scholarly journals Genes and Enzymes of Azetidine-2-Carboxylate Metabolism: Detoxification and Assimilation of an Antibiotic

2008 ◽  
Vol 190 (14) ◽  
pp. 4859-4864 ◽  
Author(s):  
Carol Gross ◽  
Roderick Felsheim ◽  
Lawrence P. Wackett
Keyword(s):  
Specific Activity ◽  
Periplasmic Fraction ◽  
Gene Encoding ◽  
Haloacid Dehalogenase ◽  
Protein Mass ◽  
Protein Mass Spectrometry ◽  
Chaperone Protein ◽  
Marker Proteins ◽  
Had Superfamily ◽  
Cell Fractions

ABSTRACT l-(−)-Azetidine-2-carboxylate (AC) is a toxic, natural product analog of l-proline. This study revealed the genes and biochemical strategy employed by Pseudomonas sp. strain A2C to detoxify and assimilate AC as its sole nitrogen source. The gene region from Pseudomonas sp. strain A2C required for detoxification was cloned into Escherichia coli and sequenced. The 7.0-kb region contained eight identifiable genes. Four encoded putative transporters or permeases for γ-amino acids or drugs. Another gene encoded a homolog of 2-haloacid dehalogenase (HAD). The encoded protein, denoted l-azetidine-2-carboxylate hydrolase (AC hydrolase), was highly overexpressed by subcloning. The AC hydrolase was shown to catalyze azetidine ring opening with the production of 2-hydroxy-4-aminobutyrate. AC hydrolase was further demonstrated to be a new hydrolytic member of the HAD superfamily by showing loss of activity upon changing aspartate-12, the conserved active site nucleophile in this family, to an alanine residue. The presence of a gene encoding a potential export chaperone protein, CsaA, adjacent to the AC hydrolase gene suggested that AC hydrolase might be found inside the periplasm in the native Pseudomonas strain. Periplasmic and cytoplasmic cell fractions from Pseudomonas sp. strain A2C were prepared. A higher specific activity for AC hydrolysis was found in the periplasmic fraction. Protein mass spectrometry further identified AC hydrolase and known periplasmic marker proteins in the periplasmic fraction. A model was proposed in which AC is hydrolyzed in the periplasm and the product of that reaction is transported into and further metabolized in the cytoplasm.

Cloning and expression of DL-2-haloacid dehalogenase gene from Burkholderia cepacia

2000 ◽  
Vol 42 (7-8) ◽  
pp. 261-268 ◽  
Author(s):  
Y. Ohkouchi ◽  
H. Koshikawa ◽  
Y. Terashima
Keyword(s):  
Burkholderia Cepacia ◽  
Specific Activity ◽  
Wild Strain ◽  
Cloning And Expression ◽  
Gene Encoding ◽  
Haloacid Dehalogenase ◽  
E Coli ◽  
Vector Systems ◽  
Lac Promoter ◽  
Acetic Acids

Burkholderia cepacia strain KY, which can utilize a herbicide 2,4-D as a sole carbon and energy source, catalyzes the hydrolytic dehalogenation of both D- and L-2-haloalkanoic acids. We have cloned the gene encoding DL-2-haloacid dehalogenase, and obtained a recombinant plasmid (pUCDEXL) containing approximately 4.5 kbp insert. In both of B. cepacia strain KY and this clone E. coli JM109/pUCDEXL, DL-2-haloacid dehalogenase was induced significantly with monohalogenated acetic acids, such as chloroacetate, bromoacetate and iodoacetate. This dehalogenase was also overexpressed in E. coli using three different promoters. In pET vector systems with T7 lac promoter, a large amount of dehalogenase was selectively expressed, but some parts of the protein were accumulated in the form of inclusion bodies. This problem was overcome to carry on growth and induction at 22°C, and at the same time, the maximum specific activity of dehalogenase was reached at 12.6 U/mg, 500-fold higher activity than in wild strain, B. cepacia strain KY grown with 2,4-D.

DIE INITIALE VERTEILUNG VON RADIO-C IN DEN ZELLFRAKTIONEN EINIGER RATTENORGANE NACH INJEKTION VON TESTOSTERON-4-14C

1964 ◽  
Vol 47 (1) ◽  
pp. 51-57 ◽  
Author(s):  
K.-O. Mosebach ◽  
W. Dirscherl
Keyword(s):  
Intraperitoneal Injection ◽  
Specific Activity ◽  
Initial Distribution ◽  
Male Rats ◽  
Initial Formation ◽  
Thigh Muscles ◽  
The Absolute ◽  
Cell Fractions

ABSTRACT The initial distribution of radioactive C was studied in the cell fractions of the liver, kidney, testes and thigh muscles after intraperitoneal injection of testosterone-4-14C into 40 day old male rats. To make this possible, the absolute and specific activity values (μc/mg C) were determined. After both ten and twenty minutes the cytoplasm fractions possessed the highest activity values, the only exception being the specific activity of the liver cytoplasm ten minutes after injection when the microsomes of the liver showed a higher activity. After 20 min the mitochondria possessed the highest specific activity values among the corpuscular fractions. The specific activity values in the microsomes of all four organs studied were lower 20 min after the time of injection than after 10 min, a fact, which is suspected to be the result of the initial formation of conjugates in the microsomes.

Molecular characterization of three mutations in katG affecting the activity of hydroperoxidase I of Escherichia coli

1990 ◽  
Vol 68 (7-8) ◽  
pp. 1037-1044 ◽  
Author(s):  
Peter C. Loewen ◽  
Jacek Switala ◽  
Mark Smolenski ◽  
Barbara L. Triggs-Raine
Keyword(s):  
Escherichia Coli ◽  
Specific Activity ◽  
Polymerase Chain Reaction Amplification ◽  
Protein A ◽  
Wild Type ◽  
Wild Type Enzyme ◽  
Gene Encoding ◽  
Reaction Amplification ◽  
Mutant Genes

Hydroperoxidase I (HPI) of Escherichia coli is a bifunctional enzyme exhibiting both catalase and peroxidase activities. Mutants lacking appreciable HPI have been generated using nitrosoguanidine and the gene encoding HPI, katG, has been cloned from three of these mutants using either classical probing methods or polymerase chain reaction amplification. The mutant genes were sequenced and the changes from wild-type sequence identified. Two mutants contained G to A changes in the coding strand, resulting in glycine to aspartate changes at residues 119 (katG15) and 314 (katG16) in the deduced amino acid sequence of the protein. A third mutant contained a C to T change resulting in a leucine to phenylalanine change at residue 139 (katG14). The Phe139-, Asp119-, and Asp314-containing mutants exhibited 13, < 1, and 18%, respectively, of the wild-type catalase specific activity and 43, 4, and 45% of the wild-type peroxidase specific activity. All mutant enzymes bound less protoheme IX than the wild-type enzyme. The sensitivities of the mutant enzymes to the inhibitors hydroxylamine, azide, and cyanide and the activators imidazole and Tris were similar to those of the wild-type enzyme. The mutant enzymes were more sensitive to high temperature and to β-mercaptoethanol than the wild-type enzyme. The pH profiles of the mutant catalases were unchanged from the wild-type enzyme.Key words: catalase, hydroperoxidase I, mutants, sequence analysis.

scholarly journals Improving production of Streptomyces griseus trypsin for its application in processing insulin precursor

2019 ◽  
Author(s):  
YunFeng Zhang ◽  
Qixing Liang ◽  
Chuanzhi Zhang ◽  
Juan Zhang ◽  
Guocheng Du ◽  
...  
Keyword(s):  
Pichia Pastoris ◽  
Specific Activity ◽  
Streptomyces Griseus ◽  
Dynamics Simulation ◽  
Flask Culture ◽  
Insulin Production ◽  
Chaperone Protein ◽  
Selection Approach ◽  
Pharmaceutical Manufacture ◽  
Hydrolysis Activity

Abstract Background: Trypsin has a plenty application in food and pharmaceutical manufacture. While, the commercial trypsin is usually extracted from pork pancreas, which has the risk of infectious and immunogenicity. Therefore, the microbial Streptomyces griseus trypsin (SGT) is a prior alternation because it processes efficient hydrolysis activity without the aforementioned risk. The remarkable hydrolysis efficiency of SGT caused its autolysis, and five autolysis sites R21, R32, K122, R153, and R201 were identified from its' autolysate. Results: The tbcf (K101A, R201V) mutant was screened by directed selection approach for improved activity in flask culture (60.85 ± 3.42 U·mL -1 , increased 1.5-fold). From the molecular dynamics simulation, the K101A/R201V mutation shortened the distant between catalytical residues D102 and H57 from 6.5 Å vs 7.0 Å, which afforded the improved specific activity 1527.96 ± 62.81 U·mg -1 . Further, the production of trypsin was increased 302.8% (689.47 ± 6.78 U·mL −1 ) in 3-L bio-reactor, with co-overexpression of chaperones SSO2 and UBC1 in Pichia pastoris. Conclusions: The SGT protein could be an adequate trypsin for insulin production. When working with hydrolysates analysis and direction selection, the tbcf (K101A, R201V) mutant increased 1.5-fold activity. Further, the production of trypsin was improved 3-fold by overexpressing chaperone protein in Pichia pastoris . The future study should be emphasized on the application of SGT in insulin manufacture and pharmaceutical.

scholarly journals EXPLORATION OF BROTH CHICKEN GUT AS GROWTH MEDIA OF Escherichia coli BL21 pET-Endo FOR ENDO-Β-1,4-D-XYLANASE PRODUCTION

2017 ◽  
Vol 13 (2) ◽  
pp. 191
Author(s):  
Anak Agung Istri Ratnadewi ◽  
Moch. Yoris Alidion ◽  
Agung Budi Santoso ◽  
Ika Oktavianawatia
Keyword(s):  
Large Scale ◽  
Incubation Temperature ◽  
Specific Activity ◽  
Hydrolytic Enzyme ◽  
Optimal Growth ◽  
Good Alternative ◽  
Growth Media ◽  
Gene Encoding ◽  
Xylanase Production ◽  
E Coli

<p>Endo-β-1,4-D-xylanase is a hydrolytic enzyme that breakdown the 1.4 chain of xylan polysaccharide. We have succes to transform the plasmid pET-Endo gene encoding endo-1,4-β-D-xylanase from Bacillus sp. originally from termites abdominal to E. coli BL21. The clone was ready for large scale of enzyme production. To reduce production cost, we look for subtitute media for the expensive Luria Berthani broth. Chicken guts broth is good alternative while rich of protein and very cheap. The content of N dissolved chicken guts broth reaches 87 % of LB broth. Growth of E. Coli BL21 in Chicken guts broth and LB broth (as control) was observed by Optical Density (OD) using spectrofotometer. Concentration of glucose added in broth and incubation temperature was varied. The result showed that optimal growth was in addition of 1.5 % glucose and incubated at  37 <sup>o</sup>C for 16 h. This optimal condition was used to grow E. coli BL21 pET-Endo for xylanase production. Enzyme purification was done by Ni-NTA affinity chromatography. Highest protein yield was 0.076 mg/mL obtained in 100 mM imidazole elucidation. The activity and specific activity of xylanase were estimated as 0.042 U/mL and 0.556 U/µg, respectively. The purification factor was 3.16 time and the molecular weight of enzyme was ± 30, 000 Dalton</p>

scholarly journals Cloning and expression of haloacid dehalogenase gene from Bacillus cereus IndB1

2018 ◽  
Vol 22 (2) ◽  
pp. 55
Author(s):  
Enny Ratnaningsih ◽  
Idris Idris
Keyword(s):  
Recombinant Protein ◽  
Bacillus Cereus ◽  
Tertiary Structure ◽  
Specific Activity ◽  
Halogen Bond ◽  
Expression System ◽  
Industrial Sector ◽  
Cloning And Expression ◽  
Haloacid Dehalogenase ◽  
Organohalogen Compounds

Organohalogen compounds, widely used as pesticides in agriculture and solvents in the industrial sector, cause environmental pollution and health problems due to their toxicity and persistence. Numerous studies have been conducted on the biodegradation of organohalogen compounds, with many focusing on the use of dehalogenase from bacteria. Haloacid dehalogenase is a group of enzymes that cleaves the carbon-halogen bond in halogenated aliphatic acids. In a previous study, the bcfd1 gene encoded haloacid dehalogenase from Bacillus cereus IndB1 was successfully isolated and characterized. This research aimed to create an expression system of the bcfd1 gene by subcloning this gene into pET expression vector and to overexpress the gene in Escherichia coli BL21 (DE3). In addition, the recombinant protein was characterized to gain a better understanding of the catalytic action of this enzyme. A high expression of bcfd1 was obtained by inducing the culture at OD550 0.8–1.0  using 0.01 mM IPTG as determined by SDS-PAGE. Zymogram analysis proved that the recombinant protein possessed dehalogenase activity. Bcfd1 activity toward monochloroacetic acid (MCA) showed specific activity of 37 U/mg at 30°C, pH 9. The predicted tertiary structure of Bcfd1 was estimated has conserved α/ß hydrolase folding motif for haloacid dehalogenase superfamily.

Sign in / Sign up

Export Citation Format

Share Document