title: Glycosylation of the enhanced aromatic sequon is similarly stabilizing in three distinct reverse turn contexts.
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.
authors.affiliation: Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
authors.forename: Joshua L
authors.initials: JL
authors.lastname: Price
authors.forename: David L
authors.initials: DL
authors.lastname: Powers
authors.forename: Evan T
authors.initials: ET
authors.lastname: Powers
authors.forename: Jeffery W
authors.initials: JW
authors.lastname: Kelly
mesh_terms: D000595:Amino Acid Sequence; D024322:Amino Acids, Aromatic / Q000378:metabolism*; D006031:Glycosylation; D016014:Linear Models; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D017510:Protein Folding; D055550:Protein Stability; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism*; D009626:Terminology as Topic; D013816:Thermodynamics
chemical_list: D024322:Amino Acids, Aromatic; D011506:Proteins