scholarly journals Genes Involved in Anaerobic Metabolism of Phenol in the Bacterium Thauera aromatica

2000 ◽  
Vol 182 (20) ◽  
pp. 5849-5863 ◽  
Author(s):  
Sabine Breinig ◽  
Emile Schiltz ◽  
Georg Fuchs

ABSTRACT Genes involved in the anaerobic metabolism of phenol in the denitrifying bacterium Thauera aromatica have been studied. The first two committed steps in this metabolism appear to be phosphorylation of phenol to phenylphosphate by an unknown phosphoryl donor (“phenylphosphate synthase”) and subsequent carboxylation of phenylphosphate to 4-hydroxybenzoate under release of phosphate (“phenylphosphate carboxylase”). Both enzyme activities are strictly phenol induced. Two-dimensional gel electrophoresis allowed identification of several phenol-induced proteins. Based on N-terminal and internal amino acid sequences of such proteins, degenerate oligonucleotides were designed to identify the corresponding genes. A chromosomal DNA segment of about 14 kbp was sequenced which contained 10 genes transcribed in the same direction. These are organized in two adjacent gene clusters and include the genes coding for five identified phenol-induced proteins. Comparison with sequences in the databases revealed the following similarities: the gene products of two open reading frames (ORFs) are each similar to either the central part and N-terminal part of phosphoenolpyruvate synthases. We propose that these ORFs are components of the phenylphosphate synthase system. Three ORFs showed similarity to the ubiD gene product, 3-octaprenyl-4-hydroxybenzoate carboxy lyase; UbiD catalyzes the decarboxylation of a 4-hydroxybenzoate analogue in ubiquinone biosynthesis. Another ORF was similar to the ubiX gene product, an isoenzyme of UbiD. We propose that (some of) these four proteins are involved in the carboxylation of phenylphosphate. A 700-bp PCR product derived from one of these ORFs cross-hybridized with DNA from different Thauera and Azoarcusstrains, even from those which have not been reported to grow with phenol. One ORF showed similarity to the mutT gene product, and three ORFs showed no strong similarities to sequences in the databases. Upstream of the first gene cluster, an ORF which is transcribed in the opposite direction codes for a protein highly similar to the DmpR regulatory protein of Pseudomonas putida. DmpR controls transcription of the genes of aerobic phenol metabolism, suggesting a similar regulation of anaerobic phenol metabolism by the putative regulator.

2001 ◽  
Vol 183 (3) ◽  
pp. 968-979 ◽  
Author(s):  
Diana Laempe ◽  
Martina Jahn ◽  
Klaus Breese ◽  
Hermann Schägger ◽  
Georg Fuchs

ABSTRACT The anaerobic metabolism of 3-hydroxybenzoate was studied in the denitrifying bacterium Thauera aromatica. Cells grown with this substrate were adapted to grow with benzoate but not with 4-hydroxybenzoate. Vice versa, 4-hydroxybenzoate-grown cells did not utilize 3-hydroxybenzoate. The first step in 3-hydroxybenzoate metabolism is a coenzyme A (CoA) thioester formation, which is catalyzed by an inducible 3-hydroxybenzoate–CoA ligase. The enzyme was purified and characterized. Further metabolism of 3-hydroxybenzoyl-CoA by cell extract required MgATP and was coupled to the oxidation of 2 mol of reduced viologen dyes per mol of substrate added. Purification of the 3-hydroxybenzoyl-CoA reducing enzyme revealed that this activity was due to benzoyl-CoA reductase, which reduced the 3-hydroxy analogue almost as efficiently as benzoyl-CoA. The further metabolism of the alicyclic dienoyl-CoA product containing the hydroxyl substitution obviously required additional specific enzymes. Comparison of the protein pattern of 3-hydroxybenzoate-grown cells with benzoate-grown cells revealed several 3-hydroxybenzoate-induced proteins; the N-terminal amino acid sequences of four induced proteins were determined and the corresponding genes were identified and sequenced. A cluster of six adjacent genes contained the genes for substrate-induced proteins 1 to 3; this cluster may not yet be complete. Protein 1 is a short-chain alcohol dehydrogenase. Protein 2 is a member of enoyl-CoA hydratase enzymes. Protein 3 was identified as 3-hydroxybenzoate–CoA ligase. Protein 4 is another member of the enoyl-CoA hydratases. In addition, three genes coding for enzymes of β-oxidation were present. The anaerobic 3-hydroxybenzoate metabolism here obviously combines an enzyme (benzoyl-CoA reductase) and electron carrier (ferredoxin) of the general benzoyl-CoA pathway with enzymes specific for the 3-hydroxybenzoate pathway. This raises some questions concerning the regulation of both pathways.


Genetics ◽  
1999 ◽  
Vol 152 (4) ◽  
pp. 1307-1314
Author(s):  
Arnulf Kletzin ◽  
Angelika Lieke ◽  
Tim Urich ◽  
Robert L Charlebois ◽  
Christoph W Sensen

Abstract The 7598-bp plasmid pDL10 from the extremely thermophilic, acidophilic, and chemolithoautotrophic Archaeon Acidianus ambivalens was sequenced. It contains 10 open reading frames (ORFs) organized in five putative operons. The deduced amino acid sequence of the largest ORF (909 aa) showed similarity to bacterial Rep proteins known from phages and plasmids with rolling-circle (RC) replication. From the comparison of the amino acid sequences, a novel family of RC Rep proteins was defined. The pDL10 Rep protein shared 45-80% identical residues with homologous protein genes encoded by the Sulfolobus islandicus plasmids pRN1 and pRN2. Two DNA regions capable of forming extended stem-loop structures were also conserved in the three plasmids (48-69% sequence identity). In addition, a putative plasmid regulatory protein gene (plrA) was found, which was conserved among the three plasmids and the conjugative Sulfolobus plasmid pNOB8. A homolog of this gene was also found in the chromosome of S. solfataricus. Single-stranded DNA of both pDL10 strands was detected with a mung bean nuclease protection assay using PCR detection of protected fragments, giving additional evidence for an RC mechanism of replication.


2003 ◽  
Vol 47 (12) ◽  
pp. 3733-3738 ◽  
Author(s):  
Eun-Woo Lee ◽  
M. Nazmul Huda ◽  
Teruo Kuroda ◽  
Tohru Mizushima ◽  
Tomofusa Tsuchiya

ABSTRACT A DNA fragment responsible for resistance to antimicrobial agents was cloned from the chromosomal DNA of Enterococcus faecalis ATCC 29212 by using drug-hypersensitive mutant Escherichia coli KAM32 as a host cell. Cells of E. coli KAM32 harboring a recombinant plasmid (pAEF82) carrying the DNA fragment became resistant to many structurally unrelated antimicrobial agents, such as norfloxacin, ciprofloxacin, doxycycline, acriflavine, 4′,6-diamidino-2-phenylindole, tetraphenylphosphonium chloride, daunorubicin, and doxorubicin. Since the sequence of the whole genome of E. faecalis is known, we sequenced several portions of the DNA insert in plasmid pAEF82 and identified two open reading frames within the insert. We designated the genes efrA and efrB. A search of the deduced amino acid sequences of EfrA and EfrB revealed that they are similar to each other and that they belong to the ATP-binding cassette (ABC) family of multidrug efflux transporters. Transformed E. coli KAM32 cells harboring efrAB showed energy-dependent efflux of acriflavine. The efflux activity was inhibited by reserpine, verapamil, and sodium-o-vanadate, known inhibitors of ABC efflux pumps.


2006 ◽  
Vol 72 (5) ◽  
pp. 3321-3329 ◽  
Author(s):  
Kengo Inoue ◽  
Hiroshi Habe ◽  
Hisakazu Yamane ◽  
Hideaki Nojiri

ABSTRACT Nocardioides aromaticivorans IC177 is a gram-positive carbazole degrader. The genes encoding carbazole degradation (car genes) were cloned into a cosmid clone and sequenced partially to reveal 19 open reading frames. The car genes were clustered into the carAaCBaBbAcAd and carDFE gene clusters, encoding the enzymes responsible for the degradation of carbazole to anthranilate and 2-hydroxypenta-2,4-dienoate and of 2-hydroxypenta-2,4-dienoate to pyruvic acid and acetyl coenzyme A, respectively. The conserved amino acid motifs proposed to bind the Rieske-type [2Fe-2S] cluster and mononuclear iron, the Rieske-type [2Fe-2S] cluster, and flavin adenine dinucleotide were found in the deduced amino acid sequences of carAa, carAc, and carAd, respectively, which showed similarities with CarAa from Sphingomonas sp. strain KA1 (49% identity), CarAc from Pseudomonas resinovorans CA10 (31% identity), and AhdA4 from Sphingomonas sp. strain P2 (37% identity), respectively. Escherichia coli cells expressing CarAaAcAd exhibited major carbazole 1,9a-dioxygenase (CARDO) activity. These data showed that the IC177 CARDO is classified into class IIB, while gram-negative CARDOs are classified into class III or IIA, indicating that the respective CARDOs have diverse types of electron transfer components and high similarities of the terminal oxygenase. Reverse transcription-PCR (RT-PCR) experiments showed that the carAaCBaBbAcAd and carDFE gene clusters are operonic. The results of quantitative RT-PCR experiments indicated that transcription of both operons is induced by carbazole or its metabolite, whereas anthranilate is not an inducer. Biotransformation analysis showed that the IC177 CARDO exhibits significant activities for naphthalene, carbazole, and dibenzo-p-dioxin but less activity for dibenzofuran and biphenyl.


1998 ◽  
Vol 180 (24) ◽  
pp. 6642-6648 ◽  
Author(s):  
Toshiaki Hiramatsu ◽  
Kazuyo Kodama ◽  
Teruo Kuroda ◽  
Tohru Mizushima ◽  
Tomofusa Tsuchiya

ABSTRACT We cloned several genes encoding an Na+/H+antiporter of Staphylococcus aureus from chromosomal DNA by using an Escherichia coli mutant, lacking all of the major Na+/H+ antiporters, as the host. E. coli cells harboring plasmids for the cloned genes were able to grow in medium containing 0.2 M NaCl (or 10 mM LiCl). Host cells without the plasmids were unable to grow under the same conditions. Na+/H+ antiport activity was detected in membrane vesicles prepared from transformants. We determined the nucleotide sequence of the cloned 7-kbp region. We found that seven open reading frames (ORFs) were necessary for antiporter function. A promoter-like sequence was found in the upstream region from the first ORF. One inverted repeat followed by a T-cluster, which may function as a terminator, was found in the downstream region from the seventh ORF. Neither terminator-like nor promoter-like sequences were found between the ORFs. Thus, it seems that the seven ORFs comprise an operon and that the Na+/H+antiporter consists of seven kinds of subunits, suggesting that this is a novel type of multisubunit Na+/H+antiporter. Hydropathy analysis of the deduced amino acid sequences of the seven ORFs suggested that all of the proteins are hydrophobic. As a result of a homology search, we found that components of the respiratory chain showed sequence similarity with putative subunits of the Na+/H+ antiporter. We observed a large Na+ extrusion activity, driven by respiration in E. coli cells harboring the plasmid carrying the genes. The Na+ extrusion was sensitive to an H+conductor, supporting the idea that the system is not a respiratory Na+ pump but an Na+/H+ antiporter. Introduction of the plasmid into E. coli mutant cells, which were unable to grow under alkaline conditions, enabled the cells to grow under such conditions.


1999 ◽  
Vol 65 (12) ◽  
pp. 5198-5206 ◽  
Author(s):  
Toru Shigematsu ◽  
Satoshi Hanada ◽  
Masahiro Eguchi ◽  
Yoichi Kamagata ◽  
Takahiro Kanagawa ◽  
...  

ABSTRACT The soluble MMO (sMMO) gene clusters from group I methanotrophs were characterized. An 8.1-kb KpnI fragment fromMethylomonas sp. strain KSWIII and a 7.5-kbSalI fragment from Methylomonas sp. strain KSPIII which contained the sMMO gene clusters were cloned and sequenced. The sequences of these two fragments were almost identical. The sMMO gene clusters in the fragment consisted of six open reading frames which were 52 to 79% similar to the corresponding genes of previously described sMMO gene clusters of the group II and group X methanotrophs. The phylogenetic analysis of the predicted amino acid sequences of sMMO demonstrated that the sMMOs from these strains were closer to that from M. capsulatus Bath in the group X methanotrophs than to those from Methylosinus trichosporiumOB3b and Methylocystis sp. strain M in the group II methanotrophs. Based on the sequence data of sMMO genes of our strains and other methanotrophs, we designed a new PCR primer to amplify sMMO gene fragments of all the known methanotrophs harboring themmoX gene. The primer set was successfully used for detecting methanotrophs in the groundwater of trichloroethylene-contaminated sites during in situ-biostimulation treatments.


1990 ◽  
Vol 111 (1) ◽  
pp. 95-102 ◽  
Author(s):  
J Vandekerckhove ◽  
G Bauw ◽  
K Vancompernolle ◽  
B Honoré ◽  
J Celis

A systematic comparison of the protein synthesis patterns of cultured normal and transformed human fibroblasts and epithelial cells, using two-dimensional gel protein analysis combined with computerized imaging and data acquisition, identified a 90-kD protein (SSP 5714) as one of the most striking downregulated markers typical of the transformed state. Using the information stored in the comprehensive human cellular protein database, we found this protein strongly expressed in several fetal tissues and one of them, epidermis, served as a source for preparative two-dimensional gel electrophoresis. Partial amino acid sequences were generated from peptides obtained by in situ digestion of the electroblotted protein. These sequences identified the marker protein as gelsolin, a finding that was confirmed by two-dimensional immunoblotting of human MRC-5 fibroblast proteins using specific antibodies and by coelectrophoresis with purified human gelsolin. These results suggest that an important regulatory protein of the microfilament system may play a role in defining the phenotype of transformed human fibroblast and epithelial cells in culture.


1992 ◽  
Vol 284 (1) ◽  
pp. 87-93 ◽  
Author(s):  
U Murdiyatmo ◽  
W Asmara ◽  
J S H Tsang ◽  
A J Baines ◽  
A T Bull ◽  
...  

The structural gene (hdl IVa) for the Pseudomonas cepacia MBA4 2-haloacid halidohydrolase IVa (Hdl IVa) was isolated on a 1.6 kb fragment of Ps. cepacia MBA4 chromosomal DNA. The recombinant halidohydrolase was expressed in Escherichia coli and Pseudomonas putida and the structural gene was subcloned on to the tac expression vector pBTac1. High-level expression from the tac promoter was seen to be temperature-dependent, a consequence of the nucleotide sequence adjacent to the fragment encoding the halidohydrolase. The nucleotide sequence of the fragment encoding the Hdl IVa was determined and analysed. Three ATG codons were identified in one of the open reading frames and the one corresponding to the start of the hdl IVa structural gene was determined by comparison of the predicted amino acid sequences with the experimentally determined N-terminal sequences of halidohydrolase IVa. The hdl IVa gene encoded a 231-amino acid-residue protein of M(r) 25,900. The sequence and predicted structural data are discussed and comparison is made with sequence data for other halidohydrolases.


2005 ◽  
Vol 18 (4) ◽  
pp. 324-333 ◽  
Author(s):  
Shi-En Lu ◽  
Nian Wang ◽  
Jianlin Wang ◽  
Z. Jeffrey Chen ◽  
Dennis C. Gross

The salA gene is a key regulatory element for syringomycin production by Pseudomonas syringae pv. syringae and encodes a member of the LuxR regulatory protein family. Previous studies revealed that salA, a member of the GacS/GacA signal transduction system, was required for bacterial virulence, syringomycin production, and expression of the syrB1 synthetase gene. To define the SalA regulon, the spotted oligonucleotide microarray was constructed using gene-specific 70-mer oligonucleotides of all open reading frames (ORFs) predicted in the syringomycin (syr) and syringopeptin (syp) gene clusters along with representative genes important to bacterial virulence, growth, and survival. The microarray containing 95 oligos was used to analyze transcriptional changes in a salA mutant (B301DSL07) and its wild-type strain, B301D. Expression of 16 genes was significantly higher (> twofold) in B301D than in the salA mutant; the maximum change in expression was 15-fold for some toxin biosynthesis genes. Except for the sylD synthetase gene for syringolin production, all ORFs controlled by SalA were located in the syr-syp genomic island and were associated with biosynthesis, secretion, and regulation of syringomycin and syringopeptin. The positive regulatory effect of SalA on transcription of sypA, syrB1, syrC, and sylD was verified by reporter fusions or real-time polymerase chain reaction analysis. None of the genes or ORFs was significantly down-regulated by the salA gene. These results demonstrated that a subgenomic oligonucleotide microarray is a powerful tool for defining the SalA regulon and its relationship to other genes important to plant pathogenesis.


2004 ◽  
Vol 186 (14) ◽  
pp. 4556-4567 ◽  
Author(s):  
Karola Schühle ◽  
Georg Fuchs

ABSTRACT The anaerobic metabolism of phenol in the beta-proteobacterium Thauera aromatica proceeds via carboxylation to 4-hydroxybenzoate and is initiated by the ATP-dependent conversion of phenol to phenylphosphate. The subsequent para carboxylation of phenylphosphate to 4-hydroxybenzoate is catalyzed by phenylphosphate carboxylase, which was purified and studied. This enzyme consists of four proteins with molecular masses of 54, 53, 18, and 10 kDa, whose genes are located adjacent to each other in the phenol gene cluster which codes for phenol-induced proteins. Three of the subunits (54, 53, and 10 kDa) were sufficient to catalyze the exchange of 14CO2 and the carboxyl group of 4-hydroxybenzoate but not phenylphosphate carboxylation. Phenylphosphate carboxylation was restored when the 18-kDa subunit was added. The following reaction model is proposed. The 14CO2 exchange reaction catalyzed by the three subunits of the core enzyme requires the fully reversible release of CO2 from 4-hydroxybenzoate with formation of a tightly enzyme-bound phenolate intermediate. Carboxylation of phenylphosphate requires in addition the 18-kDa subunit, which is thought to form the same enzyme-bound energized phenolate intermediate from phenylphosphate with virtually irreversible release of phosphate. The 54- and 53-kDa subunits show similarity to UbiD of Escherichia coli, which catalyzes the decarboxylation of a 4-hydroxybenzoate derivative in ubiquinone (ubi) biosynthesis. They also show similarity to components of various decarboxylases acting on aromatic carboxylic acids, such as 4-hydroxybenzoate or vanillate, whereas the 10-kDa subunit is unique. The 18-kDa subunit belongs to a hydratase/phosphatase protein family. Phenylphosphate carboxylase is a member of a new family of carboxylases/decarboxylases that act on phenolic compounds, use CO2 as a substrate, do not contain biotin or thiamine diphosphate, require K+ and a divalent metal cation (Mg2+or Mn2+) for activity, and are strongly inhibited by oxygen.


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