Cross-Talk Between the Octarepeat Domain and the Fifth Binding Site of Prion Protein Driven by the Interaction of Copper(II) with the N-terminus(597 views) Di Natale G, Turi I, Pappalardo G, Sóvágó I, Rizzarelli E
Chemistry (ISSN: 0947-6539, 1521-3765, 1521-3765electronic), 2015 Mar 2; 21(10): 4071-4084.
Keywords: Circular Dichroism, Copper, Human Prion Protein, Mass Spectrometry, Peptides, Amides, Binding Energy, Crosstalk, Drug Products, Electrospray Ionization, Neurodegenerative Diseases, Physiology, Complexation Properties, Conformational Conversion, Electrospray Ionisation Mass Spectrometries, Metal Binding Affinity, Metal Binding Domain, Physiological Functions, Physiological Ph Range, Binding Sites, Peptide Fragments,
Affiliations: *** IBB - CNR ***
CNR Institute of Biostructures and Bioimaging, Via P. Gaifami 18, 95126 Catania (Italy), Fax: (+39)0957338422.
Department of Inorganic and Analytical Chemistry, University of Debrecen, 4010 Debrecen (Hungary)
[a] CNR Institute of Biostructures and Bioimaging, Via P. Gaifami 18, 95126 Catania (Ital
References: Not available.
Cross-Talk Between the Octarepeat Domain and the Fifth Binding Site of Prion Protein Driven by the Interaction of Copper(II) with the N-terminus
Prion diseases are a group of neurodegenerative diseases based on the conformational conversion of the normal form of the prion protein (PrP(C) ) to the disease-related scrapie isoform (PrP(Sc) ). Copper(II) coordination to PrP(C) has attracted considerable interest for almost 20 years, mainly due to the possibility that such an interaction would be an important event for the physiological function of PrP(C) . In this work, we report the copper(II) coordination features of the peptide fragment Ac(PEG11 )3 PrP(60-114) [Ac=acetyl] as a model for the whole N-terminus of the PrP(C) metal-binding domain. We studied the complexation properties of the peptide by means of potentiometric, UV/Vis, circular dichroism and electrospray ionisation mass spectrometry techniques. The results revealed that the preferred histidyl binding sites largely depend on the pH and copper(II)/peptide ratio. Formation of macrochelate species occurs up to a 2:1 metal/peptide ratio in the physiological pH range and simultaneously involves the histidyl residues present both inside and outside the octarepeat domain. However, at increased copper(II)/peptide ratios amide-bound species form, especially within the octarepeat domain. On the contrary, at basic pH the amide-bound species predominate at any copper/peptide ratio and are formed preferably with the binding sites of His96 and His111, which is similar to the metal-binding-affinity order observed in our previous studies. 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Cross-Talk Between the Octarepeat Domain and the Fifth Binding Site of Prion Protein Driven by the Interaction of Copper(II) with the N-terminus