Selective aromatic interactions in beta-hairpin peptides.
To probe the selectivity possible in hydrophobic clusters, we have compared the cross-strand interactions of phenylalanine (Phe) and cyclohexylalanine (Cha) in a beta-hairpin peptide. We have found a preference for self-association among the aromatic residues, which provides 0.55 kcal/mol in stability relative to Cha-Cha cross-strand pair. NMR analysis of the Phe-Phe cross-strand pair indicates that it interacts in an edge-face interaction, despite the fact that it is highly solvent-exposed. The interaction geometry as well as the enthalpic and entropic values for the peptide containing the Phe-Phe cross-strand pair suggest that the preference for self-association arises from inherent differences in the nature of aromatic and aliphatic interactions in water.
Tatko
Chad D
CD
Department of Chemistry, University of North Carolina, Chapel Hill 27599-3290, USA.
Waters
Marcey L
ML
D010455:Peptides / Q000737:chemistry*; D055672:Static Electricity; D013816:Thermodynamics
D010455:Peptides