Impact of copper ions on chemistry and biology of prion protein

The current state of art in the studies on Cu2+ ions interactions with mammalian and chicken prion protein (PrP) is discussed. The specificity of Cu2+ binding by tandem repeat domains of PrPs is actually well supported although the major contradictions still exist as far as the fifth binding site is concerned. The biological relevance of Cu2+ coordination to octarepeat region of mammalian PrP seems to be generally accepted although the binding of the fifth metal ion may be just a chemical property of PrP.