Design and synthesis of 3α-helix peptides forming a cavity for a fluorescent ligand

As a model of receptor protein. a series of 3 alpha -helix bundle peptides constructed on a template peptide were designed so as to possess a hydrophobic core. The size of cavity was modulated by simple replacements of Leu residues to Aln residues in the hydrophobic core. Binding abilities to 8-anilino-1-naphthalenesulfonic acid (ANS) were estimated by the increase of fluorescence intensity: The peptide having three or four Ala residues in the hydrophobic core remarkably increased the binding ability for ANS, though the peptide having two Ala residues gave an efficient cavity for ANS. The peptide having six Ala residues decreased the binding ability due to crucial destabilization of the helix bundle structure. This scaffold can be utilized to a receptor model, while further tuning of the sequence is necessary. (C) 2001 John Wiley & Sons, Inc.