scholarly journals Glutamyl-tRNA Reductase of Chlorobium vibrioforme Is a Dissociable Homodimer That Contains One Tightly Bound Heme per Subunit

2005 ◽  
Vol 187 (13) ◽  
pp. 4444-4450 ◽  
Author(s):  
Alaka Srivastava ◽  
Samuel I. Beale
Keyword(s):  
Molecular Mass ◽  
Column Chromatography ◽  
Aminolevulinic Acid ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Affinity Column ◽  
Chlorobium Vibrioforme ◽  
Sds Page

ABSTRACT δ-Aminolevulinic acid, the biosynthetic precursor of tetrapyrroles, is synthesized from glutamate via the tRNA-dependent five-carbon pathway in the green sulfur bacterium Chlorobium vibrioforme. The enzyme glutamyl-tRNA reductase (GTR), encoded by the hemA gene, catalyzes the first committed step in this pathway, which is the reduction of tRNA-bound glutamate to produce glutamate 1-semialdehyde. To characterize the GTR protein, the hemA gene from C. vibrioforme was cloned into expression plasmids that added an N-terminal His6 tag to the expressed protein. The His-tagged GTR protein was purified using Ni affinity column chromatography. GTR was observable as a 49-kDa band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gels. The native molecular mass, as determined by gel filtration chromatography, appeared to be approximately 40 kDa, indicating that native GTR is a monomer. However, when the protein was mixed with 5% (vol/vol) glycerol, the product had an apparent molecular mass of 95 kDa, indicating that the protein is a dimer under these conditions. Purified His6-GTR was catalytically active in vitro when it was incubated with Escherichia coli glutamyl-tRNAGlu and purified recombinant Chlamydomonas reinhardtii glutamate-1-semialdehyde aminotransferase. The expressed GTR contained 1 mol of tightly bound heme per mol of pep tide subunit. The heme remained bound to the protein throughout purification and was not removed by anion- or cation-exchange column chromatography. However, the bound heme was released during SDS-PAGE if the protein was denatured in the presence of β-mercaptoethanol. Added heme did not inhibit the activity of purified expressed GTR in vitro. However, when the GTR was expressed in the presence of 3-amino-2,3- dihydrobenzoic acid (gabaculine), an inhibitor of heme synthesis, the purified GTR had 60 to 70% less bound heme than control GTR, and it was inhibited by hemin in vitro.

A metalloproteinase extracellularly released byCrithidia deanei

2003 ◽  
Vol 49 (10) ◽  
pp. 625-632 ◽  
Author(s):  
Claudia Masini d'Avila-Levy ◽  
Rodrigo F Souza ◽  
Rosana C Gomes ◽  
Alane B Vermelho ◽  
Marta H Branquinha
Keyword(s):  
Molecular Mass ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Residual Activity ◽  
Major Protein ◽  
Motile Cells ◽  
Sds Page ◽  
Triton X

Actively motile cells from a cured strain of Crithidia deanei released proteins in phosphate buffer (pH 7.4). The molecular mass of the released polypeptides, which included some proteinases, ranged from 19 to 116 kDa. One of the major protein bands was purified to homogeneity by a combination of anion-exchange and gel filtration chromatographs. The apparent molecular mass of this protein was estimated to be 62 kDa by sodium dodecyl sulfate – polyacrylamide gel electrophoresis (SDS–PAGE). The incorporation of gelatin into SDS–PAGE showed that the purified protein presented proteolytic activity in a position corresponding to a molecular mass of 60 kDa. The enzyme was optimally active at 37 °C and pH 6.0 and showed 25% of residual activity at 28 °C for 30 min. The proteinase was inhibited by 1,10-phenanthroline and EDTA, showing that it belonged to the metalloproteinase class. A polyclonal antibody to the leishmanial gp63 reacted strongly with the released C. deanei protease. After Triton X-114 extraction, an enzyme similar to the purified metalloproteinase was detected in aqueous and detergent-rich phases. The detection of an extracellular metalloproteinase produced by C. deanei and some other Crithidia species suggests a potential role of this released enzyme in substrate degradation that may be relevant to the survival of trypanosomatids in the host.Key words: endosymbiont, trypanosomatid, extracellular, proteinase.

scholarly journals Isolation and Characterization of Two Proteins fromMoraxella catarrhalis That Bear a Common Epitope

1998 ◽  
Vol 66 (9) ◽  
pp. 4374-4381 ◽  
Author(s):  
John C. McMichael ◽  
Michael J. Fiske ◽  
Ross A. Fredenburg ◽  
Deb N. Chakravarti ◽  
Karl R. VanDerMeid ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Bacterial Attachment ◽  
Vaccine Candidates ◽  
Isolation And Characterization ◽  
Sds Page

ABSTRACT The UspA1 and UspA2 proteins of Moraxella catarrhalisare potential vaccine candidates for preventing disease caused by this organism. We have characterized both proteins and evaluated their vaccine potential using both in vitro and in vivo assays. Both proteins were purified from the O35E isolate by Triton X-100 extraction, followed by ion-exchange and hydroxyapatite chromatography. Analysis of the sequences of internal peptides, prepared by enzymatic and chemical cleavage of the proteins, revealed that UspA1 and UspA2 exhibited distinct structural differences but shared a common sequence including an epitope recognized by the monoclonal antibody 17C7. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), purified UspA1 exhibited a molecular weight of approximately 350,000 when unheated and a molecular weight of 100,000 after being heated for 10 min at 100°C. In contrast, purified UspA2 exhibited an apparent molecular weight of 240,000 by SDS-PAGE that did not change with the length of time of heating. Their sizes as determined by gel filtration were 1,150,000 and 830,000 for UspA1 and UspA2, respectively. Preliminary results indicate the proteins have separate functions in bacterial pathogenesis. Purified UspA1 was found to bind HEp-2 cells, and sera against UspA1, but not against UspA2, blocked binding of the O35E isolate to the HEp-2 cells. UspA1 also bound fibronectin and appears to have a role in bacterial attachment. Purified UspA2, however, did not bind fibronectin but had an affinity for vitronectin. Both proteins elicited bactericidal antibodies in mice to homologous and heterologous disease isolates. Finally, mice immunized with each of the proteins, followed by pulmonary challenge with either the homologous or a heterologous isolate, cleared the bacteria more rapidly than mock-immunized mice. These results suggest that UspA1 and UspA2 serve different virulence functions and that both are promising vaccine candidates.

scholarly journals Characterization of Biosynthetic Enzymes for Ectoine as a Compatible Solute in a Moderately Halophilic Eubacterium, Halomonas elongata

1999 ◽  
Vol 181 (1) ◽  
pp. 91-99 ◽  
Author(s):  
Hisayo Ono ◽  
Kazuhisa Sawada ◽  
Nonpanga Khunajakr ◽  
Tao Tao ◽  
Mihoko Yamamoto ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Apparent Molecular Mass ◽  
Optimum Temperature ◽  
Sds Page ◽  
Halomonas Elongata ◽  
Optimum Ph

ABSTRACT 1,4,5,6-Tetrahydro-2-methyl-4-pyrimidinecarboxylic acid (ectoine) is an excellent osmoprotectant. The biosynthetic pathway of ectoine from aspartic β-semialdehyde (ASA), in Halomonas elongata, was elucidated by purification and characterization of each enzyme involved. 2,4-Diaminobutyrate (DABA) aminotransferase catalyzed reversively the first step of the pathway, conversion of ASA to DABA by transamination with l-glutamate. This enzyme required pyridoxal 5′-phosphate and potassium ions for its activity and stability. The gel filtration estimated an apparent molecular mass of 260 kDa, whereas molecular mass measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was 44 kDa. This enzyme exhibited an optimum pH of 8.6 and an optimum temperature of 25°C and had Km s of 9.1 mM forl-glutamate and 4.5 mM for dl-ASA. DABA acetyltransferase catalyzed acetylation of DABA to γ-N-acetyl-α,γ-diaminobutyric acid (ADABA) with acetyl coenzyme A and exhibited an optimum pH of 8.2 and an optimum temperature of 20°C in the presence of 0.4 M NaCl. The molecular mass was 45 kDa by gel filtration. Ectoine synthase catalyzed circularization of ADABA to ectoine and exhibited an optimum pH of 8.5 to 9.0 and an optimum temperature of 15°C in the presence of 0.5 M NaCl. This enzyme had an apparent molecular mass of 19 kDa by SDS-PAGE and a Km of 8.4 mM in the presence of 0.77 M NaCl. DABA acetyltransferase and ectoine synthase were stabilized in the presence of NaCl (>2 M) and DABA (100 mM) at temperatures below 30°C.

scholarly journals Role of plasmin in the degradation of the stroma-derived fibrin in human ovarian carcinoma

Blood ◽  
1990 ◽  
Vol 75 (8) ◽  
pp. 1673-1678 ◽  
Author(s):  
O Wilhelm ◽  
R Hafter ◽  
A Henschen ◽  
M Schmitt ◽  
H Graeff
Keyword(s):  
Ovarian Cancer ◽  
High Performance ◽  
Degradation Products ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Fibrin Degradation Products ◽  
Sds Page ◽  
Human Ovarian Carcinoma

Abstract The aim of this study was to evaluate the type of enzymes involved in tumor-associated fibrinolysis of the stroma component fibrin in ovarian cancer patients. For this purpose, the high-molecular-mass fibrin degradation products (HMM-XDP) were isolated from malignant ascitic fluid by protamine sulfate precipitation and further purified by gel filtration and acid precipitation. After reduction with 2- mercaptoethanol, the peptide chain components were separated by reverse- phase high-performance liquid chromatography (RP-HPLC). The nature of these components was elucidated by sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE) and N-terminal amino acid sequence analysis and compared with fibrin-derived fragments formed in vitro. The results indicate that plasmin is the essential protease involved in the degradation of the stroma-derived fibrin portion found in ovarian cancer ascites.

scholarly journals Purification and Characterization of Turnip Mosaic Virus Helper Component Protein

1999 ◽  
Vol 89 (7) ◽  
pp. 564-567 ◽  
Author(s):  
R. Y. Wang ◽  
T. P. Pirone
Keyword(s):  
Molecular Mass ◽  
Mosaic Virus ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Turnip Mosaic Virus ◽  
Biologically Active ◽  
Helper Component ◽  
Pass Through

The helper component (HC) protein of turnip mosaic virus (TuMV) was concentrated by differential centrifugation followed by ammonium sulfate precipitation. The partially purified HC was then loaded onto a Ni2+-resin column that bound the HC; a histidine tag was not required for binding. The HC eluted from the column migrated as a band of about 50 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In its native state, the HC did not pass through an ultrafiltration membrane with a molecular mass cutoff of 100 kDa, which suggested that the HC is in a multimeric form when it is biologically active. The molecular mass of the multimeric form was determined by gel filtration to be approximately 145 kDa. Purified HC retained its activity for several months at -20°C. Using a protein blotting-overlay protocol, purified HC interacted in vitro with an aphid-transmissible TuMV isolate, but not with a non-aphid-transmissible isolate.

scholarly journals Role of plasmin in the degradation of the stroma-derived fibrin in human ovarian carcinoma

Blood ◽  
1990 ◽  
Vol 75 (8) ◽  
pp. 1673-1678
Author(s):  
O Wilhelm ◽  
R Hafter ◽  
A Henschen ◽  
M Schmitt ◽  
H Graeff
Keyword(s):  
Ovarian Cancer ◽  
High Performance ◽  
Degradation Products ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Fibrin Degradation Products ◽  
Sds Page ◽  
Human Ovarian Carcinoma

The aim of this study was to evaluate the type of enzymes involved in tumor-associated fibrinolysis of the stroma component fibrin in ovarian cancer patients. For this purpose, the high-molecular-mass fibrin degradation products (HMM-XDP) were isolated from malignant ascitic fluid by protamine sulfate precipitation and further purified by gel filtration and acid precipitation. After reduction with 2- mercaptoethanol, the peptide chain components were separated by reverse- phase high-performance liquid chromatography (RP-HPLC). The nature of these components was elucidated by sodium dodecyl sulfate- polyacrylamide gel electrophoresis (SDS-PAGE) and N-terminal amino acid sequence analysis and compared with fibrin-derived fragments formed in vitro. The results indicate that plasmin is the essential protease involved in the degradation of the stroma-derived fibrin portion found in ovarian cancer ascites.

scholarly journals Purification and Characterization of 2,6-β-d-Fructan 6-Levanbiohydrolase fromStreptomyces exfoliatus F3-2

2000 ◽  
Vol 66 (1) ◽  
pp. 252-256 ◽  
Author(s):  
Katsuichi Saito ◽  
Kazuya Kondo ◽  
Ichiro Kojima ◽  
Atsushi Yokota ◽  
Fusao Tomita
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Extracellular Enzyme ◽  
Molecular Weights ◽  
Sds Page ◽  
Monomeric Structure ◽  
Ph Range ◽  
Hydrolysis Of

ABSTRACT Streptomyces exfoliatus F3-2 produced an extracellular enzyme that converted levan, a β-2,6-linked fructan, into levanbiose. The enzyme was purified 50-fold from culture supernatant to give a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The molecular weights of this enzyme were 54,000 by SDS-PAGE and 60,000 by gel filtration, suggesting the monomeric structure of the enzyme. The isoelectric point of the enzyme was determined to be 4.7. The optimal pH and temperature of the enzyme for levan degradation were pH 5.5 and 60°C, respectively. The enzyme was stable in the pH range 3.5 to 8.0 and also up to 50°C. The enzyme gave levanbiose as a major degradation product from levan in an exo-acting manner. It was also found that this enzyme catalyzed hydrolysis of such fructooligosaccharides as 1-kestose, nystose, and 1-fructosylnystose by liberating fructose. Thus, this enzyme appeared to hydrolyze not only β-2,6-linkage of levan, but also β-2,1-linkage of fructooligosaccharides. From these data, the enzyme from S. exfoliatus F3-2 was identified as a novel 2,6-β-d-fructan 6-levanbiohydrolase (EC 3.2.1.64 ).

scholarly journals Characterization of proteins from the cytoskeleton of Giardia lamblia

1983 ◽  
Vol 59 (1) ◽  
pp. 81-103 ◽  
Author(s):  
R. Crossley ◽  
D.V. Holberton
Keyword(s):  
Molecular Weight ◽  
Sodium Dodecyl Sulphate ◽  
Giardia Lamblia ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Molecular Size ◽  
Molecular Weights

Proteins from the axonemes and disc cytoskeleton of Giardia lamblia have been examined by sodium dodecyl sulphate/polyacrylamide gel electrophoresis. In addition to tubulin and the 30 X 10(3) molecular weight disc protein, at least 18 minor components copurify with the two major proteins in Triton-insoluble structures. The most prominent minor bands have the apparent molecular weights of 110 X 10(3), 95 X 10(3) and 81 X 10(3). Protein of 30 X 10(3) molecular weight accounts for about 20% of organelle protein on gels. In continuous 25 mM-Tris-glycine buffer it migrates mostly as a close-spaced doublet of polypeptides, which are here given the name giardins. Giardia tubulin and giardin have been purified by gel filtration chromatography in the presence of sodium dodecyl sulphate. Well-separated fractions were obtained that could be further characterized. Both proteins are heterogeneous when examined by isoelectric focusing. Five tubulin chains were detected by PAGE Blue 83 dye-binding after focusing in a broad-range ampholyte gel. Giardin is slightly less acidic than tubulin. On gels it splits into four major and four minor chains with isoelectric points in the pI range from 5.8 to 6.2. The amino acid composition of the giardin fraction has been determined, and compared to Giardia tubulin and a rat brain tubulin standard. Giardins are rich in helix-forming residues, particularly leucine. They have a low content of proline and glycine; therefore they may have extensive alpha-helical regions and be rod-shaped. As integral proteins of disc microribbons, giardins in vivo associate closely with tubulin. The properties of giardins indicate that in a number of respects - molecular size, charge, stoichiometry - their structural interaction with tubulin assemblies will be different from other tubulin-accessory protein copolymers studied in vitro.

scholarly journals Heterologous Expression and Characterization of A Novel Ochratoxin A Degrading Enzyme, N-acyl-L-amino Acid Amidohydrolase, from Alcaligenes faecalis

Toxins ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 518
Author(s):  
Honghai Zhang ◽  
Yunpeng Zhang ◽  
Tie Yin ◽  
Jing Wang ◽  
Xiaolin Zhang
Keyword(s):  
Amino Acid ◽  
Ochratoxin A ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Alcaligenes Faecalis ◽  
Degrading Enzyme ◽  
Sds Page ◽  
Ochratoxin Α ◽  
Acid Amidohydrolase

Ochratoxin A (OTA) is a well-known, natural contaminant in foods and feeds because of its toxic effects, such as nephrotoxicity in various animals. Recent studies have revealed that Alcaligenes faecalis could generate enzymes to efficiently degrade OTA to ochratoxin α (OTα) in vitro. In an effort to obtain the OTA degrading mechanism, we purified and identified a novel degrading enzyme, N-acyl-L-amino acid amidohydrolase (AfOTase), from A. faecalis DSM 16503 via mass spectrometry. The same gene of the enzyme was also encountered in other A. faecalis strains. AfOTase belongs to peptidase family M20 and contains metal ions at the active site. In this study, recombination AfOTase was expressed and characterized in Escherichia coli. The molecular mass of recombinant rAfOTase was approximately 47.0 kDa, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme exhibited a wide temperature range (30–70 °C) and pH adaptation (4.5–9.0) and the optimal temperature and pH were 50 °C and 6.5, respectively.

scholarly journals Extraction, Characterization and Antioxidant Activity in vitro of Proteins from Semen Allii Fistulosi

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3235
Author(s):  
Min Zuo ◽  
Xiao-xiao Liu ◽  
Di Liu ◽  
Hang-yun Zhao ◽  
Lu-lu Xuan ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
High Performance ◽  
Orthogonal Design ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Reducing Power ◽  
Raw Material ◽  
Extraction Solvent ◽  
Sds Page

Semen Allii Fistulosi (PSAF) is the seed of Allium fistulosum L. of the Liliaceae family. The purpose of this study was to extract, characterize, and evaluate the antioxidant activity in vitro of proteins. Using single factor and orthogonal design, the optimum conditions of extraction were determined to be as follows: extraction time 150 min, pH 8.5, temperature 60 °C, and ratio (v/w, mL/g) of extraction solvent to raw material 35. The isoelectric point of the pH was determined to be about 4.4 and 10.2, by measuring the protein content of PSAF solutions at different pH values. The amino acid composition of PSAF was determined by high performance liquid chromatography (HPLC), and the results suggested that the species of amino acids contained in the PSAF was complete. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS–PAGE) analysis showed the molecular weight was mainly between 40 and 55 kDa, and Fourier-transform infrared spectroscopy (FTIR) characterized prevalent protein absorption peaks. PSAF exhibited potent scavenging activities against DPPH assays, via targeting of hydroxyl and superoxide radicals, while chelating Fe2+ activity and demonstrating weak reducing power. This work revealed that PSAF possessed potential antioxidant activity in vitro, suggesting potential for use of PSAF as a natural antioxidant.

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