NR AOVF
AU Kuczius,T.; Buschmann,A.; Karch,H.; Groschup,M.H.
TI Stabilization of prion protein against proteolytic effects of proteinase K by copper ions
QU International Conference - Prion diseases: from basic research to intervention concepts - TSE-Forum, 08.10.-10.10.2003, Gasteig, München - Poster session - BR-64
PT Konferenz-Poster
AB Prion diseases are characterized by a conformational conversion of the cellular prion protein (PrPc) into its pathological isoform (PrPsc) which is structurally altered and partial resistant to proteinase K (PK) digestion. It has been reported that especially copper ions are able to bind to the octapeptide region in the N-terminal half of PrPc. The presence of copper can change the structure of prions, thus modifying detergent solubility and stability of PrPc and the molecular mass of PrPsc after PK treatment. In this study we analysed the influence of copper and other metal ions on the enzymatic activity of PK as well as on the hydrolysis of ovine PrPc and ovine and murine PrPsc. In contrast to other metals, the addition of >200µM copper sulfate to brain homogenates containing PrPc and PrPsc had a clear inhibitory effect on the proteolytic activity of proteinase K. This inhibition was found using PrP, ovalbumin or N-benzoyl-L-tyrosine ethyl ester (BTEE) as substrates. Moreover, a stabilization of PrP against PK degradation by copper ions but by no other divalent cations was revealed. PrP preincubated with copper cations and subsequently precipitated to remove unbound metal ions remained resistant to proteinase K. This stability was dependant on the preincubation time and the concentration of copper used in the sample. In contrast, ovalbumin was completely digested under the same conditions. Our results suggest a direct (in terms of proteolysis) protective effect of copper ions on PrPc and PrPsc. This adds to an inhibitory effect at higher concentrations of positively charged copper ions on proteinase K itself.
AD T. Kuczius, H. Karch, Institute for Hygiene, University Hospital Muenster, Germany; A. Buschmann, M.H. Groschup, Institute for Novel and Emerging Infectious Diseases, Federal Research Centre for Virus Diseases of Animals, Greifswald - Insel Riems, Germany
SP englisch
PO Deutschland