1
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Gonzalez M, Guberman-Pfeffer MJ, Koone JC, Dashnaw CM, Lato TJ, Shaw BF. Proton-coupled electron transfer at a mis-metalated zinc site detected with protein charge ladders. Phys Chem Chem Phys 2024. [PMID: 39193659 DOI: 10.1039/d4cp01989j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/29/2024]
Abstract
Distinguishing proton-coupled electron transfer (PCET) from uncoupled electron transfer (ET) in proteins can be challenging. A recent investigation [J. C. Koone, M. Simmang, D. L. Saenger, M. L. Hunsicker-Wang and B. F. Shaw, J. Am. Chem. Soc., 145, 16488-16497] reported that protein charge ladders and capillary electrophoresis can distinguish between single ET, PCET, and two-proton coupled ET (2PCET) by directly measuring the change in protein net charge upon reduction/oxidation (ΔZET). The current study used similar methods to assess PCET in zinc-free, "double copper" superoxide dismutase-1 (4Cu-SOD1), where one copper is bound at the copper site of each monomer and one copper is bound at the bridging zinc site, resulting in a quasi-type III Cu center. At pH 7.4, the net charge (Z) of the 4Cu-SOD1 dimer was unaffected by reduction of all four Cu2+ ions, i.e., ΔZ4ET = -0.09 ± 0.05 per dimer (-0.02 ± 0.01 per copper atom). These values suggest that PCET is taking place at all four Cu atoms of the homodimer. Molecular dynamics and Poisson-Boltzmann calculations suggest that a metal-coordinating histidine at the zinc site (His71) is the proton acceptor. These data show how ligands of a naturally occurring zinc site can help facilitate PCET when the right redox metal is bound.
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Affiliation(s)
- Mayte Gonzalez
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA.
| | | | - Jordan C Koone
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA.
| | - Chad M Dashnaw
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA.
| | - Travis J Lato
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA.
| | - Bryan F Shaw
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA.
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2
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Dashnaw CM, Zhang AY, Gonzalez M, Koone JC, Shaw BF. Metal migration and subunit swapping in ALS-linked SOD1: Zn 2+ transfer between mutant and wild-type occurs faster than the rate of heterodimerization. J Biol Chem 2022; 298:102610. [PMID: 36265587 PMCID: PMC9667317 DOI: 10.1016/j.jbc.2022.102610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/03/2022] [Accepted: 10/11/2022] [Indexed: 11/05/2022] Open
Abstract
The heterodimerization of WT Cu, Zn superoxide dismutase-1 (SOD1), and mutant SOD1 might be a critical step in the pathogenesis of SOD1-linked amyotrophic lateral sclerosis (ALS). Rates and free energies of heterodimerization (ΔGHet) between WT and ALS-mutant SOD1 in mismatched metalation states-where one subunit is metalated and the other is not-have been difficult to obtain. Consequently, the hypothesis that under-metalated SOD1 might trigger misfolding of metalated SOD1 by "stealing" metal ions remains untested. This study used capillary zone electrophoresis and mass spectrometry to track heterodimerization and metal transfer between WT SOD1, ALS-variant SOD1 (E100K, E100G, D90A), and triply deamidated SOD1 (modeled with N26D/N131D/N139D substitutions). We determined that rates of subunit exchange between apo dimers and metalated dimers-expressed as time to reach 30% heterodimer-ranged from t30% = 67.75 ± 9.08 to 338.53 ± 26.95 min; free energies of heterodimerization ranged from ΔGHet = -1.21 ± 0.31 to -3.06 ± 0.12 kJ/mol. Rates and ΔGHet values of partially metalated heterodimers were more similar to those of fully metalated heterodimers than apo heterodimers, and largely independent of which subunit (mutant or WT) was metal-replete or metal-free. Mass spectrometry and capillary electrophoresis demonstrated that mutant or WT 4Zn-SOD1 could transfer up to two equivalents of Zn2+ to mutant or WT apo-SOD1 (at rates faster than the rate of heterodimerization). This result suggests that zinc-replete SOD1 can function as a chaperone to deliver Zn2+ to apo-SOD1, and that WT apo-SOD1 might increase the toxicity of mutant SOD1 by stealing its Zn2+.
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3
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Tian R, Geng Y, Guo H, Yang C, Seim I, Yang G. Comparative analysis of the superoxide dismutase gene family in Cetartiodactyla. J Evol Biol 2021; 34:1046-1060. [PMID: 33896059 DOI: 10.1111/jeb.13792] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/29/2021] [Accepted: 04/16/2021] [Indexed: 12/18/2022]
Abstract
Cetacea, whales, dolphins and porpoises form an order of mammals adapted to aquatic life. Their transition to an aquatic habitat resulted in exceptional protection against cellular insults, including oxidative and osmotic stress. Here, we considered the structure and molecular evolution of the superoxide dismutase (SOD) gene family, which encodes essential enzymes in the mammalian antioxidant system, in the superorder Cetartiodactyla. To this end, we juxtaposed cetaceans and their closest extant relatives (order Artiodactyla). We identified 94 genes in 23 species, of which 70 are bona fide intact genes. Although the SOD gene family is conserved in Cetartiodactyla, lineage-specific gene duplications and deletions were observed. Phylogenetic analyses show that the SOD2 subfamily diverged from a clade containing SOD1 and SOD3, suggesting that cytoplasmic, extracellular and mitochondrial SODs have started down independent evolutionary paths. Specific-amino acid changes (e.g. K130N in SOD2) that may enhance ROS elimination were identified in cetaceans. In silico analysis suggests that the core transcription factor repertoire of cetartiodactyl SOD genes may include Sp1, NF-κB, Nrf2 and AHR. Putative transcription factors binding sites responding to hypoxia were (e.g. Suppressor of Hairless; Su(H)) found in the cetacean SOD1 gene. We found significant evidence for positive selection in cetaceans using codon models. Cetaceans with different diving abilities also show divergent evolution of SOD1 and SOD2. Our genome-wide analysis of SOD genes helps clarify their relationship and evolutionary trajectory and identify putative functional changes in cetaceans.
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Affiliation(s)
- Ran Tian
- Integrative Biology Laboratory, College of Life Sciences, Nanjing Normal University, Nanjing, China.,Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Yuepan Geng
- Integrative Biology Laboratory, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Han Guo
- Integrative Biology Laboratory, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Chen Yang
- Integrative Biology Laboratory, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Inge Seim
- Integrative Biology Laboratory, College of Life Sciences, Nanjing Normal University, Nanjing, China.,School of Biology and Environmental Science, Queensland University of Technology, Brisbane, QLD, Australia
| | - Guang Yang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
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4
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Trist BG, Hilton JB, Hare DJ, Crouch PJ, Double KL. Superoxide Dismutase 1 in Health and Disease: How a Frontline Antioxidant Becomes Neurotoxic. Angew Chem Int Ed Engl 2021; 60:9215-9246. [PMID: 32144830 PMCID: PMC8247289 DOI: 10.1002/anie.202000451] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Indexed: 12/11/2022]
Abstract
Cu/Zn superoxide dismutase (SOD1) is a frontline antioxidant enzyme catalysing superoxide breakdown and is important for most forms of eukaryotic life. The evolution of aerobic respiration by mitochondria increased cellular production of superoxide, resulting in an increased reliance upon SOD1. Consistent with the importance of SOD1 for cellular health, many human diseases of the central nervous system involve perturbations in SOD1 biology. But far from providing a simple demonstration of how disease arises from SOD1 loss-of-function, attempts to elucidate pathways by which atypical SOD1 biology leads to neurodegeneration have revealed unexpectedly complex molecular characteristics delineating healthy, functional SOD1 protein from that which likely contributes to central nervous system disease. This review summarises current understanding of SOD1 biology from SOD1 genetics through to protein function and stability.
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Affiliation(s)
- Benjamin G. Trist
- Brain and Mind Centre and Discipline of PharmacologyThe University of Sydney, CamperdownSydneyNew South Wales2050Australia
| | - James B. Hilton
- Department of Pharmacology and TherapeuticsThe University of MelbourneParkvilleVictoria3052Australia
| | - Dominic J. Hare
- Brain and Mind Centre and Discipline of PharmacologyThe University of Sydney, CamperdownSydneyNew South Wales2050Australia
- School of BioSciencesThe University of MelbourneParkvilleVictoria3052Australia
- Atomic Medicine InitiativeThe University of Technology SydneyBroadwayNew South Wales2007Australia
| | - Peter J. Crouch
- Department of Pharmacology and TherapeuticsThe University of MelbourneParkvilleVictoria3052Australia
| | - Kay L. Double
- Brain and Mind Centre and Discipline of PharmacologyThe University of Sydney, CamperdownSydneyNew South Wales2050Australia
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5
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Trist BG, Hilton JB, Hare DJ, Crouch PJ, Double KL. Superoxide Dismutase 1 in Health and Disease: How a Frontline Antioxidant Becomes Neurotoxic. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202000451] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Benjamin G. Trist
- Brain and Mind Centre and Discipline of Pharmacology The University of Sydney, Camperdown Sydney New South Wales 2050 Australia
| | - James B. Hilton
- Department of Pharmacology and Therapeutics The University of Melbourne Parkville Victoria 3052 Australia
| | - Dominic J. Hare
- Brain and Mind Centre and Discipline of Pharmacology The University of Sydney, Camperdown Sydney New South Wales 2050 Australia
- School of BioSciences The University of Melbourne Parkville Victoria 3052 Australia
- Atomic Medicine Initiative The University of Technology Sydney Broadway New South Wales 2007 Australia
| | - Peter J. Crouch
- Department of Pharmacology and Therapeutics The University of Melbourne Parkville Victoria 3052 Australia
| | - Kay L. Double
- Brain and Mind Centre and Discipline of Pharmacology The University of Sydney, Camperdown Sydney New South Wales 2050 Australia
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6
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Draper ACE, Wilson Z, Maile C, Faccenda D, Campanella M, Piercy RJ. Species-specific consequences of an E40K missense mutation in superoxide dismutase 1 (SOD1). FASEB J 2019; 34:458-473. [PMID: 31914665 DOI: 10.1096/fj.201901455r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/25/2019] [Accepted: 10/08/2019] [Indexed: 11/11/2022]
Abstract
A glutamic acid to lysine (E40K) residue substitution in superoxide dismutase 1 (SOD1) is associated with canine degenerative myelopathy: the only naturally occurring large animal model of amyotrophic lateral sclerosis (ALS). The E40 residue is highly conserved across mammals, except the horse, which naturally carries the (dog mutant) K40 residue. Here we hypothesized that in vitro expression of mutant dog SOD1 would recapitulate features of human ALS (ie, SOD1 protein aggregation, reduced cell viability, perturbations in mitochondrial morphology and membrane potential, reduced ATP production, and increased superoxide ion levels); further, we hypothesized that an equivalent equine SOD1 variant would share similar perturbations in vitro, thereby explain horses' susceptibility to certain neurodegenerative diseases. As in human ALS, expression of mutant dog SOD1 was associated with statistically significant increased aggregate formation, raised superoxide levels (ROS), and altered mitochondrial morphology (increased branching (form factor)), when compared to wild-type dog SOD1-expressing cells. Similar deficits were not detected in cells expressing the equivalent horse SOD1 variant. Our data helps explain the ALS-associated cellular phenotype of dogs expressing the mutant SOD1 protein and reveals that species-specific sequence conservation does not necessarily predict pathogenicity. The work improves understanding of the etiopathogenesis of canine degenerative myelopathy.
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Affiliation(s)
- Alexandra C E Draper
- Comparative Neuromuscular Disease Laboratory, Royal Veterinary College, University of London, London, UK
| | - Zoe Wilson
- Comparative Neuromuscular Disease Laboratory, Royal Veterinary College, University of London, London, UK
| | - Charlotte Maile
- Comparative Neuromuscular Disease Laboratory, Royal Veterinary College, University of London, London, UK
| | - Danilo Faccenda
- Mitochondrial Cell Biology and Pharmaceutical Research Unit, Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, UK
| | - Michelangelo Campanella
- Mitochondrial Cell Biology and Pharmaceutical Research Unit, Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, UK.,University College London Consortium for Mitochondrial Research, University College London, University of London, London, UK
| | - Richard J Piercy
- Comparative Neuromuscular Disease Laboratory, Royal Veterinary College, University of London, London, UK
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7
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Zahler CT, Shaw BF. What Are We Missing by Not Measuring the Net Charge of Proteins? Chemistry 2019; 25:7581-7590. [PMID: 30779227 DOI: 10.1002/chem.201900178] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Indexed: 12/21/2022]
Abstract
The net electrostatic charge (Z) of a folded protein in solution represents a bird's eye view of its surface potentials-including contributions from tightly bound metal, solvent, buffer, and cosolvent ions-and remains one of its most enigmatic properties. Few tools are available to the average biochemist to rapidly and accurately measure Z at pH≠pI. Tools that have been developed more recently seem to go unnoticed. Most scientists are content with this void and estimate the net charge of a protein from its amino acid sequence, using textbook values of pKa . Thus, Z remains unmeasured for nearly all folded proteins at pH≠pI. When marveling at all that has been learned from accurately measuring the other fundamental property of a protein-its mass-one wonders: what are we missing by not measuring the net charge of folded, solvated proteins? A few big questions immediately emerge in bioinorganic chemistry. When a single electron is transferred to a metalloprotein, does the net charge of the protein change by approximately one elementary unit of charge or does charge regulation dominate, that is, do the pKa values of most ionizable residues (or just a few residues) adjust in response to (or in concert with) electron transfer? Would the free energy of charge regulation (ΔΔGz ) account for most of the outer sphere reorganization energy associated with electron transfer? Or would ΔΔGz contribute more to the redox potential? And what about metal binding itself? When an apo-metalloprotein, bearing minimal net negative charge (e.g., Z=-2.0) binds one or more metal cations, is the net charge abolished or inverted to positive? Or do metalloproteins regulate net charge when coordinating metal ions? The author's group has recently dusted off a relatively obscure tool-the "protein charge ladder"-and used it to begin to answer these basic questions.
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Affiliation(s)
- Collin T Zahler
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, 76706, USA
| | - Bryan F Shaw
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, 76706, USA
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8
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Kumar Ghosh D, Nanaji Shrikondawar A, Ranjan A. Local structural unfolding at the edge-strands of beta sheets is the molecular basis for instability and aggregation of G85R and G93A mutants of superoxide dismutase 1. J Biomol Struct Dyn 2019; 38:647-659. [DOI: 10.1080/07391102.2019.1584125] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Debasish Kumar Ghosh
- Computational and Functional Genomics Group, Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad, India
- Graduate Studies, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Akshaykumar Nanaji Shrikondawar
- Computational and Functional Genomics Group, Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad, India
- Graduate Studies, Regional Centre for Biotechnology, Faridabad, Haryana, India
| | - Akash Ranjan
- Computational and Functional Genomics Group, Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad, India
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9
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Rasouli S, Abdolvahabi A, Croom CM, Plewman DL, Shi Y, Ayers JI, Shaw BF. Lysine acylation in superoxide dismutase-1 electrostatically inhibits formation of fibrils with prion-like seeding. J Biol Chem 2017; 292:19366-19380. [PMID: 28974578 DOI: 10.1074/jbc.m117.805283] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/28/2017] [Indexed: 11/06/2022] Open
Abstract
The acylation of lysine residues in superoxide dismutase-1 (SOD1) has been previously shown to decrease its rate of nucleation and elongation into amyloid-like fibrils linked to amyotrophic lateral sclerosis. The chemical mechanism underlying this effect is unclear, i.e. hydrophobic/steric effects versus electrostatic effects. Moreover, the degree to which the acylation might alter the prion-like seeding of SOD1 in vivo has not been addressed. Here, we acylated a fraction of lysine residues in SOD1 with groups of variable hydrophobicity, charge, and conformational entropy. The effect of each acyl group on the rate of SOD1 fibril nucleation and elongation were quantified in vitro with thioflavin-T (ThT) fluorescence, and we performed 594 iterate aggregation assays to obtain statistically significant rates. The effect of the lysine acylation on the prion-like seeding of SOD1 was assayed in spinal cord extracts of transgenic mice expressing a G85R SOD1-yellow fluorescent protein construct. Acyl groups with >2 carboxylic acids diminished self-assembly into ThT-positive fibrils and instead promoted the self-assembly of ThT-negative fibrils and amorphous complexes. The addition of ThT-negative, acylated SOD1 fibrils to organotypic spinal cord failed to produce the SOD1 inclusion pathology that typically results from the addition of ThT-positive SOD1 fibrils. These results suggest that chemically increasing the net negative surface charge of SOD1 via acylation can block the prion-like propagation of oligomeric SOD1 in spinal cord.
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Affiliation(s)
- Sanaz Rasouli
- From the Department of Chemistry and Biochemistry and.,the Institute of Biomedical Studies, Baylor University, Waco, Texas 76706 and
| | | | | | | | - Yunhua Shi
- From the Department of Chemistry and Biochemistry and
| | - Jacob I Ayers
- the Department of Neuroscience, University of Florida, Gainesville, Florida 32611
| | - Bryan F Shaw
- From the Department of Chemistry and Biochemistry and
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10
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Dasmeh P, Kepp KP. Superoxide dismutase 1 is positively selected to minimize protein aggregation in great apes. Cell Mol Life Sci 2017; 74:3023-3037. [PMID: 28389720 PMCID: PMC11107616 DOI: 10.1007/s00018-017-2519-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/17/2017] [Accepted: 04/03/2017] [Indexed: 12/14/2022]
Abstract
Positive (adaptive) selection has recently been implied in human superoxide dismutase 1 (SOD1), a highly abundant antioxidant protein with energy signaling and antiaging functions, one of very few examples of direct selection on a human protein product (exon); the molecular drivers of this selection are unknown. We mapped 30 extant SOD1 sequences to the recently established mammalian species tree and inferred ancestors, key substitutions, and signatures of selection during the protein's evolution. We detected elevated substitution rates leading to great apes (Hominidae) at ~1 per 2 million years, significantly higher than in other primates and rodents, although these paradoxically generally evolve much faster. The high evolutionary rate was partly due to relaxation of some selection pressures and partly to distinct positive selection of SOD1 in great apes. We then show that higher stability and net charge and changes at the dimer interface were selectively introduced upon separation from old world monkeys and lesser apes (gibbons). Consequently, human, chimpanzee and gorilla SOD1s have a net charge of -6 at physiological pH, whereas the closely related gibbons and macaques have -3. These features consistently point towards selection against the malicious aggregation effects of elevated SOD1 levels in long-living great apes. The findings mirror the impact of human SOD1 mutations that reduce net charge and/or stability and cause ALS, a motor neuron disease characterized by oxidative stress and SOD1 aggregates and triggered by aging. Our study thus marks an example of direct selection for a particular chemical phenotype (high net charge and stability) in a single human protein with possible implications for the evolution of aging.
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Affiliation(s)
- Pouria Dasmeh
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Department of Biochemistry and Cedergren Center for Bioinformatics and Genomics, Faculty of Medicine, University of Montreal, 2900 Edouard-Montpetit, Montreal, QC, H3T 1J4, Canada
| | - Kasper P Kepp
- Technical University of Denmark, DTU Chemistry, 2800, Kongens Lyngby, Denmark.
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11
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Kyne C, Jordon K, Filoti DI, Laue TM, Crowley PB. Protein charge determination and implications for interactions in cell extracts. Protein Sci 2017; 26:258-267. [PMID: 27813264 PMCID: PMC5275725 DOI: 10.1002/pro.3077] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/24/2016] [Accepted: 10/27/2016] [Indexed: 01/30/2023]
Abstract
Decades of dilute-solution studies have revealed the influence of charged residues on protein stability, solubility and stickiness. Similar characterizations are now required in physiological solutions to understand the effect of charge on protein behavior under native conditions. Toward this end, we used free boundary and native gel electrophoresis to explore the charge of cytochrome c in buffer and in Escherichia coli extracts. We find that the charge of cytochrome c was ∼2-fold lower than predicted from primary structure analysis. Cytochrome c charge was tuned by sulfate binding and was rendered anionic in E. coli extracts due to interactions with macroanions. Mutants in which three or four cationic residues were replaced with glutamate were charge-neutral and "inert" in extracts. A comparison of the interaction propensities of cytochrome c and the mutants emphasizes the role of negative charge in stabilizing physiological environments. Charge-charge repulsion and preferential hydration appear to prevent aggregation. The implications for molecular organization in vivo are discussed.
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Affiliation(s)
- Ciara Kyne
- School of ChemistryNational University of IrelandGalway, University RoadGalwayIreland
| | - Kiara Jordon
- Spin Analytical468 Portland StreetBerwickMaine03901
| | - Dana I. Filoti
- Centre to Advance Macromolecular Interaction Sciences University of New HampshireDurhamNew Hampshire03824
| | - Thomas M. Laue
- Spin Analytical468 Portland StreetBerwickMaine03901
- Centre to Advance Macromolecular Interaction Sciences University of New HampshireDurhamNew Hampshire03824
| | - Peter B. Crowley
- School of ChemistryNational University of IrelandGalway, University RoadGalwayIreland
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12
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Shi Y, Acerson MJ, Abdolvahabi A, Mowery RA, Shaw BF. Gibbs Energy of Superoxide Dismutase Heterodimerization Accounts for Variable Survival in Amyotrophic Lateral Sclerosis. J Am Chem Soc 2016; 138:5351-62. [DOI: 10.1021/jacs.6b01742] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yunhua Shi
- Department of Chemistry and
Biochemistry, Baylor University, Waco, Texas 76798-7348, United States
| | - Mark J. Acerson
- Department of Chemistry and
Biochemistry, Baylor University, Waco, Texas 76798-7348, United States
| | - Alireza Abdolvahabi
- Department of Chemistry and
Biochemistry, Baylor University, Waco, Texas 76798-7348, United States
| | - Richard A. Mowery
- Department of Chemistry and
Biochemistry, Baylor University, Waco, Texas 76798-7348, United States
| | - Bryan F. Shaw
- Department of Chemistry and
Biochemistry, Baylor University, Waco, Texas 76798-7348, United States
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13
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Abdolvahabi A, Shi Y, Rhodes NR, Cook NP, Martí AA, Shaw BF. Arresting amyloid with coulomb's law: acetylation of ALS-linked SOD1 by aspirin impedes aggregation. Biophys J 2016; 108:1199-212. [PMID: 25762331 DOI: 10.1016/j.bpj.2015.01.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 12/04/2014] [Accepted: 01/13/2015] [Indexed: 12/15/2022] Open
Abstract
Although the magnitude of a protein's net charge (Z) can control its rate of self-assembly into amyloid, and its interactions with cellular membranes, the net charge of a protein is not viewed as a druggable parameter. This article demonstrates that aspirin (the quintessential acylating pharmacon) can inhibit the amyloidogenesis of superoxide dismutase (SOD1) by increasing the intrinsic net negative charge of the polypeptide, i.e., by acetylation (neutralization) of multiple lysines. The protective effects of acetylation were diminished (but not abolished) in 100 mM NaCl and were statistically significant: a total of 432 thioflavin-T amyloid assays were performed for all studied proteins. The acetylation of as few as three lysines by aspirin in A4V apo-SOD1-a variant that causes familial amyotrophic lateral sclerosis (ALS)-delayed amyloid nucleation by 38% and slowed amyloid propagation by twofold. Lysines in wild-type- and ALS-variant apo-SOD1 could also be peracetylated with aspirin after fibrillization, resulting in supercharged fibrils, with increases in formal net charge of ∼2 million units. Peracetylated SOD1 amyloid defibrillized at temperatures below unacetylated fibrils, and below the melting temperature of native Cu2,Zn2-SOD1 (e.g., fibril Tm = 84.49°C for acetylated D90A apo-SOD1 fibrils). Targeting the net charge of native or misfolded proteins with small molecules-analogous to how an enzyme's Km or Vmax are medicinally targeted-holds promise as a strategy in the design of therapies for diseases linked to protein self-assembly.
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Affiliation(s)
| | - Yunhua Shi
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas
| | - Nicholas R Rhodes
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas
| | - Nathan P Cook
- Department of Chemistry, Rice University, Houston, Texas
| | - Angel A Martí
- Department of Chemistry, Rice University, Houston, Texas; Department of Bioengineering, Rice University, Houston, Texas
| | - Bryan F Shaw
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas.
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14
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Shi Y, Acerson MJ, Shuford KL, Shaw BF. Voltage-Induced Misfolding of Zinc-Replete ALS Mutant Superoxide Dismutase-1. ACS Chem Neurosci 2015. [PMID: 26207449 DOI: 10.1021/acschemneuro.5b00146] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The monomerization of Cu, Zn superoxide dismutase (SOD1) is an early step along pathways of misfolding linked to amyotrophic lateral sclerosis (ALS). Monomerization requires the reversal of two post-translational modifications that are thermodynamically favorable: (i) dissociation of active-site metal ions and (ii) reduction of intramolecular disulfide bonds. This study found, using amide hydrogen/deuterium (H/D) exchange, capillary electrophoresis, and lysine-acetyl protein charge ladders, that ALS-linked A4V SOD1 rapidly monomerizes and partially unfolds in an external electric field (of physiological strength), without loss of metal ions, exposure to disulfide-reducing agents, or Joule heating. Voltage-induced monomerization was not observed for metal-free A4V SOD1, metal-free WT SOD1, or metal-loaded WT SOD1. Computational modeling suggested a mechanism for this counterintuitive effect: subunit macrodipoles of dimeric SOD1 are antiparallel and amplified 2-fold by metal coordination, which increases torque at the dimer interface as subunits rotate to align with the electric field.
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Affiliation(s)
- Yunhua Shi
- Department
of Chemistry and
Biochemistry, Baylor University, Waco, Texas 76706, United States
| | - Mark J. Acerson
- Department
of Chemistry and
Biochemistry, Baylor University, Waco, Texas 76706, United States
| | - Kevin L. Shuford
- Department
of Chemistry and
Biochemistry, Baylor University, Waco, Texas 76706, United States
| | - Bryan F. Shaw
- Department
of Chemistry and
Biochemistry, Baylor University, Waco, Texas 76706, United States
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Roudeau S, Chevreux S, Carmona A, Ortega R. Reduced net charge and heterogeneity of pI isoforms in familial amyotrophic lateral sclerosis mutants of copper/zinc superoxide dismutase. Electrophoresis 2015; 36:2482-8. [PMID: 26084641 DOI: 10.1002/elps.201500187] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 05/23/2015] [Accepted: 05/25/2015] [Indexed: 01/20/2023]
Abstract
Familial cases of amyotrophic lateral sclerosis (fALS) are related to mutations of copper/zinc superoxide dismutase 1 (SOD1). Aggregation of SOD1 plays a central role in the pathogenesis of fALS and altered metallation of SOD1 mutants could be involved in this process. Using IEF gel electrophoresis under non-denaturating conditions and particle induced X-ray emission (PIXE) analysis, we studied the pI distribution and metallation status of fALS SOD1 mutants (A4V, G93A, D125H) compared to human wild-type (hWT). SOD1 fALS mutants are characterized by a variable number of isoforms and higher pI compared to hWT, reflecting a reduced net charge that might explain their greater propensity to precipitation and aggregation. Cu/Zn ratios were slightly different for the predominant expressed isoforms of A4V, G93A, and D125H mutants compared to hWT. Differences in metallation were observed within each genotype, the more basic isoforms exhibiting lower Cu/Zn ratios. Moreover, we revealed the existence of a pool of fALS mutants SOD1 pI isoforms, slightly expressed (<10%), with a low Cu/Zn ratio and high pI values. Overall, IEF-PIXE results suggest that the toxicity of SOD1 mutants should be studied at the pI isoform level with a particular attention to the species with the lowest charges.
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Affiliation(s)
- Stéphane Roudeau
- University of Bordeaux, CENBG, UMR 5797, Gradignan, France.,CNRS, IN2P3, CENBG, UMR 5797, Gradignan, France
| | - Sylviane Chevreux
- University of Bordeaux, CENBG, UMR 5797, Gradignan, France.,CNRS, IN2P3, CENBG, UMR 5797, Gradignan, France
| | - Asuncion Carmona
- University of Bordeaux, CENBG, UMR 5797, Gradignan, France.,CNRS, IN2P3, CENBG, UMR 5797, Gradignan, France
| | - Richard Ortega
- University of Bordeaux, CENBG, UMR 5797, Gradignan, France.,CNRS, IN2P3, CENBG, UMR 5797, Gradignan, France
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