1
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Hashimoto K, Watanabe S, Akutsu M, Muraki N, Kamishina H, Furukawa Y, Yamanaka K. Intrinsic structural vulnerability in the hydrophobic core induces species-specific aggregation of canine SOD1 with degenerative myelopathy-linked E40K mutation. J Biol Chem 2023:104798. [PMID: 37156398 DOI: 10.1016/j.jbc.2023.104798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 04/27/2023] [Accepted: 04/30/2023] [Indexed: 05/10/2023] Open
Abstract
Canine degenerative myelopathy (DM), a fatal neurodegenerative disease in dogs, shares clinical and genetic features with amyotrophic lateral sclerosis (ALS), a human motor neuron disease. Mutations in the SOD1 gene encoding Cu/Zn superoxide dismutase (SOD1) cause canine DM and a subset of inherited human ALS. The most frequent DM causative mutation is homozygous E40K mutation which induces the aggregation of canine SOD1 but not of human SOD1. However, the mechanism through which canine E40K mutation induces species-specific aggregation of SOD1 remains unknown. By screening human/canine chimeric SOD1s, we identified that the humanized mutation of the 117th residue (M117L), encoded by exon 4, significantly reduced aggregation propensity of canine SOD1E40K. Conversely, introducing a mutation of leucine 117 to methionine, a residue homologous to canine, promoted E40K-dependent aggregation in human SOD1. M117L mutation improved protein stability and reduced cytotoxicity of canine SOD1E40K. Furthermore, crystal structural analysis of canine SOD1 proteins revealed that M117L increased the packing within the hydrophobic core of the β-barrel structure, contributing to the increased protein stability. Our findings indicate that the structural vulnerability derived intrinsically from Met 117 in the hydrophobic core of the β-barrel structure induces E40K-dependent species-specific aggregation in canine SOD1.
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Affiliation(s)
- Kei Hashimoto
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Aichi, Japan; Department of Neuroscience and Pathobiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Seiji Watanabe
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Aichi, Japan; Department of Neuroscience and Pathobiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
| | - Masato Akutsu
- Department of Chemistry, Keio University, Yokohama, Kanagawa, Japan
| | - Norifumi Muraki
- Department of Chemistry, Keio University, Yokohama, Kanagawa, Japan
| | - Hiroaki Kamishina
- Life Science Research Center, Gifu University, Gifu, Japan; Kyoto AR Advanced Veterinary Medical Center, Kyoto, Japan
| | | | - Koji Yamanaka
- Department of Neuroscience and Pathobiology, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Aichi, Japan; Department of Neuroscience and Pathobiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan; Institute for Glyco-core Research (iGCORE), Nagoya University, Aichi, Japan; Center for One Medicine Innovative Translational Research (COMIT), Nagoya University, Nagoya, Japan.
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2
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Wakayama K, Kimura S, Kobatake Y, Kamishina H, Nishii N, Takashima S, Honda R, Kamatari YO. Molecular Mechanisms of Aggregation of Canine SOD1 E40K Amyloidogenic Mutant Protein. MOLECULES (BASEL, SWITZERLAND) 2022; 28:molecules28010156. [PMID: 36615350 PMCID: PMC9822309 DOI: 10.3390/molecules28010156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/17/2022] [Accepted: 12/21/2022] [Indexed: 12/29/2022]
Abstract
Canine degenerative myelopathy (DM) is a human amyotrophic lateral sclerosis (ALS)-like neurodegenerative disease. It is a unique, naturally occurring animal model of human ALS. Canine DM is associated with the aggregation of canine superoxide dismutase 1 (cSOD1), which is similar to human ALS. Almost 100% of cases in dogs are familial, and the E40K mutation in cSOD1 is a major causative mutation of DM. Therefore, it is important to understand the molecular mechanisms underlying cSOD1(E40K) aggregation. To address this, we first analyzed the structural model of wild type cSOD1. Interactions were evident between amino acid E40 and K91. Therefore, the mutation at residue E40 causes loss of the interaction and may destabilize the native structure of cSOD1. Differential scanning fluorimetry revealed that the E40K mutant was less stable than the wild type. Moreover, stability could be recovered by the E40K and K91E double mutation. Acceleration of amyloid fibril formation in vitro and aggregate formation in cells of cSOD1(E40K) was also suppressed by the introduction of this double mutation in thioflavin T fluorescence assay results and in transfectant cells, respectively. These results clearly show the importance of the interaction between amino acid residues E40 and K91 in cSOD1 for the stability of the native structure and aggregation.
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Affiliation(s)
- Kento Wakayama
- Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Shintaro Kimura
- Life Science Research Center, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02129, USA
| | - Yui Kobatake
- Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Hiroaki Kamishina
- Life Science Research Center, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
- Kyoto AR, 33 Sayama-Nakamichi, Kumiyama, Kuze, Kyoto 613-0036, Japan
| | - Naohito Nishii
- Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
- The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Satoshi Takashima
- Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Ryo Honda
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Yuji O. Kamatari
- Life Science Research Center, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
- Institute for Glyco-Core Research (iGCORE), Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
- Correspondence: ; Tel.: +81-58-293-3900
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3
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Bonaccorsi M, Knight MJ, Le Marchand T, Dannatt HRW, Schubeis T, Salmon L, Felli IC, Emsley L, Pierattelli R, Pintacuda G. Multimodal Response to Copper Binding in Superoxide Dismutase Dynamics. J Am Chem Soc 2020; 142:19660-19667. [PMID: 33166153 DOI: 10.1021/jacs.0c09242] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Copper/zinc superoxide dismutase (SOD) is a homodimeric metalloenzyme that has been extensively studied as a benchmark for structure-function relationships in proteins, in particular because of its implication in the familial form of the neurodegenerative disease amyotrophic lateral sclerosis. Here, we investigate microcrystalline preparations of two differently metalated forms of SOD, namely, the fully mature functional Cu,Zn state and the E,Zn-SOD state in which the Cu site is empty. By using solid-state NMR with fast magic-angle spinning (MAS) at high magnetic fields (1H Larmor frequency of 800-1000 MHz), we quantify motions spanning a dynamic range from ns to ms. We determine that metal ion uptake does not act as a rigidification element but as a switch redistributing motional processes on different time scales, with coupling of the dynamics of histidine side chains and those of remote key backbone elements of the protein.
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Affiliation(s)
- Marta Bonaccorsi
- Centre de RMN à Très Hauts Champs, FRE 2034 (CNRS/Université Claude Bernard Lyon 1/Ecole Normale Supérieure de Lyon), University of Lyon, 69100 Villeurbanne, France
| | - Michael J Knight
- Centre de RMN à Très Hauts Champs, FRE 2034 (CNRS/Université Claude Bernard Lyon 1/Ecole Normale Supérieure de Lyon), University of Lyon, 69100 Villeurbanne, France
| | - Tanguy Le Marchand
- Centre de RMN à Très Hauts Champs, FRE 2034 (CNRS/Université Claude Bernard Lyon 1/Ecole Normale Supérieure de Lyon), University of Lyon, 69100 Villeurbanne, France
| | - Hugh R W Dannatt
- Centre de RMN à Très Hauts Champs, FRE 2034 (CNRS/Université Claude Bernard Lyon 1/Ecole Normale Supérieure de Lyon), University of Lyon, 69100 Villeurbanne, France
| | - Tobias Schubeis
- Centre de RMN à Très Hauts Champs, FRE 2034 (CNRS/Université Claude Bernard Lyon 1/Ecole Normale Supérieure de Lyon), University of Lyon, 69100 Villeurbanne, France
| | - Loïc Salmon
- Centre de RMN à Très Hauts Champs, FRE 2034 (CNRS/Université Claude Bernard Lyon 1/Ecole Normale Supérieure de Lyon), University of Lyon, 69100 Villeurbanne, France
| | - Isabella C Felli
- Department of Chemistry "Ugo Schiff" and CERM, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Lyndon Emsley
- Laboratory of Magnetic Resonance, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Roberta Pierattelli
- Department of Chemistry "Ugo Schiff" and CERM, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Guido Pintacuda
- Centre de RMN à Très Hauts Champs, FRE 2034 (CNRS/Université Claude Bernard Lyon 1/Ecole Normale Supérieure de Lyon), University of Lyon, 69100 Villeurbanne, France
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4
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Tompa DR, Kadhirvel S. Far positioned ALS associated mutants of Cu/Zn SOD forms partially metallated, destabilized misfolding intermediates. Biochem Biophys Res Commun 2019; 516:494-499. [PMID: 31230748 DOI: 10.1016/j.bbrc.2019.06.086] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 06/16/2019] [Indexed: 11/18/2022]
Abstract
Loss of stability of proteins is associated with their misfolding and aggregation which results in disease. Despite of the higher stability of Cu/Zn superoxide dismutase (SOD1), the point mutations destabilize its structure, results in oligomerization and the aggregation of SOD1 which is closely associated with the motor neuron disorder, amyotrophic lateral sclerosis. In the present study, we analyzed the role of two SOD1 mutants V14G and E100G which are located far away from the metal sites, dimer interface and disulfide region. The SOD1 mutants were recombinantly produced and their activity, structure and stability were investigated using biochemical methods, CD and DSC methods. In comparison with wild-type SOD1, the mutants exhibited reduced activity and the CD data showed comparable secondary structures composition. However, the stability studies using chemical and thermal denaturation methods showed the mutants are destabilized. Interestingly, our DSC data strongly suggested the destabilization of the mutants is due to the partial metalation of Cu/Zn ions. This observation emphasizes that although the mutations V14G and E100G are located away from the metal sites, they could affect the metal binding similar to metal binding region mutants, which are more susceptible to misfold and aggregate.
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Affiliation(s)
- Dharma Rao Tompa
- Biomolecular Crystallography Laboratory, Department of Bioinformatics, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, 613401, Tamil Nadu, India
| | - Saraboji Kadhirvel
- Biomolecular Crystallography Laboratory, Department of Bioinformatics, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, 613401, Tamil Nadu, India.
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5
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Abstract
Biological molecules are often highly dynamic, and this flexibility can be critical for function. The large range of sampled timescales and the fact that many of the conformers that are continually explored are only transiently formed and sparsely populated challenge current biophysical approaches. Solution nuclear magnetic resonance (NMR) spectroscopy has emerged as a powerful method for characterizing biomolecular dynamics in detail, even in cases where excursions involve short-lived states. Here, we briefly review a number of NMR experiments for studies of biomolecular dynamics on the microsecond-to-second timescale and focus on applications to protein and nucleic acid systems that clearly illustrate the functional relevance of motion in both health and disease.
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Affiliation(s)
- Ashok Sekhar
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - Lewis E. Kay
- Departments of Molecular Genetics, Biochemistry, and Chemistry, University of Toronto, Toronto, Ontario M5S 1A8, Canada
- Program in Molecular Medicine, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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6
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Srinivasan E, Rajasekaran R. Quantum chemical and molecular mechanics studies on the assessment of interactions between resveratrol and mutant SOD1 (G93A) protein. J Comput Aided Mol Des 2018; 32:1347-1361. [PMID: 30368622 DOI: 10.1007/s10822-018-0175-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 10/24/2018] [Indexed: 12/29/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that has been associated with mutations in metalloenzyme superoxide dismutase (SOD1) causing protein structural destabilization and aggregation. However, the mechanistic action and the cure for the disease still remain obscure. Herein, we initially studied the conformational preferences of SOD1 protein structures upon substitution of Ala at Gly93 in comparison with that of wild type. Our results corroborated with the previous experimental studies on the aggregation and the destabilizing activity of mutant SOD1 protein G93A. On the therapeutic point of view, we computationally analyzed the influence of resveratrol, a natural polyphenol widely found in red wine on mutant SOD1 relative to wild type, using molecular docking studies. Further, FMO calculations were performed, using GAMESS to study the pair residual interaction on the wild type and mutant complex systems. Consequently, the resveratrol showed greater interaction with mutant than the wild type. Subsequently, we evaluated the conformational preferences of wild type and mutant complex systems, where the protein conformational structures of mutant that were earlier found to lose their conformational stability was regained, upon binding with resveratrol. Similar trend of results were found on the 2-D free energy landscapes of both the wild type and mutant systems. Hence, the combined biophysical and quantum chemical studies in our study supported the results of previous experimental studies, thereby stipulating an action of resveratrol on mutant SOD1 and paving a way for the design of highly potent effective inhibitors against fALS affecting the mankind.
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Affiliation(s)
- E Srinivasan
- Bioinformatics Lab, Department of Biotechnology, School of Bio Sciences and Technology, VIT (Deemed to be University), Vellore, Tamil Nadu, 632014, India
| | - R Rajasekaran
- Bioinformatics Lab, Department of Biotechnology, School of Bio Sciences and Technology, VIT (Deemed to be University), Vellore, Tamil Nadu, 632014, India.
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7
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Bunck DN, Atsavapranee B, Museth AK, VanderVelde D, Heath JR. Modulating the Folding Landscape of Superoxide Dismutase 1 with Targeted Molecular Binders. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201802269] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- David N. Bunck
- Division of Chemistry and Chemical Engineering California Institute of Technology 1200 East California Boulevard MC 172-27 USA
| | - Beatriz Atsavapranee
- Division of Chemistry and Chemical Engineering California Institute of Technology 1200 East California Boulevard MC 172-27 USA
| | - Anna K. Museth
- Division of Chemistry and Chemical Engineering California Institute of Technology 1200 East California Boulevard MC 172-27 USA
| | - David VanderVelde
- Division of Chemistry and Chemical Engineering California Institute of Technology 1200 East California Boulevard MC 172-27 USA
| | - James R. Heath
- Division of Chemistry and Chemical Engineering California Institute of Technology 1200 East California Boulevard MC 172-27 USA
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8
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Bunck DN, Atsavapranee B, Museth AK, VanderVelde D, Heath JR. Modulating the Folding Landscape of Superoxide Dismutase 1 with Targeted Molecular Binders. Angew Chem Int Ed Engl 2018; 57:6212-6215. [PMID: 29645329 DOI: 10.1002/anie.201802269] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Indexed: 01/20/2023]
Abstract
Amyotrophic lateral sclerosis, or Lou Gehrig's disease, is characterized by motor neuron death, with average survival times of two to five years. One cause of this disease is the misfolding of superoxide dismutase 1 (SOD1), a phenomenon influenced by point mutations spanning the protein. Herein, we used an epitope-specific high-throughput screen to identify a peptide ligand that stabilizes the SOD1 native conformation and accelerates its folding by a factor of 2.5. This strategy may be useful for fundamental studies of protein energy landscapes as well as designing new classes of therapeutics.
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Affiliation(s)
- David N Bunck
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, MC, 172-27, USA
| | - Beatriz Atsavapranee
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, MC, 172-27, USA
| | - Anna K Museth
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, MC, 172-27, USA
| | - David VanderVelde
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, MC, 172-27, USA
| | - James R Heath
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, MC, 172-27, USA
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9
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Brasil AA, Magalhães RSS, De Carvalho MDC, Paiva I, Gerhardt E, Pereira MD, Outeiro TF, Eleutherio ECA. Implications of fALS Mutations on Sod1 Function and Oligomerization in Cell Models. Mol Neurobiol 2017; 55:5269-5281. [PMID: 28884318 PMCID: PMC5948255 DOI: 10.1007/s12035-017-0755-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 08/23/2017] [Indexed: 02/07/2023]
Abstract
Among the familial forms of amyotrophic lateral sclerosis (fALS), 20% are associated with the Cu,Zn-superoxide dismutase (Sod1). fALS is characterized by the accumulation of aggregated proteins and the increase in oxidative stress markers. Here, we used the non-invasive bimolecular fluorescence complementation (BiFC) assay in human H4 cells to investigate the kinetics of aggregation and subcellular localization of Sod1 mutants. We also studied the effect of the different Sod1 mutants to respond against oxidative stress by following the levels of reactive oxygen species (ROS) after treatment with hydrogen peroxide. Our results showed that only 30% of cells transfected with A4VSod1 showed no inclusions while for the other Sod1 mutants tested (L38V, G93A and G93C), this percentage was at least 70%. In addition, we found that 10% of cells transfected with A4VSod1 displayed more than five inclusions per cell and that A4V and G93A Sod1 formed inclusions more rapidly than L38V and G93C Sod1. Expression of WTSod1 significantly decreased the intracellular oxidation levels in comparison with expression of fALS Sod1 mutants, suggesting the mutations induce a functional impairment. All fALS mutations impaired nuclear localization of Sod1, which is important for maintaining genomic stability. Consistently, expression of WTSod1, but not of fALS Sod1 mutants, reduced DNA damage, as measured by the comet assay. Altogether, our study sheds light into the effects of fALS Sod1 mutations on inclusion formation, dynamics, and localization as well as on antioxidant response, opening novel avenues for investigating the role of fALS Sod1 mutations in pathogenesis.
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Affiliation(s)
- Aline A Brasil
- Department of Experimental Neurodegeneration, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, 37073, Göttingen, Germany.,Departamento de Química, Instituto de Química, Centro de Tecnologia, Cidade Universitária, Universidade Federal do Rio de Janeir, Av. Athos da Silveira Ramos, n 149, Bloco A - sala 547, Rio de Janeiro, RJ, 21941-909, Brazil
| | - Rayne S S Magalhães
- Department of Experimental Neurodegeneration, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, 37073, Göttingen, Germany.,Departamento de Química, Instituto de Química, Centro de Tecnologia, Cidade Universitária, Universidade Federal do Rio de Janeir, Av. Athos da Silveira Ramos, n 149, Bloco A - sala 547, Rio de Janeiro, RJ, 21941-909, Brazil
| | - Mariana D C De Carvalho
- Department of Experimental Neurodegeneration, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, 37073, Göttingen, Germany.,Departamento de Química, Instituto de Química, Centro de Tecnologia, Cidade Universitária, Universidade Federal do Rio de Janeir, Av. Athos da Silveira Ramos, n 149, Bloco A - sala 547, Rio de Janeiro, RJ, 21941-909, Brazil
| | - Isabel Paiva
- Department of Experimental Neurodegeneration, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, 37073, Göttingen, Germany
| | - Ellen Gerhardt
- Department of Experimental Neurodegeneration, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, 37073, Göttingen, Germany
| | - Marcos D Pereira
- Departamento de Química, Instituto de Química, Centro de Tecnologia, Cidade Universitária, Universidade Federal do Rio de Janeir, Av. Athos da Silveira Ramos, n 149, Bloco A - sala 547, Rio de Janeiro, RJ, 21941-909, Brazil
| | - Tiago F Outeiro
- Department of Experimental Neurodegeneration, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, 37073, Göttingen, Germany. .,Max Planck Institute for Experimental Medicine, Göttingen, Germany.
| | - Elis C A Eleutherio
- Departamento de Química, Instituto de Química, Centro de Tecnologia, Cidade Universitária, Universidade Federal do Rio de Janeir, Av. Athos da Silveira Ramos, n 149, Bloco A - sala 547, Rio de Janeiro, RJ, 21941-909, Brazil.
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10
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Tiiman A, Luo J, Wallin C, Olsson L, Lindgren J, Jarvet J, Per R, Sholts SB, Rahimipour S, Abrahams JP, Karlström AE, Gräslund A, Wärmländer SK. Specific Binding of Cu(II) Ions to Amyloid-Beta Peptides Bound to Aggregation-Inhibiting Molecules or SDS Micelles Creates Complexes that Generate Radical Oxygen Species. J Alzheimers Dis 2016; 54:971-982. [DOI: 10.3233/jad-160427] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Ann Tiiman
- Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, Sweden
| | - Jinghui Luo
- Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, Sweden
- Chemical Research Laboratory, University of Oxford, UK
| | - Cecilia Wallin
- Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, Sweden
| | - Lisa Olsson
- Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, Sweden
| | | | - Jϋri Jarvet
- Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, Sweden
- The National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Roos Per
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Physiology, Capio St.Göran Hospital, Stockholm, Sweden
| | - Sabrina B. Sholts
- Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, Sweden
- Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Shai Rahimipour
- Department of Chemistry, Bar-Ilan University, Ramat-Gan, Israel
| | - Jan Pieter Abrahams
- Biozentrum, University of Basel, Switzerland & Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland
| | | | - Astrid Gräslund
- Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, Sweden
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11
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Doyle CM, Rumfeldt JA, Broom HR, Sekhar A, Kay LE, Meiering EM. Concurrent Increases and Decreases in Local Stability and Conformational Heterogeneity in Cu, Zn Superoxide Dismutase Variants Revealed by Temperature-Dependence of Amide Chemical Shifts. Biochemistry 2016; 55:1346-61. [PMID: 26849066 DOI: 10.1021/acs.biochem.5b01133] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The chemical shifts of backbone amide protons in proteins are sensitive reporters of local structural stability and conformational heterogeneity, which can be determined from their readily measured linear and nonlinear temperature-dependences, respectively. Here we report analyses of amide proton temperature-dependences for native dimeric Cu, Zn superoxide dismutase (holo pWT SOD1) and structurally diverse mutant SOD1s associated with amyotrophic lateral sclerosis (ALS). Holo pWT SOD1 loses structure with temperature first at its periphery and, while having extremely high global stability, nevertheless exhibits extensive conformational heterogeneity, with ∼1 in 5 residues showing evidence for population of low energy alternative states. The holo G93A and E100G ALS mutants have moderately decreased global stability, whereas V148I is slightly stabilized. Comparison of the holo mutants as well as the marginally stable immature monomeric unmetalated and disulfide-reduced (apo(2SH)) pWT with holo pWT shows that changes in the local structural stability of individual amides vary greatly, with average changes corresponding to differences in global protein stability measured by differential scanning calorimetry. Mutants also exhibit altered conformational heterogeneity compared to pWT. Strikingly, substantial increases as well as decreases in local stability and conformational heterogeneity occur, in particular upon maturation and for G93A. Thus, the temperature-dependence of amide shifts for SOD1 variants is a rich source of information on the location and extent of perturbation of structure upon covalent changes and ligand binding. The implications for potential mechanisms of toxic misfolding of SOD1 in disease and for general aspects of protein energetics, including entropy-enthalpy compensation, are discussed.
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Affiliation(s)
| | | | | | | | - Lewis E Kay
- Program in Molecular Structure and Function, Hospital for Sick Children , Toronto, Canada
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12
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Hennig J, Andrésen C, Museth AK, Lundström P, Tibell LAE, Jonsson BH. Local Destabilization of the Metal-Binding Region in Human Copper–Zinc Superoxide Dismutase by Remote Mutations Is a Possible Determinant for Progression of ALS. Biochemistry 2015; 54:323-33. [DOI: 10.1021/bi500606j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Janosch Hennig
- Division
of Molecular Biotechnology, Department of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping, Sweden
- Institute
of Structural Biology, Helmholtz Zentrum München GmbH, DE-85764 Neuherberg, Germany
- Chair
of Biomolecular NMR Spectroscopy, Department of Chemistry, Technische Universität München, DE-85748 Garching, Germany
| | - Cecilia Andrésen
- Division
of Molecular Biotechnology, Department of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping, Sweden
| | - A. Katrine Museth
- Division
of Molecular Biotechnology, Department of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping, Sweden
- Division
of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Patrik Lundström
- Division
of Molecular Biotechnology, Department of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping, Sweden
| | - Lena A. E. Tibell
- Department
of Science and Technology, Linköping University, SE-601 74, Norrköping, Sweden
| | - Bengt-Harald Jonsson
- Division
of Molecular Biotechnology, Department of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping, Sweden
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13
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Rotunno MS, Auclair JR, Maniatis S, Shaffer SA, Agar J, Bosco DA. Identification of a misfolded region in superoxide dismutase 1 that is exposed in amyotrophic lateral sclerosis. J Biol Chem 2014; 289:28527-38. [PMID: 25164820 DOI: 10.1074/jbc.m114.581801] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations and aberrant post-translational modifications within Cu,Zn-superoxide dismutase (SOD1) cause this otherwise protective enzyme to misfold, leading to amyotrophic lateral sclerosis (ALS). The C4F6 antibody selectively binds misfolded SOD1 in spinal cord tissues from postmortem human ALS cases, as well as from an ALS-SOD1 mouse model, suggesting that the C4F6 epitope reports on a pathogenic conformation that is common to misfolded SOD1 variants. To date, the residues and structural elements that comprise this epitope have not been elucidated. Using a chemical cross-linking and mass spectrometry approach, we identified the C4F6 epitope within several ALS-linked SOD1 variants, as well as an oxidized form of WT SOD1, supporting the notion that a similar misfolded conformation is shared among pathological SOD1 proteins. Exposure of the C4F6 epitope was modulated by the SOD1 electrostatic (loop VII) and zinc binding (loop IV) loops and correlated with SOD1-induced toxicity in a primary microglia activation assay. Site-directed mutagenesis revealed Asp(92) and Asp(96) as key residues within the C4F6 epitope required for the SOD1-C4F6 binding interaction. We propose that stabilizing the functional loops within SOD1 and/or obscuring the C4F6 epitope are viable therapeutic strategies for treating SOD1-mediated ALS.
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Affiliation(s)
- Melissa S Rotunno
- From the Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Jared R Auclair
- the Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Stephanie Maniatis
- the Proteomics and Mass Spectrometry Facility, University of Massachusetts Medical School, Shrewsbury, Massachusetts 01545, and
| | - Scott A Shaffer
- the Proteomics and Mass Spectrometry Facility, University of Massachusetts Medical School, Shrewsbury, Massachusetts 01545, and the Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Jeffrey Agar
- the Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Daryl A Bosco
- From the Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, the Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
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14
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Shi Y, Abdolvahabi A, Shaw BF. Protein charge ladders reveal that the net charge of ALS-linked superoxide dismutase can be different in sign and magnitude from predicted values. Protein Sci 2014; 23:1417-33. [PMID: 25052939 DOI: 10.1002/pro.2526] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 07/19/2014] [Accepted: 07/21/2014] [Indexed: 12/12/2022]
Abstract
This article utilized "protein charge ladders"-chemical derivatives of proteins with similar structure, but systematically altered net charge-to quantify how missense mutations that cause amyotrophic lateral sclerosis (ALS) affect the net negative charge (Z) of superoxide dismutase-1 (SOD1) as a function of subcellular pH and Zn(2+) stoichiometry. Capillary electrophoresis revealed that the net charge of ALS-variant SOD1 can be different in sign and in magnitude-by up to 7.4 units per dimer at lysosomal pH-than values predicted from standard pKa values of amino acids and formal oxidation states of metal ions. At pH 7.4, the G85R, D90A, and G93R substitutions diminished the net negative charge of dimeric SOD1 by up to +2.29 units more than predicted; E100K lowered net charge by less than predicted. The binding of a single Zn(2+) to mutant SOD1 lowered its net charge by an additional +2.33 ± 0.01 to +3.18 ± 0.02 units, however, each protein regulated net charge when binding a second, third, or fourth Zn(2+) (ΔZ < 0.44 ± 0.07 per additional Zn(2+) ). Both metalated and apo-SOD1 regulated net charge across subcellular pH, without inverting from negative to positive at the theoretical pI. Differential scanning calorimetry, hydrogen-deuterium exchange, and inductively coupled plasma mass spectrometry confirmed that the structure, stability, and metal content of mutant proteins were not significantly affected by lysine acetylation. Measured values of net charge should be used when correlating the biophysical properties of a specific ALS-variant SOD1 protein with its observed aggregation propensity or clinical phenotype.
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Affiliation(s)
- Yunhua Shi
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas, 76798-7348
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15
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Solsona C, Kahn TB, Badilla CL, Álvarez-Zaldiernas C, Blasi J, Fernandez JM, Alegre-Cebollada J. Altered thiol chemistry in human amyotrophic lateral sclerosis-linked mutants of superoxide dismutase 1. J Biol Chem 2014; 289:26722-26732. [PMID: 25096579 DOI: 10.1074/jbc.m114.565333] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Neurodegenerative diseases share a common characteristic, the presence of intracellular or extracellular deposits of protein aggregates in nervous tissues. Amyotrophic Lateral Sclerosis (ALS) is a severe and fatal neurodegenerative disorder, which affects preferentially motoneurons. Changes in the redox state of superoxide dismutase 1 (SOD1) are associated with the onset and development of familial forms of ALS. In human SOD1 (hSOD1), a conserved disulfide bond and two free cysteine residues can engage in anomalous thiol/disulfide exchange resulting in non-native disulfides, a hallmark of ALS that is related to protein misfolding and aggregation. Because of the many competing reaction pathways, traditional bulk techniques fall short at quantifying individual thiol/disulfide exchange reactions. Here, we adapt recently developed single-bond chemistry techniques to study individual disulfide isomerization reactions in hSOD1. Mechanical unfolding of hSOD1 leads to the formation of a polypeptide loop held by the disulfide. This loop behaves as a molecular jump rope that brings reactive Cys-111 close to the disulfide. Using force-clamp spectroscopy, we monitor nucleophilic attack of Cys-111 at either sulfur of the disulfide and determine the selectivity of the reaction. Disease-causing mutations G93A and A4V show greatly altered reactivity patterns, which may contribute to the progression of familial ALS.
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Affiliation(s)
- Carles Solsona
- Laboratory of Cellular and Molecular Neurobiology, Department of Pathology and Experimental Therapeutics, Faculty of Medicine-Campus Bellvitge, University of Barcelona, Feixa Llarga s/n. Hospitalet de Llobregat, 08907 Barcelona, Spain,; Bellvitge Biomedical Research Institute (IDIBELL), Gran Via de l'Hospitalet, 199-203, L'Hospitalet de Llobregat, Barcelona, 08908 Barcelona, Spain,.
| | - Thomas B Kahn
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, New York 10032,; Department of Biological Sciences, Columbia University, New York, New York 10027, and
| | - Carmen L Badilla
- Department of Biological Sciences, Columbia University, New York, New York 10027, and
| | - Cristina Álvarez-Zaldiernas
- Laboratory of Cellular and Molecular Neurobiology, Department of Pathology and Experimental Therapeutics, Faculty of Medicine-Campus Bellvitge, University of Barcelona, Feixa Llarga s/n. Hospitalet de Llobregat, 08907 Barcelona, Spain,; Bellvitge Biomedical Research Institute (IDIBELL), Gran Via de l'Hospitalet, 199-203, L'Hospitalet de Llobregat, Barcelona, 08908 Barcelona, Spain
| | - Juan Blasi
- Laboratory of Cellular and Molecular Neurobiology, Department of Pathology and Experimental Therapeutics, Faculty of Medicine-Campus Bellvitge, University of Barcelona, Feixa Llarga s/n. Hospitalet de Llobregat, 08907 Barcelona, Spain,; Bellvitge Biomedical Research Institute (IDIBELL), Gran Via de l'Hospitalet, 199-203, L'Hospitalet de Llobregat, Barcelona, 08908 Barcelona, Spain
| | - Julio M Fernandez
- Department of Biological Sciences, Columbia University, New York, New York 10027, and
| | - Jorge Alegre-Cebollada
- Department of Biological Sciences, Columbia University, New York, New York 10027, and; Vascular Biology and Inflammation Department, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Cl. Melchor Fernández Almagro 3, 28029 Madrid, Spain
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16
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Ayers JI, Xu G, Pletnikova O, Troncoso JC, Hart PJ, Borchelt DR. Conformational specificity of the C4F6 SOD1 antibody; low frequency of reactivity in sporadic ALS cases. Acta Neuropathol Commun 2014; 2:55. [PMID: 24887207 PMCID: PMC4035506 DOI: 10.1186/2051-5960-2-55] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 04/27/2014] [Indexed: 12/22/2022] Open
Abstract
Greater than 160 missense mutations in copper-zinc superoxide dismutase-1 (SOD1) can cause amyotrophic lateral sclerosis (ALS). These mutations produce conformational changes that reveal novel antibody binding epitopes. A monoclonal antibody, clone C4F6 - raised against the ALS variant G93A of SOD1, has been identified as specifically recognizing a conformation shared by many ALS mutants of SOD1. Attempts to determine whether non-mutant SOD1 adopts a C4F6-reactive conformation in spinal tissues of sporadic ALS (sALS) patients has produced inconsistent results. To define the epitope recognized by C4F6, we tested its binding to a panel of recombinant ALS-SOD1 proteins expressed in cultured cells, producing data to suggest that the C4F6 epitope minimally contains amino acids 90-93, which are normally folded into a tight hairpin loop. Multiple van der Waals interactions between the 90-93 loop and a loop formed by amino acids 37-42, particularly a leucine at position 38, form a stable structure termed the β-plug. Based on published modeling predictions, we suggest that the binding of C4F6 to multiple ALS mutants of SOD1 occurs when the local structure within the β-plug, including the loop at 90-93, is destabilized. In using the antibody to stain tissues from transgenic mice or humans, the specificity of the antibody for ALS mutant SOD1 was influenced by antigen retrieval protocols. Using conditions that showed the best discrimination between normal and misfolded mutant SOD1 in cell and mouse models, we could find no obvious difference in C4F6 reactivity to spinal motor neurons between sALS and controls tissues.
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17
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Sheng Y, Abreu IA, Cabelli DE, Maroney MJ, Miller AF, Teixeira M, Valentine JS. Superoxide dismutases and superoxide reductases. Chem Rev 2014; 114:3854-918. [PMID: 24684599 PMCID: PMC4317059 DOI: 10.1021/cr4005296] [Citation(s) in RCA: 587] [Impact Index Per Article: 58.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Yuewei Sheng
- Department
of Chemistry and Biochemistry, University
of California Los Angeles, Los
Angeles, California 90095, United States
| | - Isabel A. Abreu
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
- Instituto
de Biologia Experimental e Tecnológica, Av. da República,
Qta. do Marquês, Estação Agronómica Nacional,
Edificio IBET/ITQB, 2780-157, Oeiras, Portugal
| | - Diane E. Cabelli
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Michael J. Maroney
- Department
of Chemistry, University of Massachusetts
Amherst, Amherst, Massachusetts 01003, United States
| | - Anne-Frances Miller
- Department
of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, United States
| | - Miguel Teixeira
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Joan Selverstone Valentine
- Department
of Chemistry and Biochemistry, University
of California Los Angeles, Los
Angeles, California 90095, United States
- Department
of Bioinspired Sciences, Ewha Womans University, Seoul 120-750, Republic of Korea
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18
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Vonk WIM, Kakkar V, Bartuzi P, Jaarsma D, Berger R, Hofker MH, Klomp LWJ, Wijmenga C, Kampinga HH, van de Sluis B. The Copper Metabolism MURR1 domain protein 1 (COMMD1) modulates the aggregation of misfolded protein species in a client-specific manner. PLoS One 2014; 9:e92408. [PMID: 24691167 PMCID: PMC3972230 DOI: 10.1371/journal.pone.0092408] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 02/21/2014] [Indexed: 01/27/2023] Open
Abstract
The Copper Metabolism MURR1 domain protein 1 (COMMD1) is a protein involved in multiple cellular pathways, including copper homeostasis, NF-κB and hypoxia signalling. Acting as a scaffold protein, COMMD1 mediates the levels, stability and proteolysis of its substrates (e.g. the copper-transporters ATP7B and ATP7A, RELA and HIF-1α). Recently, we established an interaction between the Cu/Zn superoxide dismutase 1 (SOD1) and COMMD1, resulting in a decreased maturation and activation of SOD1. Mutations in SOD1, associated with the progressive neurodegenerative disorder Amyotrophic Lateral Sclerosis (ALS), cause misfolding and aggregation of the mutant SOD1 (mSOD1) protein. Here, we identify COMMD1 as a novel regulator of misfolded protein aggregation as it enhances the formation of mSOD1 aggregates upon binding. Interestingly, COMMD1 co-localizes to the sites of mSOD1 inclusions and forms high molecular weight complexes in the presence of mSOD1. The effect of COMMD1 on protein aggregation is client-specific as, in contrast to mSOD1, COMMD1 decreases the abundance of mutant Parkin inclusions, associated with Parkinson’s disease. Aggregation of a polyglutamine-expanded Huntingtin, causative of Huntington’s disease, appears unaltered by COMMD1. Altogether, this study offers new research directions to expand our current knowledge on the mechanisms underlying aggregation disease pathologies.
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Affiliation(s)
- Willianne I. M. Vonk
- University Medical Center Utrecht, Department of Metabolic and Endocrine Diseases, and Netherlands Metabolomics Center, Utrecht, the Netherlands
- University Medical Center Utrecht, Complex Genetics Section, Utrecht, the Netherlands
| | - Vaishali Kakkar
- University of Groningen, University Medical Center Groningen, Department of Cell Biology, Groningen, the Netherlands
| | - Paulina Bartuzi
- University of Groningen, University Medical Center Groningen, Molecular Genetics, Groningen, the Netherlands
| | - Dick Jaarsma
- Erasmus Medical Center, Department of Neuroscience, Rotterdam, the Netherlands
| | - Ruud Berger
- University Medical Center Utrecht, Department of Metabolic and Endocrine Diseases, and Netherlands Metabolomics Center, Utrecht, the Netherlands
| | - Marten H. Hofker
- University of Groningen, University Medical Center Groningen, Molecular Genetics, Groningen, the Netherlands
| | - Leo W. J. Klomp
- University Medical Center Utrecht, Department of Metabolic and Endocrine Diseases, and Netherlands Metabolomics Center, Utrecht, the Netherlands
| | - Cisca Wijmenga
- University Medical Center Utrecht, Complex Genetics Section, Utrecht, the Netherlands
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, the Netherlands
| | - Harm H. Kampinga
- University of Groningen, University Medical Center Groningen, Department of Cell Biology, Groningen, the Netherlands
| | - Bart van de Sluis
- University of Groningen, University Medical Center Groningen, Molecular Genetics, Groningen, the Netherlands
- * E-mail:
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19
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Redler RL, Shirvanyants D, Dagliyan O, Ding F, Kim DN, Kota P, Proctor EA, Ramachandran S, Tandon A, Dokholyan NV. Computational approaches to understanding protein aggregation in neurodegeneration. J Mol Cell Biol 2014; 6:104-15. [PMID: 24620031 DOI: 10.1093/jmcb/mju007] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The generation of toxic non-native protein conformers has emerged as a unifying thread among disorders such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. Atomic-level detail regarding dynamical changes that facilitate protein aggregation, as well as the structural features of large-scale ordered aggregates and soluble non-native oligomers, would contribute significantly to current understanding of these complex phenomena and offer potential strategies for inhibiting formation of cytotoxic species. However, experimental limitations often preclude the acquisition of high-resolution structural and mechanistic information for aggregating systems. Computational methods, particularly those combine both all-atom and coarse-grained simulations to cover a wide range of time and length scales, have thus emerged as crucial tools for investigating protein aggregation. Here we review the current state of computational methodology for the study of protein self-assembly, with a focus on the application of these methods toward understanding of protein aggregates in human neurodegenerative disorders.
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Affiliation(s)
- Rachel L Redler
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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20
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Rotunno MS, Bosco DA. An emerging role for misfolded wild-type SOD1 in sporadic ALS pathogenesis. Front Cell Neurosci 2013; 7:253. [PMID: 24379756 PMCID: PMC3863749 DOI: 10.3389/fncel.2013.00253] [Citation(s) in RCA: 167] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Accepted: 11/25/2013] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder that targets motor neurons, leading to paralysis and death within a few years of disease onset. While several genes have been linked to the inheritable, or familial, form of ALS, much less is known about the cause(s) of sporadic ALS, which accounts for ~90% of ALS cases. Due to the clinical similarities between familial and sporadic ALS, it is plausible that both forms of the disease converge on a common pathway and, therefore, involve common factors. Recent evidence suggests the Cu,Zn-superoxide dismutase (SOD1) protein to be one such factor that is common to both sporadic and familial ALS. In 1993, mutations were uncovered in SOD1 that represent the first known genetic cause of familial ALS. While the exact mechanism of mutant-SOD1 toxicity is still not known today, most evidence points to a gain of toxic function that stems, at least in part, from the propensity of this protein to misfold. In the wild-type SOD1 protein, non-genetic perturbations such as metal depletion, disruption of the quaternary structure, and oxidation, can also induce SOD1 to misfold. In fact, these aforementioned post-translational modifications cause wild-type SOD1 to adopt a “toxic conformation” that is similar to familial ALS-linked SOD1 variants. These observations, together with the detection of misfolded wild-type SOD1 within human post-mortem sporadic ALS samples, have been used to support the controversial hypothesis that misfolded forms of wild-type SOD1 contribute to sporadic ALS pathogenesis. In this review, we present data from the literature that both support and contradict this hypothesis. We also discuss SOD1 as a potential therapeutic target for both familial and sporadic ALS.
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Affiliation(s)
- Melissa S Rotunno
- Department of Neurology, University of Massachusetts Medical Center Worcester, MA, USA
| | - Daryl A Bosco
- Department of Neurology, University of Massachusetts Medical Center Worcester, MA, USA
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21
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Muneeswaran G, Kartheeswaran S, Muthukumar K, Dharmaraj CD, Karunakaran C. Comparative structural and conformational studies on H43R and W32F mutants of copper-zinc superoxide dismutase by molecular dynamics simulation. Biophys Chem 2013; 185:70-8. [PMID: 24369116 DOI: 10.1016/j.bpc.2013.11.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 11/30/2013] [Accepted: 11/30/2013] [Indexed: 11/16/2022]
Abstract
Recently, mutations in copper-zinc superoxide dismutase (SOD1) have been linked to familial amyotrophic lateral sclerosis (fALS), a progressive neurodegenerative disease involving motor neuron loss, paralysis and death. It is mainly due to protein misfolding and aggregation resulting from the enhanced peroxidase activity of SOD1 mutants. In this study, we have carried out a 20 ns molecular dynamics simulation for wild type (WT), H43R and W32F mutated SOD1's dimer and compared their structure and conformational properties by extracting several quantitative properties from the trajectory to understand the pathology of fALS disease. Our results show considerable differences in H43R compared to WT and W32F mutated SOD1, such as increasing distances between the critical residues results in open conformation at the active site, strong fluctuations in the important loops (Zinc and electrostatic loops) and weakening of important hydrogen bonds especially between N (His 43/Arg 43) and carbonyl oxygen (His 120) in agreement with the experimental report. The calculated buried surface area of dimer interface for WT, H43R and W32F are 682, 726 and 657 Å(2) respectively, representing the loss of dimerization in H43R. Essential dynamics reveal that overall motions of WT and W32F are mainly involved in three to four eigenvectors, but in H43R the overall motions are mainly in the first eigenvector. These data thus provide a unifying description for the structural destabilization, enhanced peroxidase activity, loss of dismutation activity and increase in aggregation propensity in the pathology of fALS diseases.
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Affiliation(s)
- Gurusamy Muneeswaran
- Biomedical Research Laboratory, Department of Chemistry, VHNSN College (Autonomous), Virudhunagar, 626001 Tamilnadu, India
| | - Subramanian Kartheeswaran
- Biomedical Research Laboratory, Department of Computer Science, VHNSN College (Autonomous), Virudhunagar, 626001 Tamilnadu, India
| | - Kaliappan Muthukumar
- Institute for Theoretical Physics, Goethe University, Frankfurt Am Main, Germany
| | - Christopher D Dharmaraj
- Biomedical Research Laboratory, Department of Computer Science, VHNSN College (Autonomous), Virudhunagar, 626001 Tamilnadu, India
| | - Chandran Karunakaran
- Biomedical Research Laboratory, Department of Chemistry, VHNSN College (Autonomous), Virudhunagar, 626001 Tamilnadu, India.
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22
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Oladzad Abbasabadi A, Javanian A, Nikkhah M, Meratan AA, Ghiasi P, Nemat-Gorgani M. Disruption of mitochondrial membrane integrity induced by amyloid aggregates arising from variants of SOD1. Int J Biol Macromol 2013; 61:212-7. [DOI: 10.1016/j.ijbiomac.2013.07.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 05/15/2013] [Accepted: 07/12/2013] [Indexed: 11/25/2022]
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23
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Lindgren J, Wahlström A, Danielsson J, Markova N, Ekblad C, Gräslund A, Abrahmsén L, Karlström AE, Wärmländer SKTS. N-terminal engineering of amyloid-β-binding Affibody molecules yields improved chemical synthesis and higher binding affinity. Protein Sci 2011; 19:2319-29. [PMID: 20886513 DOI: 10.1002/pro.511] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The aggregation of amyloid-β (Aβ) peptides is believed to be a major factor in the onset and progression of Alzheimer's disease. Molecules binding with high affinity and selectivity to Aβ-peptides are important tools for investigating the aggregation process. An Aβ-binding Affibody molecule, ZAβ3 , has earlier been selected by phage display and shown to bind Aβ(1-40) with nanomolar affinity and to inhibit Aβ-peptide aggregation. In this study, we create truncated functional versions of the ZAβ3 Affibody molecule better suited for chemical synthesis production. Engineered Affibody molecules of different length were produced by solid phase peptide synthesis and allowed to form covalently linked homodimers by S-S-bridges. The N-terminally truncated Affibody molecules ZAβ3 (12-58), ZAβ3 (15-58), and ZAβ3 (18-58) were produced in considerably higher synthetic yield than the corresponding full-length molecule ZAβ3 (1-58). Circular dichroism spectroscopy and surface plasmon resonance-based biosensor analysis showed that the shortest Affibody molecule, ZAβ3 (18-58), exhibited complete loss of binding to the Aβ(1-40)-peptide, while the ZAβ3 (12-58) and ZAβ3 (15-58) Affibody molecules both displayed approximately one order of magnitude higher binding affinity to the Aβ(1-40)-peptide compared to the full-length Affibody molecule. Nuclear magnetic resonance spectroscopy showed that the structure of Aβ(1-40) in complex with the truncated Affibody dimers is very similar to the previously published solution structure of the Aβ(1-40)-peptide in complex with the full-length ZAβ3 Affibody molecule. This indicates that the N-terminally truncated Affibody molecules ZAβ3 (12-58) and ZAβ3 (15-58) are highly promising for further engineering and future use as binding agents to monomeric Aβ(1-40).
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Affiliation(s)
- Joel Lindgren
- Division of Molecular Biotechnology, School of Biotechnology, Royal Institute of Technology (KTH), AlbaNova University Centre, 106 91 Stockholm, Sweden
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24
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Chandran K, McCracken J, Peterson FC, Antholine WE, Volkman BF, Kalyanaraman B. Oxidation of histidine residues in copper-zinc superoxide dismutase by bicarbonate-stimulated peroxidase and thiol oxidase activities: pulse EPR and NMR studies. Biochemistry 2010; 49:10616-22. [PMID: 21038859 DOI: 10.1021/bi1010305] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this work, we investigated the oxidative modification of histidine residues induced by peroxidase and thiol oxidase activities of bovine copper-zinc superoxide dismutase (Cu-ZnSOD) using NMR and pulse EPR spectroscopy. 1D NMR and 2D-NOESY were used to determine the oxidative damage at the Zn(II) and Cu(II) active sites as well as at distant histidines. Results indicate that during treatment of SOD with hydrogen peroxide (H(2)O(2)) or cysteine in the absence of bicarbonate anion (HCO(3)(-)), both exchangeable and nonexchangeable protons were affected. Both His-44 and His-46 in the Cu(II) active site were oxidized based on the disappearance of NOESY cross-peaks between CH and NH resonances of the imidazole rings. In the Zn(II) site, only His-69, which is closer to His-44, was oxidatively modified. However, addition of HCO(3)(-) protected the active site His residues. Instead, resonances assigned to the His-41 residue, 11 Å away from the Cu(II) site, were completely abolished during both HCO(3)(-)-stimulated peroxidase activity and thiol oxidase activity in the presence of HCO(3)(-) . Additionally, ESEEM/HYSCORE and ENDOR studies of SOD treated with peroxide/Cys in the absence of HCO(3)(-) revealed that hyperfine couplings to the distal and directly coordinated nitrogens of the His-44 and His-46 ligands at the Cu(II) active site were modified. In the presence of HCO(3)(-), these modifications were absent. HCO(3)(-)-mediated, selective oxidative modification of histidines in SOD may be relevant to understanding the molecular mechanism of SOD peroxidase and thiol oxidase activities.
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Affiliation(s)
- Karunakaran Chandran
- Department of Biophysics, Free Radical Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, United States
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25
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Hwang YM, Stathopulos PB, Dimmick K, Yang H, Badiei HR, Tong MS, Rumfeldt JAO, Chen P, Karanassios V, Meiering EM. Nonamyloid aggregates arising from mature copper/zinc superoxide dismutases resemble those observed in amyotrophic lateral sclerosis. J Biol Chem 2010; 285:41701-11. [PMID: 20974846 DOI: 10.1074/jbc.m110.113696] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Protein aggregation is a hallmark of many diseases, including amyotrophic lateral sclerosis (ALS) where aggregation of copper/zinc superoxide dismutase (SOD1) is implicated in pathogenesis. We report here that fully metallated (holo) SOD1 under physiologically relevant solution conditions can undergo changes in metallation and/or dimerization over time and form aggregates that do not exhibit classical characteristics of amyloid. The relevance of the observed aggregation to disease is demonstrated by structural and tinctorial analyses, including the novel observation of binding of an anti-SOD1 antibody that specifically recognizes aggregates in ALS patients and mice models. ALS-associated SOD1 mutations can promote aggregation but are not essential. The SOD1 aggregation is characterized by a lag phase, which is diminished by self- or cross-seeding and by heterogeneous nucleation. We interpret these findings in terms of an expanded aggregation mechanism consistent with other in vitro and in vivo findings that point to multiple pathways for the formation of toxic aggregates by different forms of SOD1.
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Affiliation(s)
- Young-Mi Hwang
- Department of Chemistry and Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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26
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Svensson AKE, Bilsel O, Kayatekin C, Adefusika JA, Zitzewitz JA, Matthews CR. Metal-free ALS variants of dimeric human Cu,Zn-superoxide dismutase have enhanced populations of monomeric species. PLoS One 2010; 5:e10064. [PMID: 20404910 PMCID: PMC2852398 DOI: 10.1371/journal.pone.0010064] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Accepted: 02/22/2010] [Indexed: 12/05/2022] Open
Abstract
Amino acid replacements at dozens of positions in the dimeric protein human, Cu,Zn superoxide dismutase (SOD1) can cause amyotrophic lateral sclerosis (ALS). Although it has long been hypothesized that these mutations might enhance the populations of marginally-stable aggregation-prone species responsible for cellular toxicity, there has been little quantitative evidence to support this notion. Perturbations of the folding free energy landscapes of metal-free versions of five ALS-inducing variants, A4V, L38V, G93A, L106V and S134N SOD1, were determined with a global analysis of kinetic and thermodynamic folding data for dimeric and stable monomeric versions of these variants. Utilizing this global analysis approach, the perturbations on the global stability in response to mutation can be partitioned between the monomer folding and association steps, and the effects of mutation on the populations of the folded and unfolded monomeric states can be determined. The 2- to 10-fold increase in the population of the folded monomeric state for A4V, L38V and L106V and the 80- to 480-fold increase in the population of the unfolded monomeric states for all but S134N would dramatically increase their propensity for aggregation through high-order nucleation reactions. The wild-type-like populations of these states for the metal-binding region S134N variant suggest that even wild-type SOD1 may also be prone to aggregation in the absence of metals.
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Affiliation(s)
- Anna-Karin E. Svensson
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Osman Bilsel
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Can Kayatekin
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Jessica A. Adefusika
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Jill A. Zitzewitz
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail: (JAZ); (CRM)
| | - C. Robert Matthews
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail: (JAZ); (CRM)
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27
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Shaw BF, Moustakas DT, Whitelegge JP, Faull KF. Taking Charge of Proteins. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2010; 79:127-64. [DOI: 10.1016/s1876-1623(10)79004-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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28
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Galaleldeen A, Strange RW, Whitson LJ, Antonyuk SV, Narayana N, Taylor AB, Schuermann JP, Holloway SP, Hasnain SS, Hart PJ. Structural and biophysical properties of metal-free pathogenic SOD1 mutants A4V and G93A. Arch Biochem Biophys 2009; 492:40-7. [PMID: 19800308 PMCID: PMC2787720 DOI: 10.1016/j.abb.2009.09.020] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Revised: 09/25/2009] [Accepted: 09/27/2009] [Indexed: 02/06/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal, progressive neurodegenerative disease characterized by the destruction of motor neurons in the spinal cord and brain. A subset of ALS cases are linked to dominant mutations in copper-zinc superoxide dismutase (SOD1). The pathogenic SOD1 variants A4V and G93A have been the foci of multiple studies aimed at understanding the molecular basis for SOD1-linked ALS. The A4V variant is responsible for the majority of familial ALS cases in North America, causing rapidly progressing paralysis once symptoms begin and the G93A SOD1 variant is overexpressed in often studied murine models of the disease. Here we report the three-dimensional structures of metal-free A4V and of metal-bound and metal-free G93A SOD1. In the metal-free structures, the metal-binding loop elements are observed to be severely disordered, suggesting that these variants may share mechanisms of aggregation proposed previously for other pathogenic SOD1 proteins.
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Affiliation(s)
- Ahmad Galaleldeen
- Department of Biochemistry and the X-ray Crystallography Core Laboratory, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA
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29
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Museth AK, Brorsson AC, Lundqvist M, Tibell LAE, Jonsson BH. The ALS-associated mutation G93A in human copper-zinc superoxide dismutase selectively destabilizes the remote metal binding region. Biochemistry 2009; 48:8817-29. [PMID: 19655787 DOI: 10.1021/bi900703v] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
More than 100 distinct mutations in the gene (SOD1) for human copper-zinc superoxide dismutase (CuZnSOD) have been associated with familial amyotrophic lateral sclerosis (fALS). Studies of these mutant proteins, which often have been performed under far from physiological conditions, have indicated effects on protein stabilities, catalytic activity, and metal binding affinities but with no common pattern. Also, with the knowledge that ALS is a late onset disease it is apparent that protein interactions which contribute to the disorder might, in the natural cellular milieu, depend on a delicate balance between intrinsic protein properties. In this study, we have used experimental conditions as near as possible to the in vivo conditions to reduce artifacts emanating from the experimental setup. Using 1H-15N HSQC NMR spectroscopy, we have analyzed hydrogen exchange at the amide groups of wild-type (wt) CuZnSOD and the fALS-associated G93A SOD variant in their fully metalated states. From analyses of the exchange pattern, we have characterized the local dynamics at 64% of all positions in detail in both the wt and G93A protein. The results show that the G93A mutation had no effect on the dynamics at a majority of the investigated positions. However, the mutation results in local destabilization at the site of the mutation and also in stabilization at a few positions that were apparently scattered over the entire protein surface. Most remarkably, the mutation selectively destabilized the remote metal binding region. The results indicate that the metal binding region may affect the intermolecular protein-protein interactions which cause formation of protein aggregates.
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Affiliation(s)
- Anna Katrine Museth
- Division of Molecular Biotechnology, Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden
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30
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Tiwari A, Liba A, Sohn SH, Seetharaman SV, Bilsel O, Matthews CR, Hart PJ, Valentine JS, Hayward LJ. Metal deficiency increases aberrant hydrophobicity of mutant superoxide dismutases that cause amyotrophic lateral sclerosis. J Biol Chem 2009; 284:27746-58. [PMID: 19651777 DOI: 10.1074/jbc.m109.043729] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mechanisms by which mutant variants of Cu/Zn-superoxide dismutase (SOD1) cause familial amyotrophic lateral sclerosis are not clearly understood. Evidence to date suggests that altered conformations of amyotrophic lateral sclerosis mutant SOD1s trigger perturbations of cellular homeostasis that ultimately cause motor neuron degeneration. In this study we correlated the metal contents and disulfide bond status of purified wild-type (WT) and mutant SOD1 proteins to changes in electrophoretic mobility and surface hydrophobicity as detected by 1-anilinonaphthalene-8-sulfonic acid (ANS) fluorescence. As-isolated WT and mutant SOD1s were copper-deficient and exhibited mobilities that correlated with their expected negative charge. However, upon disulfide reduction and demetallation at physiological pH, both WT and mutant SOD1s underwent a conformational change that produced a slower mobility indicative of partial unfolding. Furthermore, although ANS did not bind appreciably to the WT holoenzyme, incubation of metal-deficient WT or mutant SOD1s with ANS increased the ANS fluorescence and shifted its peak toward shorter wavelengths. This increased interaction with ANS was greater for the mutant SOD1s and could be reversed by the addition of metal ions, especially Cu(2+), even for SOD1 variants incapable of forming the disulfide bond. Overall, our findings support the notion that misfolding associated with metal deficiency may facilitate aberrant interactions of SOD1 with itself or with other cellular constituents and may thereby contribute to neuronal toxicity.
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Affiliation(s)
- Ashutosh Tiwari
- Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA.
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31
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Molnar KS, Karabacak NM, Johnson JL, Wang Q, Tiwari A, Hayward LJ, Coales SJ, Hamuro Y, Agar JN. A common property of amyotrophic lateral sclerosis-associated variants: destabilization of the copper/zinc superoxide dismutase electrostatic loop. J Biol Chem 2009; 284:30965-73. [PMID: 19635794 DOI: 10.1074/jbc.m109.023945] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
At least 119 mutations in the gene encoding copper/zinc superoxide dismutase (SOD1) cause amyotrophic lateral sclerosis by an unidentified toxic gain of function. We compared the dynamic properties of 13 as-isolated, partially metallated, SOD1 variant enzymes using hydrogen-deuterium exchange. We identified a shared property of these familial amyotrophic lateral sclerosis-related SOD1 variants, namely structural and dynamic change affecting the electrostatic loop (loop VII) of SOD1. Furthermore, SOD1 variants that have severely compromised metal binding affinities demonstrated additional structural and dynamic changes to the zinc-binding loop (loop IV) of SOD1. Although the biological consequences of increased loop VII mobility are not fully understood, this common property is consistent with the hypotheses that SOD1 mutations exert toxicity via aggregation or aberrant association with other cellular constituents.
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Affiliation(s)
- Kathleen S Molnar
- Department of Chemistry, Volen Center, Brandeis University, Waltham, Massachusetts 02454, USA
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32
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Seetharaman SV, Prudencio M, Karch C, Holloway SP, Borchelt DR, Hart PJ. Immature copper-zinc superoxide dismutase and familial amyotrophic lateral sclerosis. Exp Biol Med (Maywood) 2009; 234:1140-54. [PMID: 19596823 DOI: 10.3181/0903-mr-104] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Mutations in human copper-zinc superoxide dismutase (SOD1) cause an inherited form of amyotrophic lateral sclerosis (ALS, Lou Gehrig's disease, motor neuron disease). Insoluble forms of mutant SOD1 accumulate in neural tissues of human ALS patients and in spinal cords of transgenic mice expressing these polypeptides, suggesting that SOD1-linked ALS is a protein misfolding disorder. Understanding the molecular basis for how the pathogenic mutations give rise to SOD1 folding intermediates, which may themselves be toxic, is therefore of keen interest. A critical step on the SOD1 folding pathway occurs when the copper chaperone for SOD1 (CCS) modifies the nascent SOD1 polypeptide by inserting the catalytic copper cofactor and oxidizing its intrasubunit disulfide bond. Recent studies reveal that pathogenic SOD1 proteins coming from cultured cells and from the spinal cords of transgenic mice tend to be metal-deficient and/or lacking the disulfide bond, raising the possibility that the disease-causing mutations may enhance levels of SOD1-folding intermediates by preventing or hindering CCS-mediated SOD1 maturation. This mini-review explores this hypothesis by highlighting the structural and biophysical properties of the pathogenic SOD1 mutants in the context of what is currently known about CCS structure and action. Other hypotheses as to the nature of toxicity inherent in pathogenic SOD1 proteins are not covered.
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Affiliation(s)
- Sai V Seetharaman
- Department of Biochemistry and the X-ray Crystallography Core Laboratory, The University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229, USA
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33
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Lee HJ, Yoon YJ, Jang DS, Kim C, Cha HJ, Hong BH, Choi KY, Lee HC. 15N NMR Relaxation Studies of Y14F Mutant of Ketosteroid Isomerase: The Influence of Mutation on Backbone Mobility. ACTA ACUST UNITED AC 2008; 144:159-66. [DOI: 10.1093/jb/mvn053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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34
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Dubinina EE, Pustygina AV. Free radical processes in aging, neurodegenerative diseases and other pathological states. BIOCHEMISTRY (MOSCOW) SUPPLEMENT SERIES B: BIOMEDICAL CHEMISTRY 2007. [DOI: 10.1134/s1990750807040026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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35
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Jarymowycz VA, Stone MJ. Fast time scale dynamics of protein backbones: NMR relaxation methods, applications, and functional consequences. Chem Rev 2007; 106:1624-71. [PMID: 16683748 DOI: 10.1021/cr040421p] [Citation(s) in RCA: 312] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Virginia A Jarymowycz
- Department of Chemistry and Interdisciplinary Biochemistry Program, Indiana University, Bloomington, Indiana 47405-0001, USA
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36
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Rakhit R, Chakrabartty A. Structure, folding, and misfolding of Cu,Zn superoxide dismutase in amyotrophic lateral sclerosis. Biochim Biophys Acta Mol Basis Dis 2006; 1762:1025-37. [PMID: 16814528 DOI: 10.1016/j.bbadis.2006.05.004] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2006] [Revised: 05/15/2006] [Accepted: 05/16/2006] [Indexed: 11/16/2022]
Abstract
Fourteen years after the discovery that mutations in Cu, Zn superoxide dismutase (SOD1) cause a subset of familial amyotrophic lateral sclerosis (fALS), the mechanism by which mutant SOD1 exerts toxicity remains unknown. The two principle hypotheses are (a) oxidative damage stemming from aberrant SOD1 redox chemistry, and (b) misfolding of the mutant protein. Here we review the structure and function of wild-type SOD1, as well as the changes to the structure and function in mutant SOD1. The relative merits of the two hypotheses are compared and a common unifying principle is outlined. Lastly, the potential for therapies targeting SOD1 misfolding is discussed.
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Affiliation(s)
- Rishi Rakhit
- Department of Biochemistry, University of Toronto, University Health Network, Toronto Medical Discovery Tower, Medical and Related Sciences (MaRS), 101 College Street, Toronto, ON, Canada, M5G 1L7
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37
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Tiwari A, Hayward LJ. Mutant SOD1 instability: implications for toxicity in amyotrophic lateral sclerosis. NEURODEGENER DIS 2006; 2:115-27. [PMID: 16909016 DOI: 10.1159/000089616] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The biological basis of preferential motor neuron degeneration in amyotrophic lateral sclerosis (ALS) remains incompletely understood, and effective therapies to prevent the lethal consequences of this disorder are not yet available. Since 1993, more than 100 mutant variants of the antioxidant enzyme Cu/Zn superoxide dismutase (SOD1) have been identified in familial ALS. Many studies have sought to distinguish abnormal properties shared by these proteins that may contribute to their toxic effects and cause age-dependent motor neuron loss. Complex networks of cellular interactions and changes associated with aging may link mutant SOD1s and other stresses to motor neuron death in ALS. Our laboratory and collaborators have compared physicochemical properties of biologically metallated wild-type and mutant SOD1 proteins to discern specific vulnerabilities that may be relevant to the mutant toxicity in vivo. X-ray crystal structures obtained from metallated 'wild-type-like' (WTL) SOD1 mutants, which retain the ability to bind copper and zinc and exhibit normal specific activity, indicate a native-like structure with only subtle changes to the backbone fold. In contrast, a group of 'metal-binding region' (MBR) SOD1 mutants that are deficient in copper and zinc exhibit severe thermal destabilization and structural disorder of conserved loops near the metal-binding sites. A growing body of evidence highlights specific stresses in vivo that may perturb well-folded, metallated SOD1 variants and thereby favor an increased burden of partially unfolded, metal-deficient species. For example, WTL SOD1 mutants are more susceptible than wild-type SOD1 to reduction of the intrasubunit disulfide bond between Cys-57 and Cys-146 at physiological pH and temperature. This bond anchors the disulfide loop to the SOD1 beta-barrel and helps to maintain the dimeric configuration of the protein. Cleavage of the disulfide linkage renders the well-folded WTL mutants vulnerable to metal loss and monomerization such that they may resemble the destabilized and locally misfolded MBR mutant species. SOD1 proteins with disordered loops or monomeric structure are expected to be more susceptible to aberrant self-association or detrimental interactions with other cellular constituents. The challenge for future investigations is to relate these abnormal properties of partially unfolded SOD1 to specific mechanisms of toxicity in motor neurons, supporting cells, or target tissues.
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Affiliation(s)
- Ashutosh Tiwari
- Department of Neurology, University of Massachusetts Medical School, Worcester, 01655, USA
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38
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Gaggelli E, Kozlowski H, Valensin D, Valensin G. Copper Homeostasis and Neurodegenerative Disorders (Alzheimer's, Prion, and Parkinson's Diseases and Amyotrophic Lateral Sclerosis). Chem Rev 2006; 106:1995-2044. [PMID: 16771441 DOI: 10.1021/cr040410w] [Citation(s) in RCA: 1221] [Impact Index Per Article: 67.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Elena Gaggelli
- Department of Chemistry, University of Siena, Via Aldo Moro 2, Siena 53100, Italy
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39
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Shaw BF, Durazo A, Nersissian AM, Whitelegge JP, Faull KF, Valentine JS. Local Unfolding in a Destabilized, Pathogenic Variant of Superoxide Dismutase 1 Observed with H/D Exchange and Mass Spectrometry. J Biol Chem 2006; 281:18167-76. [PMID: 16644738 DOI: 10.1074/jbc.m600623200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hydrogen exchange monitored by mass spectrometry has been used to study the structural behavior of the pathogenic A4V variant of superoxide dismutase 1 (SOD1) in the metal-free (apo) form. Mass spectrometric data revealed that in the disulfide-intact (S-S) form, the A4V variant is destabilized at residues 50-53, in the disulfide subloop of the dimer interface, but many other regions of the A4V protein exhibited hydrogen exchange properties identical to that of the wild type protein. Additionally, mass spectrometry revealed that A4V apoSOD1(S-S) undergoes slow localized unfolding in a large segment of the beta-barrel that included beta3, beta4, and loops II and III. In the disulfide-reduced form, A4V apoSOD1 exchanged like a "random coil" polypeptide at 20 degrees C and began to populate folded states at 4 degrees C. These local and global unfolding events could facilitate intermolecular protein-protein interactions that cause the aggregation or neurotoxicity of A4V SOD1.
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Affiliation(s)
- Bryan Francis Shaw
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095, USA
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40
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Hart PJ. Pathogenic superoxide dismutase structure, folding, aggregation and turnover. Curr Opin Chem Biol 2006; 10:131-8. [PMID: 16516535 DOI: 10.1016/j.cbpa.2006.02.034] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2005] [Accepted: 02/22/2006] [Indexed: 11/25/2022]
Abstract
Significant advances have been made during the past two years toward an understanding of the molecular basis for how mutations in human cytosolic copper-zinc superoxide dismutase (SOD1) cause the inherited form of amyotrophic lateral sclerosis (ALS). Biophysical studies suggest that the pathogenic mutations destabilize loop or beta-barrel structural elements of the protein. With few exceptions, the loss of metal ions and reduction of the intrasubunit disulfide bond enhance this destabilization. In mouse models of the disease, the formation of visible aggregates containing mutant SOD1 occurs relatively late in the lifespan, hinting that the quality control and protein turnover systems of motor neurons eventually become overwhelmed or compromised. Studies probing SOD1 turnover have suggested the possibility that proteolytic breakdown products may play a role in pathogenesis.
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Affiliation(s)
- P John Hart
- Department of Biochemistry, Department of Veterans Affairs, South Texas Veterans Health Care System, The University of Texas Health Science Center at San Antonio, 78229-3900, USA.
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41
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Matsumoto A, Okada Y, Nakamichi M, Nakamura M, Toyama Y, Sobue G, Nagai M, Aoki M, Itoyama Y, Okano H. Disease progression of human SOD1 (G93A) transgenic ALS model rats. J Neurosci Res 2006; 83:119-33. [PMID: 16342121 DOI: 10.1002/jnr.20708] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The recent development of a rat model of amyotrophic lateral sclerosis (ALS) in which the rats harbor a mutated human SOD1 (G93A) gene has greatly expanded the range of potential experiments, because the rats' large size permits biochemical analyses and therapeutic trials, such as the intrathecal injection of new drugs and stem cell transplantation. The precise nature of this disease model remains unclear. We described three disease phenotypes: the forelimb-, hindlimb-, and general-types. We also established a simple, non-invasive, and objective evaluation system using the body weight, inclined plane test, cage activity, automated motion analysis system (SCANET), and righting reflex. Moreover, we created a novel scale, the Motor score, which can be used with any phenotype and does not require special apparatuses. With these methods, we uniformly and quantitatively assessed the onset, progression, and disease duration, and clearly presented the variable clinical course of this model; disease progression after the onset was more aggressive in the forelimb-type than in the hindlimb-type. More importantly, the disease stages defined by our evaluation system correlated well with the loss of spinal motor neurons. In particular, the onset of muscle weakness coincided with the loss of approximately 50% of spinal motor neurons. This study should provide a valuable tool for future experiments to test potential ALS therapies.
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Affiliation(s)
- Arifumi Matsumoto
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
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42
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Stathopulos PB, Rumfeldt JAO, Karbassi F, Siddall CA, Lepock JR, Meiering EM. Calorimetric Analysis of Thermodynamic Stability and Aggregation for Apo and Holo Amyotrophic Lateral Sclerosis-associated Gly-93 Mutants of Superoxide Dismutase. J Biol Chem 2006; 281:6184-93. [PMID: 16407238 DOI: 10.1074/jbc.m509496200] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Differential scanning calorimetry was used to measure changes in thermodynamic stability and aggregation for glycine 93 mutants of human copper, zinc-superoxide dismutase (SOD). Glycine 93 is a conserved residue at position i + 3 of a tight turn and has been found to be a mutational hot spot in familial amyotrophic lateral sclerosis (fALS). The fALS-associated mutations, G93A, G93S, G93R, G93D, and G93V, were made in a pseudo wild-type background containing no free cysteines, which prevented the formation of aberrant disulfide bonds upon thermal unfolding, and enabled quantitative thermodynamic analysis of the effects of the mutations. Thermal unfolding was highly reversible for all the SODs in both the fully metallated (holo) and metal-free (apo) forms. The data for all the holo-SODs and for the apo-pseudo-wild-type SOD were well fit by a 2-state unfolding model for native dimer (N2) to two unfolded monomers (2U), N2 <--> 2U. The holo- and apo-forms of the mutants are significantly destabilized (by 1.5-3.5 kcal mol(-1) monomer) relative to the corresponding forms of pseudo wild-type, with the relative stabilities being correlated with statistical preferences for amino acids in this structural context. Although van't Hoff (DeltaHvH) to calorimetric (DeltaHcal) enthalpy ratios are close to unity for all the holo-SODs and for apo-pseudo-wild-type, consistent with a 2-state transition, DeltaHvH is considerably larger than DeltaHcal for all the apo-mutants. This suggests that the mutations cause apo-SOD to have an increased propensity to misfold or aggregate, which may be linked to increased toxic mutant SOD aggregation in fALS.
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43
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Khare SD, Dokholyan NV. Common dynamical signatures of familial amyotrophic lateral sclerosis-associated structurally diverse Cu, Zn superoxide dismutase mutants. Proc Natl Acad Sci U S A 2006; 103:3147-52. [PMID: 16488975 PMCID: PMC1413921 DOI: 10.1073/pnas.0511266103] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
More than 100 structurally diverse point mutations leading to aggregation in the dimeric enzyme Cu, Zn superoxide dismutase (SOD1) are implicated in familial amyotrophic lateral sclerosis (FALS). Although SOD1 dimer dissociation is a known requirement for its aggregation, the common structural basis for diverse FALS mutations resulting in aggregation is not fully understood. In molecular dynamics simulations of wild-type SOD1 and three structurally diverse FALS mutants (A4V, G37R, and H46R), we find that a common effect of mutations on SOD1 dimer is the mutation-induced disruption of dynamic coupling between monomers. In the wild-type dimer, the principal coupled motion corresponds to a "breathing motion" of the monomers around an axis parallel to the dimer interface, and an opening-closing motion of the distal metal-binding loops. These coupled motions are disrupted in all three mutants independent of the mutation location. Loss of coupled motions in mutant dimers occurs with increased disruption of a key stabilizing structural element (the beta-plug) leading to the de-protection of edge strands. To rationalize disruption of coupling, which is independent of the effect of the mutation on global SOD1 stability, we analyze the residue-residue interaction network formed in SOD1. We find that the dimer interface and metal-binding loops, both involved in coupled motions, are regions of high connectivity in the network. Our results suggest that independent of the effect on protein stability, altered protein dynamics, due to long-range communication within its structure, may underlie the aggregation of mutant SOD1 in FALS.
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Affiliation(s)
- Sagar D. Khare
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - Nikolay V. Dokholyan
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC 27599
- To whom correspondence should be addressed. E-mail:
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44
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Zhang F, Zhu H. Intracellular conformational alterations of mutant SOD1 and the implications for fALS-associated SOD1 mutant induced motor neuron cell death. Biochim Biophys Acta Gen Subj 2006; 1760:404-14. [PMID: 16431026 DOI: 10.1016/j.bbagen.2005.11.024] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2005] [Revised: 11/09/2005] [Accepted: 11/28/2005] [Indexed: 10/25/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by the selective death of motor neurons. Approximately 10% of ALS cases are familial (fALS) and about 25% of fALS patients inherit autosomal dominant mutations in the gene encoding copper-zinc superoxide dismutase (SOD1). Over 90 different SOD1 mutations have been identified in fALS patients. It has been established that the ALS-linked SOD1 mutations provoke a new toxic function, the nature of which remains unclear. In vitro studies using various biophysical techniques have demonstrated that the SOD1 mutants share a reduced conformational stability. However, conformational alterations of the ALS mutants have not been directly demonstrated in vivo. We employed an SOD1-GFP fusion protein system in this study to monitor the intracellular protein conformation. We demonstrate that the ALS-linked SOD1 mutants adopt different conformations from the wild-type (WT) protein in living cells. Moreover, the conformational alterations of mutant SOD1 render the mutants susceptible to the formation of high-molecular-weight complexes prior to the appearance of detergent-resistant aggregates. Finally, we show that the motor neuron-like cells expressing mutant SOD1 are more susceptible to H2O2 induced cell death compared to the cells expressing WT SOD1. This study provides direct evidence of in vivo conformational differences between WT and mutant SOD1. In addition, the SOD1-GFP system can be exploited in future studies to investigate how conformational alterations of mutant SOD1 lead to protein aggregation and to study the potential toxicity of such aggregates in familial ALS.
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Affiliation(s)
- Fujian Zhang
- Department of Molecular and Cellular Biochemistry, College of Medicine University of Kentucky, 741 South Limestone, Lexington, KY 40536, USA
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Rumfeldt JAO, Stathopulos PB, Chakrabarrty A, Lepock JR, Meiering EM. Mechanism and Thermodynamics of Guanidinium Chloride-induced Denaturation of ALS-associated Mutant Cu,Zn Superoxide Dismutases. J Mol Biol 2006; 355:106-23. [PMID: 16307756 DOI: 10.1016/j.jmb.2005.10.042] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Revised: 09/16/2005] [Accepted: 10/18/2005] [Indexed: 11/21/2022]
Abstract
Mutations in human copper zinc superoxide dismutase (hSOD) that are associated with amyotrophic lateral sclerosis (ALS) have been proposed to destabilize the protein and thereby enhance toxic protein aggregation. In previous studies, denaturation of metallated (holo) hSODs was found to be irreversible, and complicated by the formation of intermolecular disulfide bonds. Here, ALS-associated mutations (E100G, G93A, G85R and A4V) are introduced into a pseudo wild-type background containing no free cysteine residues. The guanidinium chloride-induced denaturation of the holo proteins is generally found to be highly reversible (except for A4V, which tended to aggregate), enabling quantitative analysis of the effects of the mutations on protein stability. Denaturation and renaturation curves were monitored by tryptophan fluorescence, circular dichroism, enzyme activity, chemical cross-linking and analytical sedimentation, as a function of equilibration time and protein concentration. There is strong kinetic hysteresis, with curves requiring exceptionally long times (many days for pseudo wild-type) to reach equilibrium, and evidence for the formation of kinetic and equilibrium intermediate(s), which are more highly populated at lower protein concentrations. The effects of metal dissociation were included in the data fitting. The full protein concentration dependence is best described using a three-state model involving metallated native dimer, metallated monomeric intermediate and unfolded monomers with no bound metals; however, at high protein concentrations the unfolding approaches a two-state transition with metal binding to both the native dimers and unfolded monomers. We show that the E100G, G93A and G85R mutations decrease overall protein stability, largely by decreasing monomer stability with little effect on dimer dissociation. Comparison of the chemical denaturation data with ALS disease characteristics suggests that aggregation of some mutant hSOD may occur through increased population of partially folded states that are less stable than the monomeric intermediate and accessed from the destabilized holo protein.
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Affiliation(s)
- Jessica A O Rumfeldt
- Guelph-Waterloo Centre for Graduate Work in Chemistry and Biochemistry and Department of Chemistry, University of Waterloo, Waterloo, Ont. Canada N2L 3G1
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Banci L, Bertini I, D'Amelio N, Gaggelli E, Libralesso E, Matecko I, Turano P, Valentine JS. Fully Metallated S134N Cu,Zn-Superoxide Dismutase Displays Abnormal Mobility and Intermolecular Contacts in Solution. J Biol Chem 2005; 280:35815-21. [PMID: 16105836 DOI: 10.1074/jbc.m506637200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
S134N copper-zinc superoxide dismutase (SOD1) is one of the many mutant SOD1 proteins known to cause familial amyotrophic lateral sclerosis. Earlier studies demonstrated that partially metal-deficient S134N SOD1 crystallized in filament-like arrays with abnormal contacts between the individual protein molecules. Because protein aggregation is implicated in SOD1-linked familial amyotrophic lateral sclerosis, abnormal intermolecular interactions between mutant SOD1 proteins could be relevant to the mechanism of pathogenesis in the disease. We have therefore applied NMR methods to ascertain whether abnormal contacts also form between S134N SOD1 molecules in solution and whether Cys-6 or Cys-111 plays any role in the aggregation. Our studies demonstrate that the behavior of fully metallated S134N SOD1 is dramatically different from that of fully metallated wild type SOD1 with a region of subnanosecond mobility located close to the site of the mutation. Such a high degree of mobility is usually seen only in the apo form of wild type SOD1, because binding of zinc to the zinc site normally immobilizes that region. In addition, concentration-dependent chemical shift differences were observed for S134N SOD1 that were not observed for wild type SOD1, indicative of abnormal intermolecular contacts in solution. We have here also established that the two free cysteines (6 and 111) do not play a role in this behavior.
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Affiliation(s)
- Lucia Banci
- Magnetic Resonance Center, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
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Abstract
Copper-zinc superoxide dismutase (CuZnSOD, SOD1 protein) is an abundant copper- and zinc-containing protein that is present in the cytosol, nucleus, peroxisomes, and mitochondrial intermembrane space of human cells. Its primary function is to act as an antioxidant enzyme, lowering the steady-state concentration of superoxide, but when mutated, it can also cause disease. Over 100 different mutations have been identified in the sod1 genes of patients diagnosed with the familial form of amyotrophic lateral sclerosis (fALS). These mutations result in a highly diverse group of mutant proteins, some of them very similar to and others enormously different from wild-type SOD1. Despite their differences in properties, each member of this diverse set of mutant proteins causes the same clinical disease, presenting a challenge in formulating hypotheses as to what causes SOD1-associated fALS. In this review, we draw together and summarize information from many laboratories about the characteristics of the individual mutant SOD1 proteins in vivo and in vitro in the hope that it will aid investigators in their search for the cause(s) of SOD1-associated fALS.
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Affiliation(s)
- Joan Selverstone Valentine
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA.
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Banci L, Benvenuti M, Bertini I, Cabelli DE, Calderone V, Fantoni A, Mangani S, Migliardi M, Viezzoli MS. From an Inactive Prokaryotic SOD Homologue to an Active Protein through Site-Directed Mutagenesis. J Am Chem Soc 2005; 127:13287-92. [PMID: 16173759 DOI: 10.1021/ja052790o] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
It is known that several prokaryotic protein sequences, characterized by high homology with the eukaryotic Cu,ZnSODs, lack some of the metal ligands. In the present work, we have stepwise reintroduced the two missing copper ligands in the SOD-like protein of Bacillus subtilis, through site-directed mutagenesis. The mutant with three out of the four His that bind copper is not active, whereas the fully reconstituted mutant displays an activity of about 10% that of human Cu,ZnSOD. The mutated proteins have been characterized in solution and in the solid state. In solution, the proteins experience conformational disorder, which is believed to be partly responsible for the decreased enzymatic activity and sheds light on the tendency of several human SOD mutants to introduce mobility in the protein frame. In the crystal, on the contrary, the protein has a well-defined conformation, giving rise to dimers through the coordination of an exogenous zinc ion. The catalytic properties of the double mutant, which might be regarded as a step in an artificial evolution from a nonactive SOD to a fully functioning enzyme, are discussed on the basis of the structural and dynamical properties.
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Affiliation(s)
- Lucia Banci
- Department of Chemistry and Centro Risonanze Magnetiche, University of Florence, 50019 Sesto Fiorentino, Italy
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Banci L, Bertini I, Cantini F, Migliardi M, Rosato A, Wang S. An Atomic-level Investigation of the Disease-causing A629P Mutant of the Menkes Protein, ATP7A. J Mol Biol 2005; 352:409-17. [PMID: 16083905 DOI: 10.1016/j.jmb.2005.07.034] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2005] [Revised: 07/08/2005] [Accepted: 07/12/2005] [Indexed: 10/25/2022]
Abstract
Menkes disease is a fatal disease that can be induced by various mutations in the ATP7A gene, leading to unpaired uptake of dietary copper. The ATP7A gene encodes a copper(I)-translocating ATPase. Here the disease-causing A629P mutation, which occurs in the last of the six copper(I)-binding soluble domains of the ATPase (hereafter MNK6), was investigated. To understand why this apparently minor amino acid replacement is pathogenic, the solution structures and dynamics on various time-scales of wild-type and A629P-MNK6 were determined both in the apo- and copper(I)-loaded forms. The interaction in vitro with the physiological ATP7A copper(I)-donor (HAH1) was additionally studied. The A629P mutation makes the protein beta-sheet more solvent accessible, possibly resulting in an enhanced susceptibility of ATP7A to proteolytic cleavage and/or in reduced capability of copper(I)-translocation. A small reduction of the affinity for copper(I) is also observed. Both effects could concur to pathogenicity.
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Affiliation(s)
- Lucia Banci
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
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Tiwari A, Xu Z, Hayward LJ. Aberrantly Increased Hydrophobicity Shared by Mutants of Cu,Zn-Superoxide Dismutase in Familial Amyotrophic Lateral Sclerosis. J Biol Chem 2005; 280:29771-9. [PMID: 15958382 DOI: 10.1074/jbc.m504039200] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
More than 100 different mutations in the gene encoding Cu,Zn-superoxide dismutase (SOD1) cause preferential motor neuron degeneration in familial amyotrophic lateral sclerosis (ALS). Although the cellular target(s) of mutant SOD1 toxicity have not been precisely specified, evidence to date supports the hypothesis that ALS-related mutations may increase the burden of partially unfolded SOD1 species. Influences that may destabilize SOD1 in vivo include impaired metal ion binding, reduction of the intrasubunit disulfide bond, or oxidative modification. In this study, we observed that metal-deficient as-isolated SOD1 mutants (H46R, G85R, D124V, D125H, and S134N) with disordered electrostatic and zinc-binding loops exhibited aberrant binding to hydrophobic beads in the absence of other destabilizing agents. Other purified ALS-related mutants that can biologically incorporate nearly normal amounts of stabilizing zinc ions (A4V, L38V, G41S, D90A, and G93A) exhibited maximal hydrophobic behavior after exposure to both a disulfide reducing agent and a metal chelator, while normal SOD1 was more resistant to these agents. Moreover, we detected hydrophobic SOD1 species in lysates from affected tissues in G85R and G93A mutant but not wildtype SOD1 transgenic mice. These findings suggest that a susceptibility to the cellular disulfide reducing environment and zinc loss may convert otherwise stable SOD1 mutants into metal-deficient forms with locally destabilized electrostatic and zinc-binding loops. These abnormally hydrophobic SOD1 species may promote aberrant interactions of the enzyme with itself or with other cellular constituents to produce toxicity in familial ALS.
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Affiliation(s)
- Ashutosh Tiwari
- Department of Neurology, University of Massachusetts Medical School, Worcester, 01655, USA
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