scholarly journals NMR characterization of the pH 4 β-intermediate of the prion protein: the N-terminal half of the protein remains unstructured and retains a high degree of flexibility

2006 ◽  
Vol 401 (2) ◽  
pp. 533-540 ◽  
Author(s):  
Denis B. D. O'Sullivan ◽  
Christopher E. Jones ◽  
Salama R. Abdelraheim ◽  
Andrew R. Thompsett ◽  
Marcus W. Brazier ◽  
...  

Prion diseases are associated with the misfolding of the PrP (prion protein) from a largely α-helical isoform to a β-sheet-rich oligomer. CD has shown that lowering the pH to 4 under mildly denaturing conditions causes recombinant PrP to convert from an α-helical protein into one that contains a high proportion of β-sheet-like conformation. In the present study, we characterize this soluble pH 4 folding intermediate using NMR. 15N-HSQC (heteronuclear single-quantum correlation) studies with mPrP (mouse PrP)-(23–231) show that a total of 150 dispersed amide signals are resolved in the native form, whereas only 65 amide signals with little chemical shift dispersion are observable in the pH 4 form. Three-dimensional 15N-HSQC-TOCSY and NOESY spectra indicate that the observable residues are all assigned to amino acids in the N-terminus: residues 23–118. 15N transverse relaxation measurements indicate that these N-terminal residues are highly flexible with additional fast motions. These observations are confirmed via the use of truncated mPrP-(112–231), which shows only 16 15N-HSQC amide peaks at pH 4. The loss of signals from the C-terminus can be attributed to line broadening due to an increase in the molecular size of the oligomer or exchange broadening in a molten-globule state.

2000 ◽  
Vol 346 (3) ◽  
pp. 785-791 ◽  
Author(s):  
David R. BROWN

The inherited prion diseases such as Gerstmann-Sträussler-Scheinker syndrome (GSS) are linked to point mutations in the gene coding for the cellular isoform of the prion protein (PrPC). One particular point mutation A117V (Ala117 → Val) is linked to a variable pathology that usually includes deposition of neurofibrillary tangles. A prion protein peptide carrying this point mutation [PrP106-126(117V)] was generated and compared with a peptide based on the normal human sequence [PrP106-126(117A)]. The inclusion of this point mutation increased the toxicity of PrP106-126 which could be linked to an increased β-sheet content. An assay of microtubule formation in the presence of tau indicated that PrP106-126 decreased the rate of microtubule formation that could be related to the displacement of tau. PrP106-126 carrying the 117 mutation was more efficient at inhibiting microtubule formation. These results suggest a possible mechanism of toxicity for protein carrying this mutation via destabilization of the cytoskeleton and deposition of tau in filaments, as observed in GSS.


2014 ◽  
Author(s):  
Alessandro Didonna ◽  
Anja Colja Venturini ◽  
Katrina Hartman ◽  
Tanja Vranac ◽  
Vladka Curin Serbec ◽  
...  

Prion diseases are a group of fatal neurodegenerative disorders that affect humans and animals. They are characterized by the accumulation in the central nervous system of a pathological form of the host-encoded prion protein (PrPC). The prion protein is a membrane glycoprotein that consists of two domains: a globular, structured C-terminus and an unstructured N-terminus. The N-terminal part of the protein is involved in different functions in both health and disease. In the present work we discuss the production and biochemical characterization of a panel of four monoclonal antibodies (mAbs) against the distal N-terminus of PrPC using a well-established methodology based on the immunization of Prnp0/0 mice. Additionally, we show their ability to block prion (PrPSc) replication at nanomolar concentrations in a cell culture model of prion infection. These mAbs represent a promising tool for prion diagnostics and for studying the physiological role of the N-terminal domain of PrPC.


Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 482
Author(s):  
Simote Foliaki ◽  
Bradley Groveman ◽  
Jue Yuan ◽  
Ryan Walters ◽  
Shulin Zhang ◽  
...  

Cerebral organoids (COs) are a self-organizing three-dimensional brain tissue mimicking the human cerebral cortex. COs are a promising new system for modelling pathological features of neurological disorders, including prion diseases. COs expressing normal prion protein (PrPC) are susceptible to prion infection when exposed to the disease isoforms of PrP (PrPD). This causes the COs to develop aspects of prion disease pathology considered hallmarks of disease, including the production of detergent-insoluble, protease-resistant misfolded PrPD species capable of seeding the production of more misfolded species. To determine whether COs can model aspects of familial prion diseases, we produced COs from donor fibroblasts carrying the E200K mutation, the most common cause of human familial prion disease. The mature E200K COs were assessed for the hallmarks of prion disease. We found that up to 12 months post-differentiation, E200K COs harbored no PrPD as confirmed by the absence of detergent-insoluble, protease-resistant, and seeding-active PrP species. Our results suggest that the presence of the E200K mutation within the prion gene is insufficient to cause disease in neuronal tissue. Therefore, other factors, such as further genetic modifiers or aging processes, may influence the onset of misfolding.


2014 ◽  
Vol 289 (44) ◽  
pp. 30355-30363 ◽  
Author(s):  
Ryo P. Honda ◽  
Kei-ichi Yamaguchi ◽  
Kazuo Kuwata

The conversion of a cellular prion protein (PrPC) to its pathogenic isoform (PrPSc) is a critical event in the pathogenesis of prion diseases. Pathogenic conversion is usually associated with the oligomerization process; therefore, the conformational characteristics of the pre-oligomer state may provide insights into the conversion process. Previous studies indicate that PrPC is prone to oligomer formation at low pH, but the conformation of the pre-oligomer state remains unknown. In this study, we systematically analyzed the acid-induced conformational changes of PrPC and discovered a unique acid-induced molten globule state at pH 2.0 termed the “A-state.” We characterized the structure of the A-state using far/near-UV CD, 1-anilino-8-naphthalene sulfonate fluorescence, size exclusion chromatography, and NMR. Deuterium exchange experiments with NMR detection revealed its first unique structure ever reported thus far; i.e. the Strand 1-Helix 1-Strand 2 segment at the N terminus was preferentially unfolded, whereas the Helix 2-Helix 3 segment at the C terminus remained marginally stable. This conformational change could be triggered by the protonation of Asp144, Asp147, and Glu196, followed by disruption of key salt bridges in PrPC. Moreover, the initial population of the A-state at low pH (pH 2.0–5.0) was well correlated with the rate of the β-rich oligomer formation, suggesting that the A-state is the pre-oligomer state. Thus, the specific conformation of the A-state would provide crucial insights into the mechanisms of oligomerization and further pathogenic conversion as well as facilitating the design of novel medical chaperones for treating prion diseases.


2020 ◽  
Vol 4 (2) ◽  
pp. 155-167
Author(s):  
Jacob I. Ayers ◽  
Nick A. Paras ◽  
Stanley B. Prusiner

Prions were initially discovered in studies of scrapie, a transmissible neurodegenerative disease (ND) of sheep and goats thought to be caused by slow viruses. Once scrapie was transmitted to rodents, it was discovered that the scrapie pathogen resisted inactivation by procedures that modify nucleic acids. Eventually, this novel pathogen proved to be a protein of 209 amino acids, which is encoded by a chromosomal gene. After the absence of a nucleic acid within the scrapie agent was established, the mechanism of infectivity posed a conundrum and eliminated a hypothetical virus. Subsequently, the infectious scrapie prion protein (PrPSc) enriched for β-sheet was found to be generated from the cellular prion protein (PrPC) that is predominantly α-helical. The post-translational process that features in nascent prion formation involves a templated conformational change in PrPC that results in an infectious copy of PrPSc. Thus, prions are proteins that adopt alternative conformations, which are self-propagating and found in organisms ranging from yeast to humans. Prions have been found in both Alzheimer's (AD) and Parkinson's (PD) diseases. Mutations in APP and α-synuclein genes have been shown to cause familial AD and PD. Recently, AD was found to be a double prion disorder: both Aβ and tau prions feature in this ND. Increasing evidence argues for α-synuclein prions as the cause of PD, multiple system atrophy, and Lewy body dementia.


Viruses ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 429 ◽  
Author(s):  
Angélique Igel-Egalon ◽  
Jan Bohl ◽  
Mohammed Moudjou ◽  
Laetitia Herzog ◽  
Fabienne Reine ◽  
...  

Prions are proteinaceous infectious agents responsible for a range of neurodegenerative diseases in animals and humans. Prion particles are assemblies formed from a misfolded, β-sheet rich, aggregation-prone isoform (PrPSc) of the host-encoded cellular prion protein (PrPC). Prions replicate by recruiting and converting PrPC into PrPSc, by an autocatalytic process. PrPSc is a pleiomorphic protein as different conformations can dictate different disease phenotypes in the same host species. This is the basis of the strain phenomenon in prion diseases. Recent experimental evidence suggests further structural heterogeneity in PrPSc assemblies within specific prion populations and strains. Still, this diversity is rather seen as a size continuum of assemblies with the same core structure, while analysis of the available experimental data points to the existence of structurally distinct arrangements. The atomic structure of PrPSc has not been elucidated so far, making the prion replication process difficult to understand. All currently available models suggest that PrPSc assemblies exhibit a PrPSc subunit as core constituent, which was recently identified. This review summarizes our current knowledge on prion assembly heterogeneity down to the subunit level and will discuss its importance with regard to the current molecular principles of the prion replication process.


PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247248
Author(s):  
Li-Juan Wang ◽  
Xiao-Dan Gu ◽  
Xiao-Xiao Li ◽  
Liang Shen ◽  
Hong-Fang Ji

The conversion of cellular prion protein (PrPC) to disease-provoking conformer (PrPSc) is crucial in the pathogenesis of prion diseases. Heparin has been shown to enhance mammalian prion protein misfolding. As spontaneous prion disease has not been reported in non-mammalian species, such as chicken, it is interesting to explore the influence of heparin on the conversion of chicken prion protein (ChPrP). Herein, we investigated the influences of heparin on biochemical properties of full-length recombinant ChPrP, with murine prion protein (MoPrP) as control. The results showed that at low heparin concentration (10 μg/mL), a great loss of solubility was observed for both MoPrP and ChPrP using solubility assays. In contrast, when the concentration of heparin was high (30 μg/mL), the solubility of MoPrP and ChPrP both decreased slightly. Using circular dichroism, PK digestion and transmission electron microscopy, significantly increased β-sheet content, PK resistance and size of aggregates were observed for MoPrP interacted with 30 μg/mL heparin, whereas 30 μg/mL heparin-treated ChPrP showed less PK resistance and slight increase of β-sheet structure. Therefore, heparin can induce conformational changes in both MoPrP and ChPrP and the biochemical properties of the aggregates induced by heparin could be modified by heparin concentration. These results highlight the importance of concentration of cofactors affecting PrP misfolding.


2003 ◽  
Vol 370 (1) ◽  
pp. 351-355 ◽  
Author(s):  
Adrian R. WALMSLEY ◽  
Nigel M. HOOPER

Cell-specific differences in the utilization of the two N-glycosylation sequons (Asn180-Ile-Thr and Asn196-Phe-Thr) of the prion protein (PrP) have been proposed to influence the aetiology of the neurodegenerative prion diseases. As the N-glycosylation of PrP is ablated by deletion of the C-terminal glycosyl-phosphatidylinositol (GPI) anchor signal sequence, we have investigated the determinants for PrP sequon utilization in human neuronal cells using the novel approach of restoring N-glycosylation to secreted forms of PrP lacking a GPI anchor. N-glycosylation was restored to an efficiency comparable with that of GPI anchored PrP when the distance of the sequon to the C-terminus was increased so that it was sufficient to reach the active site of oligosaccharyltransferase before chain termination. Our findings indicate that sequon utilization in PrP is a co-translational process that precedes GPI anchor addition and, as such, will be greatly influenced by the dynamics of the translocon—oligosaccharyltransferase complex.


2016 ◽  
Vol 113 (48) ◽  
pp. 13851-13856 ◽  
Author(s):  
Jin-Kyu Choi ◽  
Ignazio Cali ◽  
Krystyna Surewicz ◽  
Qingzhong Kong ◽  
Pierluigi Gambetti ◽  
...  

Recombinant C-terminally truncated prion protein PrP23-144 (which corresponds to the Y145Stop PrP variant associated with a Gerstmann–Sträussler–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 (bothtga20and 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 (PrPres) fragments of ∼17–32 kDa, similar to those observed in classical scrapie strains. Shorter, Gerstmann–Sträussler–Scheinker-like PrPresfragments 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.


2005 ◽  
Vol 386 (6) ◽  
pp. 569-580 ◽  
Author(s):  
Karl-Werner Leffers ◽  
Holger Wille ◽  
Jan Stöhr ◽  
Erika Junger ◽  
Stanley B. Prusiner ◽  
...  

AbstractThe conversion of the α-helical, cellular isoform of the prion protein (PrPC) to the insoluble, β-sheet-rich, infectious, disease-causing isoform (PrPSc) is the fundamental event in the prion diseases. The C-terminal fragment of PrPSc(PrP 27–30) is formed by limited proteolysis and retains infectivity. Unlike full-length PrPSc, PrP 27–30 polymerizes into rod-shaped structures with the ultra-structural and tinctorial properties of amyloid. To study the folding of PrP, both with respect to the formation of PrPScfrom PrPCand the assembly of rods from PrP 27–30, we solubilized Syrian hamster (sol SHa) PrP 27–30 in low concentrations (0.2%) of sodium dodecyl sulfate (SDS) under conditions previously used to study the structural transitions of this protein. Sol SHaPrP 27–30 adopted a β-sheet-rich structure at SDS concentrations between 0.02% and 0.04% and remained soluble. Here we report that NaCl stabilizes SHaPrP 27–30 in a soluble, β-sheet-rich state that allows fibril assembly to proceed over several weeks. Under these conditions, fibril formation occurred not only with sol PrP 27–30, but also with native SHaPrPC. Addition of sphingolipids seems to increase fibril growth. When recombinant (rec) SHaPrP(90–231) was exposed to low concentrations of SDS, similar to those used to polymerize sol SHaPrP 27–30 in the presence of 250 mM NaCl, fibril formation occurred regularly. When fibrils formed from PrP 27–30 or PrPCwere bioassayed in transgenic mice overexpressing full-length SHaPrP, no infectivity was obtained, whereas amyloid fibrils formed of rec mouse PrP(89–230) were infectious. At present, it cannot be determined whether the lack of infectivity is caused by a difference in the structure of the fibrils or in the bioassay conditions.


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