The copper(II) binding properties of the cyclic peptide c(HGHK).
The new cyclic tetrapeptide c(HGHK) was synthesised in the solid phase and its complexes with copper(II) were studied in aqueous solution at various pH values by means of potentiometric and spectroscopic methods (UV, EPR, CD). Six mononuclear coordination species were clearly identified within the pH range 3-11. Spectroscopic data strongly suggest sequential formation of N, 2N, 3N and 4N equatorial donor sets around the copper(II) centre from the lowest to the highest pH, involving both imidazole nitrogens and amide nitrogens. A detailed comparison with the copper(II) binding properties of HGHG and Ac-HGHG ligands is also reported.
Brasun
Justyna
J
Department of Basic Medical Sciences, Wrocław Medical University, Kochanowskiego 14, 51-601 Wrocław, Poland. jbrasun@basmed.am.wroc.pl
Gabbiani
Chiara
C
Ginanneschi
Mauro
M
Messori
Luigi
L
Orfei
Marco
M
Swiatek-Kozlowska
Jolanta
J
D000577:Amides / Q000737:chemistry; D002942:Circular Dichroism; D003300:Copper / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D006639:Histidine / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D015394:Molecular Structure; D009584:Nitrogen / Q000737:chemistry; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism*; D011199:Potentiometry; D011485:Protein Binding; D012996:Solutions / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D014867:Water / Q000737:chemistry
D000577:Amides; D008024:Ligands; D010455:Peptides; D012996:Solutions; C050632:polypeptide C; D014867:Water; D006639:Histidine; D003300:Copper; D009584:Nitrogen