NR AMOV
AU Wille,H.; Baldwin,M.A.; Cohen,F.E.; DeArmond,S.J.; Prusiner,S.B.; Masters,C.L.; Goldgaber,D.; Maeda,N.
TI Prion protein amyloid: separation of scrapie infectivity from PrP polymers.
QU Ciba Foundation Symposium 1996; 199: 181-99; discussion 199-201
PT journal article
AB The prion protein (PrP) undergoes a profound conformational change when the cellular isoform (PrPc) is converted into the scrapie form (PrPsc). Limited proteolysis of PrPsc produces PrP27-30 which readily polymerizes into amyloid. To study the structure of PrP amyloid, we employed organic solvents that perturb protein conformation. 1,1,1,3,3,3-Hexafluoro-2-propanol (HFIP), which promotes alpha-helix formation, modified the ultrastructure of rod-shaped PrP amyloids, producing flattened ribbons with a more regular substructure. As the concentration of HFIP was increased, the beta-sheet content and proteinase K resistance of PrP27-30 as well as prion infectivity diminished. HFIP reversibly decreased the binding of Congo red dye to the rods, whereas inactivation of prion infectivity was irreversible. In contrast to 10% HFIP, 1,1,1-trifluoro-2-propanol (TFIP) did not inactivate prion infectivity but, similarly to HFIP, TFIP did alter the morphology of the rods and abolished Congo red binding. Our studies separate prion infectivity from the amyloid properties of PrP27-30 and underscore the dependence of prion infectivity on PrPsc conformation. Our results also demonstrate that the specific beta-sheet-rich structures required for prion infectivity are different from those needed for amyloid formation.
IN Das organische Lösungsmittel 1,1,1,3,3,3-Hexafluor-2-Propanol fördert die Bildung von Alphahelices und die Umwandlung der stabförmigen Prionproteinamyloide in flache Bänder mit regelmäßigerer Strukturierung. Mit zunehmender Konzentration von 1,1,1,3,3,3-Hexafluor-2-Propanol nehmen der Anteil der Betafaltblätter, die Proteinase K - Resistenz, die Kongorot-Bindung und die Infektiosität ab. Während die Infektiosität anscheinend irreversibel verloren geht, ist die Abnahme der Kongorot-Bindung reversibel. Im Gegensatz dazu bewirkt 1,1,1-Trifluor-2-Propanol zwar ähnlich wie 1,1,1,3,3,3-Hexafluor-2-Propanol eine Veränderung der Prionstruktur und der Kongorot-Bindung, jedoch keine Abnahme der Infektiosität. Die Infektiosität scheint also eher mit der Betafaltblatt-Konformation als mit der Amyloidstruktur verbunden zu sein.
ZR 55
MH 1-Propanol/pharmacology; Amyloid/biosynthesis/*metabolism; Animal; Congo Red; Endopeptidase K/metabolism; Hamsters; Human; Mice; Mice, Transgenic; PrPc Proteins/chemistry/*metabolism/ultrastructure; PrPsc Proteins/metabolism; Prion Diseases/etiology/*metabolism; Propanols; Protein Conformation; Scrapie/metabolism; Solvents/pharmacology; Spectroscopy, Fourier Transform Infrared; Sucrose/pharmacology; Support, Non-U.S. Gov't; Support, U.S. Gov't, P.H.S.
AD Department of Neurology, University of California, San Francisco 94143, USA
SP englisch
PO Niederlande