Purification, cloning, and sequencing of an enzyme mediating the reductive dechlorination of tetrachloroethylene (PCE) fromClostridium bifermentansDPH-1

2001 ◽  
Vol 47 (5) ◽  
pp. 448-456 ◽  
Author(s):  
Benedict C Okeke ◽  
Young C Chang ◽  
Masahiro Hatsu ◽  
Tohru Suzuki ◽  
Kazuhiro Takamizawa
Keyword(s):  
Enzymatic Activity ◽  
Reductive Dechlorination ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Maximal Activity ◽  
Degenerate Primers ◽  
Flight Mass Spectrometry ◽  
Oxygen Sensitive ◽  
Clostridium Bifermentans ◽  
Pce Dehalogenase

An enzyme mediating the reductive dechlorination of tetrachloroethylene (PCE) from cell-free extracts of Clostridium bifermentans DPH-1 was purified, cloned, and sequenced. The enzyme catalyzed the reductive dechlorination of PCE to cis-1,2-dichloroethylene via trichloroethylene, at a Vmaxand Kmof 73 nmol/mg protein and 12 µM, respectively. Maximal activity was recorded at 35°C and pH 7.5. Enzymatic activity was independent of metal ions but was oxygen sensitive. A mixture of propyl iodide and titanium citrate caused a light-reversible inhibition of enzymatic activity suggesting the involvement of a corrinoid cofactor. The molecular mass of the native enzyme was estimated to be approximately 70 kDa. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption ionization-time of flight/mass spectrometry (MALDI–TOF/MS) revealed molecular masses of approximately 35 kDa and 35.7 kDa, respectively. A broad spectrum of chlorinated aliphatic compounds (PCE, trichloroethylene, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, 1,1-dichloroethylene, 1,2-dichloropropane, and 1,1,2-trichloroethane) was degraded. With degenerate primers designed from the N-terminal sequence (27 amino acid residues), a partial sequence (81 bp) of the encoding gene was amplified by polymerase chain reaction (PCR) and sequenced. Southern analysis of C. bifermentans genomic DNA using the PCR product as a probe revealed restriction fragment bands. A 5.0 kb ClaI fragment, harboring the relevant gene (designated pceC) was cloned (pDEHAL5) and the complete nucleotide sequence of pceC was determined. The gene showed homology mainly with microbial membrane proteins and no homology with any known dehalogenase, suggesting a distinct PCE dehalogenase.Key words: tetrachloroethylene, Clostridium bifermentans DPH-1, PCE dehalogenase, gene cloning.

scholarly journals Molecular Characterization of a Recombinant Manganese Superoxide Dismutase fromLactococcus lactisM4

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Boon Hooi Tan ◽  
Thean Chor Leow ◽  
Hooi Ling Foo ◽  
Raha Abdul Rahim
Keyword(s):  
Superoxide Dismutase ◽  
Active Sites ◽  
Manganese Superoxide Dismutase ◽  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Maximal Activity ◽  
Gel Filtration Chromatography ◽  
T7 Promoter

A superoxide dismutase (SOD) gene ofLactococcus lactisM4 was cloned and expressed in a prokaryotic system. Sequence analysis revealed an open reading frame of 621 bp which codes for 206 amino acid residues. Expression ofsodAunder T7 promoter exhibited a specific activity of 4967 U/mg when induced with 1 mM of isopropyl-β-D-thiogalactopyranoside. The recombinant SOD was purified to homogeneity by immobilised metal affinity chromatography and Superose 12 gel filtration chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blot analyses of the recombinant SOD detected a molecular mass of approximately 27 kDa. However, the SOD was in dimer form as revealed by gel filtration chromatography. The purified recombinant enzyme had a pI of 4.5 and exhibited maximal activity at 25°C and pH 7.2. It was stable up to 45°C. The insensitivity of this lactococcal SOD to cyanide and hydrogen peroxide established that it was a MnSOD. Although it has 98% homology to SOD ofL. lactisIL1403, this is the first elucidated structure of lactococcal SOD revealing active sites containing the catalytic manganese coordinated by four ligands (H-27, H-82, D-168, and H-172).

scholarly journals Identification of a Second Collagen-Like Glycoprotein Produced by Bacillus anthracis and Demonstration of Associated Spore-Specific Sugars

2005 ◽  
Vol 187 (13) ◽  
pp. 4592-4597 ◽  
Author(s):  
Lashanda N. Waller ◽  
Michael J. Stump ◽  
Karen F. Fox ◽  
William M. Harley ◽  
Alvin Fox ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Bacillus Anthracis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gas Chromatography Mass Spectrometry ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Flight Mass Spectrometry ◽  
Carbohydrate Components ◽  
Protein Moiety

ABSTRACT Certain carbohydrates (rhamnose, 3-O-methyl rhamnose, and galactosamine) have been demonstrated to be present in Bacillus anthracis spores but absent in vegetative cells. Others have demonstrated that these spore-specific sugars are constituents of the glycoprotein BclA. In the current work, spore extracts were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A second collagen-like glycoprotein, BclB, was identified in B. anthracis. The protein moiety of this glycoprotein was identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MS) and the carbohydrate components by gas chromatography-mass spectrometry and tandem mass spectrometry. Spore-specific sugars were also demonstrated to be components of BclB.

scholarly journals Microbial Proline 4-Hydroxylase Screening and Gene Cloning

1999 ◽  
Vol 65 (9) ◽  
pp. 4028-4031 ◽  
Author(s):  
Takeshi Shibasaki ◽  
Hideo Mori ◽  
Shigeru Chiba ◽  
Akio Ozaki
Keyword(s):  
Amino Acid ◽  
Molecular Mass ◽  
Genomic Library ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Open Reading Frames ◽  
Original Strain ◽  
Degenerate Primers ◽  
E Coli ◽  
Dna Fragment

ABSTRACT Microbial proline 4-hydroxylases, which hydroxylate freel-proline totrans-4-hydroxy-l-proline, were screened in order to establish an industrial system for biotransformation of l-proline totrans-4-hydroxy-l-proline. Enzyme activities were detected in eight strains, including strains ofDactylosporangium spp. and Amycolatopsis spp. The Dactylosporangium sp. strain RH1 enzyme was partially purified 3,300-fold and was estimated to be a monomer polypeptide with an apparent molecular mass of 31 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Degenerate primers based on the N-terminal amino acid sequence of the 31-kDa polypeptide were synthesized in order to amplify the corresponding 71-bp DNA fragment. A 5.5-kbp DNA fragment was isolated by using the 71-bp fragment labeled with digoxigenin as a probe for a genomic library ofDactylosporangium sp. strain RH1 constructed inEscherichia coli. One of the open reading frames found in the cloned DNA, which encoded a 272-amino-acid polypeptide (molecular mass, 29,715 daltons), was thought to be a proline 4-hydroxylase gene. The gene was expressed in E. coli as a fused protein with the N-terminal 34 amino acids of the β-galactosidase α-fragment. The E. coli recombinant exhibited proline 4-hydroxylase activity that was 13.6-fold higher than the activity in the original strain, Dactylosporangium sp. strain RH1. No homology was detected with other 2-oxoglutarate-dependent dioxygenases when databases were searched; however, the histidine motif conserved in 2-oxoglutarate-dependent dioxygenases was found in the gene.

Bacterial adhesion to stainless steel is reduced by aqueous fish extract coatings

Biofilms ◽  
2006 ◽  
Vol 3 (1) ◽  
pp. 25-36 ◽  
Author(s):  
N. Bernbom ◽  
R. L. Jørgensen ◽  
Y. Y. Ng ◽  
R. L. Meyer ◽  
P. Kingshott ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Photoelectron Spectroscopy ◽  
Bacterial Adhesion ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Vibrio Anguillarum ◽  
Aeromonas Salmonicida ◽  
Bacterial Attachment ◽  
Stainless Steel Surface ◽  
Flight Mass Spectrometry

ABSTRACTMicrobial adhesion and biofilm formation on surfaces pose major problems and risks to human health. One way to circumvent this problem is to coat surfaces (in this report stainless steel) with a non-toxic fish extract that generates an abiotic surface with less bacterial attachment than uncoated surfaces or surfaces coated with, for example, tryptone soy broth. The bacteria grow well in the fish extract; hence a general bacteriocidal effect is not the reason for the antifouling effect. Bacterial attachment was quantified by different methods including (a) direct fluorescence microscopy, (b) removal by ultrasound and subsequent quantification of the adhered bacteria, and (c) regrowth of the adhered bacteria measured by indirect conductometry. Surprisingly, the bacterial counts on surfaces coated with aqueous fish extract were 10–100 times lower than on surfaces coated with laboratory broths when surfaces were submerged in bacterial suspensions. The effect was seen forPseudomonas fluorescensAH2,Pseudomonas aeruginosaPAO1,Escherichia coliMG1655,Vibrio anguillarum90-11-287 andAeromonas salmonicidaJno 3175/88. It lasted for at least 7 days. Atomic force microscopy showed that steel surfaces conditioned with fish extract were covered by a thin layer of spherical, nanosized particles. Chemical analysis of the surfaces coated with adsorbed fish extract using X-ray photoelectron spectroscopy revealed that the layer was proteinaceous and had a thickness less than 2 nm. Numerous protein bands/peaks were also detected by sodium dodecyl sulphate–polyacrylamide gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry techniques. We conclude that coating the stainless steel surface with fish extract results in a thin protein layer that reduces bacterial adhesion significantly.

scholarly journals Purification and Characterization of an Extracellular Protease from the Fish Pathogen Yersinia ruckeri and Effect of Culture Conditions on Production

1999 ◽  
Vol 65 (9) ◽  
pp. 3969-3975 ◽  
Author(s):  
P. Secades ◽  
J. A. Guijarro
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Maximal Activity ◽  
Exchange Chromatography ◽  
Casamino Acid ◽  
Exponential Growth Phase ◽  
Yersinia Ruckeri ◽  
Fish Pathogen ◽  
Sds Page

ABSTRACT A novel protease, hydrolyzing azocasein, was identified, purified, and characterized from the culture supernatant of the fish pathogenYersinia ruckeri. Exoprotease production was detected at the end of the exponential growth phase and was temperature dependent. Activity was detected in peptone but not in Casamino Acid medium. Its synthesis appeared to be under catabolite repression and ammonium control. The protease was purified in a simple two-step procedure involving ammonium sulfate precipitation and ion-exchange chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the purified protein indicated an estimated molecular mass of 47 kDa. The protease had characteristics of a cold-adapted protein, i.e., it was more active in the range of 25 to 42°C and had an optimum activity at 37°C. The activation energy for the hydrolysis of azocasein was determined to be 15.53 kcal/mol, and the enzyme showed a rapid decrease in activity at 42°C. The enzyme had an optimum pH of around 8. Characterization of the protease showed that it required certain cations such as Mg2+ or Ca2+ for maximal activity and was inhibited by EDTA, 1,10-phenanthroline, and EGTA but not by phenylmethylsulfonyl fluoride. TwoN-methyl-N-nitro-N-nitrosoguanidine mutants were isolated and analyzed; one did not show caseinolytic activity and lacked the 47-kDa protein, while the other was hyperproteolytic and produced increased amounts of the 47-kDa protein. Azocasein activity, SDS-PAGE, immunoblotting by using polyclonal anti-47-kDa-protease serum, and zymogram analyses showed that protease activity was present in 8 of 14 strains tested and that two Y. ruckeri groups could be established based on the presence or absence of the 47-kDa protease.

scholarly journals Triticum mosaic virus: A New Virus Isolated from Wheat in Kansas

Plant Disease ◽  
2008 ◽  
Vol 92 (5) ◽  
pp. 808-817 ◽  
Author(s):  
Dallas L. Seifers ◽  
T. J. Martin ◽  
Tom L. Harvey ◽  
John P. Fellers ◽  
James P. Stack ◽  
...  
Keyword(s):  
Coat Protein ◽  
Mosaic Virus ◽  
Polyclonal Antibodies ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Cesium Chloride ◽  
High Plains ◽  
Flight Mass Spectrometry ◽  
Sds Page ◽  
Systemic Symptoms

In 2006, a mechanically-transmissible and previously uncharacterized virus was isolated in Kansas from wheat plants with mosaic symptoms. The physiochemical properties of the virus were examined by purification on cesium chloride density gradients, electron microscopy, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), sequencing of the nucleotides and amino acids of the coat protein, and immunological reactivity. Purified preparations contained flexuous, rod-shaped particles that resembled potyviruses. The coat protein was estimated from SDS-PAGE to have a mass of approximately 35 kDa. Its amino acid sequence, as deduced from DNA sequencing of cloned, reverse-transcribed viral RNA and separately determined by time-of-flight mass spectrometry, was most closely related (49% similarity) to Sugarcane streak mosaic virus, a member of the Tritimovirus genus of the family Potyviridae. The virus gave strong positive reactions during enzyme-linked immunosorbent assays using polyclonal antibodies raised against purified preparations of the cognate virus but gave consistent negative reactions against antibodies to Wheat streak mosaic virus (WSMV), other wheat potyviruses, and the High Plains virus. When the virus was inoculated on the WSMV-resistant wheat cv. RonL, systemic symptoms appeared and plant growth was diminished significantly in contrast with WSMV-inoculated RonL. Taken together, the data support consideration of this virus as a new potyvirus, and the name Triticum mosaic virus (TriMV) is proposed.

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