Glycosylation of the enhanced aromatic sequon is similarly stabilizing in three distinct reverse turn contexts

Proc Natl Acad Sci U S A. 2011 Aug 23;108(34):14127-32. doi: 10.1073/pnas.1105880108. Epub 2011 Aug 8.

Abstract

Cotranslational N-glycosylation can accelerate protein folding, slow protein unfolding, and increase protein stability, but the molecular basis for these energetic effects is incompletely understood. N-glycosylation of proteins at naïve sites could be a useful strategy for stabilizing proteins in therapeutic and research applications, but without engineering guidelines, often results in unpredictable changes to protein energetics. We recently introduced the enhanced aromatic sequon as a family of portable structural motifs that are stabilized upon glycosylation in specific reverse turn contexts: a five-residue type I β-turn harboring a G1 β-bulge (using a Phe-Yyy-Asn-Xxx-Thr sequon) and a type II β-turn within a six-residue loop (using a Phe-Yyy-Zzz-Asn-Xxx-Thr sequon) [Culyba EK, et al. (2011) Science 331:571-575]. Here we show that glycosylating a new enhanced aromatic sequon, Phe-Asn-Xxx-Thr, in a type I' β-turn stabilizes the Pin 1 WW domain. Comparing the energetic effects of glycosylating these three enhanced aromatic sequons in the same host WW domain revealed that the glycosylation-mediated stabilization is greatest for the enhanced aromatic sequon complementary to the type I β-turn with a G1 β-bulge. However, the portion of the stabilization from the tripartite interaction between Phe, Asn(GlcNAc), and Thr is similar for each enhanced aromatic sequon in its respective reverse turn context. Adding the Phe-Asn-Xxx-Thr motif (in a type I' β-turn) to the enhanced aromatic sequon family doubles the number of proteins that can be stabilized by glycosylation without having to alter the native reverse turn type.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amino Acids, Aromatic / metabolism*
  • Glycosylation
  • Linear Models
  • Models, Molecular
  • Molecular Sequence Data
  • Mutation / genetics
  • Protein Folding
  • Protein Stability*
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Proteins / chemistry*
  • Proteins / metabolism*
  • Terminology as Topic
  • Thermodynamics

Substances

  • Amino Acids, Aromatic
  • Proteins