Tunable CH/π Interactions within a Tryptophan Zipper Motif to Stabilize the Fold of Long β-Hairpin Peptides.

ABSTRACT: The tryptophan zipper (Trpzip) is an iconic folding motif of β-hairpin peptides capitalizing on two pairs of cross-strand tryptophans, each stabilized by an aromatic-aromatic stacking in an edge-to-face (EtF) geometry. Yet, the origins and the contribution of this EtF packing to the unique Trpzip stability remain poorly understood. To address this question of structure-stability relationship, a library of Trpzip hairpins was developed by incorporating readily accessible nonproteinogenic tryptophans of varying electron densities. We found that each EtF geometry was, in fact, stabilized by an intricate combination of XH/π interactions. By tuning the π-electron density of Trp^face rings, CH/π interactions are strengthened to gain additional stability. On

SUBMITTER: Richaud AD 

PROVIDER: S-EPMC11736618 | biostudies-literature | 2023 Dec

REPOSITORIES: biostudies-literature