Please use this identifier to cite or link to this item: http://hdl.handle.net/20.500.12779/5504
Title: CuII binding sites located at His-96 and His-111 of the human prion protein: thermodynamic and spectroscopic studies on model peptides
Authors: Gralka, E
Valensin, Daniela 
Porciatti, E
Gajda, C
Gaggelli, Elena 
Valensin, Gianni 
Kamysz, W
Nadolny, R
Guerrini, R
Bacco, D
Remelli, M
Kozlowski, H.
Issue Date: 2008
Project: None 
Journal: DALTON TRANSACTIONS
Abstract: 
The prion protein (PrP) is a Cu2+-binding cell-surface glycoprotein. Using PrP peptide fragments, by means of potentiometric, spectroscopic and thermodynamic techniques, we have shown that Cu2+ ions bind to the region comprising His-96, His-111 and the octarepeat domain within residues 60–91. Cu2+ may bind in different modes, which strongly depend both on His position within the peptide sequence and on the adjacent residues. We have used a series of protected oligopeptides having His at the C- or the N-terminus, inducing different binding modes to amide nitrogens around the His residue, either towards the N- or C-terminus. His imidazole acts as an anchoring site for Cu2+ and then binding to ionized amide nitrogens follows. When it is directed towards the C-terminus the formation of a less stable seven-membered chelate ring with a {Nim, N-} binding mode occurs. When coordination goes towards the N-terminus the thermodynamically more stable six-membered chelate ring is formed. NMR data suggest that both the coordination modes are possible for the model peptides; however, the thermodynamic measurements show that they only slightly differ in energy and the influence of the adjacent amino acid residues can address the coordination toward the C- or the N-terminus.
Description: 
35684
URI: http://hdl.handle.net/20.500.12779/5504
ISSN: 1477-9226
DOI: 10.1039/b806192k
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