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Khachatryan L, Rezk MY, Nde D, Hasan F, Lomnicki S, Boldor D, Cook R, Sprunger P, Hall R, Cormier S. New Features of Laboratory-Generated EPFRs from 1,2-Dichlorobenzene (DCB) and 2-Monochlorophenol (MCP). ACS OMEGA 2024; 9:9226-9235. [PMID: 38434874 PMCID: PMC10905596 DOI: 10.1021/acsomega.3c08271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/18/2023] [Accepted: 01/22/2024] [Indexed: 03/05/2024]
Abstract
The present research is primarily focused on investigating the characteristics of environmentally persistent free radicals (EPFRs) generated from commonly recognized aromatic precursors, namely, 1,2-dichlorobenzene (DCB) and 2-monochlorophenol (MCP), within controlled laboratory conditions at a temperature of 230 °C, termed as DCB230 and MCP230 EPFRs, respectively. An intriguing observation has emerged during the creation of EPFRs from MCP and DCB utilizing a catalyst 5% CuO/SiO2, which was prepared through various methods. A previously proposed mechanism, advanced by Dellinger and colleagues (a conventional model), postulated a positive correlation between the degree of hydroxylation on the catalyst's surface (higher hydroxylated, HH and less hydroxylated, LH) and the anticipated EPFR yields. In the present study, this correlation was specifically confirmed for the DCB precursor. Particularly, it was observed that increasing the degree of hydroxylation at the catalyst's surface resulted in a greater yield of EPFRs for DCB230. The unexpected finding was the indifferent behavior of MCP230 EPFRs to the surface morphology of the catalyst, i.e., no matter whether copper oxide nanoparticles are distributed densely, sparsely, or completely agglomerated. The yields of MCP230 EPFRs remained consistent regardless of the catalyst type or preparation protocol. Although current experimental results confirm the early model for the generation of DCB EPFRs (i.e., the higher the hydroxylation is, the higher the yield of EPFRs), it is of utmost importance to closely explore the heterogeneous alternative mechanism(s) responsible for generating MCP230 EPFRs, which may run parallel to the conventional model. In this study, detailed spectral analysis was conducted using the EPR technique to examine the nature of DCB230 EPFRs and the aging phenomenon of DCB230 EPFRs while they exist as surface-bound o-semiquinone radicals (o-SQ) on copper sites. Various aspects concerning bound radicals were explored, including the hydrogen-bonding tendencies of o-semiquinone (o-SQ) radicals, the potential reversibility of hydroxylation processes occurring on the catalyst's surface, and the analysis of selected EPR spectra using EasySpin MATLAB. Furthermore, alternative routes for EPFR generation were thoroughly discussed and compared with the conventional model.
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Affiliation(s)
- Lavrent Khachatryan
- Department
of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Marwan Y. Rezk
- Department
of Engineering Science, Biological Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Divine Nde
- Department
of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Farhana Hasan
- Department
of Environmental Sciences, Louisiana State
University, Baton
Rouge, Louisiana 70803, United States
| | - Slawomir Lomnicki
- Department
of Environmental Sciences, Louisiana State
University, Baton
Rouge, Louisiana 70803, United States
| | - Dorin Boldor
- Department
of Engineering Science, Biological Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Robert Cook
- Department
of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Phillip Sprunger
- Department
of Physics and Astronomy, Louisiana State
University, Baton
Rouge, Louisiana 70803, United States
| | - Randall Hall
- Natural
Sciences and Mathematics, School of Health and Natural Sciences, Dominican University of California, San Rafael, California 94901, United States
| | - Stephania Cormier
- Department
of Biological Sciences, LSU Superfund Research
Program and Pennington Biomedical Research Center, Baton Rouge, Louisiana 70808, United States
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Sołtys K, Tarczewska A, Bystranowska D. Modulation of biomolecular phase behavior by metal ions. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119567. [PMID: 37582439 DOI: 10.1016/j.bbamcr.2023.119567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 08/04/2023] [Accepted: 08/08/2023] [Indexed: 08/17/2023]
Abstract
Liquid-liquid phase separation (LLPS) appears to be a newly appreciated aspect of the cellular organization of biomolecules that leads to the formation of membraneless organelles (MLOs). MLOs generate distinct microenvironments where particular biomolecules are highly concentrated compared to those in the surrounding environment. Their thermodynamically driven formation is reversible, and their liquid nature allows them to fuse with each other. Dysfunctional biomolecular condensation is associated with human diseases. Pathological states of MLOs may originate from the mutation of proteins or may be induced by other factors. In most aberrant MLOs, transient interactions are replaced by stronger and more rigid interactions, preventing their dissolution, and causing their uncontrolled growth and dysfunction. For these reasons, there is great interest in identifying factors that modulate LLPS. In this review, we discuss an enigmatic and mostly unexplored aspect of this process, namely, the regulatory effects of metal ions on the phase behavior of biomolecules.
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Affiliation(s)
- Katarzyna Sołtys
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
| | - Aneta Tarczewska
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Dominika Bystranowska
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
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3
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Barrera J, H Haeri H, Heinrich J, Stein M, Hinderberger D, Kulak N. Impact of N-heteroaromatic N-termini in Cu(II) ATCUN metallopeptides on their biorelevant redox activity. Dalton Trans 2023; 52:3279-3286. [PMID: 36633467 DOI: 10.1039/d2dt02044k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Cu(II) complexes with ATCUN peptide ligands have been investigated for their ROS (reactive oxygen species) generation and oxidative DNA degradation abilities. The biological activity of most ATCUN complexes such as Cu-GGH (Gly-Gly-His) is, however, low. Tuning the redox chemistry by incorporation of N-heteroaromatics reinstates ROS production which leads to efficient DNA cleavage.
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Affiliation(s)
- Jannis Barrera
- Institute of Chemistry, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany. .,Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Haleh H Haeri
- Institute of Chemistry, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle, Germany
| | - Julian Heinrich
- Institute of Chemistry, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany.
| | - Matthias Stein
- Max Planck Institute for Dynamics of Complex Technical Systems, Molecular Simulations and Design Group, Sandtorstrasse 1, 39106 Magdeburg, Germany
| | - Dariush Hinderberger
- Institute of Chemistry, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle, Germany
| | - Nora Kulak
- Institute of Chemistry, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany.
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Roy M, Nath AK, Pal I, Dey SG. Second Sphere Interactions in Amyloidogenic Diseases. Chem Rev 2022; 122:12132-12206. [PMID: 35471949 DOI: 10.1021/acs.chemrev.1c00941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amyloids are protein aggregates bearing a highly ordered cross β structural motif, which may be functional but are mostly pathogenic. Their formation, deposition in tissues and consequent organ dysfunction is the central event in amyloidogenic diseases. Such protein aggregation may be brought about by conformational changes, and much attention has been directed toward factors like metal binding, post-translational modifications, mutations of protein etc., which eventually affect the reactivity and cytotoxicity of the associated proteins. Over the past decade, a global effort from different groups working on these misfolded/unfolded proteins/peptides has revealed that the amino acid residues in the second coordination sphere of the active sites of amyloidogenic proteins/peptides cause changes in H-bonding pattern or protein-protein interactions, which dramatically alter the structure and reactivity of these proteins/peptides. These second sphere effects not only determine the binding of transition metals and cofactors, which define the pathology of some of these diseases, but also change the mechanism of redox reactions catalyzed by these proteins/peptides and form the basis of oxidative damage associated with these amyloidogenic diseases. The present review seeks to discuss such second sphere modifications and their ramifications in the etiopathology of some representative amyloidogenic diseases like Alzheimer's disease (AD), type 2 diabetes mellitus (T2Dm), Parkinson's disease (PD), Huntington's disease (HD), and prion diseases.
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Affiliation(s)
- Madhuparna Roy
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Arnab Kumar Nath
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Ishita Pal
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Somdatta Ghosh Dey
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
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La Penna G, Morante S. Aggregates Sealed by Ions. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2022; 2340:309-341. [PMID: 35167080 DOI: 10.1007/978-1-0716-1546-1_14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The chapter draws a line connecting some recent results where the role of ions is found essential in sealing more or less pre-organized assemblies of macromolecules. We draw some dots along the line that starts from the effect of the ionic atmosphere and ends with the chemical bonds formed by multivalent ions acting as bridges between macromolecules. Many of these dots involve structurally disordered peptides and disordered regions of proteins. A broad perspective of the role of multivalent ions in assisting the assembly process, shifting population in polymorphic states, and sealing protein aggregates, is suggested.
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Affiliation(s)
- Giovanni La Penna
- Institute for Chemistry of Organo-Metallic Compounds, National Research Council of Italy, Florence, Italy.
| | - Silvia Morante
- Department of Physics, University of Roma Tor Vergata, Roma, Italy
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6
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Schilling KM, Tao L, Wu B, Kiblen JTM, Ubilla-Rodriguez NC, Pushie MJ, Britt RD, Roseman GP, Harris DA, Millhauser GL. Both N-Terminal and C-Terminal Histidine Residues of the Prion Protein Are Essential for Copper Coordination and Neuroprotective Self-Regulation. J Mol Biol 2020; 432:4408-4425. [PMID: 32473880 PMCID: PMC7387163 DOI: 10.1016/j.jmb.2020.05.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 05/25/2020] [Accepted: 05/26/2020] [Indexed: 01/19/2023]
Abstract
The cellular prion protein (PrPC) comprises two domains: a globular C-terminal domain and an unstructured N-terminal domain. Recently, copper has been observed to drive tertiary contact in PrPC, inducing a neuroprotective cis interaction that structurally links the protein's two domains. The location of this interaction on the C terminus overlaps with the sites of human pathogenic mutations and toxic antibody docking. Combined with recent evidence that the N terminus is a toxic effector regulated by the C terminus, there is an emerging consensus that this cis interaction serves a protective role, and that the disruption of this interaction by misfolded PrP oligomers may be a cause of toxicity in prion disease. We demonstrate here that two highly conserved histidines in the C-terminal domain of PrPC are essential for the protein's cis interaction, which helps to protect against neurotoxicity carried out by its N terminus. We show that simultaneous mutation of these histidines drastically weakens the cis interaction and enhances spontaneous cationic currents in cultured cells, the first C-terminal mutant to do so. Whereas previous studies suggested that Cu2+ coordination was localized solely to the protein's N-terminal domain, we find that both domains contribute equatorially coordinated histidine residue side-chains, resulting in a novel bridging interaction. We also find that extra N-terminal histidines in pathological familial mutations involving octarepeat expansions inhibit this interaction by sequestering copper from the C terminus. Our findings further establish a structural basis for PrPC's C-terminal regulation of its otherwise toxic N terminus.
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Affiliation(s)
- Kevin M Schilling
- Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, CA 95064, USA
| | - Lizhi Tao
- Department of Chemistry, University of California, 1 Shields Ave., Davis, CA 95616, USA
| | - Bei Wu
- Department of Biochemistry, Boston University School of Medicine, 72 E. Concord St Silvio Conte., Boston, MA 02118, USA
| | - Joseph T M Kiblen
- Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, CA 95064, USA
| | - Natalia C Ubilla-Rodriguez
- Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, CA 95064, USA
| | - M Jake Pushie
- Department of Surgery, College of Medicine, University of Saskatchewan, 107 Wiggins Rd B419, Saskatoon, SK S7N 5E5, Canada
| | - R David Britt
- Department of Chemistry, University of California, 1 Shields Ave., Davis, CA 95616, USA
| | - Graham P Roseman
- Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, CA 95064, USA
| | - David A Harris
- Department of Biochemistry, Boston University School of Medicine, 72 E. Concord St Silvio Conte., Boston, MA 02118, USA.
| | - Glenn L Millhauser
- Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, CA 95064, USA.
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7
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Structural Consequences of Copper Binding to the Prion Protein. Cells 2019; 8:cells8080770. [PMID: 31349611 PMCID: PMC6721516 DOI: 10.3390/cells8080770] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 07/22/2019] [Accepted: 07/23/2019] [Indexed: 12/24/2022] Open
Abstract
Prion, or PrPSc, is the pathological isoform of the cellular prion protein (PrPC) and it is the etiological agent of transmissible spongiform encephalopathies (TSE) affecting humans and animal species. The most relevant function of PrPC is its ability to bind copper ions through its flexible N-terminal moiety. This review includes an overview of the structure and function of PrPC with a focus on its ability to bind copper ions. The state-of-the-art of the role of copper in both PrPC physiology and in prion pathogenesis is also discussed. Finally, we describe the structural consequences of copper binding to the PrPC structure.
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8
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Physiological role of Prion Protein in Copper homeostasis and angiogenic mechanisms of endothelial cells. THE EUROBIOTECH JOURNAL 2019. [DOI: 10.2478/ebtj-2019-0007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Abstract
The Prion Protein (PrP) is mostly known for its role in prion diseases, where its misfolding and aggregation can cause fatal neurodegenerative conditions such as the bovine spongiform encephalopathy and human Creutzfeldt–Jakob disease. Physiologically, PrP is involved in several processes including adhesion, proliferation, differentiation and angiogenesis, but the molecular mechanisms behind its role remain unclear. PrP, due to its well-described structure, is known to be able to regulate copper homeostasis; however, copper dyshomeostasis can lead to developmental defects. We investigated PrP-dependent regulation of copper homeostasis in human endothelial cells (HUVEC) using an RNA-interference protocol. PrP knockdown did not influence cell viability in silenced HUVEC (PrPKD) compared to control cells, but significantly increased PrPKD HUVEC cells sensitivity to cytotoxic copper concentrations. A reduction of PrPKD cells reductase activity and copper ions transport capacity was observed. Furthermore, PrPKD-derived spheroids exhibited altered morphogenesis and their derived cells showed a decreased vitality 24 and 48 hours after seeding. PrPKD spheroid-derived cells also showed disrupted tubulogenesis in terms of decreased coverage area, tubule length and total nodes number on matrigel, preserving unaltered VEGF receptors expression levels. Our results highlight PrP physiological role in cellular copper homeostasis and in the angiogenesis of endothelial cells.
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9
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Ahmadi S, Zhu S, Sharma R, Wu B, Soong R, Dutta Majumdar R, Wilson DJ, Simpson AJ, Kraatz HB. Aggregation of Microtubule Binding Repeats of Tau Protein is Promoted by Cu 2. ACS OMEGA 2019; 4:5356-5366. [PMID: 31001602 PMCID: PMC6463671 DOI: 10.1021/acsomega.8b03595] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/05/2019] [Indexed: 06/09/2023]
Abstract
Understanding the factors that give rise to tau aggregation and reactive oxygen species (ROS) is the key aspect in Alzheimer's disease pathogenesis. Microtubule (MT) binding repeats of tau protein were suggested to play a critical role in tau aggregation. Here, we show that the interaction of Cu2+ with full-length MT binding repeats R1-R4 leads to the aggregation, and a Cys-based redox chemistry is critically involved in tau aggregation leading to disulfide-bridge dimerization of R2 and R3 and further aggregation into a fibrillar structure. Notably, ascorbate and glutathione, the most abundant antioxidants in neurons, cannot prevent the effect of Cu2+ on R2 and R3 aggregation. Detailed ESI-MS and NMR experiments demonstrate the interaction of Cu2+ with MT binding repeats. We show that redox activity of copper increases when bound to the MT repeats leading to ROS formation, which significantly contribute to cellular damage and neuron death. Results presented here provide new insights into the molecular mechanism of tau aggregation and ROS formation and suggest a new target domain for tau aggregation inhibitors.
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Affiliation(s)
- Soha Ahmadi
- Department
of Physical and Environmental Science, University
of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
- Department
of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 1A1, Canada
| | - Shaolong Zhu
- Chemistry
Department, York University, Toronto, Ontario M3J1P3, Canada
- The
Centre for Research in Mass Spectrometry, York University, 4700 Keele Street, Toronto, Ontario M3J1P3, Canada
| | - Renu Sharma
- Department
of Physical and Environmental Science, University
of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
| | - Bing Wu
- Department
of Physical and Environmental Science, University
of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
| | - Ronald Soong
- Department
of Physical and Environmental Science, University
of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
- Department
of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 1A1, Canada
| | - R. Dutta Majumdar
- Department
of Physical and Environmental Science, University
of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
| | - Derek J. Wilson
- Chemistry
Department, York University, Toronto, Ontario M3J1P3, Canada
- The
Centre for Research in Mass Spectrometry, York University, 4700 Keele Street, Toronto, Ontario M3J1P3, Canada
| | - Andre J. Simpson
- Department
of Physical and Environmental Science, University
of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
- Department
of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 1A1, Canada
| | - Heinz-Bernhard Kraatz
- Department
of Physical and Environmental Science, University
of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
- Department
of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 1A1, Canada
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10
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Reactions of superoxide dismutases with HS−/H2S and superoxide radical anion: An in vitro EPR study. Nitric Oxide 2015; 51:19-23. [DOI: 10.1016/j.niox.2015.09.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 09/24/2015] [Accepted: 09/29/2015] [Indexed: 01/10/2023]
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Cong X, Casiraghi N, Rossetti G, Mohanty S, Giachin G, Legname G, Carloni P. Role of Prion Disease-Linked Mutations in the Intrinsically Disordered N-Terminal Domain of the Prion Protein. J Chem Theory Comput 2013; 9:5158-67. [DOI: 10.1021/ct400534k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Xiaojing Cong
- Laboratory
of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), via Bonomea 265, 34136 Trieste, Italy
- Laboratory
for Computational Biophysics, German Research School for Simulation Sciences (GRS), Forschungszentrum Jülich−RWTH Aachen, 52425 Jülich, Germany
- Computational
Biomedicine Section (IAS-5), Institute of Advanced Simulation (IAS), 52425 Jülich, Germany
| | - Nicola Casiraghi
- Laboratory
for Computational Biophysics, German Research School for Simulation Sciences (GRS), Forschungszentrum Jülich−RWTH Aachen, 52425 Jülich, Germany
- Department
of Biology, University of Bologna, via Selmi 3, 40126 Bologna, Italy
- Computational
Biomedicine Section (IAS-5), Institute of Advanced Simulation (IAS), 52425 Jülich, Germany
| | - Giulia Rossetti
- Laboratory
for Computational Biophysics, German Research School for Simulation Sciences (GRS), Forschungszentrum Jülich−RWTH Aachen, 52425 Jülich, Germany
- Jülich Supercomputing Centre, Forschungszentrum Jülich, 52425 Jülich, Germany
- Computational
Biomedicine Section (IAS-5), Institute of Advanced Simulation (IAS), 52425 Jülich, Germany
- Institute for Research in Biomedicine and Barcelona Supercomputing Center Joint Research Program on Computational Biology, Barcelona Science Park, Baldiri I Reixac 10, 08028 Barcelona, Spain
| | - Sandipan Mohanty
- Jülich Supercomputing Centre, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Gabriele Giachin
- Laboratory
of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), via Bonomea 265, 34136 Trieste, Italy
| | - Giuseppe Legname
- Laboratory
of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), via Bonomea 265, 34136 Trieste, Italy
- ELETTRA Laboratory, Sincrotrone
Trieste S.C.p.A., 34149 Basovizza, Trieste, Italy
| | - Paolo Carloni
- Laboratory
for Computational Biophysics, German Research School for Simulation Sciences (GRS), Forschungszentrum Jülich−RWTH Aachen, 52425 Jülich, Germany
- Computational
Biomedicine Section (IAS-5), Institute of Advanced Simulation (IAS), 52425 Jülich, Germany
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12
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Emwas AHM, Al-Talla ZA, Guo X, Al-Ghamdi S, Al-Masri HT. Utilizing NMR and EPR spectroscopy to probe the role of copper in prion diseases. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2013; 51:255-268. [PMID: 23436479 DOI: 10.1002/mrc.3936] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 12/19/2012] [Accepted: 01/11/2013] [Indexed: 06/01/2023]
Abstract
Copper is an essential nutrient for the normal development of the brain and nervous system, although the hallmark of several neurological diseases is a change in copper concentrations in the brain and central nervous system. Prion protein (PrP) is a copper-binding, cell-surface glycoprotein that exists in two alternatively folded conformations: a normal isoform (PrP(C)) and a disease-associated isoform (PrP(Sc)). Prion diseases are a group of lethal neurodegenerative disorders that develop as a result of conformational conversion of PrP(C) into PrP(Sc). The pathogenic mechanism that triggers this conformational transformation with the subsequent development of prion diseases remains unclear. It has, however, been shown repeatedly that copper plays a significant functional role in the conformational conversion of prion proteins. In this review, we focus on current research that seeks to clarify the conformational changes associated with prion diseases and the role of copper in this mechanism, with emphasis on the latest applications of NMR and EPR spectroscopy to probe the interactions of copper with prion proteins.
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Affiliation(s)
- Abdul-Hamid M Emwas
- NMR Core Lab, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia.
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14
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15
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Arena G, La Mendola D, Pappalardo G, Sóvágó I, Rizzarelli E. Interactions of Cu2+ with prion family peptide fragments: Considerations on affinity, speciation and coordination. Coord Chem Rev 2012. [DOI: 10.1016/j.ccr.2012.03.038] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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16
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Thakur AK, Srivastava AK, Srinivas V, Chary KVR, Rao CM. Copper alters aggregation behavior of prion protein and induces novel interactions between its N- and C-terminal regions. J Biol Chem 2011; 286:38533-38545. [PMID: 21900252 DOI: 10.1074/jbc.m111.265645] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Copper is reported to promote and prevent aggregation of prion protein. Conformational and functional consequences of Cu(2+)-binding to prion protein (PrP) are not well understood largely because most of the Cu(2+)-binding studies have been performed on fragments and truncated variants of the prion protein. In this context, we set out to investigate the conformational consequences of Cu(2+)-binding to full-length prion protein (PrP) by isothermal calorimetry, NMR, and small angle x-ray scattering. In this study, we report altered aggregation behavior of full-length PrP upon binding to Cu(2+). At physiological temperature, Cu(2+) did not promote aggregation suggesting that Cu(2+) may not play a role in the aggregation of PrP at physiological temperature (37 °C). However, Cu(2+)-bound PrP aggregated at lower temperatures. This temperature-dependent process is reversible. Our results show two novel intra-protein interactions upon Cu(2+)-binding. The N-terminal region (residues 90-120 that contain the site His-96/His-111) becomes proximal to helix-1 (residues 144-147) and its nearby loop region (residues 139-143), which may be important in preventing amyloid fibril formation in the presence of Cu(2+). In addition, we observed another novel interaction between the N-terminal region comprising the octapeptide repeats (residues 60-91) and helix-2 (residues 174-185) of PrP. Small angle x-ray scattering studies of full-length PrP show significant compactness upon Cu(2+)-binding. Our results demonstrate novel long range inter-domain interactions of the N- and C-terminal regions of PrP upon Cu(2+)-binding, which might have physiological significance.
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Affiliation(s)
- Abhay Kumar Thakur
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500 007, India
| | - Atul Kumar Srivastava
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
| | - Volety Srinivas
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500 007, India
| | - Kandala Venkata Ramana Chary
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
| | - Chintalagiri Mohan Rao
- Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad 500 007, India.
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17
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Zinc modulates copper coordination mode in prion protein octa-repeat subdomains. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2011; 40:1259-70. [PMID: 21710304 DOI: 10.1007/s00249-011-0713-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Revised: 04/29/2011] [Accepted: 05/16/2011] [Indexed: 10/18/2022]
Abstract
In this work we present and analyse XAS measurements carried out on various portions of Prion-protein tetra-octa-repeat peptides in complexes with Cu(II) ions, both in the presence and in the absence of Zn(II). Because of the ability of the XAS technique to provide detailed local structural information, we are able to demonstrate that Zn acts by directly interacting with the peptide, in this way competing with Cu for binding with histidine. This finding suggests that metal binding competition can be important in the more general context of metal homeostasis.
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18
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Prion protein and its conformational conversion: a structural perspective. Top Curr Chem (Cham) 2011; 305:135-67. [PMID: 21630136 DOI: 10.1007/128_2011_165] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The key molecular event in the pathogenesis of prion diseases is the conformational conversion of a cellular prion protein, PrP(C), into a misfolded form, PrP(Sc). In contrast to PrP(C) that is monomeric and α-helical, PrP(Sc) is oligomeric in nature and rich in β-sheet structure. According to the "protein-only" model, PrP(Sc) itself represents the infectious prion agent responsible for transmissibility of prion disorders. While this model is supported by rapidly growing experimental data, detailed mechanistic and structural aspects of prion protein conversion remain enigmatic. In this chapter we describe recent advances in understanding biophysical and biochemical aspects of prion diseases, with a special focus on structural underpinnings of prion protein conversion, the structural basis of prion strains, and generation of prion infectivity in vitro from bacterially-expressed recombinant PrP.
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19
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La Mendola D, Magrì A, Campagna T, Campitiello MA, Raiola L, Isernia C, Hansson O, Bonomo RP, Rizzarelli E. A doppel alpha-helix peptide fragment mimics the copper(II) interactions with the whole protein. Chemistry 2010; 16:6212-23. [PMID: 20411530 DOI: 10.1002/chem.200902405] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The doppel protein (Dpl) is the first homologue of the prion protein (PrP(C)) to be discovered; it is overexpressed in transgenic mice that lack the prion gene, resulting in neurotoxicity. The whole prion protein is able to inhibit Dpl neurotoxicity, and its N-terminal domain is the determinant part of the protein function. This region represents the main copper(II) binding site of PrP(C). Dpl is able to bind at least one copper ion, and the specific metal-binding site has been identified as the histidine residue at the beginning of the third helical region. However, a reliable characterization of copper(II) coordination features has not been reported. In a previous paper, we studied the copper(II) interaction with a peptide that encompasses only the loop region potentially involved in metal binding. Nevertheless, we did not find a complete match between the EPR spectroscopic parameters of the copper(II) complexes formed with the synthesized peptide and those reported for the copper(II) binding sites of the whole protein. Herein, the synthesis of the human Dpl peptide fragment hDpl(122-139) (Ac-KPDNKLHQQVLWRLVQEL-NH(2)) and its copper(II) complex species are reported. This peptide encompasses the third alpha helix and part of the loop linking the second and the third helix of human doppel protein. The single-point-mutated peptide, hDpl(122-139)D124N, in which aspartate 124 replaces an asparagine residue, was also synthesized. This peptide was used to highlight the role of the carboxylate group on both the conformation preference of the Dpl fragment and its copper(II) coordination features. NMR spectroscopic measurements show that the hDpl(122-139) peptide fragment is in the prevailing alpha-helix conformation. It is localized within the 127-137 amino acid residue region that represents a reliable conformational mimic of the related protein domain. A comparison with the single-point-mutated hDpl(122-139)D124N reveals the significant role played by the aspartic residue in addressing the peptide conformation towards a helical structure. It is further confirmed by CD measurements. Potentiometric titrations were carried out in aqueous solutions to obtain the stability constant values of the species formed by copper(II) with the hDpl peptides. Spectroscopic studies (EPR, NMR, CD, UV/Vis) were performed to characterize the coordination environments of the different metal complexes. The EPR parameters of the copper(II) complexes with hDpl(122-139) match those of the previously reported copper(II) binding sites of the whole hDpl. Addition of the copper(II) ion to the peptide fragment does not alter the helical conformation of hDpl(122-139), as shown by CD spectra in the far-UV region. The aspartate-driven preorganized secondary structure is not significantly modified by the involvement of Asp124 in the copper(II) complex species that form in the physiological pH range. To elaborate on the potential role of copper(II) in the recently reported interaction between the PrP(C) and Dpl, the affinity of the copper(II) complexes towards the prion N terminus domain and the binding site of Dpl was reported.
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Affiliation(s)
- Diego La Mendola
- Istituto di Biostrutture e Bioimmagini-CNR, c/o Dipartimento di Scienze Chimiche, Viale A. Doria 6, 95125 Catania, Italy
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20
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Kozlowski H, Luczkowski M, Remelli M. Prion proteins and copper ions. Biological and chemical controversies. Dalton Trans 2010; 39:6371-85. [PMID: 20422067 DOI: 10.1039/c001267j] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The Prion protein (PrP(c)) involvement in some neurodegenerative diseases is well assessed although its "normal" biological role is not completely understood. It is known that PrP(C) can bind Cu(II) ions with high specificity but the order of magnitude of the corresponding affinity constant(s) is still highly debated. This perspective is an attempt to collect the current knowledge on these topics and to build up a bridge between the biological and the chemical points of view.
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Affiliation(s)
- Henryk Kozlowski
- Faculty of Chemistry, University of Wroclaw, F. Joliot-Curie 14, 50-383, Wroclaw, Poland
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21
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Watanabe Y, Hiraoka W, Igarashi M, Ito K, Shimoyama Y, Horiuchi M, Yamamori T, Yasui H, Kuwabara M, Inagaki F, Inanami O. A novel copper(II) coordination at His186 in full-length murine prion protein. Biochem Biophys Res Commun 2010; 394:522-8. [DOI: 10.1016/j.bbrc.2010.03.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Accepted: 03/02/2010] [Indexed: 10/19/2022]
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22
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Walter ED, Stevens DJ, Spevacek AR, Visconte MP, Dei Rossi A, Millhauser GL. Copper binding extrinsic to the octarepeat region in the prion protein. Curr Protein Pept Sci 2010; 10:529-35. [PMID: 19538144 DOI: 10.2174/138920309789352056] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Accepted: 03/12/2009] [Indexed: 11/22/2022]
Abstract
Current research suggests that the function of the prion protein (PrP) is linked to its ability to bind copper. PrP is implicated in copper regulation, copper buffering and copper-dependent signaling. Moreover, in the development of prion disease, copper may modulate the rate of protein misfolding. PrP possesses a number of copper sites, each with distinct chemical characteristics. Most studies thus far have concentrated on elucidating chemical features of the octarepeat region (residues 60-91, hamster sequence), which can take up to four equivalents of copper, depending on the ratio of Cu2+ to protein. However, other sites have been proposed, including those at histidines 96 and 111, which are adjacent to the octarepeats, and also at histidines within PrP's folded C-terminal domain. Here, we review the literature of these copper sites extrinsic to the octarepeat region and add new findings and insights from recent experiments.
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Affiliation(s)
- Eric D Walter
- Department of Chemistry & Biochemistry, University of California, Santa Cruz, Santa Cruz, CA 95064, USA.
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23
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Hodak M, Bernholc J. Insights into prion protein function from atomistic simulations. Prion 2010; 4:13-9. [PMID: 20118658 PMCID: PMC2850415 DOI: 10.4161/pri.4.1.10969] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2009] [Accepted: 12/16/2009] [Indexed: 11/19/2022] Open
Abstract
Computer simulations are a powerful tool for studies of biological systems. They have often been used to study prion protein (PrP), a protein responsible for neurodegenerative diseases, which include "mad cow disease" in cattle and Creutzfeldt-Jacob disease in humans. An important aspect of the prion protein is its interaction with copper ion, which is thought to be relevant for PrP's yet undetermined function and also potentially play a role in prion diseases. for studies of copper attachment to the prion protein, computer simulations have often been used to complement experimental data and to obtain binding structures of Cu-PrP complexes. This paper summarizes the results of recent ab initio calculations of copper-prion protein interactions focusing on the recently discovered concentration-dependent binding modes in the octarepeat region of this protein. In addition to determining the binding structures, computer simulations were also used to make predictions about PrP's function and the role of copper in prion diseases. The results demonstrate the predictive power and applicability of ab initio simulations for studies of metal-biomolecular complexes.
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Affiliation(s)
- Miroslav Hodak
- Center for High Performance Simulation and Department of Physics; North Carolina State University; Raleigh, NC USA
| | - Jerzy Bernholc
- Center for High Performance Simulation and Department of Physics; North Carolina State University; Raleigh, NC USA
- Computer Science and Mathematics Division; Oak Ridge National Laboratory; Oak Ridge, TN USA
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24
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Site-directed mutagenesis reveals a conservation of the copper-binding site and the crucial role of His24 in CopH from Cupriavidus metallidurans CH34. J Inorg Biochem 2009; 103:1721-8. [DOI: 10.1016/j.jinorgbio.2009.09.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2009] [Revised: 09/07/2009] [Accepted: 09/25/2009] [Indexed: 11/21/2022]
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25
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Prion metal interaction: Is prion pathogenesis a cause or a consequence of metal imbalance? Chem Biol Interact 2009; 181:282-91. [PMID: 19660443 DOI: 10.1016/j.cbi.2009.07.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 07/22/2009] [Accepted: 07/27/2009] [Indexed: 12/14/2022]
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26
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Functional implications of multistage copper binding to the prion protein. Proc Natl Acad Sci U S A 2009; 106:11576-81. [PMID: 19561303 DOI: 10.1073/pnas.0903807106] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The prion protein (PrP) is responsible for a group of neurodegenerative diseases called the transmissible spongiform encephalopathies. The normal function of PrP has not yet been discovered, but indirect evidence suggests a linkage to its ability to bind copper. In this article, low-copper-concentration bindings of Cu(2+) to PrP are investigated by using a recently developed hybrid density functional theory (DFT)/DFT method. It is found that at the lowest copper concentrations, the binding site consists of 4 histidine residues coordinating the copper through epsilon imidazole nitrogens. At higher concentrations, 2 histidines are involved in the binding, one of them in the axial position. These results are in good agreement with existing experimental data. Comparison of free energies for all modes of coordination shows that when enough copper is available, the binding sites will spontaneously rearrange to accommodate more copper ions, despite the fact that binding energy per copper ion decreases with concentration. These findings support the hypothesis that PrP acts as a copper buffer in vivo, protecting other proteins from the attachment of copper ions. Using large-scale classical molecular dynamics, we also probe the structure of full-length copper-bound PrP, including its unfolded N-terminal domain. The results show that copper attachment leads to rearrangement of the structure of the Cu-bonded octarepeat region and to development of turns in areas separating copper-bound residues. These turns make the flexible N-terminal domain more rigid and thus more resistant to misfolding. The last result suggests that copper binding plays a beneficial role in the initial stages of prion diseases.
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27
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Bellingham SA, Coleman LA, Masters CL, Camakaris J, Hill AF. Regulation of prion gene expression by transcription factors SP1 and metal transcription factor-1. J Biol Chem 2009; 284:1291-301. [PMID: 18990686 DOI: 10.1074/jbc.m804755200] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Prion diseases are associated with the conformational conversion of the host-encoded cellular prion protein into an abnormal pathogenic isoform. Reduction in prion protein levels has potential as a therapeutic approach in treating these diseases. Key targets for this goal are factors that affect the regulation of the prion protein gene. Recent in vivo and in vitro studies have suggested a role for prion protein in copper homeostasis. Copper can also induce prion gene expression in rat neurons. However, the mechanism involved in this regulation remains to be determined. We hypothesized that transcription factors SP1 and metal transcription factor-1 (MTF-1) may be involved in copper-mediated regulation of human prion gene. To test the hypothesis, we utilized human fibroblasts that are deleted or overexpressing the Menkes protein (MNK), a major mammalian copper efflux protein. Menkes deletion fibroblasts have high intracellular copper, whereas Menkes overexpressed fibroblasts have severely depleted intracellular copper. We have utilized this system previously to demonstrate copper-dependent regulation of the Alzheimer amyloid precursor protein. Here we demonstrate that copper depletion in MNK overexpressed fibroblasts decreases cellular prion protein and PRNP gene levels. Conversely, expression of transcription factors SP1 and/or MTF-1 significantly increases prion protein levels and up-regulates prion gene expression in copper-replete MNK deletion cells. Furthermore, siRNA "knockdown" of SP1 or MTF-1 in MNK deletion cells decreases prion protein levels and down-regulates prion gene expression. These data support a novel mechanism whereby SP1 and MTF-1 act as copper-sensing transcriptional activators to regulate human prion gene expression and further support a role for the prion protein to function in copper homeostasis. Expression of the prion protein is a vital component for the propagation of prion diseases; thus SP1 and MTF-1 represent new targets in the development of key therapeutics toward modulating the expression of the cellular prion protein and ultimately the prevention of prion disease.
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Affiliation(s)
- Shayne A Bellingham
- Department of Biochemistry & Molecular Biology, The University of Melbourne, Victoria, Australia
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28
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Modeling the interplay of glycine protonation and multiple histidine binding of copper in the prion protein octarepeat subdomains. J Biol Inorg Chem 2008; 14:361-74. [PMID: 19048309 DOI: 10.1007/s00775-008-0454-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Accepted: 11/14/2008] [Indexed: 11/26/2022]
Abstract
The octarepeat region of the prion protein can bind Cu(2+) ions up to full occupancy (one ion per octarepeat) at neutral pH. While crystallographic data show that the HGGG octarepeat subdomain is the basic binding unit, multiple histidine coordination at lower Cu occupancy has been reported by X-ray absorption spectroscopy, EPR, and potentiometric experiments. In this paper we investigate, with first principles Car-Parrinello simulations, the first step for the formation of the Cu low-level binding mode, where four histidine side chains are coordinated to the same Cu(2+) ion. This step involves the further binding of a second histidine to an already HGGG domain bonded Cu(2+) ion. The influence of the pH on the ability of Cu to bind two histidine side chains was taken into account by simulating different protonation states of the amide N atoms of the two glycines lying nearest to the first histidine. Multiple histidine coordination is also seen to occur when glycine deprotonation occurs and the presence of the extra histidine stabilizes the Cu-peptide complex. Though the stabilization effect slightly decreases with the number of deprotonated glycines (reaching a minimum when both N atoms of the two nearest glycines are available as Cu ligands), the system is still capable of binding the second histidine in a 4N tetrahedral (though slightly distorted) coordination, whose energy is very near to that of the crystallographic square-planar 3N1O coordination. This result suggests that at low metal concentration the reorganization energy associated with Cu(II)/Cu(I) reduction is small also at pH approximately 7, when glycines are deprotonated.
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29
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Hureau C, Mathé C, Faller P, Mattioli TA, Dorlet P. Folding of the prion peptide GGGTHSQW around the copper(II) ion: identifying the oxygen donor ligand at neutral pH and probing the proximity of the tryptophan residue to the copper ion. J Biol Inorg Chem 2008; 13:1055-64. [DOI: 10.1007/s00775-008-0389-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Accepted: 05/13/2008] [Indexed: 10/22/2022]
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30
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Kozlowski H, Janicka-Klos A, Stanczak P, Valensin D, Valensin G, Kulon K. Specificity in the Cu2+ interactions with prion protein fragments and related His-rich peptides from mammals to fishes. Coord Chem Rev 2008. [DOI: 10.1016/j.ccr.2007.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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31
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Colombo MC, Vandevondele J, Van Doorslaer S, Laio A, Guidoni L, Rothlisberger U. Copper binding sites in the C-terminal domain of mouse prion protein: A hybrid (QM/MM) molecular dynamics study. Proteins 2008; 70:1084-98. [PMID: 17876822 DOI: 10.1002/prot.21604] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We present a hybrid QM/MM Car-Parrinello molecular dynamics study of the copper-loaded C-terminal domain of the mouse prion protein. By means of a statistical analysis of copper coordination in known protein structures, we localized the protein regions with the highest propensity for copper ion binding. The identified candidate structures were subsequently refined via QM/MM simulations. Their EPR characteristics were computed to make contact with the experimental data and to probe the sensitivity to structural and chemical changes. Overall best agreement with the experimental EPR data (Van Doorslaer et al., J Phys Chem B 2001; 105: 1631-1639) and the information currently available in the literature is observed for a binding site involving H187. Moreover, a reinterpretation of the experimental proton hyperfine couplings was possible in the light of the present computational findings.
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Affiliation(s)
- Maria Carola Colombo
- Laboratory of Computational Chemistry and Biochemistry, Institute of Chemical Sciences and Engineering, EPFL, CH-1015 Lausanne, Switzerland
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32
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Zidar J, Pirc ET, Hodoscek M, Bukovec P. Copper(II) ion binding to cellular prion protein. J Chem Inf Model 2008; 48:283-7. [PMID: 18247504 DOI: 10.1021/ci700226c] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Prion diseases are fatal neurodegenerative diseases thought to arise from the post-translational conversion of normal cellular prion protein to a scrapie isoform. Experimental data suggest a role for copper(II) ions in the process. An ab initio QM/MM approach and available experimental data were combined in order to identify and evaluate three potential copper(II) ion binding sites in the C-terminal portion of the normal cellular prion protein. Our results suggest that copper(II) ion binds to His 187 but not to His 140 and His 177 of the binding site in the cellular prion protein.
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Affiliation(s)
- Jernej Zidar
- National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia.
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33
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Drew SC, Barnham KJ. Biophysical investigations of the prion protein using electron paramagnetic resonance. Methods Mol Biol 2008; 459:173-196. [PMID: 18576156 DOI: 10.1007/978-1-59745-234-2_13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The binding of paramagnetic metal ions is thought to be an essential function of the prion protein and lends itself to interrogation by electron paramagnetic resonance (EPR), which probes the local coordination environment of bound metal ions to provide details of the metal-binding affinity, stoichiometry, and the symmetry and identity of its ligating atoms. It is also capable of identifying reactive oxygen/nitrogen species and peptide-derived radicals, in addition to monitoring protein-membrane dynamics and conformation by using site-directed spin labeling. An overview of the EPR technique as applied to the prion protein is given, key results are summarized, and some future experimental avenues are outlined.
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Affiliation(s)
- Simon C Drew
- Department of Pathology and Mental Health Research Institute of Victoria, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Australia
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34
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Grasso D, Grasso G, Guantieri V, Impellizzeri G, La Rosa C, Milardi D, Micera G, Osz K, Pappalardo G, Rizzarelli E, Sanna D, Sóvágó I. Environmental effects on a prion's helix II domain: copper(II) and membrane interactions with PrP180-193 and its analogues. Chemistry 2007; 12:537-47. [PMID: 16163753 DOI: 10.1002/chem.200500534] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
An abnormal interaction between copper and the prion protein is believed to play a pivotal role in the pathogenesis of prion diseases. Copper binding has been mainly attributed to the N-terminal domain of the prion protein, but this hypothesis has recently been challenged in some papers which suggest that the C-terminal domain might also compete for metal anchoring. In particular, the segment corresponding to the helix II region of the prion protein, namely PrP180-193, has been shown both to bind copper and to exhibit a copper-enhanced cytotoxicity, as well as to interact with artificial membranes. The present work is aimed at extending these results by choosing the most representative model of this domain and by determining its copper affinity. With this aim, the different role played by the electrostatic properties of the C- and N-termini of PrP180-193 (VNITIKQHTVTTTT) in determining its conformational behaviour, copper coordination and ability to perturb model membranes was investigated. Owing to the low solubility of PrP180-193, its copper affinity was evaluated by using the shorter PrPAc184-188NH2 (IKQHT) analogue as a model. ESI-MS, ESR, UV/Vis, and CD measurements were carried out on the copper(II)/PrPAc184-188NH2 and copper(II)/PrP180-193NH2 systems, and showed that PrPAc184-188NH2 is a reliable model for the metal interaction with the helix II domain. The affinity of copper(II) for the helix II fragment is higher than that for the octarepeat and PrP106-126 peptides. Finally, the different ability of PrP180-193 analogues to perturb the DPPC model membrane was assessed by DSC measurements. The possible biological consequences of these findings are also discussed briefly.
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Affiliation(s)
- Domenico Grasso
- Università di Catania, Dipartimento di Scienze Chimiche, Viale Andrea Doria 6, 95125 Catania, Italy
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35
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Van Doorslaer S, Vinck E. The strength of EPR and ENDOR techniques in revealing structure-function relationships in metalloproteins. Phys Chem Chem Phys 2007; 9:4620-38. [PMID: 17700864 DOI: 10.1039/b701568b] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent technological and methodological advances have strongly increased the potential of electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR) techniques to characterize the structure and dynamics of metalloproteins. These developments include the introduction of powerful pulsed EPR/ENDOR methodologies and the development of spectrometers operating at very high microwave frequencies and high magnetic fields. This overview focuses on how valuable information about metalloprotein structure-function relations can be obtained using a combination of EPR and ENDOR techniques. After an overview of the historical development and a limited theoretical description of some of the key EPR and ENDOR techniques, their potential will be highlighted using selected examples of applications to iron-, nickel-, cobalt-, and copper-containing proteins. We will end with an outlook of future developments.
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Affiliation(s)
- Sabine Van Doorslaer
- SIBAC Laboratory, University of Antwerp, Universiteitsplein 1, B-2160, Wilrijk-Antwerp, Belgium.
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36
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Moudjou M, Bernard J, Sabuncu E, Langevin C, Laude H. Glycan chains modulate prion protein binding to immobilized metal ions. Neurochem Int 2007; 50:689-95. [PMID: 17293006 DOI: 10.1016/j.neuint.2007.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2006] [Revised: 12/18/2006] [Accepted: 01/03/2007] [Indexed: 12/15/2022]
Abstract
PrP(c) is the normal isoform of the prion protein which can be converted into PrP(Sc), the pathology-associated conformer in prion diseases. It contains two N-linked glycan chains attached to the C-proximal globular domain. While the biological functions of PrP(c) are still unknown, its ability to bind Cu(2+) is well documented. The main Cu(2+)-binding sites are located in the N-proximal, unstructured region of the molecule. Here we report that PrP(c) glycans influence the capacity of PrP(c) from sheep brain or cultured Rov cells to bind IMAC columns loaded with Cu(2+) or Co(2+). Using different anti-PrP antibodies and PrP(c) glycosylation mutants, we show that the full length non-glycosylated form of PrP(c) has a higher binding efficiency for column-bound Cu(2+) and Co(2+) than the corresponding glycosylated form. Our findings raise the possibility that the accessibility of the PrP(c) metal ion-binding sites might be controlled by the glycan chains.
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Affiliation(s)
- Mohammed Moudjou
- Unité de Virologie et Immunologie Moléculaires, INRA, 78350 Jouy-en-Josas, France
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37
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Leach SP, Salman MD, Hamar D. Trace elements and prion diseases: a review of the interactions of copper, manganese and zinc with the prion protein. Anim Health Res Rev 2007; 7:97-105. [PMID: 17389057 DOI: 10.1017/s1466252307001181] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Transmissible spongiform encephalopathies (TSEs) are a family of neurodegenerative diseases characterized by their long incubation periods, progressive neurological changes, and spongiform appearance in the brain. There is much evidence to show that TSEs are caused by an isoform of the normal cellular surface prion protein PrPC. The normal function of PrPC is still unknown, but it exhibits properties of a cupro-protein, capable of binding up to six copper ions. There are two differing views on copper's role in prion diseases. While one view looks at the PrPC copper-binding as the trigger for conversion to PrPSc, the opposing viewpoint sees a lack of PrPC copper-binding resulting in the conformational change into the disease causing isoform. Manganese and zinc have been shown to interact with PrPC as well and have been found in abnormal levels in prion diseases. This review addresses the interaction between select trace elements and the PrPC.
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Affiliation(s)
- Scott P Leach
- Colorado Department of Agriculture, Division of Animal Industry, 700 Kipling Street, Suite 4000, Lakewood, CO 80215-8000, USA
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38
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Furlan S, La Penna G, Guerrieri F, Morante S, Rossi GC. Ab initio simulations of Cu binding sites on the N-terminal region of prion protein. J Biol Inorg Chem 2007; 12:571-83. [PMID: 17333299 DOI: 10.1007/s00775-007-0218-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Accepted: 01/29/2007] [Indexed: 11/29/2022]
Abstract
The human prion protein binds Cu2+ ions in the octarepeat domain of the N-terminal tail up to full occupancy at pH 7.4. Recent experiments have shown that the HGGG octarepeat subdomain is responsible for holding the metal bound in a square-planar configuration. By using first principle ab initio molecular dynamics simulations of the Car-Parrinello type, the coordination of copper to the binding sites of the prion protein octarepeat region is investigated. Simulations are carried out for a number of structured binding sites. Results for the complexes Cu(HGGGW)(wat), Cu(HGGG), and [Cu(HGGG)]2 are presented. While the presence of a Trp residue and a water molecule does not seem to affect the nature of the copper coordination, high stability of the bond between copper and the amide nitrogen of deprotonated Gly residues is confirmed in all cases. For the more interesting [Cu(HGGG)]2 complex, a dynamically entangled arrangement of the two domains with exchange of amide nitrogen bonds between the two copper centers emerges, which is consistent with the short Cu-Cu distance observed in experiments at full copper occupancy.
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Affiliation(s)
- Sara Furlan
- National Research Council, Institute for Chemistry of Organo-metallic Compounds, Via Madonna Del Piano, 50019, Sesto Fiorentino (Florence), Italy
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39
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Berti F, Gaggelli E, Guerrini R, Janicka A, Kozlowski H, Legowska A, Miecznikowska H, Migliorini C, Pogni R, Remelli M, Rolka K, Valensin D, Valensin G. Structural and Dynamic Characterization of Copper(II) Binding of the Human Prion Protein Outside the Octarepeat Region. Chemistry 2007; 13:1991-2001. [PMID: 17152102 DOI: 10.1002/chem.200601225] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Human prion protein (hPrP) fragments encompassing the 91-120 region, namely hPrP92-100 (SP1), hPrP106-113 (SP2), hPrP91-120 (LP1), and hPrP91-114 (LP2), were considered for delineation of the Cu(II)-binding site(s). NMR and EPR spectroscopy results obtained from LP1 or LP2 were compared with those obtained from SP1 and SP2. The coexistence of two binding sites, one centered at His96 and the other at His111, was evidenced and ratified by ESI mass spectrometry at low and high metal:peptide ratios. While room-temperature NMR spectroscopy data were consistent with the binding site centered on His111 being approximately fourfold stronger than that centered on His96, low-temperature EPR spectroscopy results yielded evidence for the opposite trend. This disagreement, which has also occurred in the literature, was clarified by temperature-dependent molecular dynamics runs that demonstrated Met112 approaching the metal at room temperature, a process that is expected to stabilize the His111-centered binding site through hydrophobic shielding of the metal coordination sphere.
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Affiliation(s)
- Francesco Berti
- Faculty of Chemistry, University of Wroclaw, F. Joliot-Curie 15, 50383 Wroclaw, Poland
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40
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Ronga L, Tizzano B, Palladino P, Ragone R, Urso E, Maffia M, Ruvo M, Benedetti E, Rossi F. The prion protein: Structural features and related toxic peptides. Chem Biol Drug Des 2007; 68:139-47. [PMID: 17062011 DOI: 10.1111/j.1747-0285.2006.00427.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Prion diseases are characterized by the conversion of the physiological cellular form of the prion protein (PrP(C)) into an insoluble, partially protease-resistant abnormal scrapie form (PrP(Sc)). PrP(C) is normally expressed in mammalian cell and is highly conserved among species, although its role in cellular function remains elusive. The conversion of PrP(C) to PrP(Sc) parallels a conformational change of the polypeptide from a predominantly alpha-helical to a highly beta-sheet secondary structure. The pathogenesis and molecular basis of the consequent nerve cell loss are not understood. Limited structural information is available on aggregate formation by this protein as the possible cause of these diseases and on its toxicity. This brief overview focuses on the large amount of structure-activity studies based on the prion fragment approach, hinging on peptides derived from the unstructured N-terminal and globular C-terminal domains. It is well documented that most of the fragments with regular secondary structure, with the exception of helices 1 and 3, possess a high beta-sheet propensity and tendency to form beta-sheet-like aggregates. In this context, helix 2 plays a crucial role because it is able to adopt both misfolded and partially helical conformation. However, only a few mutants are able to display its intrinsic neurotoxicity.
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Affiliation(s)
- Luisa Ronga
- Dipartimento delle Scienze Biologiche, C I R Pe B, Università Federico II di Napoli and Istituto di Biostrutture e Bioimmagini, CNR, Via Mezzocannone 16, 80134 Napoli, Italy
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41
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Jószai V, Nagy Z, Osz K, Sanna D, Di Natale G, La Mendola D, Pappalardo G, Rizzarelli E, Sóvágó I. Transition metal complexes of terminally protected peptides containing histidyl residues. J Inorg Biochem 2006; 100:1399-409. [PMID: 16730799 DOI: 10.1016/j.jinorgbio.2006.04.003] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 04/10/2006] [Accepted: 04/14/2006] [Indexed: 11/26/2022]
Abstract
Histidine-containing peptide fragments of prion protein are efficient ligands to bind various transition metal ions and they have high selectivity in metal binding. The metal ion affinity follows the order: Pd(II)>>Cu(II)>>Ni(II)Zn(II)>Cd(II) approximately Co(II)>Mn(II). The high selectivity of metal binding is connected to the involvement of both imidazole and amide nitrogen atoms in metal binding for Pd(II), Cu(II) and Ni(II), while only the monodentate N(im)-coordination is possible with the other metal ions. The stoichiometry and binding mode of palladium(II) complexes show great variety depending on the metal ion to ligand ratio, pH and especially the presence of coordinating donor atoms in the side chains of peptide fragments. It is also clear from our data that the peptide fragments containing histidine outside the octarepeat (His96, His111 and His187) are more efficient ligands than the monomer peptide fragments of the octarepeat domain.
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Affiliation(s)
- Viktória Jószai
- Department of Inorganic and Analytical Chemistry, University of Debrecen, P.O. Box 21, H-4010 Debrecen, Hungary
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42
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Liu M, Yu S, Yang J, Yin X, Zhao D. RNA and CuCl2 induced conformational changes of the recombinant ovine prion protein. Mol Cell Biochem 2006; 294:197-203. [PMID: 16855791 DOI: 10.1007/s11010-006-9260-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2006] [Accepted: 06/01/2006] [Indexed: 11/25/2022]
Abstract
Prion diseases are a group of neurodegenerative illnesses caused by conformational conversion of benign, alpha-helix rich cellular prion protein (PrP(C)) into the highly stable, beta-sheet rich scrapie prion protein (PrP(Sc)) isoform. To date, the role of RNA on the conformational conversion of ovine prion protein in vitro remains unknown. To examine the effect of the interaction between RNA and PrP(C), conformations of recombinant ovine prion protein PrP23-256 (OvPrP23-256) binding various concentrations of RNA were analyzed by circular dichroism (CD) spectrum. The results indicated that the conformational conversion of OvPrP23-256 was triggered by RNA with a decrease in alpha-helix content and increase in beta-sheet. Moreover, the conformation of OvPrP23-256 interacting with both RNA and CuCl2 was also examined by CD spectrum, which showed that alpha-helix content decreased while beta-sheet increased dramatically. Proteinase K digestion assay disclosed that the recombinant ovine PrP(C) acquired PK resistance after RNA and/or Cu2+ treatment. It confirmed that the RNA/Cu2+ treatment in vitro altered the biochemical properties of ovine PrP(C). The implication of this finding, with respect to PrP(Sc), is that a dysfunctional state of a normal physiological process possibly facilitates diseases. The information gained from this study may provide useful approaches to study the pathogenesis of prion diseases.
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Affiliation(s)
- Meili Liu
- National Animal Transmissible Spongiform Encephalopathies Laboratory, College of Veterinary Medicine, China Agricultural University, Haidian District Yuanmingyuan Xi Lu 2, Beijing, 100094, China
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Tsiroulnikov K, Rezaei H, Dalgalarrondo M, Chobert JM, Grosclaude J, Haertlé T. Cu(II) induces small-size aggregates with amyloid characteristics in two alleles of recombinant ovine prion proteins. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2006; 1764:1218-26. [PMID: 16777497 DOI: 10.1016/j.bbapap.2006.04.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 03/20/2006] [Accepted: 04/04/2006] [Indexed: 11/26/2022]
Abstract
One of symptoms of transmissible spongiform encephalopathies is associated with the transformation of normal cellular prion protein, PrP, in its amyloid isoform resistant to proteolytic cleavage. The present study shows that interaction with copper ions converts both monomeric recombinant scrapie-susceptible PrP-VRQ and scrapie-resistant PrP-ARR variants into protease-resistant soluble oligomers with amyloid characteristics -- dominant beta-sheet secondary structure and interaction with thioflavine S. In contrast, binding of zinc ions resulting in the same resistance to proteolysis does not provoke transformation of alpha-helical monomeric structure of both PrP polymorphic variants. Cleavage of PrP N-terminus destabilises soluble form of such aggregates, and N-truncated PrPrec complexed with metal cations precipitate. N-truncated PrPrec complexed with Zn precipitated much faster than N-truncated PrPrec complexed with Cu. According to the hypothesis about the key role of small PrP oligomers in PrP(C)-PrP(Sc) transformation, formation of soluble oligomers of PrP complexed with Cu can constitute an additional element in TSE propagation. Identical metal-chelating behaviour of two studied polymorphic PrPrec variants conferring different susceptibilities of sheep to scrapie could indicate their different capabilities to form fibrils. This could imply also that other factors than physico-chemical differences between PrP-VRQ and PrP-ARR and the differences in PrP transformation are responsible for the onset of TSE.
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Affiliation(s)
- Kirill Tsiroulnikov
- Institut National de la Recherche Agronomique, BIA-FIPL, B.P. 71627, F-44316 Nantes Cedex 3, France
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Leclerc E, Serban H, Prusiner SB, Burton DR, Williamson RA. Copper induces conformational changes in the N-terminal part of cell-surface PrPC. Arch Virol 2006; 151:2103-9. [PMID: 16791441 DOI: 10.1007/s00705-006-0804-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Accepted: 05/10/2006] [Indexed: 12/13/2022]
Abstract
Prion diseases are caused by misfolding of the cellular prion protein, PrPC. In vitro studies have shown that PrP binds copper via the octarepeat region lying within the unstructured N-terminal segment of the protein, but the significance of copper in PrP metabolism remains unclear. Here, six specific antibodies recognizing different epitope regions of PrP were used to measure the effect of copper on the conformation of the molecule at the cell surface. Binding of an antibody, E149, to an epitope within the octarepeat domain of PrP is halved in the presence of copper, whereas binding of antibodies recognizing epitope motifs C-terminal to residue 90 of PrP remain relatively unaltered under equivalent conditions. These experiments strongly suggest that copper induces localized conformational change within the N-terminal portion of cell-surface PrPC.
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Affiliation(s)
- E Leclerc
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037, USA
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45
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Tsiroulnikov K, Chobert JM, Haertlé T. Copper-dependent degradation of recombinant ovine prion protein. Phosphatidylinositol stimulates aggregation and copper-driven disappearance of prion protein. FEBS J 2006; 273:1959-65. [PMID: 16640559 DOI: 10.1111/j.1742-4658.2006.05209.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Prion protein (PrP) plays an important role in cell protection from oxidative stress due to its action as copper-chelating protein. The present study demonstrates that PrP participates in reductions of Cu2+ to Cu+ ions, and that this process results in fragmentation of protein. The interaction with phosphatidylinositol, a natural phospholipid moiety bound to PrP, strongly enhances recombinant PrP aggregation and degradation. The copper-dependent PrP degradation could promote the formation of amyloid structures, destabilizing the PrP soluble form by the cleavage of the N-terminal part.
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46
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Langella E, Improta R, Crescenzi O, Barone V. Assessing the acid–base and conformational properties of histidine residues in human prion protein (125–228) by means of pK
a
calculations and molecular dynamics simulations. Proteins 2006; 64:167-77. [PMID: 16639746 DOI: 10.1002/prot.20979] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A thorough study of the acid-base behavior of the four histidines and the other titratable residues of the structured domain of human prion protein (125-228) is presented. By using multi-tautomer electrostatic calculations, average titration curves have been built for all titratable residues, using the whole bundles of NMR structures determined at pH 4.5 and 7.0. According to our results, (1) only histidine residues are likely to be involved in the first steps of the pH-driven conformational transition of prion protein; (2) the pK(a)'s of His140 and His177 are approximately 7.0, whereas those of His155 and His187 are < 5.5. 10-ns long molecular dynamics simulations have been performed on five different models, corresponding to the most significant combinations of histidine protonation states. A critical comparison between the available NMR structures and our computational results (1) confirms that His155 and His187 are the residues whose protonation is involved in the conformational rearrangement of huPrP in mildly acidic condition, and (2) shows how their protonation leads to the destructuration of the C-terminal part of HB and to the loss of the last turn of HA that represent the crucial microscopic steps of the rearrangement.
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Affiliation(s)
- Emma Langella
- Dipartimento di Chimica, Universitá Federico II, Complesso di Monte S. Angelo, Napoli, Italy
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Thompsett AR, Abdelraheim SR, Daniels M, Brown DR. High Affinity Binding between Copper and Full-length Prion Protein Identified by Two Different Techniques. J Biol Chem 2005; 280:42750-8. [PMID: 16258172 DOI: 10.1074/jbc.m506521200] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cellular prion protein is known to be a copper-binding protein. Despite the wide range of studies on the copper binding of PrP, there have been no studies to determine the affinity of the protein on both full-length prion protein and under physiological conditions. We have used two techniques, isothermal titration calorimetry and competitive metal capture analysis, to determine the affinity of copper for wild type mouse PrP and a series of mutants. High affinity copper binding by wild type PrP has been confirmed by the independent techniques indicating the presence of specific tight copper binding sites up to femtomolar affinity. Altogether, four high affinity binding sites of between femto- and nanomolar affinities are located within the octameric repeat region of the protein at physiological pH. A fifth copper binding site of lower affinity than those of the octameric repeat region has been detected in full-length protein. Binding to this site is modulated by the histidine at residue 111. Removal of the octameric repeats leads to the enhancement of affinity of this fifth site and a second binding site outside of the repeat region undetected in the wild type protein. High affinity copper binding allows PrP to compete effectively for copper in the extracellular milieu. The copper binding affinities of PrP have been compared with those of proteins of known function and are of magnitudes compatible with an extracellular copper buffer or an enzymatic function such as superoxide dismutase like activity.
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Affiliation(s)
- Andrew R Thompsett
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, United Kingdom
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48
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DeMarco ML, Daggett V. Local environmental effects on the structure of the prion protein. C R Biol 2005; 328:847-62. [PMID: 16286076 DOI: 10.1016/j.crvi.2005.05.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2005] [Revised: 04/27/2005] [Accepted: 05/01/2005] [Indexed: 01/24/2023]
Abstract
Prion diseases are neurodegenerative diseases causally linked to the partial unfolding and subsequent misfolding and aggregation of the prion protein (PrP). While most proteins fold into a single low energy state, PrP can fold into two distinct isoforms. In its innocuous state, denoted as PrPC, the protein has predominantly alpha-helical secondary structure, however, PrPC can misfold into an isoform rich in extended structure capable of forming toxic and infectious aggregates. While prion disease is believed to be a protein-only disease, one not requiring any non-protein elements for propagation, the different environments the protein finds itself in vivo likely influence its ability to misfold and aggregate. In this review we will examine various molecules, covalent modifications and environments PrP faces in vivo and the effect they have on PrP's local environment and, potentially, conformation. Included in this discussion are: (1) pH, (2) carbohydrates, (3) lipid membranes, (4) metal ions, and (5) small molecules.
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Affiliation(s)
- Mari L DeMarco
- Department of Medicinal Chemistry, Biomolecular Structure and Design Program, University of Washington, Seattle, WA 98195-7610, USA
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Mentler M, Weiss A, Grantner K, del Pino P, Deluca D, Fiori S, Renner C, Klaucke WM, Moroder L, Bertsch U, Kretzschmar HA, Tavan P, Parak FG. A new method to determine the structure of the metal environment in metalloproteins: investigation of the prion protein octapeptide repeat Cu2+ complex. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2004; 34:97-112. [PMID: 15452673 DOI: 10.1007/s00249-004-0434-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2004] [Revised: 07/02/2004] [Accepted: 07/05/2004] [Indexed: 10/26/2022]
Abstract
Since high-intensity synchrotron radiation is available, "extended X-ray absorption fine structure" spectroscopy (EXAFS) is used for detailed structural analysis of metal ion environments in proteins. However, the information acquired is often insufficient to obtain an unambiguous picture. ENDOR spectroscopy allows the determination of hydrogen positions around a metal ion. However, again the structural information is limited. In the present study, a method is proposed which combines computations with spectroscopic data from EXAFS, EPR, electron nuclear double resonance (ENDOR) and electron spin echo envelope modulation (ESEEM). From EXAFS a first picture of the nearest coordination shell is derived which has to be compatible with EPR data. Computations are used to select sterically possible structures, from which in turn structures with correct H and N positions are selected by ENDOR and ESEEM measurements. Finally, EXAFS spectra are re-calculated and compared with the experimental data. This procedure was successfully applied for structure determination of the Cu(2+) complex of the octapeptide repeat of the human prion protein. The structure of this octarepeat complex is rather similar to a pentapeptide complex which was determined by X-ray structure analysis. However, the tryptophan residue has a different orientation: the axial water is on the other side of the Cu.
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Affiliation(s)
- Matthias Mentler
- Physik-Department E17, Technische Universität München, Garching, Germany
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50
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Langella E, Improta R, Barone V. Checking the pH-induced conformational transition of prion protein by molecular dynamics simulations: effect of protonation of histidine residues. Biophys J 2004; 87:3623-32. [PMID: 15377536 PMCID: PMC1304876 DOI: 10.1529/biophysj.104.043448] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The role of acidic pH in the conversion of human prion protein to the pathogenic isoform is investigated by means of molecular dynamics simulations, focusing the attention on the effect of protonation of histidine residues on the conformational behavior of human PrPC globular domain. Our simulations reveal a significant loss of alpha-helix content under mildly acidic conditions, due to destructuration of the C-terminal part of HB (thus suggesting a possible involvement of HB into the conformational transition leading to the pathogenic isoform) and a transient lengthening of the native beta-sheet. Protonation of His-187 and His-155 seems to be crucial for the onset of the conformational rearrangement. This finding can be related to the existence of a pathogenic mutation, H187R, which is associated with GSS syndrome. Finally, the relevance of our results for the location of a Cu2+-binding pocket in the C-terminal part of the prion is discussed.
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Affiliation(s)
- Emma Langella
- Dipartimento di Chimica, Università Federico II, Complesso Monte S. Angelo, via Cintia, Naples, Italy
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