NR AVPZ
AU Wells,M.A.; Jelinska,C.; Hosszu,L.L.P.; Craven,C.J.; Clarke,A.R.; Collinge,J.; Waltho,J.P.; Jackson,G.S.
TI Multiple forms of copper (II) co-ordination occur throughout the disordered N-terminal region of the prion protein at pH 7.4.
QU Biochemical Journal 2006 Dec 15; 400(3): 501-10
PT journal article; research support, non-u.s. gov't
AB Although the physiological function of the prion protein remains unknown, in vitro experiments suggest that the protein may bind copper (II) ions and play a role in copper transport or homoeostasis in vivo. The unstructured N-terminal region of the prion protein has been shown to bind up to six copper (II) ions, with each of these ions co-ordinated by a single histidine imidazole and nearby backbone amide nitrogen atoms. Individually, these sites have micromolar affinities, which is weaker than would be expected of a true cuproprotein. In the present study, we show that with subsaturating levels of copper, different forms of co-ordination will occur, which have higher affinity. We have investigated the copper-binding properties of two peptides representing the known copper-binding regions of the prion protein: residues 57-91, which contains four tandem repeats of the octapeptide GGGWGQPH, and residues 91-115. Using equilibrium dialysis and spectroscopic methods, we unambiguously demonstrate that the mode of copper co-ordination in both of these peptides depends on the number of copper ions bound and that, at low copper occupancy, copper ions are co-ordinated with sub-micromolar affinity by multiple histidine imidazole groups. At pH 7.4, three different modes of copper co-ordination are accessible within the octapeptide repeats and two within the peptide comprising residues 91-115. The highest affinity copper (II)-binding modes cause self-association of both peptides, suggesting a role for copper (II) in controlling prion protein self-association in vivo.
MH Binding Sites; Copper/chemistry/*metabolism; Humans; Hydrogen-Ion Concentration; Molecular Structure; Prions/*chemistry/*metabolism; Protein Binding
AD Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
SP englisch
PO England