scholarly journals Cloning, Sequencing, and Expression of the Gene Encoding Cyclic 2,3-Diphosphoglycerate Synthetase, the Key Enzyme of Cyclic 2,3-Diphosphoglycerate Metabolism in Methanothermus fervidus

1998 ◽  
Vol 180 (22) ◽  
pp. 5997-6004 ◽  
Author(s):  
Karl Matussek ◽  
Patrick Moritz ◽  
Nina Brunner ◽  
Christoph Eckerskorn ◽  
Reinhard Hensel
Keyword(s):  
Substrate Affinity ◽  
Kinetic Properties ◽  
Gene Encoding ◽  
Enzyme Preparations ◽  
E Coli ◽  
Gene Coding ◽  
Key Enzyme ◽  
Methanothermus Fervidus ◽  
Synthetic Reaction ◽  
Sequencing And Expression

ABSTRACT Cyclic 2,3-diphosphoglycerate synthetase (cDPGS) catalyzes the synthesis of cyclic 2,3-diphosphoglycerate (cDPG) by formation of an intramolecular phosphoanhydride bond in 2,3-diphosphoglycerate. cDPG is known to be accumulated to high intracellular concentrations (>300 mM) as a putative thermoadapter in some hyperthermophilic methanogens. For the first time, we have purified active cDPGS from a methanogen, the hyperthermophilic archaeon Methanothermus fervidus, sequenced the coding gene, and expressed it in Escherichia coli. cDPGS purification resulted in enzyme preparations containing two isoforms differing in their electrophoretic mobility under denaturing conditions. Since both polypeptides showed the same N-terminal amino acid sequence and Southern analyses indicate the presence of only one gene coding for cDPGS in M. fervidus, the two polypeptides originate from the same gene but differ by a not yet identified modification. The native cDPGS represents a dimer with an apparent molecular mass of 112 kDa and catalyzes the reversible formation of the intramolecular phosphoanhydride bond at the expense of ATP. The enzyme shows a clear preference for the synthetic reaction: the substrate affinity and the V max of the synthetic reaction are a factor of 8 to 10 higher than the corresponding values for the reverse reaction. Comparison with the kinetic properties of the electrophoretically homogeneous, apparently unmodified recombinant enzyme from E. coli revealed a twofold-higher V max of the enzyme from M. fervidus in the synthesizing direction.

scholarly journals Cloning and Characterization of the Zymobacter palmae Pyruvate Decarboxylase Gene (pdc) and Comparison to Bacterial Homologues

2002 ◽  
Vol 68 (6) ◽  
pp. 2869-2876 ◽  
Author(s):  
Krishnan Chandra Raj ◽  
Lee A. Talarico ◽  
Lonnie O. Ingram ◽  
Julie A. Maupin-Furlow
Keyword(s):  
Codon Usage ◽  
Specific Activity ◽  
Pyruvate Decarboxylase ◽  
Biochemical Properties ◽  
Kinetic Properties ◽  
E Coli ◽  
Genes Encoding ◽  
Key Enzyme ◽  
Zymobacter Palmae

ABSTRACT Pyruvate decarboxylase (PDC) is the key enzyme in all homo-ethanol fermentations. Although widely distributed among plants, yeasts, and fungi, PDC is absent in animals and rare in bacteria (established for only three organisms). Genes encoding the three known bacterial pdc genes have been previously described and expressed as active recombinant proteins. The pdc gene from Zymomonas mobilis has been used to engineer ethanol-producing biocatalysts for use in industry. In this paper, we describe a new bacterial pdc gene from Zymobacter palmae. The pattern of codon usage for this gene appears quite similar to that for Escherichia coli genes. In E. coli recombinants, the Z. palmae PDC represented approximately 1/3 of the soluble protein. Biochemical and kinetic properties of the Z. palmae enzyme were compared to purified PDCs from three other bacteria. Of the four bacterial PDCs, the Z. palmae enzyme exhibited the highest specific activity (130 U mg of protein−1) and the lowest Km for pyruvate (0.24 mM). Differences in biochemical properties, thermal stability, and codon usage may offer unique advantages for the development of new biocatalysts for fuel ethanol production.

scholarly journals Treponema pallidum 3-Phosphoglycerate Mutase Is a Heat-Labile Enzyme That May Limit the Maximum Growth Temperature for the Spirochete

2001 ◽  
Vol 183 (16) ◽  
pp. 4702-4708 ◽  
Author(s):  
Stéphane Benoit ◽  
James E. Posey ◽  
Matthew R. Chenoweth ◽  
Frank C. Gherardini
Keyword(s):  
Treponema Pallidum ◽  
Maximum Growth ◽  
Biochemical Properties ◽  
Maximum Activity ◽  
Phosphoglycerate Mutase ◽  
Heat Sensitivity ◽  
Dependent Manner ◽  
Gene Encoding ◽  
E Coli ◽  
Key Enzyme

ABSTRACT In the causative agent of syphilis, Treponema pallidum, the gene encoding 3-phosphoglycerate mutase, gpm, is part of a six-gene operon (tro operon) that is regulated by the Mn-dependent repressor TroR. Since substrate-level phosphorylation via the Embden-Meyerhof pathway is the principal way to generate ATP inT. pallidum and Gpm is a key enzyme in this pathway, Mn could exert a regulatory effect on central metabolism in this bacterium. To study this, T. pallidum gpm was cloned, Gpm was purified from Escherichia coli, and antiserum against the recombinant protein was raised. Immunoblots indicated that Gpm was expressed in freshly extracted infective T. pallidum. Enzyme assays indicated that Gpm did not require Mn2+ while 2,3-diphosphoglycerate (DPG) was required for maximum activity. Consistent with these observations, Mn did not copurify with Gpm. The purified Gpm was stable for more than 4 h at 25°C, retained only 50% activity after incubation for 20 min at 34°C or 10 min at 37°C, and was completely inactive after 10 min at 42°C. The temperature effect was attenuated when 1 mM DPG was added to the assay mixture. The recombinant Gpm from pSLB2 complemented E. coli strain PL225 (gpm) and restored growth on minimal glucose medium in a temperature-dependent manner. Increasing the temperature of cultures of E. coli PL225 harboring pSLB2 from 34 to 42°C resulted in a 7- to 11-h period in which no growth occurred (compared to wild-type E. coli). These data suggest that biochemical properties of Gpm could be one contributing factor to the heat sensitivity of T. pallidum.

scholarly journals S-Adenosylmethionine Transport in Rickettsia prowazekii

2003 ◽  
Vol 185 (10) ◽  
pp. 3031-3035 ◽  
Author(s):  
Aimee M. Tucker ◽  
Herbert H. Winkler ◽  
Lonnie O. Driskell ◽  
David O. Wood
Keyword(s):  
Evolutionary Relationship ◽  
Host Cells ◽  
Transport Systems ◽  
Rickettsia Prowazekii ◽  
Gene Encoding ◽  
E Coli ◽  
Obligate Intracellular ◽  
Gene Coding ◽  
Epidemic Typhus ◽  
Methionine Transport

ABSTRACT Rickettsia prowazekii, the causative agent of epidemic typhus, is an obligate, intracellular, parasitic bacterium that grows within the cytoplasm of eucaryotic host cells. Rickettsiae exploit this intracellular environment by using transport systems for the compounds available in the host cell's cytoplasm. Analysis of the R. prowazekii Madrid E genome sequence revealed the presence of a mutation in the rickettsial metK gene, the gene encoding the enzyme responsible for the synthesis of S-adenosylmethionine (AdoMet). Since AdoMet is required for rickettsial processes, the apparent inability of this strain to synthesize AdoMet suggested the presence of a rickettsial AdoMet transporter. We have confirmed the presence of an AdoMet transporter in the rickettsiae which, to our knowledge, is the first bacterial AdoMet transporter identified. The influx of AdoMet into rickettsiae was a saturable process with a KT of 2.3 μM. Transport was inhibited by S-adenosylethionine and S-adenosylhomocysteine but not by sinfungin or methionine. Transport was also inhibited by 2,4-dinitrophenol, suggesting an energy-linked transport mechanism, and by N-ethylmaleimide. AdoMet transporters with similar properties were also identified in the Breinl strain of R. prowazekii and in Rickettsia typhi. By screening Escherichia coli clone banks for AdoMet transport, the R. prowazekii gene coding for a transporter, RP076 (sam), was identified. AdoMet transport in E. coli containing the R. prowazekii sam gene exhibited kinetics similar to that seen in rickettsiae. The existence of a rickettsial transporter for AdoMet raises intriguing questions concerning the evolutionary relationship between the synthesis and transport of this essential metabolite.

scholarly journals VERIFIKASI cDNA T29 SEBAGAI KANDIDAT GEN PENGKODE PROTEIN Toxoplasma gondii DENGAN METODE SDS PAGE

2005 ◽  
Vol 11 (1) ◽  
pp. 61-66
Author(s):  
Ira Djajanegara ◽  
Wayan Artama ◽  
Retno Lestari ◽  
Sabar Pambudi
Keyword(s):  
Toxoplasma Gondii ◽  
Recombinant Plasmid ◽  
Restriction Site ◽  
Standard Procedure ◽  
Pcr Amplification ◽  
Gene Encoding ◽  
E Coli ◽  
Gene Coding ◽  
Sds Page ◽  
Encoding Protein

The process of cDNA construction from mRNA isolated from Toxoplasma gondii has been done. There were 7 candidates cDNA which one of them is called T29. Since Toxoplasma gondii is the cause of toxoplasmosis infection, cloning the gene encoding protein from this parasite provides an important tool for developing diagnostic kit for detection of toxoplasmosis. Digestion of the cDNA T29 with EcoRI which is the restriction site where the cDNA was inserted yielded a 1.862 bp fragment. The fragment was subcloned into E. coli expression vector pMal-p2x and transformed into E.coli strain TB1. Colonies of TB1 were grown on ampicillin plates and the recombinant plasmid was extracted using the standard procedure. The plasmid was digested using EcoRI and PstI, checked by PCR amplification using malE and M13/pUC primers. The recombinant plasmid was expressed in TB1 and the protein extracted was ran in SDS PAGE to observe the presence of the expressed protein. Based on the data from this experiment, there was no expression result of the expressed cDNA which was confirm by the PCR result. Therefore, it was concluded that cDNA T29 was not carrying the gene coding for protein from parasite Toxoplasma gondii.

scholarly journals Requirement of Purine and Pyrimidine Synthesis for Colonization of the Mouse Intestine by Escherichia coli

2010 ◽  
Vol 76 (15) ◽  
pp. 5181-5187 ◽  
Author(s):  
Jacqueline Vogel-Scheel ◽  
Carl Alpert ◽  
Wolfram Engst ◽  
Gunnar Loh ◽  
Michael Blaut
Keyword(s):  
Escherichia Coli ◽  
Differentially Expressed ◽  
Wild Type ◽  
Gene Encoding ◽  
E Coli ◽  
Pyrimidine Synthesis ◽  
Key Enzyme ◽  
Mouse Intestine ◽  
Gnotobiotic Mice

ABSTRACT To study the adaptation of an intestinal bacterium to its natural environment, germfree mice were associated with commensal Escherichia coli MG1655. Two-dimensional gel electrophoresis was used to identify proteins differentially expressed in E. coli MG1655 collected from either cecal contents or anaerobic in vitro cultures. Fourteen differentially expressed proteins (>3-fold; P < 0.05) were identified, nine of which were upregulated in cecal versus in vitro-grown E. coli. Four of these proteins were investigated further for their role in gut colonization. After deletion of the corresponding genes, the resulting E. coli mutants were tested for their ability to colonize the intestines of gnotobiotic mice in competition with the wild-type strain. A mutant devoid of ydjG, which encodes a putative NADH-dependent methylglyoxal reductase, reached a 1.2-log-lower cecal concentration than the wild type. Deletion of the nanA gene encoding N-acetylneuraminate lyase affected the colonization and persistence of E. coli in the intestines of the gnotobiotic mice only slightly. A mutant devoid of 5′-phosphoribosyl 4-(N-succinocarboxamide)-5-aminoimidazole synthase, a key enzyme of purine synthesis, displayed intestinal cell counts >4 logs lower than those of the wild type. Deletion of the gene encoding aspartate carbamoyltransferase, a key enzyme of pyrimidine synthesis, even resulted in the washout of the corresponding mutant from the mouse intestinal tract. These findings indicate that E. coli needs to synthesize purines and pyrimidines to successfully colonize the mouse intestine.

scholarly journals Phenotypic and Genotypic Characterization of Avian Escherichia coli O86:K61 Isolates Possessing a Gamma-Like Intimin

2002 ◽  
Vol 68 (10) ◽  
pp. 4932-4942 ◽  
Author(s):  
R. M. La Ragione ◽  
I. M. McLaren ◽  
G. Foster ◽  
W. A. Cooley ◽  
M. J. Woodward
Keyword(s):  
Escherichia Coli ◽  
Diarrheal Disease ◽  
Wild Birds ◽  
Gene Encoding ◽  
Infantile Diarrhea ◽  
E Coli ◽  
Gene Coding ◽  
Transmission Electron ◽  
Specific Pathogen

ABSTRACT Escherichia coli O86:K61 has long been associated with outbreaks of infantile diarrhea in humans and with diarrheal disease in many animal species. Studies in the late 1990s identified E. coli O86:K61 as the cause of mortality in a variety of wild birds, and in this study, 34 E. coli O86:K61 isolates were examined. All of the isolates were nonmotile, but most elaborated at least two morphologically distinct surface appendages that were confirmed to be type 1 and curli fimbriae. Thirty-three isolates were positive for the eaeA gene encoding a gamma type of intimin. No phenotypic or genotypic evidence was obtained for elaboration of Shiga-like toxins, but most isolates possessed the gene coding for the cytolethal distending toxin. Five isolates were selected for adherence assays performed with tissue explants and HEp-2 cells, and four of these strains produced attaching and effacing lesions on HEp-2 cells and invaded the cells, as determined by transmission electron microscopy. Two of the five isolates were inoculated orally into 1-day-old specific-pathogen-free chicks, and both of these isolates colonized, invaded, and persisted well in this model. Neither isolate produced attaching and effacing lesions in chicks, although some pathology was evident in the alimentary tract. No deaths were recorded in inoculated chicks. These findings are discussed in light of the possibility that wild birds are potential zoonotic reservoirs of attaching and effacing E. coli.

Creatine kinase in serum: 4. Differences in substrate affinity among the isoenzymes.

1978 ◽  
Vol 24 (2) ◽  
pp. 245-249 ◽  
Author(s):  
G Szasz ◽  
W Gruber
Keyword(s):  
Creatine Kinase ◽  
Human Serum ◽  
Substrate Concentration ◽  
Substrate Binding ◽  
Creatine Phosphate ◽  
Isolation Procedure ◽  
Substrate Affinity ◽  
Kinetic Properties ◽  
Reaction Conditions ◽  
Enzyme Preparations

Abstract The goal of this work was to find out whether it is possible to measure all three creatine kinase isoenzymes under the same reaction conditions in spite of their different kinetic properties. We found the tightest substrate binding for purified human BB, followed by the MB And MM isoenzyme preparations for both creatine phosphate and ADP. An increase in substrate concentration usually resulted in an inhibition. Nevertheless, it was possible with a method optimized for the MM isoenzyme also to measure the BB and MB isoenzymes at a rate of inhibition of only 6 and 3%, respectively. Marked differences in the apparent Km values between purified and native MM isoenzyme in human serum may indicate that the enzyme declined in substrate affinity during the isolation procedure. The use of enzyme preparations for standardization purposes, therefore, is only suitable if their kinetic properties are close to those of the enzyme in serum. Difficulties in the calculation of the apparent Km values are discussed and the graphical procedures of Lineweaver and Burk and of Eisenthal and Cornish-Bowden compared.

scholarly journals Lawsonia intracellularis Contains a Gene Encoding a Functional Rickettsia-Like ATP/ADP Translocase for Host Exploitation

2008 ◽  
Vol 190 (17) ◽  
pp. 5746-5752 ◽  
Author(s):  
Stephan Schmitz-Esser ◽  
Ilka Haferkamp ◽  
Silvia Knab ◽  
Thomas Penz ◽  
Michelle Ast ◽  
...  
Keyword(s):  
Lawsonia Intracellularis ◽  
Swine Industry ◽  
Gene Encoding ◽  
Transfer Event ◽  
E Coli ◽  
Obligate Intracellular ◽  
Gene Coding ◽  
Obligate Intracellular Pathogen ◽  
Substrate Affinities ◽  
Energy Pool

ABSTRACT ATP/ADP translocases are a hallmark of obligate intracellular pathogens related to chlamydiae and rickettsiae. These proteins catalyze the highly specific exchange of bacterial ADP against host ATP and thus allow bacteria to exploit their hosts' energy pool, a process also referred to as energy parasitism. The genome sequence of the obligate intracellular pathogen Lawsonia intracellularis (Deltaproteobacteria), responsible for one of the most economically important diseases in the swine industry worldwide, revealed the presence of a putative ATP/ADP translocase most similar to known ATP/ADP translocases of chlamydiae and rickettsiae (around 47% amino acid sequence identity). The gene coding for the putative ATP/ADP translocase of L. intracellularis (L. intracellularis nucleotide transporter 1 [NTT1 Li ]) was cloned and expressed in the heterologous host Escherichia coli. The transport properties of NTT1 Li were determined by measuring the uptake of radioactively labeled substrates by E. coli. NTT1 Li transported ATP in a counterexchange mode with ADP in a highly specific manner; the substrate affinities determined were 236.3 (± 36.5) μM for ATP and 275.2 (± 28.1) μM for ADP, identifying this protein as a functional ATP/ADP translocase. NTT1 Li is the first ATP/ADP translocase from a bacterium not related to Chlamydiae or Rickettsiales, showing that energy parasitism by ATP/ADP translocases is more widespread than previously recognized. The occurrence of an ATP/ADP translocase in L. intracellularis is explained by a relatively recent horizontal gene transfer event with rickettsiae as donors.

scholarly journals Isolating an active and inactive CACTA transposon from lettuce color mutants and characterizing their family

2021 ◽  
Author(s):  
Csanad Gurdon ◽  
Alexander Kozik ◽  
Rong Tao ◽  
Alexander Poulev ◽  
Isabel Armas ◽  
...  
Keyword(s):  
Anthocyanin Biosynthesis ◽  
Mobile Element ◽  
Bioinformatic Analysis ◽  
Relative Expression Level ◽  
Gene Coding ◽  
Genes Encoding ◽  
Key Enzyme ◽  
Natural Derivative ◽  
Dark Green ◽  
Transposon Insertions

Abstract Dietary flavonoids play an important role in human nutrition and health. Flavonoid biosynthesis genes have recently been identified in lettuce (Lactuca sativa); however, few mutants have been characterized. We now report the causative mutations in Green Super Lettuce (GSL), a natural light green mutant derived from red cultivar NAR; and GSL-Dark Green (GSL-DG), an olive-green natural derivative of GSL. GSL harbors CACTA 1 (LsC1), a 3.9-kb active nonautonomous CACTA superfamily transposon inserted in the 5′ untranslated region of anthocyanidin synthase (ANS), a gene coding for a key enzyme in anthocyanin biosynthesis. Both terminal inverted repeats (TIRs) of this transposon were intact, enabling somatic excision of the mobile element, which led to the restoration of ANS expression and the accumulation of red anthocyanins in sectors on otherwise green leaves. GSL-DG harbors CACTA 2 (LsC2), a 1.1-kb truncated copy of LsC1 that lacks one of the TIRs, rendering the transposon inactive. RNA-sequencing and reverse transcription quantitative PCR of NAR, GSL, and GSL-DG indicated the relative expression level of ANS was strongly influenced by the transposon insertions. Analysis of flavonoid content indicated leaf cyanidin levels correlated positively with ANS expression. Bioinformatic analysis of the cv Salinas lettuce reference genome led to the discovery and characterization of an LsC1 transposon family with a putative transposon copy number greater than 1,700. Homologs of tnpA and tnpD, the genes encoding two proteins necessary for activation of transposition of CACTA elements, were also identified in the lettuce genome.

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