Stabilizing impact of N-glycosylation on the WW domain depends strongly on the Asn-GlcNAc linkage

ACS Chem Biol. 2013 Oct 18;8(10):2140-4. doi: 10.1021/cb4004496. Epub 2013 Aug 20.

Abstract

N-glycans play important roles in many cellular processes and can increase protein conformational stability in specific structural contexts. Glycosylation (with a single GlcNAc) of the reverse turn sequence Phe-Yyy-Asn-Xxx-Thr at Asn stabilizes the Pin 1 WW domain by -0.85 ± 0.12 kcal mol(-1). Alternative methods exist for attaching carbohydrates to proteins; some occur naturally (e.g., the O-linkage), whereas others use chemoselective ligation reactions to mimic the natural N- or O-linkages. Here, we assess the energetic consequences of replacing the Asn linkage in the glycosylated WW domain with a Gln linkage, with two natural O-linkages, with two unnatural triazole linkages, and with an unnatural α-mercaptoacetamide linkage. Of these alternatives, only glycosylation of the triazole linkages stabilizes WW, and by a smaller amount than N-glycosylation, highlighting the need for caution when using triazole- or α-mercaptoacetamide-linked carbohydrates to mimic native N-glycans, especially where the impact of glycosylation on protein conformational stability is important.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Asparagine / chemistry*
  • Circular Dichroism
  • Cytoplasmic Dyneins / chemistry
  • Glycosylation
  • Humans
  • Models, Molecular
  • Protein Folding
  • Protein Stability
  • Protein Structure, Tertiary
  • Proteins / chemistry*
  • Thermodynamics

Substances

  • Proteins
  • Asparagine
  • DYNLL1 protein, human
  • Cytoplasmic Dyneins