Åukasz Szyrwiel , Åukasz Szczukowski, JÃ³zsef S. Pap, Bartosz Setner, Zbigniew Szewczuk, and WiesÅ‚aw Malinka, Inorg. Chem., Article ASAP; Publication Date (Web): July 14, 2014; Copyright © 2014 American Chemical Society
Three new branched peptides, namely, H-Gly-Dap(H-Gly)-Gly-NH2 (3G), H-His-Dap(H-His)-Gly-NH2 (2HG), and H-Gly-Dap(H-Gly)-His-NH2 (2GH), where Dap stands for the 2,3-diaminopropionic acid residue, were synthesized by solid phase procedures. Because of the junction at Dap these peptides have three available pending arms for metal chelation. The complex formation between these peptides and 1 equiv of Cu2+ was investigated as a function of pH by potentiometry ultravioletâ€“visible absorption, circular dichroism, and X-band electron paramagnetic resonance spectroscopy in aqueous medium. Our results clearly demonstrate that cooperation between all three peptide arms essentially contributes to the stability of copper(II) complexes.