Issue 14, 2009

Copper(ii) complexes of prion protein PEG11-tetraoctarepeat fragment: spectroscopic and voltammetric studies

Abstract

Spectroscopic (UV-Vis and EPR) and voltammetric studies have been carried out on the copper(II) complexes with the Ac-PEG11-(PHGGGWGQ)4-NH2 (L) polypeptide. In the ratios Cu : L 3 : 1 and 4 : 1, the two [Cu3(L)H−6] and [Cu4(L)H−8] complex species have been characterized at neutral pH values. All the copper atoms occupy similar coordination sites formed by imidazole, peptidic nitrogen atoms and carbonyl oxygen atoms in a square base pyramidal geometry. Voltammetric measurements on these systems point out the cooperativity in the electron transfer processes among the copper(II) sites during their reduction. NO interaction with these polynuclear copper species is characterized by the reduction of the copper sites through the formation of two different intermediate complex species. When an excess of the Ac-PEG11-(PHGGGWGQ)4-NH2 ligand is considered, frozen solution EPR parameters and UV-Vis spectroscopic data identify the [Cu(Nim)4]2+ chromophore, which does not interact with NO.

Graphical abstract: Copper(ii) complexes of prion protein PEG11-tetraoctarepeat fragment: spectroscopic and voltammetric studies

Article information

Article type
Paper
Submitted
03 Dec 2008
Accepted
04 Feb 2009
First published
25 Feb 2009

Dalton Trans., 2009, 2637-2646

Copper(II) complexes of prion protein PEG11-tetraoctarepeat fragment: spectroscopic and voltammetric studies

R. P. Bonomo, G. Di Natale, E. Rizzarelli, G. Tabbì and L. I. Vagliasindi, Dalton Trans., 2009, 2637 DOI: 10.1039/B821727K

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