Self-Assembly Of Hairpin Peptides Mediated By Cu(Ii) Ion: Effect Of Amino Acid Sequence

The alteration of amino acid register in peptides could affect their folding properties and thus functions. The effect of sequence in metal ion induced folding of peptide/ protein is important in the design of new functional protein structures, such as biomimetics. In this paper, a set of hairpin peptides with identical composition but different histidine locations have been designed to exploit the metal ion-mediated peptide intramolecular folding transformation through the adjustment of histidine and lysine residue locations. The results demonstrated that the histidine positions in peptide sequence could dramatically affect the coordination modes between peptides and Cu(II) ion. The Cu(II) coordination could affect the secondary structure transformation and self-assembly along with electrostatic interaction and hydrogen bonding synergistically. Three molecules with VHVH sequence at each side of the turn segment ((VPPT)-P-D) were apt to coordinate with Cu(II) ion with three or four histidines. The closer the VHVH motifs were to the turn segment, the more easier the molecules were to form p sheet structure with the promotion of CU(II) ions. These results demonstrated that the purposeful location of key amino acids in peptides could achieve the controllable conformation transformation of hairpin peptides, which provides useful strategies for biomimetic design, such as metalloenzymes.