NR ATFS
AU Dumpitak,C.; Panza,G.; Stöhr,J.; Birkmann,E.; Riesner,D.
TI Influences of polysaccharides on aggregation and fibrillization of the prion protein
QU International Conference - Prion 2005: Between fundamentals and society's needs - 19.10.-21.10.2005, Congress Center Düsseldorf - Oral sessions ORAL-23
PT Konferenz-Vortrag
AB
To understand the pathological properties of prions in more detail, knowledge about the influence of secondary components onto prion formation is essential. This is especially important since in vitro generation of infectivity leads only to small titers of infectivity as shown recently (1). We showed that prion rods contain a polysaccharide scaffold amounting to ~10 % (w/w) of prion rods. Analyses revealed that it consists of predominantly 1,4-linked glucose with few 1,4,6-branches and is unambiguously distinct from N-glycosylations and GPI-anchor of PrP (2). Recently we showed that the polysaccharide scaffold is a common secondary component of prions, detectable in several different prion preparations. The stereochemistry of the scaffold's glycosidic linkages was determined as predominantly, if not entirely alpha-glycosidic, pointing out a close relationship to glycogen (3).
Polysaccharides composed of alpha-1,4-linked glucose, like the prion scaffold, have unique structural properties and can form complexes with hydrophobic molecules. We therefore studied the influence of those polysaccharides on the conformational transition of PrP, applying an in vitro conversion system, in which PrP is kept soluble at low concentrations of sodiumdodecylsulfate (SDS) and undergoes conformational transition with aggregation after dilution of SDS (4) or fribrillization in the presence of sodium chloride (5). Conformational transition, aggregation and fibrillization of recombinant PrP in the presence of model polysaccharides was examined in vitro using circular dichroism spectroscopy, fluorescence correlation spectroscopy, confocal laser scanning microscopy, Thioflavin-T-fluorescence and electron microscopy.
(1) Legname G, et al. (2004). Science 305: 673-676.
(2) Appel TR, et al. (1999). Biol. Chem. 380: 1295-1306.
(3) Dumpitak C, et al. (2005), Biol. Chem., in press.
(4) Post K., et al. (1998). Biol. Chem. 379: 1307-1317
(5) Leffers K-W, et al. (2005) Biol. Chem.386: 569-580.
AD C.Dumpitak, G.Panza, J.Stöhr, E.Birkmann, D.Riesner, Institut für Physikalische Biologie und Biologisch-Medizinisches-Forschungsszentrum, Heinrich-heine-Universität Düsseldorf, 40225 Düsseldorf, Germany
SP englisch
PO Deutschland