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Structural insight into conformational change in prion protein by breakage of electrostatic network around H187 due to its protonation. Sci Rep 2019; 9:19305. [PMID: 31848406 PMCID: PMC6917724 DOI: 10.1038/s41598-019-55808-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 11/04/2019] [Indexed: 11/10/2022] Open
Abstract
A conformational change from normal prion protein(PrPC) to abnormal prion protein(PrPSC) induces fatal neurodegenerative diseases. Acidic pH is well-known factors involved in the conformational change. Because the protonation of H187 is strongly linked to the change in PrP stability, we examined the charged residues R156, E196, and D202 around H187. Interestingly, there have been reports on pathological mutants, such as H187R, E196A, and D202N. In this study, we focused on how an acidic pH and pathological mutants disrupt this electrostatic network and how this broken network destabilizes PrP structure. To do so, we performed a temperature-based replica-exchange molecular dynamics (T-REMD) simulation using a cumulative 252 μs simulation time. We measured the distance between amino acids comprising four salt bridges (R156–E196/D202 and H187–E196/D202). Our results showed that the spatial configuration of the electrostatic network was significantly altered by an acidic pH and mutations. The structural alteration in the electrostatic network increased the RMSF value around the first helix (H1). Thus, the structural stability of H1, which is anchored to the H2–H3 bundle, was decreased. It induces separation of R156 from the electrostatic network. Analysis of the anchoring energy also shows that two salt-bridges (R156-E196/D202) are critical for PrP stability.
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Lee J, Chang I, Yu W. Atomic insights into the effects of pathological mutants through the disruption of hydrophobic core in the prion protein. Sci Rep 2019; 9:19144. [PMID: 31844149 PMCID: PMC6915724 DOI: 10.1038/s41598-019-55661-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 11/26/2019] [Indexed: 12/11/2022] Open
Abstract
Destabilization of prion protein induces a conformational change from normal prion protein (PrPC) to abnormal prion protein (PrPSC). Hydrophobic interaction is the main driving force for protein folding, and critically affects the stability and solvability. To examine the importance of the hydrophobic core in the PrP, we chose six amino acids (V176, V180, T183, V210, I215, and Y218) that make up the hydrophobic core at the middle of the H2-H3 bundle. A few pathological mutants of these amino acids have been reported, such as V176G, V180I, T183A, V210I, I215V, and Y218N. We focused on how these pathologic mutations affect the hydrophobic core and thermostability of PrP. For this, we ran a temperature-based replica-exchange molecular dynamics (T-REMD) simulation, with a cumulative simulation time of 28 μs, for extensive ensemble sampling. From the T-REMD ensemble, we calculated the protein folding free energy difference between wild-type and mutant PrP using the thermodynamic integration (TI) method. Our results showed that pathological mutants V176G, T183A, I215V, and Y218N decrease the PrP stability. At the atomic level, we examined the change in pair-wise hydrophobic interactions from valine-valine to valine-isoleucine (and vice versa), which is induced by mutation V180I, V210I (I215V) at the 180th-210th (176th-215th) pair. Finally, we investigated the importance of the π-stacking between Y218 and F175.
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Affiliation(s)
- Juhwan Lee
- Center for Proteome Biophysics, DGIST, Daegu, 42988, Korea.
- Department of Emerging Material Sciences, DGIST, Daegu, 42988, Korea.
- Core Protein Resources Center, DGIST, Daegu, 42988, Korea.
- Supercomputing Bigdata Center, DGIST, Daegu, 42988, Korea.
| | - Iksoo Chang
- Center for Proteome Biophysics, DGIST, Daegu, 42988, Korea
- Core Protein Resources Center, DGIST, Daegu, 42988, Korea
- Supercomputing Bigdata Center, DGIST, Daegu, 42988, Korea
- Department of Brain and Cognitive Sciences, DGIST, Daegu, 42988, Korea
| | - Wookyung Yu
- Core Protein Resources Center, DGIST, Daegu, 42988, Korea.
- Supercomputing Bigdata Center, DGIST, Daegu, 42988, Korea.
- Department of Brain and Cognitive Sciences, DGIST, Daegu, 42988, Korea.
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Harrathi C, Fernández-Borges N, Eraña H, Elezgarai SR, Venegas V, Charco JM, Castilla J. Insights into the Bidirectional Properties of the Sheep-Deer Prion Transmission Barrier. Mol Neurobiol 2018; 56:5287-5303. [PMID: 30592012 PMCID: PMC6614146 DOI: 10.1007/s12035-018-1443-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 11/30/2018] [Indexed: 02/06/2023]
Abstract
The large chronic wasting disease (CWD)-affected cervid population in the USA and Canada, and the risk of the disease being transmitted to humans through intermediate species, is a highly worrying issue that is still poorly understood. In this case, recombinant protein misfolding cyclic amplification was used to determine, in vitro, the relevance of each individual amino acid on cross-species prion transmission. Others and we have found that the β2-α2 loop is a key modulator of transmission barriers between species and markedly influences infection by sheep scrapie, bovine spongiform encephalopathy (BSE), or elk CWD. Amino acids that differentiate ovine and deer normal host prion protein (PrPC) and associated with structural rigidity of the loop β2-α2 (S173N, N177T) appear to confer resistance to some prion diseases. However, addition of methionine at codon 208 together with the previously described rigid loop substitutions seems to hide a key in this species barrier, as it makes sheep recombinant prion protein highly susceptible to CWD-induced misfolding. These studies indicate that interspecies prion transmission is not only governed just by the β2-α2 loop amino acid sequence but also by its interactions with the α3-helix as shown by substitution I208M. Transmissible spongiform encephalopathies, characterized by long incubation periods and spongiform changes associated with neuronal loss in the brain, have been described in several mammalian species appearing either naturally (scrapie in sheep and goats, bovine spongiform encephalopathy in cattle, chronic wasting disease in cervids, Creutzfeldt-Jakob disease in humans) or by experimental transmission studies (scrapie in mice and hamsters). Much of the pathogenesis of the prion diseases has been determined in the last 40 years, such as the etiological agent or the fact that prions occur as different strains that show distinct biological and physicochemical properties. However, there are many unanswered questions regarding the strain phenomenon and interspecies transmissibility. To assess the risk of interspecies transmission between scrapie and chronic wasting disease, an in vitro prion propagation method has been used. This technique allows to predict the amino acids preventing the transmission between sheep and deer prion diseases.
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Affiliation(s)
- Chafik Harrathi
- CIC bioGUNE, Parque tecnológico de Bizkaia, 48160, Derio, Bizkaia, Spain
| | | | - Hasier Eraña
- CIC bioGUNE, Parque tecnológico de Bizkaia, 48160, Derio, Bizkaia, Spain
| | - Saioa R Elezgarai
- CIC bioGUNE, Parque tecnológico de Bizkaia, 48160, Derio, Bizkaia, Spain
| | - Vanessa Venegas
- CIC bioGUNE, Parque tecnológico de Bizkaia, 48160, Derio, Bizkaia, Spain
| | - Jorge M Charco
- CIC bioGUNE, Parque tecnológico de Bizkaia, 48160, Derio, Bizkaia, Spain
| | - Joaquín Castilla
- CIC bioGUNE, Parque tecnológico de Bizkaia, 48160, Derio, Bizkaia, Spain. .,IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Bizkaia, Spain.
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Sengupta I, Bhate SH, Das R, Udgaonkar JB. Salt-Mediated Oligomerization of the Mouse Prion Protein Monitored by Real-Time NMR. J Mol Biol 2017; 429:1852-1872. [DOI: 10.1016/j.jmb.2017.05.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 05/05/2017] [Accepted: 05/07/2017] [Indexed: 12/11/2022]
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Kovač V, Hafner-Bratkovič I, Čurin Šerbec V. Anchorless forms of prion protein - Impact of truncation on structure destabilization and prion protein conversion. Biochem Biophys Res Commun 2016; 481:1-6. [PMID: 27836542 DOI: 10.1016/j.bbrc.2016.11.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 11/07/2016] [Indexed: 10/20/2022]
Abstract
Prion diseases are a group of fatal neurodegenerative diseases caused by scrapie form of prion protein, PrPSc. Prion protein (PrP) is bound to the cell via glycophosphatidylinositol (GPI) anchor. The role of GPI anchor in PrPSc replication and propagation remains unclear. It has been shown that anchorless and truncated PrP accelerate the formation and propagation of prions in vivo and further increases the risk for transmission of prion diseases among species. To explain the role of anchorless forms of PrP in the development of prion diseases, we have prepared five C-terminal PrP truncated variants, determined their thermodynamic properties and analyzed the kinetics of conversion into amyloid fibrils. According to our results thermodynamic and kinetic properties are affected both by pH and truncation. We have shown that the shortest variant was the most destabilized and converted faster than other variants in acidic pH. Other variants converted with longer lag time of fibrillization than WT despite comparable or even decreased stability in acidic pH. Our results indicate that even the change in length for 1 amino acid residue can have a profound effect on in vitro conversion.
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Affiliation(s)
- Valerija Kovač
- Department for the Production of Diagnostic Reagents and Research & R&D Service, Blood Transfusion Centre of Slovenia, Šlajmerjeva 6, SI-1000, Ljubljana, Slovenia
| | - Iva Hafner-Bratkovič
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, SI-1000, Ljubljana, Slovenia; EN-FIST Centre of Excellence, Trg Osvobodilne fronte 13, 1000, Ljubljana, Slovenia
| | - Vladka Čurin Šerbec
- Department for the Production of Diagnostic Reagents and Research & R&D Service, Blood Transfusion Centre of Slovenia, Šlajmerjeva 6, SI-1000, Ljubljana, Slovenia.
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Hadži S, Ondračka A, Jerala R, Hafner‐Bratkovič I. Pathological mutations H187R and E196K facilitate subdomain separation and prion protein conversion by destabilization of the native structure. FASEB J 2014; 29:882-93. [DOI: 10.1096/fj.14-255646] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- San Hadži
- Department of BiotechnologyNational Institute of ChemistryLjubljanaSlovenia
| | - Andrej Ondračka
- Department of BiotechnologyNational Institute of ChemistryLjubljanaSlovenia
| | - Roman Jerala
- Department of BiotechnologyNational Institute of ChemistryLjubljanaSlovenia
- EN‐FIST Centre of ExcellenceLjubljanaSlovenia
| | - Iva Hafner‐Bratkovič
- Department of BiotechnologyNational Institute of ChemistryLjubljanaSlovenia
- EN‐FIST Centre of ExcellenceLjubljanaSlovenia
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Hafner-Bratkovič I, Benčina M, Fitzgerald KA, Golenbock D, Jerala R. NLRP3 inflammasome activation in macrophage cell lines by prion protein fibrils as the source of IL-1β and neuronal toxicity. Cell Mol Life Sci 2012; 69:4215-28. [PMID: 22926439 DOI: 10.1007/s00018-012-1140-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 08/01/2012] [Accepted: 08/13/2012] [Indexed: 12/12/2022]
Abstract
Prion diseases are fatal transmissible neurodegenerative diseases, characterized by aggregation of the pathological form of prion protein, spongiform degeneration, and neuronal loss, and activation of astrocytes and microglia. Microglia can clear prion plaques, but on the other hand cause neuronal death via release of neurotoxic species. Elevated expression of the proinflammatory cytokine IL-1β has been observed in brains affected by several prion diseases, and IL-1R-deficiency significantly prolonged the onset of the neurodegeneration in mice. We show that microglial cells stimulated by prion protein (PrP) fibrils induced neuronal toxicity. Microglia and macrophages release IL-1β upon stimulation by PrP fibrils, which depends on the NLRP3 inflammasome. Activation of NLRP3 inflammasome by PrP fibrils requires depletion of intracellular K(+), and requires phagocytosis of PrP fibrils and consecutive lysosome destabilization. Among the well-defined molecular forms of PrP, the strongest NLRP3 activation was observed by fibrils, followed by aggregates, while neither native monomeric nor oligomeric PrP were able to activate the NLRP3 inflammasome. Our results together with previous studies on IL-1R-deficient mice suggest the IL-1 signaling pathway as the perspective target for the therapy of prion disease.
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Affiliation(s)
- Iva Hafner-Bratkovič
- Department of Biotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
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