Studies of nitric oxide interaction with mono- and dinuclear copper(II) complexes of prion protein bis-octarepeat fragments
| Autor: | Laura I. Vagliasindi, Raffaele P. Bonomo, Enrico Rizzarelli, Giovanni Tabbì, Giuseppe Pappalardo |
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| Rok vydání: | 2008 |
| Předmět: |
Cations
Divalent Prions Inorganic chemistry chemistry.chemical_element Electrochemistry Ligands Nitric Oxide law.invention Inorganic Chemistry law Organometallic Compounds Molecule Electron paramagnetic resonance Aqueous solution Molecular Structure Chemistry Ligand Electron Spin Resonance Spectroscopy Cooperative binding Water Hydrogen-Ion Concentration Copper Solutions Crystallography Spectrophotometry Ultraviolet Cyclic voltammetry |
| Zdroj: | Dalton transactions (2003. Print) (2008): 3805–3816. doi:10.1039/b719930a info:cnr-pdr/source/autori:Raffaele Pietro Bonomo ; Giuseppe Pappalardo; Enrico Rizzarelli; Giovanni Tabbì; Laura Irene Vagliasindi/titolo:Studies of nitric oxide interaction with mono-and dinuclear copper(II) complexes of prion protein bis-octarepeat fragments/doi:10.1039%2Fb719930a/rivista:Dalton transactions (2003. Print)/anno:2008/pagina_da:3805/pagina_a:3816/intervallo_pagine:3805–3816/volume |
| ISSN: | 1477-9226 |
| DOI: | 10.1039/b719930a |
| Popis: | The interaction of nitric oxide with copper(ii) complexes of two octarepeat sequences belonging to the prion protein was studied, considering both mononuclear and dinuclear systems, i.e. Cu-Ac-(PHGGGWGQ)(2)-NH(2) and Cu(2)-Ac-(PHGGGWGQ)(2)-NH(2), respectively. The NO interaction with both systems was followed in aqueous solutions at physiological pH value, by using UV-Vis and EPR spectroscopic techniques as well as cyclic voltammetry. The mechanism of NO interaction with the mononuclear copper complex can be considered similar to that previously observed for the analogous copper systems with Ac-HGGG-NH(2) and Ac-PHGGGWGQ-NH(2). A more complicated behaviour was found with the copper dinuclear system, in which the involvement of two different intermediate complex species was evidenced. A positive cooperativity between the two copper ions, in the reduction process was inferred. When working with a large excess of the Ac-(PHGGGWGQ)(2)-NH(2) ligand, the frozen-solution EPR parameters pertain to the well characterized [Cu(N(im))(4)](2+) unit, which did not exhibit any interaction with NO. The presence of a free coordination site is the necessary requirement for the NO interaction to occur, as found only in the square-pyramidal geometry of [Cu(L)H(-2)] or [Cu(2)(L)H(-4)] complex species, which form when copper and ligand concentrations are similar. |
| Databáze: | OpenAIRE |
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