NR AXVI
AU Robinson,P.J.; Pinheiro,T.J.T.
TI Fibrillization of the Prion Protein at a Membrane Surface
QU International Conference - Prion 2007 (26.-28.9.2007) Edinburgh International Conference Centre, Edinburgh, Scotland, UK - Book of Abstracts: Protein Misfolding P01.23
IA http://www.prion2007.com/pdf/Prion Book of Abstracts.pdf
PT Konferenz-Poster
AB
Prion diseases or transmissible spongiform encephalopathies are fatal neurodegenerative disorders that are characterised by the misfolding of the cellular prion protein, PrPc, into the insoluble ß-sheet rich isoform, PrPsc. Evidence suggests that cellular membranes may provide the denaturing environment that promotes protein-misfolding, leading to subsequent oligomerization and fibrillization of the prion protein. The aim of this study is to characterise prion conversion and fibrillization induced by model membranes in vitro.
The interaction of the recombinant prion protein with membranes that contain varying percentages of negatively charged and zwitterionic lipids has been characterised. Binding of PrP(90-231) to lipid vesicles is monitored by the blue shift in tryptophan fluorescence as the tryptophan residues move from a polar solution environment to a hydrophobic membrane environment. The results show that prion interaction with membranes is dependent on the concentration of negatively charged lipids within the membrane.
Structural analyses, through circular dichroism, show that on membrane binding the prion protein undergoes a structural conversion that results in increased ß-sheet structure. An isodichroic point at 198 nm suggests that this is a stable two state conformational transition.
Negative stain electron microscopy was employed to characterise the morphology of aggregates formed on the membrane surface. This reveals that a high percentage of negatively charged lipid within the membrane induce the formation of amorphous aggregates, whilst lower percentages of negatively charged lipid are more likely to promote ordered aggregation.
The study highlights the cellular conditions that may promote the formation of ordered membrane-associated prion fibrils.
AD P. Robinson, T.J.T. Pinheiro, University of Warwick, Department of Biological Sciences, UK
SP englisch
PO Schottland
EA pdf-Datei und Poster (ergänzte Autorenliste, Titel: Fibrillization of the Prion Protein at a Membrane Surface: Formation of Spongiform Prions)