Conformational Stability of Mammalian Prion Protein Amyloid Fibrils Is Dictated by a Packing Polymorphism within the Core Region

Cobb, Nathan J.; Apostol, Marcin I.; Chen, Shugui; Smirnovas, Vytautas; Surewicz, Witold K.

doi:10.1074/jbc.m113.520718

Cited by 51 publications

(68 citation statements)

References 60 publications

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“…Next, we analyzed the influence of PrP b polymorphism on PrP conversion with the less stringent but commonly used in vitro recPrP amyloid fibril growth assay39. In unseeded reactions, the amyloid fibril formation by recPrP was highly variable (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…This conformational change produces recPrion, the pathogenic conformer of recPrP, that causes bona fide prion disease in wild-type mice with pathological properties identical to those of naturally occurring prions3638. In addition to PMCA, we also used a denaturant-induced recPrP amyloid fibril formation assay394041, which is commonly used to model PrP conversion.…”

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confidence: 99%

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The role of the unusual threonine string in the conversion of prion protein

Abskharon

Wang

Stel

et al. 2016

Sci Rep

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The conversion of normal prion protein (PrP) into pathogenic PrP conformers is central to prion disease, but the mechanism remains unclear. The α-helix 2 of PrP contains a string of four threonines, which is unusual due to the high propensity of threonine to form β-sheets. This structural feature was proposed as the basis for initiating PrP conversion, but experimental results have been conflicting. We studied the role of the threonine string on PrP conversion by analyzing mouse Prnpa and Prnpb polymorphism that contains a polymorphic residue at the beginning of the threonine string, and PrP mutants in which threonine 191 was replaced by valine, alanine, or proline. The PMCA (protein misfolding cyclic amplification) assay was able to recapitulate the in vivo transmission barrier between PrPa and PrPb. Relative to PMCA, the amyloid fibril growth assay is less restrictive, but it did reflect certain properties of in vivo prion transmission. Our results suggest a plausible theory explaining the apparently contradictory results in the role of the threonine string in PrP conversion and provide novel insights into the complicated relationship among PrP stability, seeded conformational change, and prion structure, which is critical for understanding the molecular basis of prion infectivity.

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

The role of the unusual threonine string in the conversion of prion protein

Abskharon

Wang

Stel

et al. 2016

Sci Rep

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“…We explored the differences between the structures using thermal unfolding experiments. If fibers treated with DLPC LUVs result in altered ␤-strand folding and hydrogen bond networks, their unfolding temperatures and enthalpy of unfolding will probably be different as a result (57)(58)(59). To this end, we studied the stability of A␤ fibers formed for 24 and 40 h, as well as fibers formed for 24 h and subsequently treated with either 5 or 20 eq of DLPC in LUVs (Fig.…”

Section: Resultsmentioning

confidence: 99%

Reduced Lipid Bilayer Thickness Regulates the Aggregation and Cytotoxicity of Amyloid-β

Korshavn

Satriano

Lin

et al. 2017

Journal of Biological Chemistry

157

158

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Edited by Paul E. FraserThe aggregation of amyloid-␤ (A␤) on lipid bilayers has been implicated as a mechanism by which A␤ exerts its toxicity in Alzheimer's disease (AD). Lipid bilayer thinning has been observed during both oxidative stress and protein aggregation in AD, but whether these pathological modifications of the bilayer correlate with A␤ misfolding is unclear. Here, we studied peptide-lipid interactions in synthetic bilayers of the shortchain lipid dilauroyl phosphatidylcholine (DLPC) as a simplified model for diseased bilayers to determine their impact on A␤ aggregate, protofibril, and fibril formation. A␤ aggregation and fibril formation in membranes composed of dioleoyl phosphatidylcholine (DOPC) or 1-palmitoyl-2-oleoyl phosphatidylcholine mimicking normal bilayers served as controls. Differences in aggregate formation and stability were monitored by a combination of thioflavin-T fluorescence, circular dichroism, atomic force microscopy, transmission electron microscopy, and NMR. Despite the ability of all three lipid bilayers to catalyze aggregation, DLPC accelerates aggregation at much lower concentrations and prevents the fibrillation of A␤ at low micromolar concentrations. DLPC stabilized globular, membrane-associated oligomers, which could disrupt the bilayer integrity. DLPC bilayers also remodeled preformed amyloid fibrils into a pseudo-unfolded, molten globule state, which resembled on-pathway, protofibrillar aggregates. Whereas the stabilized, membrane-associated oligomers were found to be nontoxic, the remodeled species displayed toxicity similar to that of conventionally prepared aggregates. These results provide mechanistic insights into the roles that pathologically thin bilayers may play in A␤ aggregation on neuronal bilayers, and pathological lipid oxidation may contribute to A␤ misfolding.

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“…Depending on the preparation method (buffer pH, concentration of chaotropes, annealing treatment), such fibrils appear to have distinct physicochemical properties, showing differences in conformational stability, packing arrangement within the core region, and the size of PK-resistant fragments (11)(12)(13)(14)(15)(16)(17)31). Unlike moPrP23-230 fibrils used as a control in our present study, one preparation of full-length PrP fibrils (characterized by longer PK-resistant species, ranging from an apparently intact protein to 17-to 19-kDa fragments) was recently reported to seed PrP C conversion in the PMCA reaction (17).…”

Section: Discussionmentioning

confidence: 99%

Amyloid fibrils from the N-terminal prion protein fragment are infectious

Choi

Calì

Surewicz

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Recombinant C-terminally truncated prion protein PrP23-144 (which corresponds to the Y145Stop PrP variant associated with a GerstmannSträussler-Scheinker-like prion disease) spontaneously forms amyloid fibrils with a parallel in-register β-sheet architecture and β-sheet core mapping to residues ∼112-139. Here we report that mice (both tga20 and wild type) inoculated with a murine (moPrP23-144) version of these fibrils develop clinical prion disease with a 100% attack rate. Remarkably, even though fibrils in the inoculum lack the entire C-terminal domain of PrP, brains of clinically sick mice accumulate longer proteinase K-resistant (PrP res ) fragments of ∼17-32 kDa, similar to those observed in classical scrapie strains. Shorter, GerstmannSträussler-Scheinker-like PrP res fragments are also present. The evidence that moPrP23-144 amyloid fibrils generated in the absence of any cofactors are bona fide prions provides a strong support for the protein-only hypothesis of prion diseases in its pure form, arguing against the notion that nonproteinaceous cofactors are obligatory structural components of all infectious prions. Furthermore, our finding that a relatively short β-sheet core of PrP23-144 fibrils (residues ∼112-139) with a parallel in-register organization of β-strands is capable of seeding the conversion of full-length prion protein to the infectious form has important implications for the ongoing debate regarding structural aspects of prion protein conversion and molecular architecture of mammalian prions.prion disease | prions | amyloid | infectivity

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Conformational Stability of Mammalian Prion Protein Amyloid Fibrils Is Dictated by a Packing Polymorphism within the Core Region

Cited by 51 publications

References 60 publications

The role of the unusual threonine string in the conversion of prion protein

The role of the unusual threonine string in the conversion of prion protein

Reduced Lipid Bilayer Thickness Regulates the Aggregation and Cytotoxicity of Amyloid-β

Amyloid fibrils from the N-terminal prion protein fragment are infectious

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