NR AORN
AU Cuccioloni,M.; Amici,M.; Eleuteri,A.M.; Biagetti,M.; Barocci,S.; Angeletti,M.
TI Binding of Recombinant PrPc to Human Plasminogen: Kinetic and Thermodynamic Study Using a Resonant Mirror Biosensor
QU International Conference - Prion diseases: from basic research to intervention concepts - TSE-Forum, 08.10.-10.10.2003, Gasteig, München - Poster session - BR-47
PT Konferenz-Poster
AB TSEs are a class of sporadic, genetic and transmissible neurodegenerative diseases that affect both humans and animals. Propagation of these diseases is thought to be due to the misfolding of a neuronal glyco-protein, PrPc, into a pathological insoluble conformer, PrPsc. In recent works, some serum components were identified as exclusive PrPsc-interacting proteins (Fisher et al. (2000) Nature 408, 479), and thus those macromolecules were thought to represent a potential diagnostic endogenous factor discriminating between normal and pathological prion protein. In this work, a detailed thermodynamic and kinetic characterization of the interaction between recombinant bovine PrPc(25-242) and the human serum component plasminogen, measured using a resonant mirror technique is presented: our results reveal a high affinity interaction between the two binding partner. Both kinetic and thermodynamic parameters are affected by the modulation exerted by the H+ ions in solution. The analysis of binding, according to canonical linkage relationships, suggests the involvement of a His residue and a mechanism of the interaction reminiscent of that between other serine (pro)enzymes and their ligands. Moreover, western blotting analysis of rec.PrPc-plasminogen complex treated with proteinase K were performed. The results showed a band corresponding to the molecolar weight of a proteinase K resistant form of PrP; these results were validated by aminoacids sequencing. These data suggest that plasminogen could act as promoter in PrPc misfolding into its pathological isoform. In fact, since glycosylation almost completely shields large areas of the protein and confers some conformational stability to the normal protein causing a delaying in the conversion, recombinant bovine PrP, expressed in Escherichia coli as a non-glycosylated protein, should lose the protective effect exerted by oligosaccaride group, with a resulting increased rate of conversion.
AD Massimiliano Cuccioloni, Manila Amici, Anna M. Eleuteri, Mauro Angeletti, University of Camerino, Camerino (MC), Italy; Massimo Biagetti, Simone Barocci, Zooprophilactic Institute, Perugia, Italy
SP englisch
PO Deutschland