gln 2 and (D)Thr 3, displays intramolecular sugar‐peptide interactions in a DMSO‐d_6/CD₂Cl₂ organic solvent mixture. A comparative ¹H NMR study between Asn 1 and Gln 2 shows sequence‐specific changes in the sugar's C5–C6 rotamer population. The diastereomeric glycopeptide 3 containing a (D)‐Thr3 residue also shows some significantly different sugar ¹H and ¹³C NMR chemical shifts compared to the parent glycopeptide 1. The GlcNAc sugar attached to the Asn1 sidechain is able to sense the stereochemistry at the remote Thr3 residue.

Keywords:

• Glycopeptide
• Sugar conformation
• Peptide‐carbohydrate interactions

Acknowledgment

We thank the NIH (R29 CA16644) for funding this work. JD also thanks the Dreyfus Foundation for a Teacher‐Scholar Award.