| First Author | Klewpatinond M | Year | 2008 |
| Journal | J Biol Chem | Volume | 283 |
| Issue | 4 | Pages | 1870-81 |
| PubMed ID | 18042548 | Mgi Jnum | J:130665 |
| Mgi Id | MGI:3772102 | Doi | 10.1074/jbc.M708472200 |
| Citation | Klewpatinond M, et al. (2008) Deconvoluting the Cu2+ binding modes of full-length prion protein. J Biol Chem 283(4):1870-81 |
| abstractText | The prion protein (PrP) is a cell-surface Cu(2+)-binding glycoprotein that when misfolded is responsible for a number of transmissible spongiform encephalopathies. Full-length PrP-(23-231) and constructs in which the octarepeat region has been removed, or His(95) and His(110) is replaced by alanine residues, have been used to elucidate the order and mode of Cu(2+) coordination to PrP-(23-231). We have built on our understanding of the appearance of visible CD spectra and EPR for various PrP fragments to characterize Cu(2+) coordination to full-length PrP. At physiological pH, Cu(2+) initially binds to full-length PrP in the amyloidogenic region between the octarepeats and the structured domain at His(95) and His(110). Only subsequent Cu(2+) ions bind to single histidine residues within the octarepeat region. Ni(2+) ions are used to further probe metal binding and, like Cu(2+), Ni(2+) will bind individually to His(95) and His(110), involving preceding main chain amides. Competitive chelators are used to determine the affinity of the first mole equivalent of Cu(2+) bound to full-length PrP; this approach places the affinity in the nanomolar range. The affinity and number of Cu(2+) binding sites support the suggestion that PrP could act as a sacrificial quencher of free radicals generated by copper redox cycling. |
