*** IBB - CNR *** Dipartimento di Scienze Chimiche, Universita di Catania, Viale A. Doria 6, 95125, Catania, Italy. rbonomo@unict. it Istituto di Biostrutture e Bioimmagini, CNR, Unit Organizzativa di Supporto di Catania, Viale A. Doria 6, 95125, Catania, Italy
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. 2009 The Royal Society of Chemistry
19 Records (19 escludendo Abstract e Conferenze). Impact factor totale: 71.143 (71.143 escludendo Abstract e Conferenze). Impact factor a 5 anni totale: 70.367 (70.367 escludendo Abstract e Conferenze).