Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Plasmid pRO1957 contains a 26.5-kb BamHI restriction endonuclease-cleaved DNA fragment cloned from the chromosome of Pseudomonas pickettii PKO1 that allows P. aeruginosa PAO1c to grow on toluene, benzene, phenol, or m-cresol as the sole carbon source. The genes encoding enzymes for meta cleavage of catechol or 3-methylcatechol, derived from catabolism of these substrates, were subcloned from pRO1957 and were shown to be organized into a single operon with the promoter proximal to tbuE. Deletion and analysis of subclones demonstrated that the order of genes in the meta cleavage operon was tbuEFGKIHJ, which encoded catechol 2,3-dioxygenase, 2-hydroxymuconate semialdehyde hydrolase, 2-hydroxymuconate semialdehyde dehydrogenase, 4-hydroxy-2-oxovalerate aldolase, 4-oxalocrotonate decarboxylase, 4-oxalocrotonate isomerase, and 2-hydroxypent-2,4-dienoate hydratase, respectively. The regulatory gene for the tbuEFGKIHJ operon, designated tbuS, was subcloned into vector plasmid pRO2317 from pRO1957 as a 1.3-kb PstI fragment, designated pRO2345. When tbuS was not present, meta pathway enzyme expression was partially derepressed, but these activity levels could not be fully induced. However, when tbuS was present in trans with tbuEFGKIHJ, meta pathway enzymes were repressed in the absence of an effector and were fully induced when an effector was present. This behavior suggests that the gene product of tbuS acts as both a repressor and an activator. Phenol and m-cresol were inducers of meta pathway enzymatic activity. Catechol, 3-methylcatechol, 4-methylcatechol, o-cresol, and p-cresol were not inducers but could be metabolized by cells previously induced by phenol or m-cresol.
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PMID:Genetic organization and regulation of a meta cleavage pathway for catechols produced from catabolism of toluene, benzene, phenol, and cresols by Pseudomonas pickettii PKO1. 185 61

A 26-kilobase BamHI restriction endonuclease DNA fragment was cloned from Pseudomonas pickettii PKO1, a strain isolated from a soil microcosm that had been amended with benzene, toluene, and xylene. This DNA fragment, cloned into vector plasmid pRO1727 and designated pRO1957, allowed Pseudomonas aeruginosa PAO1c to grow on phenol as the sole source of carbon. Physical and functional restriction endonuclease maps have been derived for the cloned DNA fragment. Two DNA fragments carried in trans and derived from subclones of pRO1957 show phenol hydroxylase activity in cell extracts of P. aeruginosa. Deletion and subcloning analyses of these fragments indicated that the gene encoding phenol hydroxylase is positively regulated. Phenol and m-cresol were shown to be inducers of the enzyme. o-Cresol and p-cresol did not induce enzymatic activity but could be metabolized by cells that had been previously exposed to phenol or m-cresol; moreover, the enzyme exhibited a rather broad substrate specificity and was sensitive to thiol-inhibiting reagents. A novel polypeptide with an estimated molecular mass of 80,000 daltons was detected in extracts of phenol-induced cells of P. aeruginosa carrying plasmid pRO1959.
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PMID:Molecular cloning, characterization, and regulation of a Pseudomonas pickettii PKO1 gene encoding phenol hydroxylase and expression of the gene in Pseudomonas aeruginosa PAO1c. 211 72

Alcaligenes eutrophus wild-type strain 345 metabolizes m- and p-toluate via a catechol meta-cleavage pathway. DNA analysis, curing studies, and transfer of this phenotype by conjugation and transformation showed that the degradative genes are encoded on a self-transmissible 85-kilobase plasmid, pRA1000. HindIII and XhoI restriction endonuclease analysis of pRA1000 showed it to be similar to the archetypal TOL plasmid, pWWO, differing in the case of HindIII only by the absence of fragments B and D present in pWWO. In strain 345, the presence of pRA1000 prevented the expression of chromosomally encoded enzymes required for the degradation of p-cresol, whereas these enzymes were expressed in strains cured of pRA1000. On the basis of studies with an R68.45-pRA1000 cointegrate plasmid, pRA1001, we conclude that the gene(s) responsible for the effect of p-cresol degradation resides within or near the m- and p-toluate degradative region on pRA1000.
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PMID:Characterization of a TOL-like plasmid from Alcaligenes eutrophus that controls expression of a chromosomally encoded p-cresol pathway. 632 99

In order to study the toluene and o-xylene catabolic genes of Pseudomonas stutzeri OX1, a genomic library was constructed. A 28-kb EcoRI restriction endonuclease DNA fragment, cloned into the vector plasmid pLAFR1 and designated pFB3401, permitted Pseudomonas putida PaW340 to convert toluene and o-xylene into the corresponding meta-ring fission products. Physical and functional endonuclease restriction maps have been derived from the cloned DNA fragment. Further subcloning into and deletion analysis in the Escherichia coli vector pGEM-3Z allowed the genes for the conversion of toluene or o-xylene into the corresponding catechols to be mapped within a 6-kb region of the pFB3401 insert and their direction of transcription to be determined. Following exposure to toluene, E. coli cells carrying this 6-kb region produce a mixture of o-cresol, m-cresol, and p-cresol, which are further converted to 3-methylcatechol and 4-methylcatechol. Similarly, a mixture of 2,3-dimethylphenol and 3,4-dimethylphenol, further converted into dimethylcatechols, was detected after exposure to o-xylene. The enzyme involved in the first step of toluene and o-xylene degradation exhibited a broad substrate specificity, being able to oxidize also benzene, ethylbenzene, m-xylene, p-xylene, styrene, and naphthalene. Deletions of the 6-kb region which affect the ability to convert toluene or o-xylene into the corresponding methylphenols compromise also their further oxidation to methylcatechols. This suggests that a single enzyme system could be involved in both steps of the early stages of toluene and o-xylene catabolism.
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PMID:Cloning of the genes for and characterization of the early stages of toluene and o-xylene catabolism in Pseudomonas stutzeri OX1. 883 26