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Pratt AJ, DiDonato M, Shin DS, Cabelli DE, Bruns CK, Belzer CA, Gorringe AR, Langford PR, Tabatabai LB, Kroll JS, Tainer JA, Getzoff ED. Structural, Functional, and Immunogenic Insights on Cu,Zn Superoxide Dismutase Pathogenic Virulence Factors from Neisseria meningitidis and Brucella abortus. J Bacteriol 2015; 197:3834-47. [PMID: 26459556 PMCID: PMC4652047 DOI: 10.1128/jb.00343-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 09/29/2015] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED Bacterial pathogens Neisseria meningitidis and Brucella abortus pose threats to human and animal health worldwide, causing meningococcal disease and brucellosis, respectively. Mortality from acute N. meningitidis infections remains high despite antibiotics, and brucellosis presents alimentary and health consequences. Superoxide dismutases are master regulators of reactive oxygen and general pathogenicity factors and are therefore therapeutic targets. Cu,Zn superoxide dismutases (SODs) localized to the periplasm promote survival by detoxifying superoxide radicals generated by major host antimicrobial immune responses. We discovered that passive immunization with an antibody directed at N. meningitidis SOD (NmSOD) was protective in a mouse infection model. To define the relevant atomic details and solution assembly states of this important virulence factor, we report high-resolution and X-ray scattering analyses of NmSOD and of SOD from B. abortus (BaSOD). The NmSOD structures revealed an auxiliary tetrahedral Cu-binding site bridging the dimer interface; mutational analyses suggested that this metal site contributes to protein stability, with implications for bacterial defense mechanisms. Biochemical and structural analyses informed us about electrostatic substrate guidance, dimer assembly, and an exposed C-terminal epitope in the NmSOD dimer. In contrast, the monomeric BaSOD structure provided insights for extending immunogenic peptide epitopes derived from the protein. These collective results reveal unique contributions of SOD to pathogenic virulence, refine predictive motifs for distinguishing SOD classes, and suggest general targets for antibacterial immune responses. The identified functional contributions, motifs, and targets distinguishing bacterial and eukaryotic SOD assemblies presented here provide a foundation for efforts to develop SOD-specific inhibitors of or vaccines against these harmful pathogens. IMPORTANCE By protecting microbes against reactive oxygen insults, SODs aid survival of many bacteria within their hosts. Despite the ubiquity and conservation of these key enzymes, notable species-specific differences relevant to pathogenesis remain undefined. To probe mechanisms that govern the functioning of Neisseria meningitidis and Brucella abortus SODs, we used X-ray structures, enzymology, modeling, and murine infection experiments. We identified virulence determinants common to the two homologs, assembly differences, and a unique metal reservoir within meningococcal SOD that stabilizes the enzyme and may provide a safeguard against copper toxicity. The insights reported here provide a rationale and a basis for SOD-specific drug design and an extension of immunogen design to target two important pathogens that continue to pose global health threats.
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Affiliation(s)
- Ashley J Pratt
- Department of Integrative Structural and Computational Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, USA Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Michael DiDonato
- Department of Integrative Structural and Computational Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, USA
| | - David S Shin
- Department of Integrative Structural and Computational Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, USA Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Diane E Cabelli
- Chemistry Department, Brookhaven National Laboratory, Upton, New York, USA
| | - Cami K Bruns
- Department of Integrative Structural and Computational Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, USA
| | - Carol A Belzer
- National Animal Disease Center, Ruminant Diseases and Immunology, Ames, Iowa, USA
| | | | - Paul R Langford
- Section of Paediatrics, Department of Medicine, Imperial College London, St. Mary's Campus, London, England, United Kingdom
| | - Louisa B Tabatabai
- National Animal Disease Center, Ruminant Diseases and Immunology, Ames, Iowa, USA
| | - J Simon Kroll
- Section of Paediatrics, Department of Medicine, Imperial College London, St. Mary's Campus, London, England, United Kingdom
| | - John A Tainer
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA
| | - Elizabeth D Getzoff
- Department of Integrative Structural and Computational Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, USA
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2
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Gottfredsen RH, Goldstrohm DA, Hartney JM, Larsen UG, Bowler RP, Petersen SV. The cellular distribution of extracellular superoxide dismutase in macrophages is altered by cellular activation but unaffected by the naturally occurring R213G substitution. Free Radic Biol Med 2014; 69:348-56. [PMID: 24512907 PMCID: PMC4440334 DOI: 10.1016/j.freeradbiomed.2014.01.038] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 01/09/2014] [Accepted: 01/30/2014] [Indexed: 11/17/2022]
Abstract
Extracellular superoxide dismutase (EC-SOD) is responsible for the dismutation of the superoxide radical produced in the extracellular space and known to be expressed by inflammatory cells, including macrophages and neutrophils. Here we show that EC-SOD is produced by resting macrophages and associated with the cell surface via the extracellular matrix (ECM)-binding region. Upon cellular activation induced by lipopolysaccharide, EC-SOD is relocated and detected both in the cell culture medium and in lipid raft structures. Although the secreted material presented a significantly reduced ligand-binding capacity, this could not be correlated to proteolytic removal of the ECM-binding region, because the integrity of the material recovered from the medium was comparable to that of the cell surface-associated protein. The naturally occurring R213G amino acid substitution located in the ECM-binding region of EC-SOD is known to affect the binding characteristics of the protein. However, the analysis of macrophages expressing R213G EC-SOD did not present evidence of an altered cellular distribution. Our results suggest that EC-SOD plays a dynamic role in the inflammatory response mounted by activated macrophages.
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Affiliation(s)
| | | | - John M Hartney
- Department of Medicine, National Jewish Health, Denver, CO 80206, USA
| | - Ulrike G Larsen
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus, Denmark
| | - Russell P Bowler
- Department of Medicine, National Jewish Health, Denver, CO 80206, USA
| | - Steen V Petersen
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus, Denmark.
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3
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Achard-Joris M, Moreau JL, Lucas M, Baudrimont M, Mesmer-Dudons N, Gonzalez P, Boudou A, Bourdineaud JP. Role of metallothioneins in superoxide radical generation during copper redox cycling: Defining the fundamental function of metallothioneins. Biochimie 2007; 89:1474-88. [PMID: 17681660 DOI: 10.1016/j.biochi.2007.06.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Accepted: 06/12/2007] [Indexed: 10/23/2022]
Abstract
In order to demonstrate the in vivo antioxidant properties of metallothioneins (MTs), the bacteria Escherichia coli was used as a cell reactor in which we compared the metal binding and antioxidative functions of MTs from different species, with different structures and polypeptide lengths. No protective effects of cytoplasmic MTs from cadmium (Cd) or zinc (Zn) contamination were observed in a wild-type E. coli strain, although these MTs can efficiently bind both Cd and Zn. To test their antioxidant properties, MTs were expressed within the cytoplasm of a sodA sodB deficient mutated strain (QC1726). However, a paradoxical MT toxicity was found when this strain was contaminated with Cd and Zn, suggesting that in a wild-type strain, superoxide dismutase counteracts MT toxicity. The most toxic MT was the one with the strongest Cd and Zn binding capacities. This toxic effect was linked to the generation of superoxide radicals, since a Cd-contaminated QC1726 strain expressing oyster MT isoforms produced 75-85% more O(2)*(-) than the control QC1726 strain. Conversely, under anaerobiosis or in the presence of a copper chelator, MTs protected QC1726 strain from Cd and Zn contamination. A model is proposed to explain the observed MT toxicity.
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Affiliation(s)
- Maud Achard-Joris
- UMR 5805 CNRS - Université Bordeaux 1, Team Géochimie et Ecotoxicologie des Métaux dans les systèmes Aquatiques, Station Marine d'Arcachon, Place du Dr. Peyneau, 33120 Arcachon, France
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4
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Abstract
The proteinaceous aggregates rich in copper, zinc superoxide dismutase (SOD1) have been shown to be involved in pathogenesis of amyotrophic lateral sclerosis (ALS). Since negatively charged species such as nucleic acids have frequently been found associated with the proteinaceous deposits in the tissues of patients with amyloid diseases, we examined here the aggregation behavior of SOD1 in the presence of DNA under acidic conditions that facilitate protein aggregation. Several forms of double-stranded DNA were tested to trigger SOD1 aggregation by light scattering, single- and double-fluorescence imaging with dyes, atomic force microscopy, and direct observations under visible light. The results reveal that DNA acts as a template for accelerating the formation of SOD1 aggregates and is incorporated into SOD1 aggregates. The spherical and ellipsoidal SOD1 aggregates were characterized in both hydrated and dried states and have morphology similar to those identified in the diseased neurons. Light scattering experiments indicate that the aggregation first undergoes a rapid phase where the aggregates with average diameters of 40-80 nm rapidly form in <2 min, and then passes through a slow phase where the average diameters of aggregates were increased to at least 200-260 nm in 2 h. All forms of DNAs tested can lead to the aggregation of SOD1 at nanomolar levels. The association of SOD1 with DNA, driven by electrostatic interactions between both, can restrict the orientation of SOD1 molecules and increase a SOD1 population along DNA strands. This facilitates the hydrophobic interactions between SOD1 molecules, as indicated by hydrophobic probe binding and chemical denaturant treatment experiments. Demonstration of the DNA-accelerated aggregation of SOD1 might establish a possible role of DNA in the pathogenesis of some diseases because of the ubiquitous expression of SOD1 and the coexistence of SOD1 and DNA in the crowded molecular environment of a cell.
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Affiliation(s)
- Wei Jiang
- Department of Chemistry, Huazhong University of Science and Technology, Wuhan 430074, China
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5
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Giovagnoli S, Luca G, Casaburi I, Blasi P, Macchiarulo G, Ricci M, Calvitti M, Basta G, Calafiore R, Rossi C. Long-term delivery of superoxide dismutase and catalase entrapped in poly(lactide-co-glycolide) microspheres: In vitro effects on isolated neonatal porcine pancreatic cell clusters. J Control Release 2005; 107:65-77. [PMID: 15993507 DOI: 10.1016/j.jconrel.2005.05.021] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2005] [Revised: 05/12/2005] [Accepted: 05/19/2005] [Indexed: 11/16/2022]
Abstract
To counterbalance the restricted availability of pancreatic islet tissue for transplant in Type 1 Diabetes Mellitus (T1DM), new methods to provide viable and functional islet cells need to be established. We report on our approach to enhance in vitro viability and function of isolated neonatal pancreatic porcine cell clusters (NPCCs) by co-culturing them with PLGA microsphere entrapped, slowly release superoxide dismutase and catalase. These powerful antioxidizing agents were shown to significantly improve morphology, viability and function, as assessed by microscopy, molecular, biochemical and functional studies, of the incubated NPCCs, as compared to control. Preliminarily, in vitro exposure of isolated NPCCs to slow release microsphere-embedded SOD and CAT could permit or contribute to overcome hurdles associated with scarcity in islet tissue procurement for transplant in T1DM.
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Affiliation(s)
- Stefano Giovagnoli
- Department of Chemistry and Technology of Drugs, Faculty of Pharmacy, University of Perugia, Via del Liceo 1, Perugia 06123, Italy.
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Banci L, Bertini I, Calderone V, Cramaro F, Del Conte R, Fantoni A, Mangani S, Quattrone A, Viezzoli MS. A prokaryotic superoxide dismutase paralog lacking two Cu ligands: from largely unstructured in solution to ordered in the crystal. Proc Natl Acad Sci U S A 2005; 102:7541-6. [PMID: 15897454 PMCID: PMC1140445 DOI: 10.1073/pnas.0502450102] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2004] [Indexed: 11/18/2022] Open
Abstract
Little is known about prokaryotic homologs of Cu,Zn superoxide dismutase (SOD), an enzyme highly conserved among eukaryotic species. In 138 Archaea and Bacteria genomes, 57 of these putative homologs were found, 11 of which lack at least one of the metal ligands. Both the solution and the crystal structures of the SOD-like protein from Bacillus subtilis, lacking two Cu ligands and found to be enzymatically inactive, were determined. In solution, the protein is monomeric. The available nuclear Overhauser effects, together with chemical-shift index values, allowed us to define and to recognize the typical Cu,Zn SOD Greek beta-barrel but with largely unstructured loops (which, therefore, sample a wide range of conformations). On the contrary, in the crystal structure (obtained in the presence of slight excess of Zn), the protein is well structured and organized in covalent dimers held by a symmetric bridge consisting of a Zn ion bound to an Asp-His dyad in a tetrahedral geometry. Couples of dimers held by hydrophobic interactions and H bonds are further organized in long chains. The order/disorder transition is discussed in terms of metal binding and physical state.
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Affiliation(s)
- Lucia Banci
- Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019 Sesto, Florence, Italy
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7
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Ray SS, Nowak RJ, Strokovich K, Brown RH, Walz T, Lansbury PT. An Intersubunit Disulfide Bond Prevents in Vitro Aggregation of a Superoxide Dismutase-1 Mutant Linked to Familial Amytrophic Lateral Sclerosis. Biochemistry 2004; 43:4899-905. [PMID: 15109247 DOI: 10.1021/bi030246r] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Familial amyotrophic lateral sclerosis (FALS) is linked to over 90 point mutations in superoxide dismutase-1 (SOD1), a dimeric metalloenzyme. The postmortem FALS brain is characterized by SOD1 inclusions in the motor neurons of regions in which neuronal loss is most significant. These findings, together with animal modeling studies, suggest that aggregation of mutant SOD1 produces a pathogenic species. We demonstrate here that a mutant form of SOD1 (A4V) that is linked to a particularly aggressive form of FALS aggregates in vitro, while wild-type SOD1 (WT) is stable. Some A4V aggregates resemble amyloid pores formed by other disease-associated proteins. The WT dimer is significantly more stable than the A4V dimer, suggesting that dimer dissociation may be the required first step of aggregation. To test this hypothesis, an intersubunit disulfide bond between symmetry-related residues at the A4V dimer interface was introduced. The resultant disulfide bond (V148C-V148C') eliminated the concentration-dependent loss of enzymatic activity of A4V, stabilized the A4V dimer, and completely abolished aggregation. A drug-like molecule that could stabilize the A4V dimer could slow the onset and progression of FALS.
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Affiliation(s)
- Soumya S Ray
- Harvard Center for Neurodegeneration and Repair and Department of Neurology, Harvard Medical School, Boston, Massachusetts 02115, USA.
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8
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Bendotti C, Atzori C, Piva R, Tortarolo M, Strong MJ, DeBiasi S, Migheli A. Activated p38MAPK Is a Novel Component of the Intracellular Inclusions Found in Human Amyotrophic Lateral Sclerosis and Mutant SOD1 Transgenic Mice. J Neuropathol Exp Neurol 2004; 63:113-9. [PMID: 14989597 DOI: 10.1093/jnen/63.2.113] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cytoskeletal abnormalities with accumulation of ubiquilated inclusions in the anterior horn cells are a pathological hallmark of both familial and sporadic amyotrophic lateral sclerosis (ALS) and of mouse models for ALS. Phosphorylated neurofilaments besides ubiquitin and dorfin have been identified as one of the major components of the abnormal intracellular perikaryal aggregates. As we recently found that p38 mitogen-activated protein kinase (p38MAPK) colocalized with phosphorylated neurofilaments in spinal motor neurons of SOD1 mutant mice, a model of familial ALS, we investigated whether this kinase also contributed to the inclusions found in ALS patients and SOD1 mutant mice. Intense immunoreactivity for activated p38MAPK was observed in degenerating motor neurons and reactive astrocytes in ALS cases. The intracellular immunostaining for activated p38MAPK appeared in some neurons as filamentous skein-like and ball-like inclusions, with an immunohistochemical pattern identical to that of ubiquitin. Intracellular p38MAPK-positive aggregates containing ubiquitin and neurofilaments were also found in the spinal motor neurons of SOD1 mutant mice. Our observations indicate that activation of p38MAPK might contribute significantly to the pathology of motor neurons in ALS.
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Affiliation(s)
- Caterina Bendotti
- Laboratory of Molecular Neurobiology, Dept. Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri, Via Eritrea, 62, 20157 Milano, Italy.
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9
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Stathopulos PB, Rumfeldt JAO, Scholz GA, Irani RA, Frey HE, Hallewell RA, Lepock JR, Meiering EM. Cu/Zn superoxide dismutase mutants associated with amyotrophic lateral sclerosis show enhanced formation of aggregates in vitro. Proc Natl Acad Sci U S A 2003; 100:7021-6. [PMID: 12773627 PMCID: PMC165823 DOI: 10.1073/pnas.1237797100] [Citation(s) in RCA: 203] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Mutations in Cu/Zn superoxide dismutase (SOD) are associated with the fatal neurodegenerative disorder amyotrophic lateral sclerosis (ALS). There is considerable evidence that mutant SOD has a gain of toxic function; however, the mechanism of this toxicity is not known. We report here that purified SOD forms aggregates in vitro under destabilizing solution conditions by a process involving a transition from small amorphous species to fibrils. The assembly process and the tinctorial and structural properties of the in vitro aggregates resemble those for aggregates observed in vivo. Furthermore, the familial ALS SOD mutations A4V, G93A, G93R, and E100G decrease protein stability, which correlates with an increase in the propensity of the mutants to form aggregates. These mutations also increase the rate of protein unfolding. Our results suggest three possible mechanisms for the increase in aggregation: (i) an increase in the equilibrium population of unfolded or of partially unfolded states, (ii) an increase in the rate of unfolding, and (iii) a decrease in the rate of folding. Our data support the hypothesis that the gain of toxic function for many different familial ALS-associated mutant SODs is a consequence of protein destabilization, which leads to an increase in the formation of cytotoxic protein aggregates.
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Affiliation(s)
- P B Stathopulos
- Guelph-Waterloo Centre for Graduate Studies in Chemistry and Biochemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1
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10
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Luquin MR, Saldise L. [Dopaminergic system and neuronal death]. Rev Neurol 1997; 25 Suppl 2:S129-40. [PMID: 9280679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The mechanism involved in dopaminergic neuronal death remains unknown. Increased oxidative stress, inhibition of mitochondrial respiratory chain and apoptosis have been suggested as possible factors mediating cellular death. This article reviews the most important findings reported in parkinsonian brains related to nigral neuronal death.
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Affiliation(s)
- M R Luquin
- Departamento de Neurología y Neurocirugía, Clínica Universitaria de Navarra, Facultad de Medicina, Pamplona, España
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11
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Abstract
Distributions of the copper/zinc-superoxide dismutase (Cu/Zn-SOD) and the manganese superoxide dismutase (Mn-SOD) in the rat cochlea were studied by immunohistochemistry with specific polyclonal antibodies to Mn-SOD and Cu/Zn-SOD. Coexpression of Mn-SOD and Cu/Zn-SOD was observed in the cochlear tissues with differing immunoactivity intensities. The presence of Cu/Zn- and Mn-SOD implies the existence of a defense system against free oxygen radical (FOR) injury in cochlear tissues.
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Affiliation(s)
- K E Rarey
- Department of Anatomy & Cell Biology, College of Medicine, University of Florida, Gainesville 32610, USA
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12
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Lai MT, Ohmichi T, Miyahara S, Mori A, Masuda Y. Superoxide dismutases in human palatine tonsils. Acta Otolaryngol Suppl 1996; 523:120-3. [PMID: 9082755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In order to investigate the protective system of human palatine tonsils against the cytotoxic superoxide radicals (O(-)(2)) generated from the oxygen-related bactericidal system, immunohistochemistry and electron spin resonance (ESR) spectrometry were used to detect the distribution and activities of superoxide dismutases (SODs) in tonsils of different related systemic diseases. Immunohistochemistry showed that SODs distribute in extrafollicular lymphatic tissue and crypt epithelium. No distribution difference could be found between tonsils of different related systemic diseases. ESR revealed no significant difference between SODs activities in tonsils of different related systemic diseases. However, the mitochondrial SOD activity was found to constitute approximately 50%-60% of the total tonsillar cellular SODs activity. The results suggest: i)tonsils possess the ability to control cytotoxic O(-)(2), ii) crypt epithelium and extrafollicular lymphatic tissue may encounter more O(-)(2) threat, iii) SODs may be important in protecting germinal centers from O(-)(2) injury, and iv) systemic diseases are less related to the local expression of tonsillar SODs.
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Affiliation(s)
- M T Lai
- Department of Otolaryngology, Okayama University Medical School, Japan
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13
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Cooper JB, Driessen HP, Wood SP, Zhang Y, Young D. Crystallization and preliminary X-ray analysis of the superoxide dismutase from Mycobacterium tuberculosis. J Mol Biol 1994; 235:1156-8. [PMID: 8289318 DOI: 10.1006/jmbi.1994.1068] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The iron-dependent superoxide dismutase from Mycobacterium tuberculosis has been crystallized by the hanging drop method. The crystals belong to the P2(1) space group and have unit cell dimensions of a = 68.5 A, b = 85.6 A, c = 66.5 A, beta = 99.8 degrees. There are four molecules per asymmetric unit which, from analysis of data to 2.5 A, appear to be related by non-crystallographic 222 symmetry.
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Affiliation(s)
- J B Cooper
- Laboratory of Molecular Biology, Birkbeck College, London, England
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14
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Head-Gordon T, Stillinger FH, Wright MH, Gay DM. Poly(L-alanine) as a universal reference material for understanding protein energies and structures. Proc Natl Acad Sci U S A 1992; 89:11513-7. [PMID: 1454840 PMCID: PMC50582 DOI: 10.1073/pnas.89.23.11513] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
We present a proposition, the "poly(L-alanine) hypothesis," which asserts that the native backbone geometry for any polypeptide or protein of M residues has a closely mimicking, mechanically stable, image in poly(L-alanine) of the same number of residues. Using a molecular mechanics force field to represent the relevant potential energy hypersurfaces, we have carried out calculations over a wide range of M values to show that poly(L-alanine) possesses the structural versatility necessary to satisfy the proposition. These include poly(L-alanine) representatives of minima corresponding to secondary and supersecondary structures, as well as poly(L-alanine) images for tertiary structures of the naturally occurring proteins bovine pancreatic trypsin inhibitor, crambin, ribonuclease A, and superoxide dismutase. The successful validation of the hypothesis presented in this paper indicates that poly(L-alanine) will serve as a good reference material in thermodynamic perturbation theory and calculations aimed at evaluating relative free energies for competing candidate tertiary structures in real polypeptides and proteins.
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15
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Parge HE, Hallewell RA, Tainer JA. Atomic structures of wild-type and thermostable mutant recombinant human Cu,Zn superoxide dismutase. Proc Natl Acad Sci U S A 1992; 89:6109-13. [PMID: 1463506 PMCID: PMC49447 DOI: 10.1073/pnas.89.13.6109] [Citation(s) in RCA: 232] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Superoxide dismutase enzymes protect aerobic organisms from oxygen-mediated free-radical damage. Crystallographic structures of recombinant human Cu,Zn superoxide dismutase have been determined, refined, and analyzed at 2.5 A resolution for wild-type and a designed thermostable double-mutant enzyme (Cys-6----Ala, Cys-111----Ser). The 10 subunits (five dimers) in the crystallographic asymmetric unit form an unusual stable open lattice with 80-A-diameter channels. The 10 independently fit and refined subunits provide high accuracy, error analysis, and insights on loop conformations. There is a helix dipole interaction with the Zn site, and 14 residues form two or more structurally conserved side-chain to main-chain hydrogen bonds that appear critical to active-site architecture, loop conformation, and the increased stability resulting from the Cys-111----Ser mutation.
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Affiliation(s)
- H E Parge
- Department of Molecular Biology, Scripps Research Institute, La Jolla, CA 92037
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16
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Djinovic K, Gatti G, Coda A, Antolini L, Pelosi G, Desideri A, Falconi M, Marmocchi F, Rotilio G, Bolognesi M. Crystal structure of yeast Cu,Zn superoxide dismutase. Crystallographic refinement at 2.5 A resolution. J Mol Biol 1992; 225:791-809. [PMID: 1602482 DOI: 10.1016/0022-2836(92)90401-5] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The structure of Cu,Zn yeast superoxide dismutase has been determined to 2.5 A resolution. The enzyme crystallizes in the P2(1)2(1)2 space group with two dimeric enzyme molecules per asymmetric unit. The structure has been solved by molecular replacement techniques using the dimer of the bovine enzyme as the search model, and refined by molecular dynamics with crystallographic pseudo-energy terms, followed by conventional crystallographic restrained refinement. The R-factor for 32,088 unique reflections in the 10.0 to 2.5 A resolution range (98.2% of all possible reflections) is 0.158 for a model comprising two protein dimers and 516 bound solvent molecules, with a root-mean-square deviation of 0.016 A from the ideal bond lengths, and an average B-factor value of 29.9 A2. A dimeric molecule of the enzyme is composed of two identical subunits related by a non-crystallographic 2-fold axis. Each subunit (153 amino acid residues) has as its structural scaffolding a flattened antiparallel eight-stranded beta-barrel, plus three external loops. The overall three-dimensional structure is quite similar to the phylogenetically distant bovine superoxide dismutase (55% amino acid homology), the largest deviations can be observed in the regions of amino acid insertions. The major insertion site hosting residues Ser25A and Gly25B, occurs in the 2,3 beta-turn between strands 2b and 3c, resulting in the structural perturbations of the two neighbouring strands. The second insertion site, at the end of the 3c beta-strand in the wide Greek-key loop, hosts the Asn35A residue, having an evident effect on the structure of the loop and possibly on the neighbouring 5,4 beta-turn. The salt bridge Arg77-Asp99 and the disulphide bridge Cys55-Cys144 stabilize the loop regions containing the metal ligands. The stereochemistry of the two metal centres is conserved, with respect to the bovine enzyme. The Cu2+ ligands show an uneven distortion from a square plane, while Zn2+ co-ordination geometry is distorted tetrahedral. The imidazole ring of the His61 residue forms a bridge between Cu and Zn ions. A solvent peak compatible with a fifth ligand is observed 2.0 A away from the copper in the active site channel, which is filled by ordered water molecules that possibly contribute to the stability and function of the enzyme. The charged residues responsible for the electrostatic guidance of the substrate to the active site (Glu130, Glu131, Lys134 and Arg141) are fairly conserved in their positions, some of them showing different interactions in the four chains due to the intermolecular contacts between the dimers.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- K Djinovic
- Dipartimento di Genetica e Microbiologia, Università di Pavia, Italy
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Affiliation(s)
- L E Greenwade
- Idaho National Engineering Laboratory, Idaho Falls 83415
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