NR AXVD
AU Riesner,D.; Elfrink,K.; Ollesch,J.; Stöhr,J.; Willbold,D.; Gerwert,K.
TI PrPc forms Intermolecular ß-Sheets when Anchored on Raft-like Lipid Membranes
QU International Conference - Prion 2007 (26.-28.9.2007) Edinburgh International Conference Centre, Edinburgh, Scotland, UK - Book of Abstracts: Protein Misfolding P01.14
IA http://www.prion2007.com/pdf/Prion Book of Abstracts.pdf
PT Konferenz-Poster
AB Whereas most studies on the structure of the prion protein were carried out on recombinant prion protein in solution, in vivo PrPc is anchored on the outer surface of the cell membrane. Therefore, we studied the structure and the interaction of posttranslationally fully modified PrPc anchored on raft-like lipid membranes. PrPc was prepared from PrPc overexpressing CHO-cells and purified as described recently (Elfrink, K. and Riesner, D. 2004 In: Methods and Tools in Biosciences and Medicine: Techniques in Prion Research (S. Lehmann, ed.) 4-15). Studies of the thermodynamics and kinetics of the anchoring process of PrPc into the membrane have shown that depending upon the saturation of the membrane the concentration of PrPc free in solution but in equilibrium with membrane binding is between 10-10 and 10-8M (Elfrink, et al., 2007, Biol. Chem. 388, 79). We extended these studies by analysing the structure of membrane-bound PrPc applying FT-IR in the attenuated total reflexion mode. The spectra exhibited a constant portion, i.e. which is independent upon the binding process and independent upon the concentration of PrPc, and a variable portion, i.e. showing up upon binding and increasing with concentration. After deconvolution of the spectra in different secondary structure components as described recently (Ollesch and Gerwert, submitted) it could be concluded from the constant portion that the globular structure of PrPc as known from NMR-analysis remains unchanged after binding to the membrane. However, the variable portion of the spectra showed, that the segment of the structure, which is flexible in solution, is involved in forming intermolecular ß strands between PrPc-molecules on the membrane. One might suggest, that ß-sheet rich aggregates which contribute to the structure of infectious PrPsc are pre-fomed already in form of PrPc-aggregates anchored on the membrane.
AD D. Riesner, K. Elfrink, J. Stöhr, D. Willbold, Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Germany; J. Ollesch, K. Gerwert, Institut für Biophysik, Heinrich-Heine-Universität Düsseldorf, Germany
SP englisch
PO Schottland