Hydrophobic association of a side chains induces reversible helix folding in a dual aromatic ring tagged short peptide

A short peptide having two naphthalene tags folds into a stable α-helix. The helix content of the peptide was 78%. The hydrophobic association of the naphthalene in the peptide was confirmed by its excimer fluorescence. When this hydrophobic association of the naphthalene was disturbed by forming inclusion complex with 2-hydroxypropyl-β-cyclodextrin (HPCD), the helix content was reduced to 64%. The binding of naphthalene on the peptide with HPCD was confirmed by its fluorescence spectra. On the other hand this inclusion complex on naphthalene and HPCD was inhibited with 1-adamantanol, the helix content of the peptide was completely recovered to 78%. The dual naphthalene tagged peptide displayed reversible folding of the α-helix.