The metallacrowns as templates for spontaneous self-assembly of polypeptides into a tetrahelical bundle

Amphiphilic peptide sequences with β-aminohydroxamic acid (βahx) at their C-termini were complexed with Cu²⁺ ions resulting in formation of stable metallacrowns composed of βahx and copper. The ESI-MS data for the obtained compounds show formation of supramolecular structures of M_W approx. 7000 Da with the compositions corresponding to metallacrowns. The addition of Cu²⁺ to a solution of βahx-containing peptides results in distinct changes in the CD spectra indicating a shift of their conformational equilibria toward helical structures. The experiments with enzymatic hydrolysis show that formation of metallacrown systems significantly increases the proteolytic stability of investigated peptides.