Structure Stabilizing Role of Aromatic Interactions is Decided by Spatial Arrangement of Aromatic Pairs: A Case Study With Designed Peptide β-Hairpins

摘要

Interaction among aromatic side chains in the hydrophobic core of proteins is a well-known mechanism for protein structure stabilization [ 1 ]. Aromatic pairs at the non-hydrogen bonding position of designed P-hairpin peptides interact by T-shaped arrangement and usually result in structured folds [2]. However, the consequences of spatial positioning and preferred packing geometry of aromatic pairs on scaffold structure and stability are still unclear. Studies on tryptophan packing geometry have revealed that the heterogeneous indole ring preferentially occupies "face" geometry in T-shaped aromatic interactions [3]. But the fate of Trp at the sterically constrained "edge" geometry is not well understood. Using P-hairpin peptide models we describe here a detailed investigation highlighting the implication of aromatic-aromatic interactions in the formation and measured stability of p-hairpin scaffolds.