Complex formation and stability of westiellamide derivatives with copper(II)

• Verfasst von: Comba, Peter [VerfasserIn]
• Verfasst von: Dovalil, Nina [VerfasserIn]
• Verfasst von: Haberhauer, Gebhard [VerfasserIn]
• Verfasst von: Hanson, Graeme R. [VerfasserIn]
• Verfasst von: Kato, Yuki [VerfasserIn]
• Verfasst von: Taura, Toshiaki [VerfasserIn]
• Titel: Complex formation and stability of westiellamide derivatives with copper(II)
• Verf.angabe: Peter Comba, Nina Dovalil, Gebhard Haberhauer, Graeme R. Hanson, Yuki Kato, Toshiaki Taura
• E-Jahr: 2010
• Jahr: 21 May 2010
• Umfang: 7 S.
• Fussnoten: Gesehen am 10.05.2023
• Titel Quelle: Enthalten in: Journal of biological inorganic chemistry
• Ort Quelle: Berlin : Springer, 1996
• Jahr Quelle: 2010
• Band/Heft Quelle: 15(2010), 7 vom: Sept., Seite 1129-1135
• ISSN Quelle: 1432-1327
• DOI: doi:10.1007/s00775-010-0673-7
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: Complex formation
• Sach-SW: Cyclic peptides
• Sach-SW: Spectroscopy
• Sach-SW: Stability constants
• Sach-SW: Westiellamide
• K10plus-PPN: 1845053672

Abstract

The CuII coordination chemistry of three synthetic analogues of westiellamide (H3Lwa) with an [18]azacrown-6 macrocyclic structure and imidazole (H3L1), oxazole (H3L2), or thiazole (H3L3) heterocyclic donors in addition to the peptide groups, is reported. The Nheterocycle-Npeptide-Nheterocycle binding sites are highly preorganized for the coordination to CuII ions. The stability constants of mono- and dinuclear CuII complexes of H3L1, H3L2, and H3L3, obtained by isothermal titration microcalorimetry, are reported. EPR and NMR spectroscopy as well as electrospray ionization mass spectrometry (ESI-MS) were used to characterize the complexes formed in solution. The stabilities of the mononuclear and dinuclear CuII complexes of the three ligands are in the range of 105 M−1, but there are subtle differences; specifically the oxazole-derived ligand has, in contrast to the other two macrocycles, a negative formation entropy for coordination to the first CuII ion and a higher stability for complexation to a second CuII center in comparison with the first CuII center (cooperativity). Differences between the three ligands are also apparent in terms of the formation mechanism. With the oxazole-based ligand H3L2, NMR spectroscopy, EPR spectroscopy, and ESI-MS indicate the formation of a ligand-CuII 2:1 intermediate, and this may explain the differences in the formation entropy as well as the cooperativity.