Details

Autor(en) / Beteiligte

• Józsa, Éva
• sz, Katalin
• Kállay, Csilla
• de Bona, Paolo
• Damante, Chiara A
• Pappalardo, Giuseppe
• Rizzarelli, Enrico
• Sóvágó, Imre

Titel

Nickel(ii) and mixed metal complexes of amyloid-β N-terminus

Ist Teil von

• Dalton transactions : an international journal of inorganic chemistry, 2010-08, Vol.39 (3), p.746-753

Ort / Verlag

England

Erscheinungsjahr

2010

Quelle

MEDLINE

Beschreibungen/Notizen

• Nickel( ii ) complexes of Aβ(1-16)Y10A and its smaller fragments including Aβ(1-4), Aβ(1-6), Ac-Aβ(1-6) and Ac-Aβ(8-16)Y10A have been studied by potentiometric, UV-Vis and circular dichroism spectroscopic measurements. The formation of mixed metal complexes and the distribution of metal ions among the possible coordination sites in the Cu( ii )-Ni( ii )-Aβ(1-16)Y10A and Cu( ii )-Ni( ii )-Zn( ii )-Aβ(1-16)Y10A systems have also been evaluated. It was found that the hexadecapeptide and its fragments are effective nickel( ii ) binding ligands and complex formation processes of nickel( ii ) ions are quite similar to those of copper( ii ). Formation of mono- and di-nuclear complexes was detected in the nickel( ii )-Aβ(1-16)Y10A system suggesting the existence of two separated metal binding motifs: the N-terminus and internal histidyl residues. The preference for the coordination at the N-terminus was supported by the spectroscopic measurements but in equilibrium with the metal binding at the internal histidyl sites. Neither zinc( ii ) nor nickel( ii ) can, however, substitute copper( ii ) in the mixed metal complexes of Aβ(1-16)Y10A, but both metal ions are able to alter the distribution of copper( ii ) ions among the various binding sites. Both N-terminus (amino and His6) and internal histidyl residues (His13 and His14) can work as dinuclear binding motifs, preferably accommodating copper(II) and zinc(II), respectively, while nickel( ii ) can occupy the remaining free coordination sites. Neither zinc( ii ) nor nickel( ii ) can substitute copper( ii ) in the complexes of Aβ(1-16)Y10A but both metal ions are able to alter the distribution of copper( ii ) ions.