Environmental effects on a prion's helix II domain: copper(II) and membrane interactions with PrP180-193 and its analogues(605 views) Grasso D, Grasso G, Guantieri V, Impellizzeri G, La Rosa C, Milardi D, Micera G, Osz K, Pappalardo G, Rizzarelli E, Sanna D, Sovago I
Chemistry (ISSN: 0947-6539, 1521-3765, 1521-3765electronic), 2005 Dec 23; 12(2): 537-547.
Keywords: Copper, Helical Structures, Membranes, Peptides, Prions, Conformations, Diseases, Mathematical Models, Pathology, Proteins, Toxicity, Artificial Membranes, Metal Interaction, Copper Compounds, Peptide Fragment, Prion Protein, Prion Protein (180 193), Prion Protein (180-193), Amino Acid Sequence, Animal, Article, Binding Site, Cell Membrane, Chemistry, Human, Molecular Genetics, Protein Secondary Structure, Protein Tertiary Structure, Spectroscopy, Molecular Sequence Data, Protein Structure, Prpc Proteins, Spectrum Analysis,
Affiliations: *** IBB - CNR ***
Università di Catania, Dipartimento di Scienze Chimiche, Viale Andrea Doria 6, 95125 Catania, Italy
Istituto CNR di Biostrutture e Bioimmagini, Sezione di Catania, Viale Andrea Doria 6, 95125 Catania, Italy
Univcrsità di Padova, Dipartimento di Chimica Inorganica, Metallorganica Ed. Analitica, Via F. Marzolo 1, 35131 Padova, Italy
Università di Sassari, Dipartimento di Chimica, via Vienna 2, 07100 Sassari, Italy
University of Debreccn, Department of Inorganic and Analytical Chemistry, 4010 Debrecen, Hungary
Istituto CNR di Chimica Biomolecolare, Sezione di Sassari, Traversa La Crucca 3, 07040 Li Punti (SS), Italy
Universit di Catania, Dipartimento di Scienze Chimiche, Viale Andrea Doria 6, 95125 Catania, Italy
Univcrsit di Padova, Dipartimento di Chimica Inorganica, Metallorganica Ed. Analitica, Via F. Marzolo 1, 35131 Padova, Italy
Universit di Sassari, Dipartimento di Chimica, via Vienna 2, 07100 Sassari, Italy
Universita di Catania, Dipartimento di Scienze Chimiche, Viale Andrea Doria 6, 95125 Catania, Italy.,
References: Not available.
Environmental effects on a prion's helix II domain: copper(II) and membrane interactions with PrP180-193 and its analogues
An abnormal interaction between copper and the prion protein is believed to play a pivotal role in the pathogenesis of prion diseases. Copper binding has been mainly attributed to the N-terminal domain of the prion protein, but this hypothesis has recently been challenged in some papers which suggest that the C-terminal domain might also compete for metal anchoring. In particular, the segment corresponding to the helix II region of the prion protein, namely PrP180-193, has been shown both to bind copper and to exhibit a copper-enhanced cytotoxicity, as well as to interact with artificial membranes. The present work is aimed at extending these results by choosing the most representative model of this domain and by determining its copper affinity. With this aim, the different role played by the electrostatic properties of the C- and N-termini of PrP180-193 (VNITIKQHTVTTTT) in determining its conformational behaviour, copper coordination and ability to perturb model membranes was investigated. Owing to the low solubility of PrP180-193, its copper affinity was evaluated by using the shorter PrPAc184-188NH2 (IKQHT) analogue as a model. ESI-MS, ESR, UV/Vis, and CD measurements were carried out on the copper(II)/PrPAc184-188NH2 and copper(II)/PrP180-193NH2 systems, and showed that PrPAc184-188NH2 is a reliable model for the metal interaction with the helix II domain. The affinity of copper(II) for the helix II fragment is higher than that for the octarepeat and PrP106-126 peptides. Finally, the different ability of PrP180-193 analogues to perturb the DPPC model membrane was assessed by DSC measurements. The possible biological consequences of these findings are also discussed briefly.
Environmental effects on a prion's helix II domain: copper(II) and membrane interactions with PrP180-193 and its analogues