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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] [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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Tuteja N, Mishra P, Yadav S, Tajrishi M, Baral S, Sabat SC. Heterologous expression and biochemical characterization of a highly active and stable chloroplastic CuZn-superoxide dismutase from Pisum sativum. BMC Biotechnol 2015; 15:3. [PMID: 25887674 PMCID: PMC4333176 DOI: 10.1186/s12896-015-0117-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 01/27/2015] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND CuZn-Superoxide dismutase (SOD) is a unique enzyme, which can catalyzes the dismutation of inevitable metabolic product i.e.; superoxide anion into molecular oxygen and hydrogen peroxide. The enzyme has gained wide interest in pharmaceutical industries due to its highly acclaimed antioxidative properties. The recombinant expression of this protein in its enzymatically active and stable form is highly desired and hence optimization of culture conditions and characterization of the related biochemical properties are essential to explore the significance of the enzyme in physiological, therapeutic, structural and transgenic research. RESULTS High-level expression of the chloroplastic isoform of Pisum sativum CuZn-SOD was achieved at 18°C, upon isopropyl β-D-1-thiogalactopyranoside induction and the process was optimized for maximum recovery of the protein in its soluble (enzymatically active) form. Both crude and purified protein fractions display significant increase in activity following supplementation of defined concentration Cu (CuSO4) and Zn (ZnSO4). Yield of the purified recombinant protein was ~ 4 mg L(-1) of culture volume and the bacterial biomass was ~ 4.5 g L(-1). The recombinant pea chloroplastic SOD was found to possess nearly 6 fold higher superoxide dismutase activity and the peroxidase activity was also 5 fold higher as compared to commercially available CuZn-superoxide dismutase. The computational, spectroscopic and biochemical characterization reveals that the protein harbors all the characteristics features of this class of enzyme. The enzyme was found to be exceptionally stable as evident from pH and temperature incubation studies and maintenance of SOD activity upon prolonged storage. CONCLUSIONS Overexpression and purification strategy presented here describes an efficient protocol for the production of a highly active and stable CuZn-superoxide dismutase in its recombinant form in E. coli system. The strategy can be utilized for the large-scale preparation of active CuZn-superoxide dismutase and thus it has wide application in pharmaceutical industries and also for elucidating the potential of this protein endowed with exceptional stability and activity.
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Affiliation(s)
- Narendra Tuteja
- Plant Molecular Biology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, 110067, India.
| | - Panchanand Mishra
- Stress Biology Laboratory, Gene Function and Regulation, Institute of Life Sciences, Bhubaneswar, 751023, Odisha, India.
| | - Sandep Yadav
- Plant Molecular Biology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, 110067, India.
| | - Marjan Tajrishi
- Plant Molecular Biology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, 110067, India.
| | - Sudhir Baral
- Stress Biology Laboratory, Gene Function and Regulation, Institute of Life Sciences, Bhubaneswar, 751023, Odisha, India.
| | - Surendra Chandra Sabat
- Stress Biology Laboratory, Gene Function and Regulation, Institute of Life Sciences, Bhubaneswar, 751023, Odisha, India.
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Mechanistic study of CuZn-SOD from Ipomoea carnea mutated at dimer interface: Enhancement of peroxidase activity upon monomerization. Biochimie 2014; 97:181-93. [DOI: 10.1016/j.biochi.2013.10.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 10/14/2013] [Indexed: 12/22/2022]
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Chillemi G, De Santis S, Falconi M, Mancini G, Migliorati V, Battistoni A, Pacello F, Desideri A, D'Angelo P. Carbon monoxide binding to the heme group at the dimeric interface modulates structure and copper accessibility in the Cu,Zn superoxide dismutase from Haemophilus ducreyi: in silico and in vitro evidences. J Biomol Struct Dyn 2012; 30:269-79. [PMID: 22686457 DOI: 10.1080/07391102.2012.680028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
X-ray absorption near-edge structure (XANES) spectroscopy and molecular dynamics (MD) simulations have been jointly applied to the study of the Cu,Zn superoxide dismutase from Haemophilus ducreyi (HdSOD) in interaction with the carbon monoxide molecule. The configurational flexibility of the Fe(II)-heme group, intercalated between the two subunits, has been sampled by MD simulations and included in the XANES data analysis without optimization in the structural parameter space. Our results provide an interpretation of the observed discrepancy in the Fe-heme distances as detected by extended X-ray absorption fine structure (EXAFS) spectroscopy and the classical XANES analysis, in which the structural parameters are optimized in a unique structure. Moreover, binding of the CO molecule to the heme induces a long range effect on the Cu,Zn active site, as evidenced by both MD simulations and in vitro experiments. MD simulation of the CO bound system, in fact, highlighted a structural rearrangement of the protein-protein hydrogen bond network in the region of the Cu,Zn active site, correlated with an increase in water accessibility at short distance from the copper atom. In line, in vitro experiments evidenced an increase of copper accessibility to a chelating agent when the CO molecule binds to the heme group, as compared to a heme deprived HdSOD. Altogether, our results support the hypothesis that the HdSOD is a heme-sensor protein, in which binding to small gaseous molecules modulates the enzyme superoxide activity as an adaptive response to the bacterial environment.
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Mori M, Jiménez B, Piccioli M, Battistoni A, Sette M. The Solution Structure of the Monomeric Copper, Zinc Superoxide Dismutase from Salmonella enterica: Structural Insights To Understand the Evolution toward the Dimeric Structure. Biochemistry 2008; 47:12954-63. [DOI: 10.1021/bi801252e] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mirko Mori
- Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, 50019 Sesto Fiorentino (FI), Italy, Department of Biology, University of Rome “Tor Vergata”, 00133 Rome, Italy, National Institute of Biostructures and Biosystems (INBB), Viale delle Medaglie d’Oro 305, 00136 Rome, Italy, and Department of Chemical Science and Technology, University of Rome “Tor Vergata”, 00133 Rome, Italy
| | - Beatriz Jiménez
- Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, 50019 Sesto Fiorentino (FI), Italy, Department of Biology, University of Rome “Tor Vergata”, 00133 Rome, Italy, National Institute of Biostructures and Biosystems (INBB), Viale delle Medaglie d’Oro 305, 00136 Rome, Italy, and Department of Chemical Science and Technology, University of Rome “Tor Vergata”, 00133 Rome, Italy
| | - Mario Piccioli
- Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, 50019 Sesto Fiorentino (FI), Italy, Department of Biology, University of Rome “Tor Vergata”, 00133 Rome, Italy, National Institute of Biostructures and Biosystems (INBB), Viale delle Medaglie d’Oro 305, 00136 Rome, Italy, and Department of Chemical Science and Technology, University of Rome “Tor Vergata”, 00133 Rome, Italy
| | - Andrea Battistoni
- Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, 50019 Sesto Fiorentino (FI), Italy, Department of Biology, University of Rome “Tor Vergata”, 00133 Rome, Italy, National Institute of Biostructures and Biosystems (INBB), Viale delle Medaglie d’Oro 305, 00136 Rome, Italy, and Department of Chemical Science and Technology, University of Rome “Tor Vergata”, 00133 Rome, Italy
| | - Marco Sette
- Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, 50019 Sesto Fiorentino (FI), Italy, Department of Biology, University of Rome “Tor Vergata”, 00133 Rome, Italy, National Institute of Biostructures and Biosystems (INBB), Viale delle Medaglie d’Oro 305, 00136 Rome, Italy, and Department of Chemical Science and Technology, University of Rome “Tor Vergata”, 00133 Rome, Italy
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D'Orazio M, Scotti R, Nicolini L, Cervoni L, Rotilio G, Battistoni A, Gabbianelli R. Regulatory and structural properties differentiating the chromosomal and the bacteriophage-associated Escherichia coli O157:H7 Cu, Zn superoxide dismutases. BMC Microbiol 2008; 8:166. [PMID: 18828904 PMCID: PMC2569942 DOI: 10.1186/1471-2180-8-166] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Accepted: 10/01/2008] [Indexed: 11/10/2022] Open
Abstract
Background Highly virulent enterohemorrhagic Escherichia coli O157:H7 strains possess three sodC genes encoding for periplasmic Cu, Zn superoxide dismutases: sodC, which is identical to the gene present in non-pathogenic E. coli strains, and sodC-F1 and sodC-F2, two nearly identical genes located within lambdoid prophage sequences. The significance of this apparent sodC redundancy in E. coli O157:H7 has not yet been investigated. Results We report that strains deleted of one or more sodC genes are less resistant than the wild type strain to a challenge with hydrogen peroxide, thus confirming their involvement in the bacterial antioxidant apparatus. To understand if the different sodC genes have truly overlapping functions, we have carried out a comparison of the functional, structural and regulatory properties of the various E. coli O157:H7 SodC enzymes. We have found that the chromosomal and prophagic sodC genes are differentially regulated in vitro. sodC is exclusively expressed in aerobic cultures grown to the stationary phase. In contrast, sodC-F1 and sodC-F2 are expressed also in the logarithmic phase and in anaerobic cultures. Moreover, the abundance of SodC-F1/SodC-F2 increases with respect to that of SodC in bacteria recovered from infected Caco-2 cells, suggesting higher expression/stability of SodC-F1/SodC-F2 in intracellular environments. This observation correlates with the properties of the proteins. In fact, monomeric SodC and dimeric SodC-F1/SodC-F2 are characterized by sharp differences in catalytic activity, metal affinity, protease resistance and stability. Conclusion Our data show that the chromosomal and bacteriophage-associated E. coli O157:H7 sodC genes have different regulatory properties and encode for proteins with distinct structural/functional features, suggesting that they likely play distinctive roles in bacterial protection from reactive oxygen species. In particular, dimeric SodC-F1 and SodC-F2 possess physico-chemical properties which make these enzymes more suitable than SodC to resist the harsh environmental conditions which are encountered by bacteria within the infected host.
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Affiliation(s)
- Melania D'Orazio
- Department of Biology, University of Rome, Tor Vergata, Rome, Italy.
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Ammendola S, Pasquali P, Pacello F, Rotilio G, Castor M, Libby SJ, Figueroa-Bossi N, Bossi L, Fang FC, Battistoni A. Regulatory and structural differences in the Cu,Zn-superoxide dismutases of Salmonella enterica and their significance for virulence. J Biol Chem 2008; 283:13688-99. [PMID: 18362154 DOI: 10.1074/jbc.m710499200] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Many of the most virulent strains of Salmonella enterica produce two distinct Cu,Zn-superoxide dismutases (SodCI and SodCII). The bacteriophage-encoded SodCI enzyme makes the greater contribution to Salmonella virulence. We have performed a detailed comparison of the functional, structural, and regulatory properties of the Salmonella SodC enzymes. Here we demonstrate that SodCI and SodCII differ with regard to specific activity, protease resistance, metal affinity, and peroxidative activity, with dimeric SodCI exhibiting superior stability and activity. In particular, monomeric SodCII is unable to retain its catalytic copper ion in the absence of zinc. We have also found that SodCI and SodCII are differentially affected by oxygen, zinc availability, and the transcriptional regulator FNR. SodCII is strongly down-regulated under anaerobic conditions and dependent on the high affinity ZnuABC zinc transport system, whereas SodCI accumulation in vitro and within macrophages is FNR-dependent. We have confirmed earlier findings that SodCII accumulation in intracellular Salmonella is negligible, whereas SodCI is strongly up-regulated in macrophages. Our observations demonstrate that differences in expression, activity, and stability help to account for the unique contribution of the bacteriophage-encoded SodCI enzyme to Salmonella virulence.
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Affiliation(s)
- Serena Ammendola
- Dipartimento di Biologia, Università di Roma Tor Vergata, 00133 Rome, Italy
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Catacchio B, D'Orazio M, Battistoni A, Chiancone E. The dimeric assembly of Photobacterium leiognathi and Salmonella typhimurium SodC1 Cu,Zn superoxide dismutases is affected differently by active site demetallation and pH: an analytical ultracentrifuge study. Arch Biochem Biophys 2008; 471:77-84. [PMID: 18179768 DOI: 10.1016/j.abb.2007.12.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 12/14/2007] [Accepted: 12/15/2007] [Indexed: 11/28/2022]
Abstract
To establish whether the species-specific variations at the subunit interface of bacterial Cu,Zn superoxide dismutases affect dimer assembly, the association state of the Photobacterium leiognathi (PlSOD) and Salmonella typhimurium (StSOD) enzymes, which differ in 11 out of 19 interface residues, was investigated by analytical ultracentrifugation. The same linkage pattern correlates quaternary assembly, active site metallation, and pH in the two enzymes albeit with quantitative differences. Both holo-enzymes are stable dimers at pH 6.8 and 8.0, although their shape is altered at alkaline pH. In contrast, dimer stability is affected differently by metal removal. Thus, apo-StSOD is a stable dimer at pH 6.8 whereas apo-PlSOD is in reversible monomer-dimer equilibrium. In both apoproteins a pH increase to 8.0 favors monomerization. These effects prove the existence of long-range communication between the active site and the subunit interface and provide a structural explanation for the known functional differences between the two enzymes.
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Affiliation(s)
- B Catacchio
- CNR Institute of Molecular Biology and Pathology, Department of Biochemical Sciences, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy
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De Domenico I, Lania A, Bonaccorsi di Patti MC, Battistoni A, Musci G, Desideri A. Purification and characterization of recombinant Caulobacter crescentus Cu,Zn superoxide dismutase. BIOCHIMICA ET BIOPHYSICA ACTA 2006; 1764:105-9. [PMID: 16213200 DOI: 10.1016/j.bbapap.2005.08.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Revised: 08/20/2005] [Accepted: 08/24/2005] [Indexed: 05/04/2023]
Abstract
Recombinant Cu,Zn Superoxide Dismutase from Caulobacter crescentus has been expressed in Escherichia coli and characterized. The corresponding recombinant protein has a molecular weight typical of a homodimeric Cu,ZnSODs and an activity comparable to that of other prokaryotic enzymes. The copper active site is characterized by a peculiar axial geometry as evidenced by its electron paramagnetic resonance spectrum, moreover, the copper atom displays a low accessibility toward external chelating agents indicating a lower solvent accessibility when compared to other prokaryotic enzymes. Investigation of the enzyme thermal stability through differential scanning calorimetry indicates the occurrence of two transitions at low and higher temperature that are found to be due to the apo and holo protein, respectively, confirming that the metals have a crucial role in the stabilization of this class of enzymes.
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Affiliation(s)
- Ivana De Domenico
- Department of Microbiological, Genetic and Molecular Sciences, University of Messina, Salita Sperone, 31, 98166 Messina, Italy
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Ammendola S, Ajello M, Pasquali P, Kroll JS, Langford PR, Rotilio G, Valenti P, Battistoni A. Differential contribution of sodC1 and sodC2 to intracellular survival and pathogenicity of Salmonella enterica serovar Choleraesuis. Microbes Infect 2005; 7:698-707. [PMID: 15823516 DOI: 10.1016/j.micinf.2005.01.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2003] [Revised: 12/30/2004] [Accepted: 01/17/2005] [Indexed: 11/29/2022]
Abstract
Several of the most virulent Salmonella enterica strains possess two genes encoding periplasmic Cu,Zn superoxide dismutase, sodC1 and sodC2, located on a lambdoid prophage and on the chromosome, respectively. These genes contribute to Salmonella virulence by protecting bacteria from superoxide generated by the host's phagocytes. To investigate the respective contributions of sodC1 and sodC2 to the virulence of a clinical isolate of Salmonella enterica serovar Choleraesuis (S. choleraesuis), we have analyzed both the intracellular survival of wild type and sodC mutant strains within J774 macrophages and Caco-2 cells, and their ability to proliferate in intraperitoneally-infected mice in competition assays. In agreement with previous studies, mutant strains lacking one or both sodC genes were equally impaired in their ability to survive within activated macrophages. However, when macrophage killing experiments were carried out with non-opsonized bacteria, sodC2 contributed to intracellular survival more than sodC1, indicating that changes in the pathways of bacterial uptake can modify the relative role of the two sodC genes. More unexpectedly, we have found that the ability of S. choleraesuis to survive within Caco-2 cells was severely affected by inactivation of sodC genes, sodC2 being more important than sodC1. As Caco-2 cells actively produce superoxide, this suggests that oxygen radical production by colonic cells has a role in controlling proliferation of facultative intracellular bacteria. Mouse infection studies confirmed that, in the S. choleraesuis strain under investigation, both sodC genes are required to confer full virulence, sodC2 contributing slightly more than sodC1 to Salmonella pathogenesis. Our findings contrast with the results of other studies carried out in S. enterica serovar Typhimurium and suggest that the relative contributions of sodC1 and sodC2 to host-pathogen interactive biology may vary depending on the Salmonella serovar or strain.
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Affiliation(s)
- Serena Ammendola
- Dipartimento di Biologia, Università di Roma Tor Vergata, Via della Ricerca Scientifica, 00133 Rome, Italy
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Berducci G, Mazzetti AP, Rotilio G, Battistoni A. Periplasmic competition for zinc uptake between the metallochaperone ZnuA and Cu,Zn superoxide dismutase. FEBS Lett 2004; 569:289-92. [PMID: 15225650 DOI: 10.1016/j.febslet.2004.06.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2004] [Revised: 06/02/2004] [Accepted: 06/02/2004] [Indexed: 10/26/2022]
Abstract
We have investigated the availability of zinc in the periplasmic space of Escherichia coli using a mutant Cu,Zn superoxide dismutase whose dimerization is triggered by zinc binding. This mutant enzyme accumulates in the monomeric form when wild type cells are grown in minimal medium, but assembles in the dimeric form when it is produced in the same medium by a mutant strain lacking the periplasmic zinc metallochaperone ZnuA. These results indicate that periplasmic zinc-containing proteins compete for metal binding when bacteria grow in environments where this element is present in traces. The effective ZnuA ability to sequester the available zinc ions from the periplasm suggests that zinc-containing cytoplasmic proteins are more important for bacterial viability than the periplasmic ones.
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Affiliation(s)
- Giovanni Berducci
- Dipartimento di Biologia, Università di Roma Tor Vergata, Via della Ricerca Scientifica, 00133 Rome, Italy
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Gabbianelli R, D'Orazio M, Pacello F, O'Neill P, Nicolini L, Rotilio G, Battistoni A. Distinctive functional features in prokaryotic and eukaryotic Cu,Zn superoxide dismutases. Biol Chem 2004; 385:749-54. [PMID: 15449711 DOI: 10.1515/bc.2004.091] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Bacterial and eukaryotic Cu,Zn superoxide dismutases show remarkable differences in the active site region and in their quaternary structure organization. We report here a functional comparison between four Cu,Zn superoxide dismutases from Gram-negative bacteria and the eukaryotic bovine enzyme. Our data indicate that bacterial dimeric variants are characterized by catalytic rates higher than that of the bovine enzyme, probably due to the solvent accessibility of their active site. Prokaryotic Cu,Zn superoxide dismutases also show higher resistance to hydrogen peroxide inactivation and lower HCO3- -dependent peroxidative activity. Moreover, unlike the eukaryotic enzyme, all bacterial variants are susceptible to inactivation by chelating agents and show variable sensitivity to proteolytic attack, with the E. coli monomeric enzyme showing higher rates of inactivation by EDTA and proteinase K. We suggest that differences between individual bacterial variants could be due to the influence of modifications at the dimer interface on the enzyme conformational flexibility.
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Affiliation(s)
- Roberta Gabbianelli
- Servizio Biologico, Istituto Superiore di Sanità, Viale Regina Elena 299, I-00161 Rome, Italy
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Cioni P, Pesce A, Morozzo della Rocca B, Castelli S, Falconi M, Parrilli L, Bolognesi M, Strambini G, Desideri A. Active-site copper and zinc ions modulate the quaternary structure of prokaryotic Cu,Zn superoxide dismutase. J Mol Biol 2003; 326:1351-60. [PMID: 12595249 DOI: 10.1016/s0022-2836(03)00047-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The influence of the constitutive metal ions on the equilibrium properties of dimeric Photobacterium leiognathi Cu,Zn superoxide dismutase has been studied for the wild-type and for two mutant protein forms bearing a negative charge in the amino acid clusters at the dimer association interface. Depletion of copper and zinc dissociates the two mutant proteins into monomers, which reassemble toward the dimeric state upon addition of stoichiometric amounts of zinc. Pressure-dependent dissociation is observed for the copper-depleted wild-type and mutated enzymes, as monitored by the fluorescence shift of a unique tryptophan residue located at the subunit association interface. The spectral shift occurs slowly, reaching a plateau after 15-20 minutes, and is fully reversible. The recovery of the original fluorescence properties, after decompression, is fast (less than four minutes), suggesting that the isolated subunit has a relatively stable structure, and excluding the presence of stable intermediates during the dimer-monomer transition. The dimer dissociation process is still incomplete at 6.5 kbar for the copper-depleted wild-type and mutated enzymes, at variance with what is generally observed for oligomeric proteins that dissociate below 3 kbar. Measurement of the degree of dissociation, at two different protein concentrations, allows us to calculate the standard volume variation upon association, Delta V, and the dissociation constant K(d0), at atmospheric pressure, (25 ml/mol and 3 x 10(-7)M, respectively). The holoprotein is fully dimeric even at 6.5 kbar, which allows us to evaluate a lower Delta G degrees limit of 11.5 kcal/mol, corresponding to a dissociation constant K(d0)<10(-9)M.
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Affiliation(s)
- P Cioni
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Area della Ricerca di Pisa, Pisa, Italy
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Sergi A, Ciccotti G, Falconi M, Desideri A, Ferrario M. Effective binding force calculation in a dimeric protein by molecular dynamics simulation. J Chem Phys 2002. [DOI: 10.1063/1.1457445] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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