title: Amyloid features and neuronal toxicity of mature prion fibrils are highly sensitive to high pressure.
abstract: Prion proteins (PrP) can aggregate into toxic and possibly infectious amyloid fibrils. This particular macrostructure confers on them an extreme and still unexplained stability. To provide mechanistic insights into this self-assembly process, we used high pressure as a thermodynamic tool for perturbing the structure of mature amyloid fibrils that were prepared from recombinant full-length mouse PrP. Application of high pressure led to irreversible loss of several specific amyloid features, such as thioflavin T and 8-anilino-1-naphthalene sulfonate binding, alteration of the characteristic proteinase K digestion pattern, and a significant decrease in the β-sheet structure and cytotoxicity of amyloid fibrils. Partial disaggregation of the mature fibrils into monomeric soluble PrP was observed. The remaining amyloid fibrils underwent a change in secondary structure that led to morphologically different fibrils composed of a reduced number of proto-filaments. The kinetics of these reactions was studied by recording the pressure-induced dissociation of thioflavin T from the amyloid fibrils. Analysis of the pressure and temperature dependence of the relaxation rates revealed partly unstructured and hydrated kinetic transition states and highlighted the importance of collapsing and hydrating inter- and intramolecular cavities to overcome the high free energy barrier that stabilizes amyloid fibrils.
authors.affiliation: University of Montpellier 2 and INSERM, U710, Montpellier F-34095, France.
authors.forename: Driss
authors.initials: D
authors.lastname: El Moustaine
authors.forename: Veronique
authors.initials: V
authors.lastname: Perrier
authors.forename: Isabelle
authors.initials: I
authors.lastname: Acquatella-Tran Van Ba
authors.forename: Filip
authors.initials: F
authors.lastname: Meersman
authors.forename: Valeriy G
authors.initials: VG
authors.lastname: Ostapchenko
authors.forename: Ilia V
authors.initials: IV
authors.lastname: Baskakov
authors.forename: Reinhard
authors.initials: R
authors.lastname: Lange
authors.forename: Joan
authors.initials: J
authors.lastname: Torrent
mesh_terms: D000682:Amyloid / Q000737:chemistry* / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D007700:Kinetics; D051379:Mice; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D009498:Neurotoxins / Q000737:chemistry* / Q000494:pharmacology; D011312:Pressure; D011328:Prions / Q000737:chemistry* / Q000494:pharmacology; D055550:Protein Stability; D017433:Protein Structure, Secondary
chemical_list: D000682:Amyloid; D009498:Neurotoxins; D011328:Prions