title: Influence of N-methylation on a cation-pi interaction produces a remarkably stable beta-hairpin peptide.
abstract: The methylation of lysine in histone tails is a common posttranslational modification that functions in histone-regulated chromatin condensation, with binding of methylated lysine occurring in aromatic pockets on chromodomain proteins. We have synthesized a highly stable 12-residue beta-hairpin peptide that exploits the histone-related cation-pi interaction between a methylated lysine residue and a tryptophan residue. Thermodynamic analysis reveals significant entropic stabilization of the peptide due to methylation of the lysine residue. Chemical denaturation of the peptide demonstrates two-state behavior. In comparison to other reported, highly stable designed beta-hairpins, this peptide is the most thermally stable beta-hairpin reported to date. This study provides insight into the role of Lys methylation in histone proteins and more generally in mediating protein-protein interactions.
authors.affiliation: Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, USA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Hughes
authors.forename: Marcey L
authors.initials: ML
authors.lastname: Waters
mesh_terms: D000595:Amino Acid Sequence; D002412:Cations; D008745:Methylation; D009842:Oligopeptides / Q000737:chemistry*; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D013329:Structure-Activity Relationship; D013816:Thermodynamics
chemical_list: D002412:Cations; D009842:Oligopeptides