Probing copper(2+) binding to the prion protein-using diamagnetic nicke(2+) and H-1 NMR: The unstructured N terminus facilitates the coordination of six copper(2+) ions at physiological concentrations

Jones, C. E., Klewpatinond, M., Abdelraheim, S. R., Brown, D. R. and Viles, J. H. (2005) Probing copper(2+) binding to the prion protein-using diamagnetic nicke(2+) and H-1 NMR: The unstructured N terminus facilitates the coordination of six copper(2+) ions at physiological concentrations. Journal of Molecular Biology, 346 5: 1393-1407. doi:10.1016/j.jmb.2004.12.043


Author Jones, C. E.
Klewpatinond, M.
Abdelraheim, S. R.
Brown, D. R.
Viles, J. H.
Title Probing copper(2+) binding to the prion protein-using diamagnetic nicke(2+) and H-1 NMR: The unstructured N terminus facilitates the coordination of six copper(2+) ions at physiological concentrations
Journal name Journal of Molecular Biology   Check publisher's open access policy
ISSN 0022-2836
Publication date 2005-01-01
Sub-type Article (original research)
DOI 10.1016/j.jmb.2004.12.043
Volume 346
Issue 5
Start page 1393
End page 1407
Total pages 15
Place of publication London, England, U.K.
Publisher Academic Press
Language eng
Subject 270100 Biochemistry and Cell Biology
Abstract The prion protein (PrP) is a Cu2+ binding cell surface glyco-protein. Misfolding of PrP into a P-sheet rich conformation is associated with transmissible spongiform encephalopathies. Here we use Ni2+ as a diamagnetic probe to further understand Cu2+ binding to PrP. Like Cu2+, Ni2+ preferentially binds to an unstructured region between residues 90 and 126 of PrP, which is a key region for amyloidogenicity and prion propagation. Using both H-1 NMR and visible-circular dichroism (CD) spectroscopy, we show that two Ni2+ ions bind to His96 and His111 independently of each other. H-1 NMR indicates that both Ni2+ binding sites form square-planar diamagnetic complexes. We have previously shown that Cu2+ forms a paramagnetic square-planar complex in this region, suggesting that Ni2+ could be used as a probe for Cu2+ binding. In addition, competition studies show that two Cu2+ ions can displace Ni2+ from these sites. Upon Ni2+ addition H-1 NMR changes in chemical shifts indicate the imidazole ring and amide nitrogen atoms to the N terminus of both His96 and His111 act as coordinating ligands. Use of peptide fragments confirm that PrP(92-96) and PrP(107-111) represent the minimal binding motif for the two Ni2+ binding sites. Analysis Of Cu2+ loaded visible-CD spectra show that as with Ni2+, PrP(90-115) binds two Cu2+ ions at His96 and His111 independently of each other. Visible CD studies with PrP(23-231Delta51-90), a construct of PrP(23-231) with the octarepeat region deleted to improve solubility, confirm binding of Ni2+ to His96 and His111 in octarepeat deleted PrP(23-231). The structure of the Cu/Ni complexes is discussed in terms of the implications for prion protein function and disease. (C) 2004 Elsevier Ltd. All rights reserved.
Keyword Biochemistry & Molecular Biology
Prion Protein
Copper
Nickel
Structure
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Chemistry and Molecular Biosciences
 
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