NR AWKX
AU Natalello,A.; Beeg,M.; Manzoni,C.; Colombo,L.; Ceci,P.; Doglia,S.M.; Tagliavini,F.; Forloni,G.; Salmona,M.
TI Structure of PrP82-146 aggregates and cross-linked oligomers
QU International Conference - Prion 2006: Strategies, advances and trends towards protection of society - 3.10.-6.10.2006, Torino, Italy, Lingotto Conference Centre - Poster sessions S-17
PT Konferenz-Poster
AB
The major component of the Gerstmann-Sträussler-Scheinker amyloid aggregates is a prion protein (PrP) peptide fragment containing residues from 81-82 to 144-153 (Salmona et al. 2003, J. Biol. Chem. 278, 48146). In the earlier stages of PrP aggregation, small oligomers with neurotoxic properties were identified (Kazlauskaite et al. 2005, Biochem. Biophys. Res. Commun. 328, 292).We stabilized PrP oligomers by photo-induced cross-linking (PICUP) and characterized their polymerisation process by surface plasmon resonance (Gobbi et al. 2006, J. Biol. Chem. 281, 843).
Here, we present a structural study of PrP82-146 and of its aggregation process, as well as that of PICUP oligomers by Fourier transform infrared spectroscopy (FT-IR) and Circular Dichroism. The monomer is mainly unstructured and starts to form low order aggregates after a lag-phase of 7 days. A this stage, the FT-IR bands around 1623.2 cm-1 and at 1689.8 cm-1 suggest that an antiparallel ß-sheet intermolecular interaction characterized the early aggregates. At later stages, the band at 1623.2 cm-1 shifts to 1626.1 cm-1 and its intensity grows abruptly as fibrils formation takes place. At 10 days, in the FT-IR spectrum only the band at 1626.1 cm-1, diagnostic of a parallel ß-sheets intermolecular interaction, is observed in mature fibrils, indicating that a structural reorganization of early aggregates is at work during fibril assembly. Interestingly, the FT-IR spectrum of photo-induced cross-linked oligomers displays two antiparallel ß-sheet bands similar to those of the early aggregates, therefore indicating a similar structure of these intermediates.
These results suggest that oligomers obtained by PICUP-technique can be used as a model to study the structural properties and the biological activity of early, short living intermediate of fibril formation.
AD A. Natalello, S.M. Doglia: Università di Milano Bicocca, Milan, Italy; . Beeg, C. Manzoni, L. Colombo, P. Ceci, G. Forloni, M. Salmona: Istituto di Ricerche Farmacologiche "Mario Negri", Milan, Italy; F. Tagliavini: Istituto Nazionale Neurologico "Carlo Besta", Milan, Italy. E-mail: Antonino.natalello@unimib.it
SP englisch
PO Italien