Purification and characterization of recombinant human superoxide dismutase integrated with resilin-like polypeptide

Human superoxide dismutase (hSOD1) plays an important role in the aerobic metabolism and free radical eliminating process in the body. However, the production of existing SOD faces problems such as complex purification methods, high costs, and poor product stability. This experiment achieved low-cost, rapid, and simple purification of hSOD1 through ammonium sulfate precipitation method and heat resistance of recombinant protein. We constructed a recombinant protein hSOD1-LR containing a resilin-like polypeptide tag and expressed it. The interest protein was purified by ammonium sulfate precipitation method, and the results showed that the purification effect of 1.5 M (NH4)2SO4 was the best, with an enzyme activity recovery rate of 80 % after purification. Then, based on its thermal stability, further purification of the interest protein at 60 °C revealed a purification fold of up to 24 folds, and the purification effect was similar to that of hSOD1-6xHis purified by nickel column affinity chromatography. The stability of hSOD1-LR showed that the recombinant protein hSOD1-LR has better stability than hSOD-6xHis. hSOD1-LR can maintain 76.57 % activity even after 150 min of reaction at 70 °C. At same time, hSOD1-LR had activity close to 80 % at pH < 5, indicating good acid resistance. In addition, after 28 days of storage at 4 °C and 40 °C, hSOD1-LR retained 92 % and 87 % activity, respectively. Therefore, the method of purifying hSOD1-LR through salt precipitation may have positive implications for the study of SOD purification.

Proteome Analysis and In Vitro Antiviral, Anticancer and Antioxidant Capacities of the Aqueous Extracts of Lentinula edodes and Pleurotus ostreatus Edible Mushrooms

In this study, we examined aqueous extracts of the edible mushrooms Pleurotus ostreatus (oyster mushroom) and Lentinula edodes (shiitake mushroom). Proteome analysis was conducted using LC-Triple TOF-MS and showed the expression of 753 proteins by Pleurotus ostreatus, and 432 proteins by Lentinula edodes. Bioactive peptides: Rab GDP dissociation inhibitor, superoxide dismutase, thioredoxin reductase, serine proteinase and lectin, were identified in both mushrooms. The extracts also included promising bioactive compounds including phenolics, flavonoids, vitamins and amino acids. The extracts showed promising antiviral activities, with a selectivity index (SI) of 4.5 for Pleurotus ostreatus against adenovirus (Ad7), and a slight activity for Lentinula edodes against herpes simplex-II (HSV-2). The extracts were not cytotoxic to normal human peripheral blood mononuclear cells (PBMCs). On the contrary, they showed moderate cytotoxicity against various cancer cell lines. Additionally, antioxidant activity was assessed using DPPH radical scavenging, ABTS radical cation scavenging and ORAC assays. The two extracts showed potential antioxidant activities, with the maximum activity seen for Pleurotus ostreatus (IC50 µg/mL) = 39.46 ± 1.27 for DPPH; 11.22 ± 1.81 for ABTS; and 21.40 ± 2.20 for ORAC assays. This study encourages the use of these mushrooms in medicine in the light of their low cytotoxicity on normal PBMCs vis à vis their antiviral, antitumor and antioxidant capabilities.

N-glycosylation on Oryza sativa root germin-like protein 1 is conserved but not required for stability or activity

Germin and germin-like proteins (GLPs) are a broad family of extracellular glycoproteins ubiquitously distributed in plants. Overexpression of Oryza sativa root germin like protein 1 (OsRGLP1) enhances superoxide dismutase (SOD) activity in transgenic plants. Here, we report bioinformatic analysis and heterologous expression of OsRGLP1 to study the role of glycosylation on OsRGLP1 protein stability and activity. Sequence analysis of OsRGLP1 homologs identified diverse N-glycosylation sequons, one of which was highly conserved. We therefore expressed OsRGLP1 in glycosylation-competent Saccharomyces cerevisiae as a Maltose Binding Protein (MBP) fusion. Mass spectrometry analysis of purified OsRGLP1 showed it was expressed by S. cerevisiae in both N-glycosylated and unmodified forms. Glycoprotein thermal profiling showed little difference in the thermal stability of the glycosylated and unmodified protein forms. Circular Dichroism spectroscopy of MBP-OsRGLP1 and a N-Q glycosylation-deficient variant showed that both glycosylated and unmodified MBP-OsRGLP1 had similar secondary structure, and both forms had equivalent SOD activity. Together, we concluded that glycosylation was not critical for OsRGLP1 protein stability or activity, and it could therefore likely be produced in Escherichia coli without glycosylation. Indeed, we found that OsRGLP1 could be efficiently expressed and purified from K12 shuffle E. coli with a specific activity of 1251 ± 70 Units/mg. In conclusion, we find that some highly conserved N-glycosylation sites are not necessarily required for protein stability or activity, and describe a suitable method for production of OsRGLP1 which paves the way for further characterization and use of this protein.

Identification and Molecular Characterization of Superoxide Dismutases Isolated From A Scuticociliate Parasite: Physiological Role in Oxidative Stress

Philasterides dicentrarchi is a free-living microaerophilic scuticociliate that can become a facultative parasite and cause a serious parasitic disease in farmed fish. Both the free-living and parasitic forms of this scuticociliate are exposed to oxidative stress associated with environmental factors and the host immune system. The reactive oxygen species (ROS) generated by the host are neutralized by the ciliate by means of antioxidant defences. In this study we aimed to identify metalloenzymes with superoxide dismutase (SOD) activity capable of inactivating the superoxide anion (•O2-) generated during induction of oxidative stress. P. dicentrarchi possesses the three characteristic types of SOD isoenzymes in eukaryotes: copper/zinc-SOD, manganese-SOD and iron-SOD. The Cu/Zn-SOD isoenzymes comprise three types of homodimeric proteins (CSD1-3) of molecular weight (MW) 34-44 kDa and with very different AA sequences. All Cu/Zn-SODs are sensitive to NaCN, located in the cytosol and in the alveolar sacs, and one of them (CSD2) is extracellular. Mn- and Fe-SOD transcripts encode homodimeric proteins (MSD and FSD, respectively) in their native state: a) MSD (MW 50 kDa) is insensitive to H2O2 and NaN3 and is located in the mitochondria; and b) FSD (MW 60 kDa) is sensitive to H2O2, NaN3 and the polyphenol trans-resveratrol and is located extracellularly. Expression of SOD isoenzymes increases when •O2- is induced by ultraviolet (UV) irradiation, and the increase is proportional to the dose of energy applied, indicating that these enzymes are actively involved in cellular protection against oxidative stress.

Expression, purification and metal utilization of recombinant SodA from Borrelia burgdorferi

Borrelia are microaerophilic spirochetes capable of causing multisystemic diseases such as Lyme disease and Relapsing Fever. The ubiquitous Fe/Mn-dependent superoxide dismutase (SOD) provides essential protection from oxidative damage by the superoxide anion. Borrelia possess a single SOD enzyme - SodA that is essential for virulence, providing protection against host-derived reactive oxygen species (ROS). Here we present a method for recombinant expression and purification of Borrelia burgdorferi SodA in E. coli. Metal exchange or insertion into the Fe/Mn-SOD is inhibited in the folded state. We therefore present a method whereby the recombinant Borrelia SodA binds to Mn under denaturing conditions and is subsequently refolded by a reduction in denaturant. SodA purified by metal affinity chromatography and size exclusion chromatography reveals a single band on SDS-PAGE. Protein folding is confirmed by circular dichroism. A coupled enzyme assay demonstrates SOD activity in the presence of Mn, but not Fe. The apparent molecular weight determined by size exclusion corresponds to a dimer of SodA; a homology model of dimeric SodA is presented revealing a surface Cys distal to the dimer interface. The method presented of acquiring a target metal under denaturing conditions may be applicable to the refolding of other metal-binding proteins.

Purification and properties of Manganese Superoxide Dismutase (MnSOD) from Tamarix aphylla L

Superoxide dismutase (SOD) of the Tamarix aphylla leaves were detected at optimum conditions that collected in April, May and June. Results indicated the specific activity in the crude extract reaching to 36.76 unit/ mg protein. Crude SOD was purified by several techniques, precipitation with ammonium sulfate (50-75) %, Ion exchange chromatography using DEAE-cellulose and two steps of size exclusion chromatography on sephacryl S-200 column. The obtained specific activity (310 unit/mg protein) and purification fold 7.91. The purified enzyme revealed one band by SDS-polyacrylamide gel electrophoresis with molecular mass 85.703 kDa. while 89.125 kDa by Sephacryl S-200. The optimal pH and temperature for enzyme activity were 7.5, and 50ºC respectively. EDTA, SDS and NaN3 reduced activity, contrariwise of H2O2 and KCN, pointed to the studied SOD is MnSOD. Michalis constant Km and maximum velocity Vmax values were 0.016 mM and 55.86 mM/min, respectively by using Pyrogallol as substrate. According to the results, we conclude Tamarix aphylla produce MnSOD which can have purified by serial purification techniques for better activity and characterized for further studies.

Characteristics of the Copper,Zinc Superoxide Dismutase of a Hadal Sea Cucumber (Paelopatides sp.) from the Mariana Trench

Superoxide dismutases (SODs) are among the most important antioxidant enzymes and show great potential in preventing adverse effects during therapeutic trials. In the present study, cloning, expression, and characterization of a novel Cu,Zn superoxide dismutase (Ps-Cu,Zn-SOD) from a hadal sea cucumber (Paelopatides sp.) were reported. Phylogenetic analysis showed that Ps-Cu,Zn-SOD belonged to a class of intracellular SOD. Its Km and Vmax were 0.0258 ± 0.0048 mM and 925.1816 ± 28.0430 units/mg, respectively. The low Km value of this enzyme represents a high substrate affinity and can adapt to the low metabolic rate of deep sea organisms. The enzyme functioned from 0 °C to 80 °C with an optimal temperature of 40 °C. Moreover, the enzyme activity was maintained up to 87.12% at 5 °C. The enzyme was active at pH 4 to 12 with an optimal pH of 8.5. Furthermore, Ps-Cu,Zn-SOD tolerated high concentration of urea and GuHCl, resisted hydrolysis by proteases, and maintained stability at high pressure. All these features demonstrated that the deep sea Ps-Cu,Zn-SOD is a potential candidate for application to the biopharmaceutical field.

Complete Amino Acid Sequence of a Copper/Zinc-Superoxide Dismutase from Ginger Rhizome

Superoxide dismutase (SOD) is an antioxidant enzyme protecting cells from oxidative stress. Ginger (Zingiber officinale) is known for its antioxidant properties, however, there are no data on SODs from ginger rhizomes. In this study, we purified SOD from the rhizome of Z. officinale (Zo-SOD) and determined its complete amino acid sequence using N terminal sequencing, amino acid analysis, and de novo sequencing by tandem mass spectrometry. Zo-SOD consists of 151 amino acids with two signature Cu/Zn-SOD motifs and has high similarity to other plant Cu/Zn-SODs. Multiple sequence alignment showed that Cu/Zn-binding residues and cysteines forming a disulfide bond, which are highly conserved in Cu/Zn-SODs, are also present in Zo-SOD. Phylogenetic analysis revealed that plant Cu/Zn-SODs clustered into distinct chloroplastic, cytoplasmic, and intermediate groups. Among them, only chloroplastic enzymes carried amino acid substitutions in the region functionally important for enzymatic activity, suggesting that chloroplastic SODs may have a function distinct from those of SODs localized in other subcellular compartments. The nucleotide sequence of the Zo-SOD coding region was obtained by reverse-translation, and the gene was synthesized, cloned, and expressed. The recombinant Zo-SOD demonstrated pH stability in the range of 5-10, which is similar to other reported Cu/Zn-SODs, and thermal stability in the range of 10-60 °C, which is higher than that for most plant Cu/Zn-SODs but lower compared to the enzyme from a Z. officinale relative Curcuma aromatica.

Purification of Cu/Zn superoxide dismutase from Piper betle leaf and its characterization in the oral cavity

The aim of this study was to purify protein(s) from Piper betle leaf for identification and further characterization. A functionally unknown protein was purified to apparent homogeneity with a molecular mass of 15.7 kDa and identified as Cu/Zn superoxide dismutase (SOD). The purified SOD appeared to be monomeric and converted to its dimeric form with increased enzymatic activity in betel nut oral extract. This irreversible conversion was mainly induced by slaked lime, resulting from the increase in pH of the oral cavity. Oral extract from chewing areca nut alone also induced SOD dimerization due to the presence of arginine. The enhanced activity of the SOD dimer was responsible for the continuous production of hydrogen peroxide in the oral cavity. Thus, SOD may contribute to oral carcinogenesis through the continuous formation of hydrogen peroxide in the oral cavity, in spite of its protective role against cancer in vivo.

Cloning of a putative extracellular Cu/Zn superoxide dismutase and functional differences of superoxide dismutases in invasive and indigenous whiteflies

Superoxide dismutases (SODs) are a group of important antioxidant defense enzymes. In this study, a putative extracellular Cu/Zn superoxide dismutase (ecCuZnSOD) complementary DNA was cloned and characterized from the whitefly, Bemisia tabaci. Quantitative polymerase chain reaction analysis showed that the expression level of BtecCuZnSOD was more than 10-fold higher in the invasive Middle East Asia Minor 1 (MEAM1) than in the native Asia II 3 species of the B. tabaci species complex. After exposure to low temperature (4 °C), the expression of Bt-ecCuZnSOD gene was significantly up-regulated in MEAM1 but not in Asia II 3. Furthermore, the expression level of B. tabaci intracellular CuZnSOD (Bt-icCuZnSOD), Bt-ecCuZnSOD and mitochondrial MnSOD (Bt-mMnSOD) was compared after transferring MEAM1 and Asia II 3 whiteflies from favorable (cotton) to unfavorable host plants (tobacco). On cotton, both CuZnSOD genes were expressed at a higher level in MEAM1 compared with Asia II 3. Interestingly, after transferring onto tobacco, the expression of Bt-ecCuZnSOD was significantly induced in Asia II 3 but not in MEAM1. On the other hand, while Bt-mMnSOD was expressed equally in both species on cotton, Bt-mMnSOD messenger RNA was up-regulated in MEAM1 on tobacco. Consistently, enzymatic activity assays of CuZnSOD and MnSOD demonstrated that CuZnSOD might play an important protective role against oxidative stress in Asia II 3, whereas MnSOD activation was critical for MEAM1 whiteflies during host adaptation. Taken together, our results suggest that the successful invasion of MEAM1 is correlated with its constitutive high activity of CuZnSOD and inducible expression of MnSOD under stress conditions.

Identification and analysis of an intracellular Cu/Zn superoxide dismutase from Sepiella maindroni under stress of Vibrio harveyi and Cd2+

Superoxide dismutases (SODs) are ubiquitous family of metalloenzymes involved in protecting organisms from excess reactive oxygen species damage. In this paper, a novel intracellular Cu/ZnSOD from Sepiella maindroni (designated as SmSOD) was identified and characterized. The full-length cDNA sequence of SmSOD (GenBank accession No. KF908850) was 709 bp containing an open reading frame (ORF) of 459 bp, encoding 153 amino acid residues peptide with predicted pI/MW (6.02/15.75 kDa), a 131 bp-5'- and 116 bp-3'- untranslated region (UTR). BLASTn analysis and phylogenetic relationship strongly suggested that the sequence shared high similarity with known Cu/Zn SODs. Several highly conserved motifs, including two typical Cu/Zn SOD family domains, two conserved Cu-/Zn-binding sites (H-47, H-49, H-64, H-120 for Cu binding, and H-64, H-72, H-81, D-84 for Zn binding) and intracellular disulfide bond (C-58 and C-146), were also identified in SmSOD. Time-dependent mRNA expression of SmSOD in hepatopancreas was recorded by quantitative real-time RT-PCR after Vibrio harveyi injection and Cd(2+) exposure. The results indicated that SmSOD was an acute-phase protein involved in the immune responses against pathogens and biological indicator for metal contaminants in aquatic environment.

Immunohistochemical localization of Nox1, Nox4 and Mn-SOD in mouse femur during endochondral ossification

Enzymes synthesizing reactive oxygen (Nox family) have recently been identified. Elucidation of the production mechanism has been initiated, and the involvement of reactive oxygen in metabolism, intracellular transport, signal transmission and apoptosis has been reported. We immunohistochemically investigated expression and localization of the Nox family in endochondral ossification using a normal mouse femur. Weakly positive reactions with Nox1, Noxa1, and Noxo1 were observed in the zones of proliferative and prehypertrophic chondrocytes at 3 weeks of age. Nox4 was widely positive from the resting over the hypertrophic cell zone. At 18 weeks of age, none of the Nox types was expressed in chondrocytes as the zones disappeared. On the other hand, positive reactions with Nox1, Noxa1, Noxo1, and Nox4 were observed in osteoblasts in the zone of ossification at 3 weeks of age, and each Nox was also positive in osteoblasts arranged on the bone marrow side in the epiphyseal cartilage at 18 weeks of age. In addition, a reactive oxygen-eliminating enzyme, Mn-SOD, was observed only in prehypertrophic chondrocytes at 3 weeks of age, and not detected in osteoblasts. It was suggested that the Nox family is closely associated with endochondral ossification of the mouse femur, and Nox1 and Nox4 are closely involved in the chondrocyte maturation process and bone matrix formation.

Detection of Structural Change of Superoxide Dismutase in Solution

We have confirmed that dissociation of the dimeric SOD molecule into a monomeric one can be readily detected in solution by the use of capillary electrophoresis (CE), which is based on the fact that the peak height in the CE profile is highly dependent on the aggregation conditions of the protein molecule. Based on this fact, it has become apparent that the hydrogen peroxide molecule induces the dissociation of the dimeric structure of SOD, and this should give reasonable explanation for the inactivation of SOD by hydrogen peroxide. Our results may give a convenient way for the early detection of the amyotrophic lateral sclerosis in patients, because we can estimate whether the SOD molecule is of a rigid or loosed dimeric structure by the use of this technique. The loosed one has been assumed to exhibit inherent toxicity of the copper center, so-called “gain-of-function” of the mutant SOD.

[Purification of superoxide dismutase from blood erythrocyte by nano magnetic chitosan microspheres]

Nano magnetic microspheres prepared by chitosan and poly acylic acid were applied to purifying superoxide dismutase from blood erythrocyte. Chitosan-polyacyilc acid graft copolymer was synthesized by free radical graft copolymerization with potassium persulfate as inititator. To prepare Fe3O4 magnetic fluids with chemical coprecipitation, chitosan-polyacylic nano magnetic microspheres were prepared with glutaraldehyde as crosslinking agent. Structure of nano magnetic microspheres was detected by FT-IR spectrometer. Particle size and morphology were characterized by JEM-4000EX technology. Chitosan-polyacylic nanometer microspheres have good paticle cize distribution, magnetic responsiveness and protein adsoption. Activity, product yield and activity recovery of SOD after purification reached 6 727 U/mg, 21.1%, and 85.7% respectively. Purification of blood superoxide dismutase by chistosan-polyacylic acid microspheres has its renewable and feasible nature.

Purification, Characterization, and Molecular Cloning of a Thermostable Superoxide Dismutase fromThermoascus aurantiacus

A thermostable superoxide dismutase [(SOD) EC 1.15.1.1] from a Thermoascus aurantiacus var. levisporus was purified to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) homogeneity by a series of column chromatographies. The molecular mass of a single band of the enzyme was estimated to be 16.8 kDa by SDS-PAGE. The molecular mass was estimated to be 33.2 kDa by gel filtration on Sephacryl S-100, indicating that the enzyme was composed of two identical subunits of 16.8 kDa each. N-terminal amino acid sequencing (seven residues) yielded VKAVAVL. Using RACE-PCR, a Cu, Zn-SOD gene was cloned from T. aurantiacus var. levisporus. The sequence was 705 bp and contained a 468 bp ORF encoding a Cu, Zn-SOD of 155 amino acid residues.

Superoxide Dismutase from the Silkworm,Bombyx mori: Sequence, Distribution, and Overexpression

Superoxide dismutase (SOD) is an enzyme facilitating the removal of superoxide anions from living organisms. This study focused on SOD from the silkworm, Bombyx mori (bmSOD). cDNA encoding bmSOD was amplified by reverse transcriptase-polymerase chain reaction. The deduced amino acid sequence of bmSOD indicated that the residues forming the Cu/Zn binding site are conserved and that the sequence is in 60% identity to that of the Drosophila melanogaster. B. mori SOD was also close to the D. melanogaster SOD in a phylogenetic tree. The bmSOD mRNA and the enzyme activity were widely distributed in diverse tissues. bmSOD functionally overexpressed in Escherichia coli in a soluble form was purified, and its stability was examined. bmSOD at 4 degrees C retained almost all of its original activity after incubation at pH 4-11 for 24 h. Incubation (pH 7) for 30 min at temperatures below 40 degrees C also affected activity insignificantly.

Expression, purification and crystallization of MnSOD from Arabidopsis thaliana

Manganese superoxide dismutase (MnSOD) is an essential primary antioxidant enzyme. MnSOD plays an important role in plant tolerance to abiotic stress and is a target candidate for increasing stress tolerance in crop plants. Although the structure and kinetic parameters of MnSODs from several organisms have been determined, this information is still lacking for plant MnSODs. Here, recombinant MnSOD from Arabidopsis thaliana (AtMnSOD) was expressed, purified and crystallized. A nearly complete data set could only be obtained when a total rotation range of 180° was imposed during data collection, despite the seemingly tetragonal metric of the AtMnSOD crystal diffraction. The data set extended to 1.95 Å resolution and the crystal belonged to space group P1. Molecular-replacement calculations using an ensemble of homologous SOD structures as a search model gave a unique and unambiguous solution corresponding to eight molecules in the asymmetric unit. Structural and kinetic analysis of AtMnSOD is currently being undertaken.

Excreted Leishmania peruviana and Leishmania amazonensis iron-superoxide dismutase purification: specific antibody detection in Colombian patients with cutaneous leishmaniasis

Leishmania sp. survival in the vertebrate host depends on the host macrophage immune response as well as on the parasite's defense against free radicals. Iron-superoxide dismutase (Fe-SOD) is a key antioxidant enzyme that contributes to radical superoxide dismutation, preventing the disease from surging and propagating itself. Leishmania sp. has various Fe-SOD isoforms, one of which (Fe-SODe) is excreted into the medium and, being highly immunogenic, can be considered a very good molecular marker. In this work, we purified the Fe-SOD enzymes excreted by L. peruviana and L. amazonensis and studied them as antigens in serodiagnosis. We used ELISA and Western blot techniques to test 51 human cutaneous leishmaniasis sera from Colombia. All 51 patients presented with dermal injuries caused by unknown Leishmania species. The results observed with the purified proteins were compared with those obtained when total soluble lysate and unpurified Fe-SODe were used as the antigen fraction. Thus, we conclude that the purified enzymes are more sensitive and specific than their unpurified counterparts and that there is no cross-reactivity between them.

Characterization of a mitochondrial manganese superoxide dismutase gene from Apis cerana cerana and its role in oxidative stress

Mitochondrial manganese superoxide dismutase (mMnSOD) plays a vital role in the defense against reactive oxygen species (ROS) in eukaryotic mitochondria. In this study, we isolated and identified a mMnSOD gene from Apis cerana cerana, which we named AccSOD2. Several putative transcription factor-binding sites were identified within the 5'-flanking region of AccSOD2, which suggests that AccSOD2 may be involved in organismal development and/or environmental stress responses. Quantitative real-time PCR analysis showed that AccSOD2 is highly expressed in larva and pupae during different developmental stages. In addition, the expression of AccSOD2 could be induced by cold (4 °C), heat (42 °C), H2O2, ultraviolet light (UV), HgCl2, and pesticide treatment. Using a disc diffusion assay, we provide evidence that recombinant AccSOD2 protein can play a functional role in protecting cells from oxidative stress. Finally, the in vivo activities of AccSOD2 were measured under a variety of stressful conditions. Taken together, our results indicate that AccSOD2 plays an important role in cellular stress responses and anti-oxidative processes and that it may be of critical importance to honeybee survival.

[Construction of prokaryotic expression vector, expression and purification of ginseng Cu/Zn superoxide dismutase]

The total RNA was extracted from ginseng leaves of Panax ginseng. The Cu/Zn-SOD gene was amplified via RT-PCR and the pET-28(a)-Cu/Zn-SOD expression vector was constructed. The pET-28 (a)-Cu/Zn-SOD recombinant plasmid was transformed into Escherichia coli BL21 (DE3) competent cells and was induced by IPTG in order to select optimal induction of expression conditions. The target protein was purified by the nickel ions (Ni ) affinity chromatography and the target protein enzyme activity was determinated by the xanthine oxidase method. The similarity of the Cu/Zn-SOD gene sequences and the Cu/Zn-SOD gene sequences of Korean ginseng in NCBI was 99. 00%. The target protein expression level was about 44.42%, and the molecular weight was 16.30 kDa after the pET-28(a)-Cu/Zn-SOD recombinants were induced by IPTG. The purified Cu/Zn-SOD protease activity reached 10,596.69 U x mg(-1). The P. ginseng pET-28(a)-Cu/Zn-SOD prokaryotic expression vector was built by the method of molecular biology, which provided the foundation for studying the Cu/Zn-SOD biology function.

In vivo detection of free radicals using molecular MRI and immuno-spin trapping in a mouse model for amyotrophic lateral sclerosis

Free radicals associated with oxidative stress play a major role in amyotrophic lateral sclerosis (ALS). By combining immuno-spin trapping and molecular magnetic resonance imaging, in vivo trapped radical adducts were detected in the spinal cords of SOD1(G93A)-transgenic (Tg) mice, a model for ALS. For this study, the nitrone spin trap DMPO (5,5-dimethyl-1-pyrroline N-oxide) was administered (ip) over 5 days before administration (iv) of an anti-DMPO probe (anti-DMPO antibody covalently bound to an albumin-gadolinium-diethylenetriamine pentaacetic acid-biotin MRI contrast agent) to trap free radicals. MRI was used to detect the presence of the anti-DMPO radical adducts by a significant sustained increase in MR signal intensities (p < 0.05) or anti-DMPO probe concentrations measured from T₁ relaxations (p < 0.01). The biotin moiety of the anti-DMPO probe was targeted with fluorescence-labeled streptavidin to locate the probe in excised tissues. Negative controls included either Tg ALS mice initially administered saline rather than DMPO followed by the anti-DMPO probe or non-Tg mice initially administered DMPO and then the anti-DMPO probe. The anti-DMPO probe was found to bind to neurons via colocalization fluorescence microscopy. DMPO adducts were also confirmed in diseased/nondiseased tissues from animals administered DMPO. Apparent diffusion coefficients from diffusion-weighted images of spinal cords from Tg mice were significantly elevated (p < 0.001) compared to wild-type controls. This is the first report regarding the detection of in vivo trapped radical adducts in an ALS model. This novel, noninvasive, in vivo diagnostic method can be applied to investigate the involvement of free radical mechanisms in ALS rodent models.

Preliminary crystallographic analysis of the Megavirus superoxide dismutase

Megavirus chilensis, a close relative of the Mimivirus giant virus, is able to replicate in Acanthamoeba castellanii. The first step of viral infection involves the internalization of the virions in host vacuoles. It has been experimentally demonstrated that Mimivirus particles contain many proteins capable of resisting oxidative stress, as encountered in the phagocytic process. These proteins are conserved in Megavirus, which has an additional gene (Mg277) encoding a putative superoxide dismutase. The Mg277 ORF product was overexpressed in Escherichia coli, purified and crystallized. A SAD data set was collected to 2.24 Å resolution at the selenium peak wavelength on the BM30 beamline at the ESRF from a single crystal of selenomethionine-substituted recombinant superoxide dismutase protein.

Identification and cloning of the Cu/Zn superoxide dismutase gene from halophyte plant Aeluropus littoralis

Reactive oxygen species (ROS) derived from molecular oxygen under biotic and abiotic stress such as salinity which have deleterious effects on cell metabolism. The toxic effect of ROS counteract by enzymatic as well as non-enzymatic antioxidant system. Superoxide dismutase (SOD) has a potential role for elimination of ROS. Halophytes respond to salt stress at different levels and can be a model for increasing salt tolerance in crop plants. Thus salt tolerance gene isolation and cloning of gene as well as subsequent transformation are first step for sensitive crop improvement. Aeluropus littoralis is a halophyte plant from poaceae family can be as a beneficial plant with high potential for creal breeding. There was no report on isolation of SOD gene from A. littoralis and little genomic study of this plant carried out. In this study a novel gene from A. littoralis isolated. This gene amplified by reverse transcription-PCR and cloned in E. coli pTZ57R/T cloning vector. The AlSOD gene sequence contained 456 bp and the deduced transcripts encoding 152 amino acids shared a high homology with those putative CuZnSOD of higher plants like Zea mays and Oryza sativa.

Molecular characterization and oxidative stress response of an intracellular Cu/Zn superoxide dismutase (CuZnSOD) of the whitefly, Bemisia tabaci

Superoxide dismutases (SODs) are important for the survival of insects under environmental and biological stresses; however, little attention has been devoted to the functional characterization of SODs in whitefly. In this study, an intracellular copper/zinc superoxide dismutase of whitefly (Bemisia tabaci) (Bt-CuZnSOD) was cloned. Sequence analysis indicated that the full length cDNA of Bt-CuZnSOD is of 907 bp with a 471 bp open reading frame encoding 157 amino acids. The deduced amino acid sequence shares common consensus patterns with the CuZnSODs of various vertebrate and invertebrate animals. Phylogenetic analysis revealed that Bt-CuZnSOD is grouped together with intracellular CuZnSODs. Bt-CuZnSOD was then over-expressed in E. coli and purified using GST purification system. The enzymatic activity of purified Bt-CuZnSOD was assayed under various temperatures. When whiteflies were exposed to low (4°C) and high (40°C) temperatures, the in vivo activity of Bt-CuZnSOD was significantly increased. Furthermore, we measured the activities of several antioxidant enzymes, including SOD, catalase and peroxidase, in the whitefly after transferring the whitefly from cotton to tobacco (an unfavorable host plant). We found that the activity of SOD increased rapidly on tobacco plant. Taken together, these results suggest that the Bt-CuZnSOD plays a major role in protecting the whitefly against various stress conditions.

Expression, purification and crystallization of Chaetomium thermophilum Cu,Zn superoxide dismutase

Cu,Zn superoxide dismutase (Cu,ZnSOD) from the thermophilic fungus Chaetomium thermophilum was expressed in Pichia pastoris and purified. Crystals were grown in over 120 conditions but only those produced with 1.4 M sodium potassium phosphate pH 8.2 as precipitant were suitable for structural studies. Data were collected to 1.9 A resolution at 100 K from a single crystal using a synchrotron-radiation source. The crystals belonged to space group P6(1)/P6(5), with unit-cell parameters a=90.2, c=314.5 A and eight molecules in the asymmetric unit. Elucidation of the crystal structure will provide insights into the active site of the enzyme and a better understanding of the structure-activity relationship, assembly and thermal stability of Cu,ZnSODs.