Cation−π Interaction in Model α-Helical Peptides

摘要: Cation−π interactions are increasingly recognized as important in chemistry and biology. Here we investigate the cation−π interaction by determining its effect on helicity of model peptides using a combination CD NMR spectroscopy. The data show that single Trp/Arg surface peptide can make significant net favorable free energy contribution to helix stability if two residues positioned with appropriate spacing orientation. solvent-exposed Trp→Arg (i, i + 4) helices contribute −0.4 kcal/mol stability, while no gain is detected have reversed orientation, Arg→Trp 4). derived consistent other experimental results studied proteins or interactions. However same system postulated Phe/Arg provides stability. Thus stronger than Phe→Arg. T...