NR AKHQ
AU Safar,J.G.; Roller,P.P.; Gajdusek,D.C.; Gibbs,C.J.Jr.
TI Thermal stability and conformational transitions of scrapie amyloid (prion) protein correlate with infectivity
QU Protein Science 1993 Dec; 2(12): 2206-16
IA http://www.proteinscience.org/cgi/reprint/2/12/2206
PT journal article
AB The scrapie amyloid (prion) protein (PrP27-30) is the protease-resistant core of a larger precursor (PrPsc) and a component of the infectious scrapie agent; the potential to form amyloid is a result of posttranslational event or conformational abnormality. The conformation, heat stability, and solvent-induced conformational transitions of PrP27-30 were studied in the solid state in films by CD spectroscopy and correlated with the infectivity of rehydrated and equilibrated films. The exposure of PrP27-30 in films to 60 degrees C, 100 degrees C, and 132 degrees C for 30 min did not change the beta-sheet secondary structure; the infectivity slightly diminished at 132 degrees C and correlated with a decreased solubility of PrP27-30 in sodium dodecyl sulfate (SDS), probably due to cross-linking. Exposing PrP27-30 films to formic acid (FA), trifluoroacetic acid (TFA), trifluoroethanol (TFE), hexafluoro-2-propanol (HFIP), and SDS transformed the amide CD band, diminished the mean residue ellipticity of aromatic bands, and inactivated scrapie infectivity. The convex constraint algorithm (CAA) deconvolution of the CD spectra of the solvent-exposed and rehydrated solid state PrP27-30 identified five common spectral components. The loss of infectivity quantitatively correlated with a decreasing proportion of native, beta-pleated sheet-like secondary structure component, an increasing amount of alpha-helical component, and an increasingly disordered tertiary structure. The results demonstrate the unusual thermal stability of the beta-sheet secondary structure of PrP27-30 protein in the solid state. The conformational perturbations of PrP27-30 parallel the changes in infectivity and suggest that the beta-sheet structure plays a key role in the physical stability of scrapie amyloid and in the ability to propagate and replicate scrapie.
IN Der Verlust der Infektiosität von isolierten 27-30 kD Fragmenten des Prionproteins korreliert mit dem abnehmenden Anteil seiner ß-Faltblattstrukturen unter dem Einfluß von Ameisensäure, Trifluoressigsäure, Trifluorethanol, Hexafluorisopropanol und SDS. Bei 132° scheint ein Crosslinking die Infektiosität binnen 30 Min. etwas zu vermindern.
MH Algorithms; Animal; Biological Assay; Circular Dichroism; Hamsters; Heat; Mesocricetus; PrP 27-30 Protein; PrPsc Proteins; Prions/*chemistry/*pathogenicity; Protein Denaturation; Protein Structure, Secondary; Scrapie/*etiology; Solvents; Spectrophotometry, Ultraviolet
AD Laboratory of Central Nervous System Studies, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892.
SP englisch
PO USA