Alcohol-Adaptive Folding of Rotatable Peptides Toward Tunable Chiroptical β-Sheet Materials

Conformational transitions in β-sheets represent critical steps in the regulatory mechanisms of certain proteins. The incorporation of synthetically designed, rotatable β-turns introduces dynamic flexibility into peptide folding, which promotes the development of intelligent and responsive materials. This study presents a β-sheet peptide folding system to achieve precise chirality expression and modulation by selectively entrapping alcohols. Glycine-phenylalanine sequenced dipeptides were conjugated to a benzimidazole core with a dual aryl axis to enable rotatability and dynamic folding behaviors, where pyrenes were further appended as a signaling luminophore. Spontaneous peptide folding enables the formation of supramolecular pockets that provide microenvironments for entrapping solvents, whereby the interplay between luminophores can be tailored. Specifically, the conformational adaptiveness shows ultrahigh sensitivity toward aliphatic alcohols, with acidity and steric hindrance evidenced as the key structural factors. The adaptive folding is precisely signaled by the luminescent and chiral properties of pyrene, which allow for accurate chiral sensing of aliphatic alcohols with respect to electronic, vibrational dichroism, and circularly polarized luminescence. This work explores the potential of peptide-based motors in adaptive molecular materials with chiroptical applications, shedding light on the solvent impacts on the functions of peptides and proteins.