NR AURM
AU Müller,H.; Stitz,L.; Riesner,D.
TI Protective effects of lipids on the thermal decontamination of prions
QU TSE-Forum, 6. Kongress - Nationale TSE-Forschungsplattform, Greifswald 26.6.-28.6.2006, Poster: Struktur und molekulare Mechanismen MOL-10
PT Konferenz-Poster
AB The inactivation of prion infectivity as well as the degradation of the PrP27-30 backbone intactness are influenced profoundly by environmental conditions. The quantitative and qualitative comparison of the hydrolysis of the most purified, concentrated, and stable form of TSE infectivity, the so-called prion rods, the loss of PK-resistance, and the inactivation of prion infectivity demonstrated differences in the reduction efficiencies of up to factor 105. Whereas the presence of fat, fatty acids, or particularly glycerol has a profound capacity to protect the structural integrity of PrP27-30 against heat degradation, only glycerol-containing mixtures do also exert a protective effect on prion infectivity. In contrast to literature speculations, assuming a lower inactivation efficiency as consequence of some kind of lipid-mediated protection against heat treatment, the inactivation of prion infectivity is even increased in presence of fat. The highest inactivation efficiency was obtained neither in pure water nor in pure fat but in a mixture of both components. Due to deviating reduction efficiencies in different environments, the distribution of prions between different phases is of vital importance. Phase distribution experiments indicated that PrP27-30 is inclined to migrate to the fat water interphase. Only by increasing temperature, detergent concentration, or salt concentration a notable amount of PrP27-30 was obtained in the water phase. Under all conditions analysed the inactivation of prion infectivity is achieved several orders of magnitude more efficiently than the degradation of PrP27-30 occurs. This suggests an at least two-step mechanism of prion inactivation involving a transformation of infectious PrP27-30 into a non-infectious form followed by a slower reaction step during which the non-infectious PrP is degraded. The first step denaturation of PrP27-30 appears to be accompanied by an increase in hydrophobic surfaces resulting in even more collapsed aggregates and providing a simple explanation for more thermostable prion subpopulations. An analysis of heat-induced structural changes of PrP27-30 as well as of the PK resistance and the insolubility of PrP27-30 after heat treatment particularly in presence of lipids is underway.
AD Henrik Müller, Detlev Riesner, Institut für Physikalische Biologie, Heinrich Heine - Universität Düsseldorf, Gebäude 26.12. U1, Universitätsstraße 1, D-40225 Düsseldorf, Germany; Lothar Stitz, Friedrich Loeffler-Institut (FLI), Bundesforschungsinstitut für Tiergesundheit, Paul Ehrlich-Straße 28, D-72076 Tübingen, Germany
SP englisch
PO Deutschland
OR Tagungsband