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Gielnik M, Szymańska A, Dong X, Jarvet J, Svedružić ŽM, Gräslund A, Kozak M, Wärmländer SKTS. Prion Protein Octarepeat Domain Forms Transient β-Sheet Structures upon Residue-Specific Binding to Cu(II) and Zn(II) Ions. Biochemistry 2023. [PMID: 37163663 DOI: 10.1021/acs.biochem.3c00129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Misfolding of the cellular prion protein (PrPC) is associated with the development of fatal neurodegenerative diseases called transmissible spongiform encephalopathies (TSEs). Metal ions appear to play a crucial role in PrPC misfolding. PrPC is a combined Cu(II) and Zn(II) metal-binding protein, where the main metal-binding site is located in the octarepeat (OR) region. Thus, the biological function of PrPC may involve the transport of divalent metal ions across membranes or buffering concentrations of divalent metal ions in the synaptic cleft. Recent studies have shown that an excess of Cu(II) ions can result in PrPC instability, oligomerization, and/or neuroinflammation. Here, we have used biophysical methods to characterize Cu(II) and Zn(II) binding to the isolated OR region of PrPC. Circular dichroism (CD) spectroscopy data suggest that the OR domain binds up to four Cu(II) ions or two Zn(II) ions. Binding of the first metal ion results in a structural transition from the polyproline II helix to the β-turn structure, while the binding of additional metal ions induces the formation of β-sheet structures. Fluorescence spectroscopy data indicate that the OR region can bind both Cu(II) and Zn(II) ions at neutral pH, but under acidic conditions, it binds only Cu(II) ions. Molecular dynamics simulations suggest that binding of either metal ion to the OR region results in the formation of β-hairpin structures. As the formation of β-sheet structures can be a first step toward amyloid formation, we propose that high concentrations of either Cu(II) or Zn(II) ions may have a pro-amyloid effect in TSE diseases.
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Affiliation(s)
- Maciej Gielnik
- Department of Macromolecular Physics, Faculty of Physics, Adam Mickiewicz University, PL 61-614 Poznań, Poland
| | - Aneta Szymańska
- Department of Biomedical Chemistry, Faculty of Chemistry, Gdańsk University, PL 80-308 Gdańsk, Poland
| | - Xiaolin Dong
- Chemistry Section, Stockholm University, 10691 Stockholm, Sweden
| | - Jüri Jarvet
- Chemistry Section, Stockholm University, 10691 Stockholm, Sweden
- The National Institute of Chemical Physics and Biophysics, 12618 Tallinn, Estonia
| | - Željko M Svedružić
- Department of Biotechnology, University of Rijeka, HR 51000 Rijeka, Croatia
| | - Astrid Gräslund
- Chemistry Section, Stockholm University, 10691 Stockholm, Sweden
| | - Maciej Kozak
- Department of Macromolecular Physics, Faculty of Physics, Adam Mickiewicz University, PL 61-614 Poznań, Poland
- National Synchrotron Radiation Centre SOLARIS, Jagiellonian University, PL 30-392 Kraków, Poland
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2
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Guadagno AH, Medina SH. The manifold role of octapeptide repeats in prion protein assembly. Pept Sci (Hoboken) 2023; 115. [PMID: 37153755 PMCID: PMC10162500 DOI: 10.1002/pep2.24303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Prion protein misfolding is associated with fatal neurodegenerative disorders such as kuru, Creutzfeldt-Jakob disease, and several animal encephalopathies. While the C-terminal 106-126 peptide has been well studied for its role in prion replication and toxicity, the octapeptide repeat (OPR) sequence found within the N-terminal domain has been relatively under explored. Recent findings that the OPR has both local and long-range effects on prion protein folding and assembly, as well as its ability to bind and regulate transition metal homeostasis, highlights the important role this understudied region may have in prion pathologies. This review attempts to collate this knowledge to advance a deeper understanding on the varied physiologic and pathologic roles the prion OPR plays, and connect these findings to potential therapeutic modalities focused on OPR-metal binding. Continued study of the OPR will not only elucidate a more complete mechanistic model of prion pathology, but may enhance knowledge on other neurodegenerative processes underlying Alzheimer's, Parkinson's, and Huntington's diseases.
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Affiliation(s)
- Amy H. Guadagno
- Nanomedicine, Intercollegiate Degree Program Pennsylvania State University University Park Pennsylvania USA
| | - Scott H. Medina
- Department of Biomedical Engineering Pennsylvania State University University Park Pennsylvania USA
- Huck Institutes of the Life Sciences Pennsylvania State University University Park Pennsylvania USA
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3
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Interdiction in the Early Folding of the p53 DNA-Binding Domain Leads to Its Amyloid-Like Misfolding. Molecules 2022; 27:molecules27154810. [PMID: 35956758 PMCID: PMC9370011 DOI: 10.3390/molecules27154810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/18/2022] [Accepted: 07/23/2022] [Indexed: 11/17/2022] Open
Abstract
In this article, we investigate two issues: (a) the initial contact formation events along the folding pathway of the DNA-binding domain of the tumor suppressor protein p53 (core p53); and (b) the intermolecular events leading to its conversion into a prion-like form upon incubation with peptide P8(250-257). In the case of (a), the calculations employ the sequential collapse model (SCM) to identify the segments involved in the initial contact formation events that nucleate the folding pathway. The model predicts that there are several possible initial non-local contacts of comparative stability. The most stable of these possible initial contacts involve the protein segments 159AMAIY163 and 251ILTII255, and it is the only native-like contact. Thus, it is predicted to constitute “Nature’s shortcut” to the native structure of the core domain of p53. In the case of issue (b), these findings are then combined with experimental evidence showing that the incubation of the core domain of p53 with peptide P8(250-257), which is equivalent to the native protein segment 250PILTIITL257, leads to an amyloid conformational transition. It is explained how the SCM predicts that P8(250-257) effectively interdicts in the formation of the most stable possible initial contact and, thereby, disrupts the subsequent normal folding. Interdiction by polymeric P8(250-257) seeds is also studied. It is then hypothesized that enhanced folding through one or several of the less stable contacts could play a role in P8(250-257)-promoted core p53 amyloid misfolding. These findings are compared to previous results obtained for the prion protein. Experiments are proposed to test the hypothesis presented regarding core p53 amyloid misfolding.
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4
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Karamanos TK, Kalverda AP, Radford SE. Generating Ensembles of Dynamic Misfolding Proteins. Front Neurosci 2022; 16:881534. [PMID: 35431773 PMCID: PMC9008329 DOI: 10.3389/fnins.2022.881534] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 03/08/2022] [Indexed: 01/09/2023] Open
Abstract
The early stages of protein misfolding and aggregation involve disordered and partially folded protein conformers that contain a high degree of dynamic disorder. These dynamic species may undergo large-scale intra-molecular motions of intrinsically disordered protein (IDP) precursors, or flexible, low affinity inter-molecular binding in oligomeric assemblies. In both cases, generating atomic level visualization of the interconverting species that captures the conformations explored and their physico-chemical properties remains hugely challenging. How specific sub-ensembles of conformers that are on-pathway to aggregation into amyloid can be identified from their aggregation-resilient counterparts within these large heterogenous pools of rapidly moving molecules represents an additional level of complexity. Here, we describe current experimental and computational approaches designed to capture the dynamic nature of the early stages of protein misfolding and aggregation, and discuss potential challenges in describing these species because of the ensemble averaging of experimental restraints that arise from motions on the millisecond timescale. We give a perspective of how machine learning methods can be used to extract aggregation-relevant sub-ensembles and provide two examples of such an approach in which specific interactions of defined species within the dynamic ensembles of α-synuclein (αSyn) and β2-microgloblulin (β2m) can be captured and investigated.
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Affiliation(s)
- Theodoros K. Karamanos
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | | | - Sheena E. Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
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5
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Abstract
Proteins have dynamic structures that undergo chain motions on time scales spanning from picoseconds to seconds. Resolving the resultant conformational heterogeneity is essential for gaining accurate insight into fundamental mechanistic aspects of the protein folding reaction. The use of high-resolution structural probes, sensitive to population distributions, has begun to enable the resolution of site-specific conformational heterogeneity at different stages of the folding reaction. Different states populated during protein folding, including the unfolded state, collapsed intermediate states, and even the native state, are found to possess significant conformational heterogeneity. Heterogeneity in protein folding and unfolding reactions originates from the reduced cooperativity of various kinds of physicochemical interactions between various structural elements of a protein, and between a protein and solvent. Heterogeneity may arise because of functional or evolutionary constraints. Conformational substates within the unfolded state and the collapsed intermediates that exchange at rates slower than the subsequent folding steps give rise to heterogeneity on the protein folding pathways. Multiple folding pathways are likely to represent distinct sequences of structure formation. Insight into the nature of the energy barriers separating different conformational states populated during (un)folding can also be obtained by resolving heterogeneity.
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Affiliation(s)
- Sandhya Bhatia
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India.,Indian Institute of Science Education and Research, Pune 411008, India
| | - Jayant B Udgaonkar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India.,Indian Institute of Science Education and Research, Pune 411008, India
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6
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Prion Protein Biology Through the Lens of Liquid-Liquid Phase Separation. J Mol Biol 2021; 434:167368. [PMID: 34808226 DOI: 10.1016/j.jmb.2021.167368] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 11/12/2021] [Accepted: 11/14/2021] [Indexed: 12/29/2022]
Abstract
Conformational conversion of the α-helix-rich cellular prion protein into the misfolded, β-rich, aggregated, scrapie form underlies the molecular basis of prion diseases that represent a class of invariably fatal, untreatable, and transmissible neurodegenerative diseases. However, despite the extensive and rigorous research, there is a significant gap in the understanding of molecular mechanisms that contribute to prion pathogenesis. In this review, we describe the historical perspective of the development of the prion concept and the current state of knowledge of prion biology including structural, molecular, and cellular aspects of the prion protein. We then summarize the putative functional role of the N-terminal intrinsically disordered segment of the prion protein. We next describe the ongoing efforts in elucidating the prion phase behavior and the emerging role of liquid-liquid phase separation that can have potential functional relevance and can offer an alternate non-canonical pathway involving conformational conversion into a disease-associated form. We also attempt to shed light on the evolutionary perspective of the prion protein highlighting the potential role of intrinsic disorder in prion protein biology and summarize a few important questions associated with the phase transitions of the prion protein. Delving deeper into these key aspects can pave the way for a detailed understanding of the critical molecular determinants of the prion phase transition and its relevance to physiology and neurodegenerative diseases.
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7
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Bhate SH, Udgaonkar JB, Das R. Destabilization of polar interactions in the prion protein triggers misfolding and oligomerization. Protein Sci 2021; 30:2258-2271. [PMID: 34558139 DOI: 10.1002/pro.4188] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 09/15/2021] [Accepted: 09/16/2021] [Indexed: 12/25/2022]
Abstract
The prion protein (PrP) misfolds and oligomerizes at pH 4 in the presence of physiological salt concentrations. Low pH and salt cause structural perturbations in the monomeric prion protein that lead to misfolding and oligomerization. However, the changes in stability within different regions of the PrP prior to oligomerization are poorly understood. In this study, we have characterized the local stability in PrP at high resolution using amide temperature coefficients (TC ) measured by nuclear magnetic resonance (NMR) spectroscopy. The local stability of PrP was investigated under native as well as oligomerizing conditions. We have also studied the rapidly oligomerizing PrP variant (Q216R) and the protective PrP variant (A6). We report that at low pH, salt destabilizes PrP at several polar residues, and the hydrogen bonds in helices α2 and α3 are weakened. In addition, salt changes the curvature of the α3 helix, which likely disrupts α2-α3 contacts and leads to oligomerization. These results are corroborated by the TC values of rapidly oligomerizing Q216R-PrP. The poly-alanine substitution in A6-PrP stabilizes α2, which prevents oligomerization. Altogether, these results highlight the importance of native polar interactions in determining the stability of PrP and reveal the structural disruptions in PrP that lead to misfolding and oligomerization.
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Affiliation(s)
- Suhas H Bhate
- National Centre for Biological Sciences, TIFR, Bangalore, India
| | - Jayant B Udgaonkar
- National Centre for Biological Sciences, TIFR, Bangalore, India.,Indian Institute for Science Education and Research, Pune, India
| | - Ranabir Das
- National Centre for Biological Sciences, TIFR, Bangalore, India
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8
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Serpa JJ, Popov KI, Petrotchenko EV, Dokholyan NV, Borchers CH. Structure of prion β-oligomers as determined by short-distance crosslinking constraint-guided discrete molecular dynamics simulations. Proteomics 2021; 21:e2000298. [PMID: 34482645 PMCID: PMC9285417 DOI: 10.1002/pmic.202000298] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 08/10/2021] [Accepted: 08/27/2021] [Indexed: 11/08/2022]
Abstract
The conversion of the native monomeric cellular prion protein (PrPC ) into an aggregated pathological β-oligomeric form (PrPβ ) and an infectious form (PrPSc ) is the central element in the development of prion diseases. The structure of the aggregates and the molecular mechanisms of the conformational changes involved in the conversion are still unknown. We applied mass spectrometry combined with chemical crosslinking, hydrogen/deuterium exchange, limited proteolysis, and surface modification for the differential characterization of the native and the urea+acid-converted prion β-oligomer structures to obtain insights into the mechanisms of conversion and aggregation. For the determination of the structure of the monomer and the dimer unit of the β-oligomer, we applied a recently-developed approach for de novo protein structure determination which is based on the incorporation of zero-length and short-distance crosslinking data as intra- and inter-protein constraints in discrete molecular dynamics simulations (CL-DMD). Based on all of the structural-proteomics experimental data and the computationally predicted structures of the monomer units, we propose the potential mode of assembly of the β-oligomer. The proposed β-oligomer assembly provides a clue on the β-sheet nucleation site, and how template-based conversion of the native prion molecule occurs, growth of the prion aggregates, and maturation into fibrils may occur.
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Affiliation(s)
- Jason J Serpa
- University of Victoria -Genome British Columbia Proteomics Centre, Victoria, British Columbia, Canada
| | - Konstantin I Popov
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Evgeniy V Petrotchenko
- Segal Cancer Proteomics Centre, Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, Quebec, Canada.,Center for Computational and Data-Intensive Science and Engineering, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Nikolay V Dokholyan
- Department of Pharmacology, Department of Biochemistry & Molecular Biology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
| | - Christoph H Borchers
- Segal Cancer Proteomics Centre, Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, Quebec, Canada.,Center for Computational and Data-Intensive Science and Engineering, Skolkovo Institute of Science and Technology, Moscow, Russia.,Gerald Bronfman Department of Oncology, Jewish General Hospital, McGill University, Montreal, Quebec, Canada
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9
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Bergasa-Caceres F, Rabitz HA. Identification of Two Early Folding Stage Prion Non-Local Contacts Suggested to Serve as Key Steps in Directing the Final Fold to Be Either Native or Pathogenic. Int J Mol Sci 2021; 22:ijms22168619. [PMID: 34445324 PMCID: PMC8395309 DOI: 10.3390/ijms22168619] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/30/2021] [Accepted: 08/04/2021] [Indexed: 12/16/2022] Open
Abstract
The initial steps of the folding pathway of the C-terminal domain of the murine prion protein mPrP(90–231) are predicted based on the sequential collapse model (SCM). A non-local dominant contact is found to form between the connecting region between helix 1 and β-sheet 1 and the C-terminal region of helix 3. This non-local contact nucleates the most populated molten globule-like intermediate along the folding pathway. A less stable early non-local contact between segments 120–124 and 179–183, located in the middle of helix 2, promotes the formation of a less populated molten globule-like intermediate. The formation of the dominant non-local contact constitutes an example of the postulated Nature’s Shortcut to the prion protein collapse into the native structure. The possible role of the less populated molten globule-like intermediate is explored as the potential initiation point for the folding for three pathogenic mutants (T182A, I214V, and Q211P in mouse prion numbering) of the prion protein.
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10
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Groveman BR, Smith A, Williams K, Haigh CL. Cerebral organoids as a new model for prion disease. PLoS Pathog 2021; 17:e1009747. [PMID: 34288977 PMCID: PMC8294539 DOI: 10.1371/journal.ppat.1009747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Bradley R. Groveman
- Prion Cell Biology Unit, Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Anna Smith
- Prion Cell Biology Unit, Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Katie Williams
- Prion Cell Biology Unit, Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Cathryn L. Haigh
- Prion Cell Biology Unit, Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
- * E-mail:
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11
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Chen YW, Rahman SK. Fatal Attraction: The Case of Toxic Soluble Dimers of Truncated PQBP-1 Mutants in X-Linked Intellectual Disability. Int J Mol Sci 2021; 22:ijms22052240. [PMID: 33668121 PMCID: PMC7956452 DOI: 10.3390/ijms22052240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 02/20/2021] [Accepted: 02/20/2021] [Indexed: 11/16/2022] Open
Abstract
The frameshift mutants K192Sfs*7 and R153Sfs*41, of the polyglutamine tract-binding protein 1 (PQBP-1), are stable intrinsically disordered proteins (IDPs). They are each associated with the severe cognitive disorder known as the Renpenning syndrome, a form of X-linked intellectual disability (XLID). Relative to the monomeric wild-type protein, these mutants are dimeric, contain more folded contents, and have higher thermal stabilities. Comparisons can be drawn to the toxic oligomerisation in the “conformational diseases”, which collectively describe medical conditions involving a substantial protein structural transition in the pathogenic mechanism. At the molecular level, the end state of these diseases is often cytotoxic protein aggregation. The conformational disease proteins contain varying extents of intrinsic disorder, and the consensus pathogenesis includes an early oligomer formation. We reviewed the experimental characterisation of the toxic oligomers in representative cases. PQBP-1 mutant dimerisation was then compared to the oligomerisation of the conformational disease proteins. The PQBP-1 mutants are unique in behaving as stable soluble dimers, which do not further develop into higher oligomers or aggregates. The toxicity of the PQBP-1 mutant dimers lies in the native functions (in transcription regulation and possibly, RNA splicing) being compromised, rather than proceeding to aggregation. Other examples of stable IDP dimers were discussed and we speculated on the roles of IDP dimerisation in protein evolution.
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Affiliation(s)
- Yu Wai Chen
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hunghom 999077, Hong Kong
- State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hunghom 999077, Hong Kong
- Correspondence:
| | - Shah Kamranur Rahman
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK;
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12
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Jankovska N, Olejar T, Matej R. Extracellular Protein Aggregates Colocalization and Neuronal Dystrophy in Comorbid Alzheimer's and Creutzfeldt-Jakob Disease: A Micromorphological Pilot Study on 20 Brains. Int J Mol Sci 2021; 22:ijms22042099. [PMID: 33672582 PMCID: PMC7924045 DOI: 10.3390/ijms22042099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/15/2021] [Accepted: 02/17/2021] [Indexed: 01/22/2023] Open
Abstract
Alzheimer’s disease (AD) and sporadic Creutzfeldt–Jakob disease (sCJD) are both characterized by extracellular pathologically conformed aggregates of amyloid proteins—amyloid β-protein (Aβ) and prion protein (PrPSc), respectively. To investigate the potential morphological colocalization of Aβ and PrPSc aggregates, we examined the hippocampal regions (archicortex and neocortex) of 20 subjects with confirmed comorbid AD and sCJD using neurohistopathological analyses, immunohistochemical methods, and confocal fluorescent microscopy. Our data showed that extracellular Aβ and PrPSc aggregates tended to be, in most cases, located separately, and “compound” plaques were relatively rare. We observed PrPSc plaque-like structures in the periphery of the non-compact parts of Aβ plaques, as well as in tau protein-positive dystrophic structures. The AD ABC score according to the NIA-Alzheimer’s association guidelines, and prion protein subtype with codon 129 methionine–valine (M/V) polymorphisms in sCJD, while representing key characteristics of these diseases, did not correlate with the morphology of the Aβ/PrPSc co-aggregates. However, our data showed that PrPSc aggregation could dominate during co-aggregation with non-compact Aβ in the periphery of Aβ plaques.
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Affiliation(s)
- Nikol Jankovska
- Department of Pathology and Molecular Medicine, Third Faculty of Medicine, Charles University and Thomayer University Hospital, Videnska 800, 4-Krc, 14059 Prague, Czech Republic; (T.O.); (R.M.)
- Correspondence: ; Tel.: +420-261-083-102
| | - Tomas Olejar
- Department of Pathology and Molecular Medicine, Third Faculty of Medicine, Charles University and Thomayer University Hospital, Videnska 800, 4-Krc, 14059 Prague, Czech Republic; (T.O.); (R.M.)
| | - Radoslav Matej
- Department of Pathology and Molecular Medicine, Third Faculty of Medicine, Charles University and Thomayer University Hospital, Videnska 800, 4-Krc, 14059 Prague, Czech Republic; (T.O.); (R.M.)
- Department of Pathology, First Faculty of Medicine, Charles University, and General University Hospital, 4-Krc, 14059 Prague, Czech Republic
- Department of Pathology, Third Faculty of Medicine, Charles University, and University Hospital Kralovske Vinohrady, 4-Krc, 14059 Prague, Czech Republic
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13
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Mustazza C, Sbriccoli M, Minosi P, Raggi C. Small Molecules with Anti-Prion Activity. Curr Med Chem 2020; 27:5446-5479. [PMID: 31560283 DOI: 10.2174/0929867326666190927121744] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 08/08/2019] [Accepted: 09/05/2019] [Indexed: 01/20/2023]
Abstract
Prion pathologies are fatal neurodegenerative diseases caused by the misfolding of the physiological Prion Protein (PrPC) into a β-structure-rich isoform called PrPSc. To date, there is no available cure for prion diseases and just a few clinical trials have been carried out. The initial approach in the search of anti-prion agents had PrPSc as a target, but the existence of different prion strains arising from alternative conformations of PrPSc, limited the efficacy of the ligands to a straindependent ability. That has shifted research to PrPC ligands, which either act as chaperones, by stabilizing the native conformation, or inhibit its interaction with PrPSc. The role of transition-metal mediated oxidation processes in prion misfolding has also been investigated. Another promising approach is the indirect action via other cellular targets, like membrane domains or the Protein- Folding Activity of Ribosomes (PFAR). Also, new prion-specific high throughput screening techniques have been developed. However, so far no substance has been found to be able to extend satisfactorily survival time in animal models of prion diseases. This review describes the main features of the Structure-Activity Relationship (SAR) of the various chemical classes of anti-prion agents.
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Affiliation(s)
- Carlo Mustazza
- National Centre for Control and Evaluation of Medicines, Italian National Institute of Health, Viale Regina Elena 299, 00161 Rome, Italy
| | - Marco Sbriccoli
- Department of Neurosciences, Italian National Institute of Health, Viale Regina Elena 299, 00161 Rome, Italy
| | - Paola Minosi
- National Centre for Drug Research and Evaluation, Italian National Institute of Health, Viale Regina Elena 299, 00161 Rome, Italy
| | - Carla Raggi
- National Centre for Control and Evaluation of Medicines, Italian National Institute of Health, Viale Regina Elena 299, 00161 Rome, Italy
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14
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Mukhopadhyay S. The Dynamism of Intrinsically Disordered Proteins: Binding-Induced Folding, Amyloid Formation, and Phase Separation. J Phys Chem B 2020; 124:11541-11560. [PMID: 33108190 DOI: 10.1021/acs.jpcb.0c07598] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Intrinsically disordered proteins (IDPs) or natively unfolded proteins do not undergo autonomous folding into a well-defined 3-D structure and challenge the conventional structure-function paradigm. They are involved in a multitude of critical physiological functions by adopting various structural states via order-to-disorder transitions or by maintaining their disordered characteristics in functional complexes. In recent times, there has been a burgeoning interest in the investigation of intriguing behavior of IDPs using highly multidisciplinary and complementary approaches due to the pivotal role of this unique class of protein chameleons in physiology and disease. Over the past decade or so, our laboratory has been actively investigating the unique physicochemical properties of this class of highly dynamic, flexible, rapidly interconverting proteins. We have utilized a diverse array of existing and emerging tools involving steady-state and time-resolved fluorescence, Raman spectroscopy, circular dichroism, light scattering, fluorescence microscopy, and atomic force microscopy coupled with site-directed mutagenesis and other biochemical and biophysical tools to study a variety of interesting and important aspects of IDPs. In this Feature Article, I describe our work on the conformational characteristics, solvation dynamics, binding-induced folding, amyloid formation, and liquid-liquid phase separation of a number of amyloidogenic IDPs. A series of these studies described here captures the role of conformational plasticity and dynamics in directing binding, folding, assembly, aggregation, and phase transitions implicated in physiology and pathology.
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Affiliation(s)
- Samrat Mukhopadhyay
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences, and Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), Mohali, India
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15
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Lazar T, Guharoy M, Vranken W, Rauscher S, Wodak SJ, Tompa P. Distance-Based Metrics for Comparing Conformational Ensembles of Intrinsically Disordered Proteins. Biophys J 2020; 118:2952-2965. [PMID: 32502383 DOI: 10.1016/j.bpj.2020.05.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 03/24/2020] [Accepted: 05/04/2020] [Indexed: 12/22/2022] Open
Abstract
Intrinsically disordered proteins are proteins whose native functional states represent ensembles of highly diverse conformations. Such ensembles are a challenge for quantitative structure comparisons because their conformational diversity precludes optimal superimposition of the atomic coordinates necessary for deriving common similarity measures such as the root mean-square deviation of these coordinates. Here, we introduce superimposition-free metrics that are based on computing matrices of the Cα-Cα distance distributions within ensembles and comparing these matrices between ensembles. Differences between two matrices yield information on the similarity between specific regions of the polypeptide, whereas the global structural similarity is captured by the root mean-square difference between the medians of the Cα-Cα distance distributions of two ensembles. Together, our metrics enable rigorous investigations of structure-function relationships in conformational ensembles of intrinsically disordered proteins derived using experimental restraints or by molecular simulations and for proteins containing both structured and disordered regions.
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Affiliation(s)
- Tamas Lazar
- VIB-VUB Center for Structural Biology (CSB), Vlaams Instituut voor Biotechnologie, Brussels, Belgium; Structural Biology Brussels (SBB), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Mainak Guharoy
- VIB-VUB Center for Structural Biology (CSB), Vlaams Instituut voor Biotechnologie, Brussels, Belgium; Structural Biology Brussels (SBB), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Wim Vranken
- Structural Biology Brussels (SBB), Vrije Universiteit Brussel (VUB), Brussels, Belgium; Interuniversity Institute of Bioinformatics in Brussels, ULB-VUB, Brussels, Belgium
| | - Sarah Rauscher
- Department of Physics & Department of Chemistry, University of Toronto, Toronto, Ontario, Canada; Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, Ontario, Canada
| | - Shoshana J Wodak
- VIB-VUB Center for Structural Biology (CSB), Vlaams Instituut voor Biotechnologie, Brussels, Belgium.
| | - Peter Tompa
- VIB-VUB Center for Structural Biology (CSB), Vlaams Instituut voor Biotechnologie, Brussels, Belgium; Structural Biology Brussels (SBB), Vrije Universiteit Brussel (VUB), Brussels, Belgium; Institute of Enzymology, Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Budapest, Hungary.
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16
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Zhang Y, Zhao Y, Zhang L, Yu W, Wang Y, Chang W. Cellular Prion Protein as a Receptor of Toxic Amyloid-β42 Oligomers Is Important for Alzheimer's Disease. Front Cell Neurosci 2019; 13:339. [PMID: 31417361 PMCID: PMC6682659 DOI: 10.3389/fncel.2019.00339] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Accepted: 07/10/2019] [Indexed: 12/26/2022] Open
Abstract
The pathological features of Alzheimer's disease (AD) include senile plaques induced by amyloid-β (Aβ) protein deposits, neurofibrillary tangles formed by aggregates of hyperphosphorylated tau proteins and neuronal cell loss in specific position within the brain. Recent observations have suggested the possibility of an association between AD and cellular prion protein (PrP C ) levels. PrP C is a high affinity receptor for oligomeric Aβ and is important for Aβ-induced neurotoxicity and thus plays a critical role in AD pathogenesis. The determination of the relationship between PrP C and AD and the characterization of PrP C binding to Aβ will facilitate the development of novel therapies for AD.
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Affiliation(s)
- Yuan Zhang
- Institute for Translational Medicine, Qingdao University, Qingdao, China
| | - Yanfang Zhao
- School for Life Science, Institute of Biomedical Research, Shandong University of Technology, Zibo, China
| | - Lei Zhang
- Institute for Translational Medicine, Qingdao University, Qingdao, China
| | - Wanpeng Yu
- Institute for Translational Medicine, Qingdao University, Qingdao, China
| | - Yu Wang
- Institute for Translational Medicine, Qingdao University, Qingdao, China
| | - Wenguang Chang
- Institute for Translational Medicine, Qingdao University, Qingdao, China
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17
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Sengupta I, Udgaonkar J. Monitoring site-specific conformational changes in real-time reveals a misfolding mechanism of the prion protein. eLife 2019; 8:44698. [PMID: 31232689 PMCID: PMC6590988 DOI: 10.7554/elife.44698] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Accepted: 06/11/2019] [Indexed: 11/25/2022] Open
Abstract
During pathological aggregation, proteins undergo remarkable conformational re-arrangements to anomalously assemble into a heterogeneous collection of misfolded multimers, ranging from soluble oligomers to insoluble amyloid fibrils. Inspired by fluorescence resonance energy transfer (FRET) measurements of protein folding, an experimental strategy to study site-specific misfolding kinetics during aggregation, by effectively suppressing contributions from inter-molecular FRET, is described. Specifically, the kinetics of conformational changes across different secondary and tertiary structural segments of the mouse prion protein (moPrP) were monitored independently, after the monomeric units transformed into large oligomers OL, which subsequently disaggregated reversibly into small oligomers OS at pH 4. The sequence segments spanning helices α2 and α3 underwent a compaction during the formation of OL and elongation into β-sheets during the formation of OS. The β1-α1-β2 and α2-α3 subdomains were separated, and the helix α1 was unfolded to varying extents in both OL and OS.
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Affiliation(s)
- Ishita Sengupta
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru, India
| | - Jayant Udgaonkar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru, India
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18
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Effects of Cu2+ on conformational change and aggregation of hPrP180-192 with a V180I mutation of the prion protein. Biochem Biophys Res Commun 2019; 514:798-802. [DOI: 10.1016/j.bbrc.2019.05.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 05/01/2019] [Indexed: 01/04/2023]
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19
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Goluguri RR, Sen S, Udgaonkar J. Microsecond sub-domain motions and the folding and misfolding of the mouse prion protein. eLife 2019; 8:e44766. [PMID: 31025940 PMCID: PMC6516828 DOI: 10.7554/elife.44766] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Accepted: 04/25/2019] [Indexed: 12/29/2022] Open
Abstract
Protein aggregation appears to originate from partially unfolded conformations that are sampled through stochastic fluctuations of the native protein. It has been a challenge to characterize these fluctuations, under native like conditions. Here, the conformational dynamics of the full-length (23-231) mouse prion protein were studied under native conditions, using photoinduced electron transfer coupled to fluorescence correlation spectroscopy (PET-FCS). The slowest fluctuations could be associated with the folding of the unfolded state to an intermediate state, by the use of microsecond mixing experiments. The two faster fluctuations observed by PET-FCS, could be attributed to fluctuations within the native state ensemble. The addition of salt, which is known to initiate the aggregation of the protein, resulted in an enhancement in the time scale of fluctuations in the core of the protein. The results indicate the importance of native state dynamics in initiating the aggregation of proteins.
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Affiliation(s)
- Rama Reddy Goluguri
- National Centre for Biological SciencesTata Institute of Fundamental ResearchBengaluruIndia
| | - Sreemantee Sen
- National Centre for Biological SciencesTata Institute of Fundamental ResearchBengaluruIndia
| | - Jayant Udgaonkar
- National Centre for Biological SciencesTata Institute of Fundamental ResearchBengaluruIndia
- Indian Institute of Science Education and ResearchPuneIndia
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20
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Spratt DE, Barber KR, Marlatt NM, Ngo V, Macklin JA, Xiao Y, Konermann L, Duennwald ML, Shaw GS. A subset of calcium-binding S100 proteins show preferential heterodimerization. FEBS J 2019; 286:1859-1876. [PMID: 30719832 DOI: 10.1111/febs.14775] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 12/19/2018] [Accepted: 01/31/2019] [Indexed: 12/22/2022]
Abstract
The assembly of proteins into dimers and oligomers is a necessary step for the proper function of transcription factors, muscle proteins, and proteases. In uncontrolled states, oligomerization can also contribute to illnesses such as Alzheimer's disease. The S100 protein family is a group of dimeric proteins that have important roles in enzyme regulation, cell membrane repair, and cell growth. Most S100 proteins have been examined in their homodimeric state, yet some of these important proteins are found in similar tissues implying that heterodimeric molecules can also be formed from the combination of two different S100 members. In this work, we have established co-expression methods in order to identify and quantify the distribution of homo- and heterodimers for four specific pairs of S100 proteins in their calcium-free states. The split GFP trap methodology was used in combination with other GFP variants to simultaneously quantify homo- and heterodimeric S100 proteins in vitro and in living cells. For the specific S100 proteins examined, NMR, mass spectrometry, and GFP trap experiments consistently show that S100A1:S100B, S100A1:S100P, and S100A11:S100B heterodimers are the predominant species formed compared to their corresponding homodimers. We expect the tools developed here will help establish the roles of S100 heterodimeric proteins and identify how heterodimerization might alter the specificity for S100 protein action in cells.
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Affiliation(s)
- Donald E Spratt
- Department of Biochemistry, The University of Western Ontario, London, Canada
| | - Kathryn R Barber
- Department of Biochemistry, The University of Western Ontario, London, Canada
| | - Nicole M Marlatt
- Department of Biochemistry, The University of Western Ontario, London, Canada
| | - Vy Ngo
- Department of Pathology and Laboratory Medicine, The University of Western Ontario, London, Canada
| | - Jillian A Macklin
- Department of Biochemistry, The University of Western Ontario, London, Canada
| | - Yiming Xiao
- Department of Chemistry, The University of Western Ontario, London, Canada
| | - Lars Konermann
- Department of Biochemistry, The University of Western Ontario, London, Canada.,Department of Chemistry, The University of Western Ontario, London, Canada
| | - Martin L Duennwald
- Department of Pathology and Laboratory Medicine, The University of Western Ontario, London, Canada
| | - Gary S Shaw
- Department of Biochemistry, The University of Western Ontario, London, Canada
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21
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Zheng Z, Zhang M, Wang Y, Ma R, Guo C, Feng L, Wu J, Yao H, Lin D. Structural basis for the complete resistance of the human prion protein mutant G127V to prion disease. Sci Rep 2018; 8:13211. [PMID: 30181558 PMCID: PMC6123418 DOI: 10.1038/s41598-018-31394-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 08/08/2018] [Indexed: 12/20/2022] Open
Abstract
Prion diseases are caused by the propagation of misfolded cellular prion proteins (PrPs). A completely prion disease-resistant genotype, V127M129, has been identified in Papua New Guinea and verified in transgenic mice. To disclose the structural basis of the disease-resistant effect of the G127V mutant, we determined and compared the structural and dynamic features of the G127V-mutated human PrP (residues 91-231) and the wild-type PrP in solution. HuPrP(G127V) contains α1, α2 and α3 helices and a stretch-strand (SS) pattern comprising residues Tyr128-Gly131 (SS1) and Val161-Arg164 (SS2), with extending atomic distances between the SS1 and SS2 strands, and a structural rearrangement of the Tyr128 side chain due to steric hindrance of the larger hydrophobic side chain of Val127. The extended α1 helix gets closer to the α2 and α3 helices. NMR dynamics analysis revealed that Tyr128, Gly131 and Tyr163 underwent significant conformational exchanges. Molecular dynamics simulations suggest that HuPrP(G127V) prevents the formation of stable β-sheets and dimers. Unique structural and dynamic features potentially inhibit the conformational conversion of the G127V mutant. This work is beneficial for understanding the molecular mechanisms underlying the complete resistance of the G127V mutant to prion disease and for developing new therapeutics for prion disease.
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Affiliation(s)
- Zhen Zheng
- MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Meilan Zhang
- MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Yongheng Wang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Rongsheng Ma
- School of Life Sciences, University of Science and Technology of China, Hefei, 230026, China
| | - Chenyun Guo
- MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Liubin Feng
- MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Jihui Wu
- School of Life Sciences, University of Science and Technology of China, Hefei, 230026, China
| | - Hongwei Yao
- MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Donghai Lin
- MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
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22
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Honda R, Yamaguchi KI, Elhelaly AE, Fuji M, Kuwata K. Poly-L-histidine inhibits prion propagation in a prion-infected cell line. Prion 2018; 12:226-233. [PMID: 30074430 DOI: 10.1080/19336896.2018.1505395] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Transmissible spongiform encephalopathies (TSEs) are a group of lethal neurodegenerative diseases involving the structural conversion of cellular prion protein (PrPC) into the pathogenic isoform (PrPSc) for which no effective treatment is currently available. Previous studies have implicated that a polymeric molecule with a repeating unit, such as pentosane polysulfate and polyamidoamide dendrimers, exhibits a potent anti-prion activity, suggesting that poly-(amino acid)s could be a candidate molecule for inhibiting prion propagation. Here, by screening a series of poly-(amino acid)s in a prion-infected neuroblastoma cell line (GTFK), we identified poly-L-His as a novel anti-prion compound with an IC50 value of 1.8 µg/mL (0.18 µM). This potent anti-prion activity was specific to a high-molecular-weight poly-L-His and absent in monomeric histidine or low-molecular-weight poly-L-His. Solution NMR data indicated that poly-L-His directly binds to the loop region connecting Helix 2 and Helix 3 of PrPC and sterically blocks the structural conversion toward PrPSc. Poly-L-His, however, did not inhibit prion propagation in a prion-infected mouse when administered intraperitoneally, suggesting that the penetration of blood-brain barrier and/or the chemical stability of this polypeptide must be addressed before its application in vivo. Taken together, this study revealed the potential use of poly-L-His as a novel treatment against TSEs. (203 words).
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Affiliation(s)
- Ryo Honda
- a United Graduate School of Drug Discovery and Medical Information Sciences , Gifu University , Gifu , Japan
| | | | - Abdelazim Elsayed Elhelaly
- a United Graduate School of Drug Discovery and Medical Information Sciences , Gifu University , Gifu , Japan
| | - Mitsuhiko Fuji
- a United Graduate School of Drug Discovery and Medical Information Sciences , Gifu University , Gifu , Japan
| | - Kazuo Kuwata
- a United Graduate School of Drug Discovery and Medical Information Sciences , Gifu University , Gifu , Japan.,c Department of Gene and Development , Graduate School of Medicine, Gifu University , Gifu , Japan
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23
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Gao Y, Zhu T, Zhang C, Zhang JZ, Mei Y. Comparison of the unfolding and oligomerization of human prion protein under acidic and neutral environments by molecular dynamics simulations. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2018.07.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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24
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Glaves JP, Ladner-Keay CL, Bjorndahl TC, Wishart DS, Sykes BD. Residue-specific mobility changes in soluble oligomers of the prion protein define regions involved in aggregation. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:982-988. [PMID: 29935976 DOI: 10.1016/j.bbapap.2018.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/15/2018] [Accepted: 06/20/2018] [Indexed: 12/12/2022]
Abstract
Prion (PrP) diseases are neurodegenerative diseases characterized by the formation of β-sheet rich, insoluble and protease resistant protein deposits (called PrPSc) that occur throughout the brain. Formation of synthetic or in vitro PrPSc can occur through on-pathway toxic oligomers. Similarly, toxic and infectious oligomers identified in cell and animal models of prion disease indicate that soluble oligomers are likely intermediates in the formation of insoluble PrPSc. Despite the critical role of prion oligomers in disease progression, little is known about their structure. In order, to obtain structural insight into prion oligomers, we generated oligomers by shaking-induced conversion of recombinant, monomeric prion protein PrPc (spanning residues 90-231). We then obtained two-dimensional solution NMR spectra of the PrPc monomer, a 40% converted oligomer, and a 94% converted oligomer. Heteronuclear single-quantum correlation (1H-15N) studies revealed that, in comparison to monomeric PrPc, the oligomer has intense amide peak signals in the N-terminal (residues 90-114) and C-terminal regions (residues 226-231). Furthermore, a core region with decreased mobility is revealed from residues ~127 to 225. Within this core oligomer region with decreased mobility, there is a pocket of increased amide peak signal corresponding to the middle of α-helix 2 and the loop between α-helices 2 and 3 in the PrPc monomer structure. Using high-resolution solution-state NMR, this work reveals detailed and divergent residue-specific changes in soluble oligomeric models of PrP.
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Affiliation(s)
- John Paul Glaves
- Department of Biochemistry, University of Alberta, Edmonton T6G 2H7, Canada
| | - Carol L Ladner-Keay
- Department of Biological Sciences, University of Alberta, Edmonton T6G 2E9, Canada
| | - Trent C Bjorndahl
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton T6G 2M9, Canada
| | - David S Wishart
- Department of Biological Sciences, University of Alberta, Edmonton T6G 2E9, Canada.
| | - Brian D Sykes
- Department of Biochemistry, University of Alberta, Edmonton T6G 2H7, Canada
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25
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What Is Our Current Understanding of PrP Sc-Associated Neurotoxicity and Its Molecular Underpinnings? Pathogens 2017; 6:pathogens6040063. [PMID: 29194372 PMCID: PMC5750587 DOI: 10.3390/pathogens6040063] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/21/2017] [Accepted: 11/27/2017] [Indexed: 01/15/2023] Open
Abstract
The prion diseases are a collection of fatal, transmissible neurodegenerative diseases that cause rapid onset dementia and ultimately death. Uniquely, the infectious agent is a misfolded form of the endogenous cellular prion protein, termed PrPSc. Despite the identity of the molecular agent remaining the same, PrPSc can cause a range of diseases with hereditary, spontaneous or iatrogenic aetiologies. However, the link between PrPSc and toxicity is complex, with subclinical cases of prion disease discovered, and prion neurodegeneration without obvious PrPSc deposition. The toxic mechanisms by which PrPSc causes the extensive neuropathology are still poorly understood, although recent advances are beginning to unravel the molecular underpinnings, including oxidative stress, disruption of proteostasis and induction of the unfolded protein response. This review will discuss the diseases caused by PrPSc toxicity, the nature of the toxicity of PrPSc, and our current understanding of the downstream toxic signaling events triggered by the presence of PrPSc.
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26
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Som Chaudhury S, Das Mukhopadhyay C. Functional amyloids: interrelationship with other amyloids and therapeutic assessment to treat neurodegenerative diseases. Int J Neurosci 2017; 128:449-463. [PMID: 29076790 DOI: 10.1080/00207454.2017.1398153] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Sutapa Som Chaudhury
- Centre for Healthcare Science and Technology, Indian Institute of Engineering Science and Technology, Shibpur, West Bengal, India
| | - Chitrangada Das Mukhopadhyay
- Centre for Healthcare Science and Technology, Indian Institute of Engineering Science and Technology, Shibpur, West Bengal, India
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27
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Kumar H, Singh J, Kumari P, Udgaonkar JB. Modulation of the extent of structural heterogeneity in α-synuclein fibrils by the small molecule thioflavin T. J Biol Chem 2017; 292:16891-16903. [PMID: 28760825 DOI: 10.1074/jbc.m117.795617] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 07/15/2017] [Indexed: 12/18/2022] Open
Abstract
The transition of intrinsically disordered, monomeric α-synuclein into β-sheet-rich oligomers and fibrils is associated with multiple neurodegenerative diseases. Fibrillar aggregates possessing distinct structures that differ in toxicity have been observed in different pathological phenotypes. Understanding the mechanism of the formation of various fibril polymorphs with differing cytotoxic effects is essential for determining how the aggregation reaction could be modulated to favor nontoxic fibrils over toxic fibrils. In this study, two morphologically different α-synuclein fibrils, one helical and the other ribbon-like, are shown to form together. Surprisingly, a widely used small molecule for probing aggregation reactions, thioflavin T (ThT), was found to tune the structural heterogeneity found in the fibrils. The ribbon-like fibrils formed in the presence of ThT were found to have a longer structural core than the helical fibrils formed in the absence of ThT. The ribbon-like fibrils are also more toxic to cells. By facilitating the formation of ribbon-like fibrils over helical fibrils, ThT reduced the extent of fibril polymorphism. This study highlights the role of a small molecule such as ThT in selectively favoring the formation of a specific type of fibril by binding to aggregates formed early on one of multiple pathways, thereby altering the structural core and external morphology of the fibrils formed.
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Affiliation(s)
- Harish Kumar
- From the National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
| | - Jogender Singh
- From the National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India.,the Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710, and
| | - Pratibha Kumari
- From the National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India.,the Laboratory of Physical Chemistry, Hönggerberg Campus, ETH Zurich, 8093 Zurich, Switzerland
| | - Jayant B Udgaonkar
- From the National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India,
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28
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Sengupta I, Udgaonkar JB. Expression and purification of single cysteine-containing mutant variants of the mouse prion protein by oxidative refolding. Protein Expr Purif 2017; 140:1-7. [PMID: 28736314 DOI: 10.1016/j.pep.2017.07.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 07/19/2017] [Accepted: 07/19/2017] [Indexed: 11/16/2022]
Abstract
The folding and aggregation of proteins has been studied extensively, using multiple probes. To facilitate such experiments, introduction of spectroscopically-active moieties in to the protein of interest is often necessary. This is commonly achieved by specifically labelling cysteine residues in the protein, which are either present naturally or introduced artificially by site-directed mutagenesis. In the case of the recombinant prion protein, which is normally expressed in inclusion bodies, the presence of the native disulfide bond complicates the correct refolding of single cysteine-containing mutant variants of the protein. To overcome this major bottleneck, a simple purification strategy for single tryptophan, single cysteine-containing mutant variants of the mouse prion protein is presented, with yields comparable to that of the wild type protein. The protein(s) obtained by this method are correctly folded, with a single reduced cysteine, and the native disulfide bond between residues C178 and C213 intact. The β-sheet rich oligomers formed from these mutant variant protein(s) are identical to the wild type protein oligomer. The current strategy facilitates sample preparation for a number of high resolution spectroscopic measurements for the prion protein, which specifically require thiol labelling.
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Affiliation(s)
- Ishita Sengupta
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
| | - Jayant B Udgaonkar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India.
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29
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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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30
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Malevanets A, Chong PA, Hansen DF, Rizk P, Sun Y, Lin H, Muhandiram R, Chakrabartty A, Kay LE, Forman-Kay JD, Wodak SJ. Interplay of buried histidine protonation and protein stability in prion misfolding. Sci Rep 2017; 7:882. [PMID: 28408762 PMCID: PMC5429843 DOI: 10.1038/s41598-017-00954-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 03/20/2017] [Indexed: 12/03/2022] Open
Abstract
Misofolding of mammalian prion proteins (PrP) is believed to be the cause of a group of rare and fatal neurodegenerative diseases. Despite intense scrutiny however, the mechanism of the misfolding reaction remains unclear. We perform nuclear Magnetic Resonance and thermodynamic stability measurements on the C-terminal domains (residues 90–231) of two PrP variants exhibiting different pH-induced susceptibilities to aggregation: the susceptible hamster prion (GHaPrP) and its less susceptible rabbit homolog (RaPrP). The pKa of histidines in these domains are determined from titration experiments, and proton-exchange rates are measured at pH 5 and pH 7. A single buried highly conserved histidine, H187/H186 in GHaPrP/RaPrP, exhibited a markedly down shifted pKa ~5 for both proteins. However, noticeably larger pH-induced shifts in exchange rates occur for GHaPrP versus RaPrP. Analysis of the data indicates that protonation of the buried histidine destabilizes both PrP variants, but produces a more drastic effect in the less stable GHaPrP. This interpretation is supported by urea denaturation experiments performed on both PrP variants at neutral and low pH, and correlates with the difference in disease susceptibility of the two species, as expected from the documented linkage between destabilization of the folded state and formation of misfolded and aggregated species.
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Affiliation(s)
- Anatoly Malevanets
- Program in Molecular Structure and Function, Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1A8, Canada
| | - P Andrew Chong
- Program in Molecular Structure and Function, Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1A8, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - D Flemming Hansen
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,University College London, Division of Biosciences, London, WC1E 6BT, UK
| | - Paul Rizk
- Program in Molecular Structure and Function, Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1A8, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Yulong Sun
- Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 2M9, Canada
| | - Hong Lin
- Program in Molecular Structure and Function, Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1A8, Canada
| | - Ranjith Muhandiram
- Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Avi Chakrabartty
- Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 2M9, Canada
| | - Lewis E Kay
- Program in Molecular Structure and Function, Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1A8, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,Department of Chemistry, University of Toronto, Toronto, ON, M5S 3H6, Canada
| | - Julie D Forman-Kay
- Program in Molecular Structure and Function, Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1A8, Canada. .,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada.
| | - Shoshana J Wodak
- Program in Molecular Structure and Function, Hospital for Sick Children, 555 University Ave, Toronto, ON, M5G 1A8, Canada. .,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 1A8, Canada. .,Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada. .,VIB Structural Biology Research Center, VUB, Pleinlaan 2, 1050, Brussels, Belgium.
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31
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Chamachi NG, Chakrabarty S. Temperature-Induced Misfolding in Prion Protein: Evidence of Multiple Partially Disordered States Stabilized by Non-Native Hydrogen Bonds. Biochemistry 2017; 56:833-844. [DOI: 10.1021/acs.biochem.6b01042] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Neharika G. Chamachi
- Physical and Materials Chemistry
Division, CSIR-National Chemical Laboratory, Pune 411008, India
| | - Suman Chakrabarty
- Physical and Materials Chemistry
Division, CSIR-National Chemical Laboratory, Pune 411008, India
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32
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Identification of novel fluorescent probes preventing PrP Sc replication in prion diseases. Eur J Med Chem 2017; 127:859-873. [DOI: 10.1016/j.ejmech.2016.10.064] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 10/12/2016] [Accepted: 10/31/2016] [Indexed: 12/11/2022]
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33
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Russo A, Diaferia C, La Manna S, Giannini C, Sibillano T, Accardo A, Morelli G, Novellino E, Marasco D. Insights into amyloid-like aggregation of H2 region of the C-terminal domain of nucleophosmin. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:176-185. [DOI: 10.1016/j.bbapap.2016.11.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 10/29/2016] [Accepted: 11/14/2016] [Indexed: 01/21/2023]
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34
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Singh RK, Chamachi NG, Chakrabarty S, Mukherjee A. Mechanism of Unfolding of Human Prion Protein. J Phys Chem B 2017; 121:550-564. [PMID: 28030950 DOI: 10.1021/acs.jpcb.6b11416] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Misfolding and aggregation of prion proteins are associated with several neurodegenerative diseases. Therefore, understanding the mechanism of the misfolding process is of enormous interest in the scientific community. It has been speculated and widely discussed that the native cellular prion protein (PrPC) form needs to undergo substantial unfolding to a more stable PrPC* state, which may further oligomerize into the toxic scrapie (PrPSc) form. Here, we have studied the mechanism of the unfolding of the human prion protein (huPrP) using a set of extensive well-tempered metadynamics simulations. Through multiple microsecond-long metadynamics simulations, we find several possible unfolding pathways. We show that each pathway leads to an unfolded state of lower free energy than the native state. Thus, our study may point to the signature of a PrPC* form that corresponds to a global minimum on the conformational free-energy landscape. Moreover, we find that these global minima states do not involve an increased β-sheet content, as was assumed to be a signature of PrPSc formation in previous simulation studies. We have further analyzed the origin of metastability of the PrPC form through free-energy surfaces of the chopped helical segments to show that the helices, particularly H2 and H3 of the prion protein, have the tendency to form either a random coil or a β-structure. Therefore, the secondary structural elements of the prion protein are only weakly stabilized by tertiary contacts and solvation forces so that relatively weak perturbations induced by temperature, pressure, pH, and so forth can lead to substantial unfolding with characteristics of intrinsically disordered proteins.
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Affiliation(s)
- Reman K Singh
- Department of Chemistry, Indian Institute of Science Education and Research , Pune 411008, Maharashtra, India
| | - Neharika G Chamachi
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory , Pune 411008, Maharashtra, India
| | - Suman Chakrabarty
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory , Pune 411008, Maharashtra, India
| | - Arnab Mukherjee
- Department of Chemistry, Indian Institute of Science Education and Research , Pune 411008, Maharashtra, India
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35
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Seelig DM, Goodman PA, Skinner PJ. Potential approaches for heterologous prion protein treatment of prion diseases. Prion 2017; 10:18-24. [PMID: 26636482 PMCID: PMC4981202 DOI: 10.1080/19336896.2015.1123372] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Prion diseases, or transmissible spongiform encephalopathies (TSEs) are progressive, fatal neurodegenerative diseases with no effective treatment. The pathology of these diseases involves the conversion of a protease sensitive form of the cellular prion protein (PrPC) into a protease resistant infectious form (PrPres). The efficiency of this conversion is predicated upon a number of factors, most notably a strong homology between cellular PrPC and PrPres. In our recently published study, we infected mice with the RML-Chandler strain of scrapie and treated them with heterologous hamster prion proteins. This treatment was seen to reduce clinical signs of prion disease, to delay the onset of clinical symptoms and to prolong survival. In this current article we discuss potential mechanisms of action of treatment with heterologous prion proteins. We also discuss potential extensions of these studies using a heterologous rabbit PrP-based treatment strategy or a peptide based strategy, and improvement of treatment delivery including a lentiviral-based system.
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Affiliation(s)
- Davis M Seelig
- a Veterinary Clinical Sciences Department , University of Minnesota , Saint Paul , MN , USA
| | - Patricia A Goodman
- b Veterinary and Biomedical Sciences Department , University of Minnesota , Saint Paul , MN , USA
| | - Pamela J Skinner
- b Veterinary and Biomedical Sciences Department , University of Minnesota , Saint Paul , MN , USA
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36
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Fruhmann G, Seynnaeve D, Zheng J, Ven K, Molenberghs S, Wilms T, Liu B, Winderickx J, Franssens V. Yeast buddies helping to unravel the complexity of neurodegenerative disorders. Mech Ageing Dev 2017; 161:288-305. [DOI: 10.1016/j.mad.2016.05.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 04/22/2016] [Accepted: 05/02/2016] [Indexed: 12/31/2022]
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37
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Chamachi NG, Chakrabarty S. Replica Exchange Molecular Dynamics Study of Dimerization in Prion Protein: Multiple Modes of Interaction and Stabilization. J Phys Chem B 2016; 120:7332-45. [DOI: 10.1021/acs.jpcb.6b03690] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Neharika G. Chamachi
- Physical and Materials Chemistry
Division, CSIR-National Chemical Laboratory, Pune 411008, India
| | - Suman Chakrabarty
- Physical and Materials Chemistry
Division, CSIR-National Chemical Laboratory, Pune 411008, India
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38
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Dalal V, Arya S, Mukhopadhyay S. Confined Water in Amyloid-Competent Oligomers of the Prion Protein. Chemphyschem 2016; 17:2804-7. [PMID: 27253720 DOI: 10.1002/cphc.201600440] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Indexed: 12/21/2022]
Abstract
Conformational switching of the prion protein into the abnormal form involves the formation of (obligatory) molten-oligomers that mature into ordered amyloid fibrils. The role of water in directing the course of amyloid formation remains poorly understood. Here, we show that the mobility of the water molecules within the on-pathway oligomers is highly retarded. The water relaxation time within the oligomers was estimated to be ≈1 ns which is about three orders of magnitude slower than the bulk water and resembles the characteristics of (trapped) nano-confined water. We propose that the coalescence of these obligatory oligomers containing trapped water is entropically favored because of the release of ordered water molecules in the bulk milieu and results in the sequestration of favorable inter-chain amyloid contacts via nucleated conformational conversion. The dynamic role of water in protein aggregation will have much broader implications in a variety of protein misfolding diseases.
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Affiliation(s)
- Vijit Dalal
- Centre for Protein Science Design and Engineering, Department of Biological Sciences and, Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), Mohali, Punjab, 140306, India
| | - Shruti Arya
- Centre for Protein Science Design and Engineering, Department of Biological Sciences and, Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), Mohali, Punjab, 140306, India
| | - Samrat Mukhopadhyay
- Centre for Protein Science Design and Engineering, Department of Biological Sciences and, Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER), Mohali, Punjab, 140306, India.
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39
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Endpoint Quaking-Induced Conversion: a Sensitive, Specific, and High-Throughput Method for Antemortem Diagnosis of Creutzfeldt-Jacob Disease. J Clin Microbiol 2016; 54:1751-1754. [PMID: 27076662 PMCID: PMC4922112 DOI: 10.1128/jcm.00542-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 04/08/2016] [Indexed: 11/20/2022] Open
Abstract
The Prion Laboratory Section of the Public Health Agency of Canada supports heath care professionals dealing with patients suspected to have Creutzfeldt-Jakob disease (CJD) by testing cerebrospinal fluid (CSF) for protein markers of CJD. To better serve Canadian diagnostic requirements, a quaking-induced conversion (QuIC)-based assay has been added to the test panel. The QuIC tests exploit the ability of disease-associated prion protein, found in the CSF of a majority of CJD patients, to convert a recombinant prion protein (rPrP) into detectable amounts of a misfolded, aggregated form of rPrP. The rPrP aggregates interact with a specific dye, causing a measurable change in the dye's fluorescence emission spectrum. Optimal test and analysis parameters were empirically determined. Taking both practical and performance considerations into account, an endpoint QuIC (EP-QuIC) configuration was chosen. EP-QuIC uses a thermo-mixer to perform the shaking necessary to produce the quaking-induced conversions. Fluorescence readings are obtained from a microwell fluorescence reader only at the beginning and the end of EP-QuIC reactions. Samples for which the relative fluorescence unit ratio between the initial and final readings represent a ≥4 increase in signal intensity in at least two of the three replicates are classified as positive. A retrospective analysis of 91 CSF samples that included 45 confirmed cases of CJD and 46 non-CJD cases was used to estimate the performance characteristics of the EP-QuIC assay. The diagnostic sensitivity and specificity of the EP-QuIC test of this set of samples were 98 and 91%, respectively.
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40
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Singh J, Udgaonkar JB. Unraveling the Molecular Mechanism of pH-Induced Misfolding and Oligomerization of the Prion Protein. J Mol Biol 2016; 428:1345-1355. [PMID: 26854758 DOI: 10.1016/j.jmb.2016.01.030] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 01/27/2016] [Accepted: 01/28/2016] [Indexed: 12/31/2022]
Abstract
The misfolding of the prion protein (PrP) to aggregated forms is linked to several neurodegenerative diseases. Misfolded oligomeric forms of PrP are associated with neurotoxicity and/or infectivity, but the molecular mechanism by which they form is still poorly understood. A reduction in pH is known to be a key factor that triggers misfolded oligomer formation by PrP, but the residues whose protonation is linked with misfolding remain unidentified. The structural consequences of the protonation of these residues also remain to be determined. In the current study, amino acid residues whose protonation is critical for PrP misfolding and oligomerization have been identified using site-directed mutagenesis and misfolding/oligomerization assays. It is shown that the protonation of either H186 or D201, which mimics the effects of pathogenic mutations (H186R and D201N) at both residue sites, is critically linked to the stability, misfolding and oligomerization of PrP. Hydrogen-deuterium exchange studies coupled with mass spectrometry show that the protonation of either H186 or D201 leads to the same common structural change: increased structural dynamics in helix 1 and that in the loop between helix 1 and β-strand 2. It is shown that the protonation of either of these residues is sufficient for accelerating misfolded oligomer formation, most likely because the protonation of either residue causes the same structural perturbation. Hence, the increased structural dynamics in helix 1 and that in the loop between helix 1 and β-strand 2 appear to play an early critical role in acid-induced misfolding of PrP.
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Affiliation(s)
- Jogender Singh
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
| | - Jayant B Udgaonkar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India.
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41
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Singh J, Udgaonkar JB. The Pathogenic Mutation T182A Converts the Prion Protein into a Molten Globule-like Conformation Whose Misfolding to Oligomers but Not to Fibrils Is Drastically Accelerated. Biochemistry 2016; 55:459-69. [DOI: 10.1021/acs.biochem.5b01266] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Jogender Singh
- National Centre for Biological
Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
| | - Jayant B. Udgaonkar
- National Centre for Biological
Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
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42
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Conformational Switching and Nanoscale Assembly of Human Prion Protein into Polymorphic Amyloids via Structurally Labile Oligomers. Biochemistry 2015; 54:7505-13. [DOI: 10.1021/acs.biochem.5b01110] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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