Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:5.5.1.1 (muconate lactonizing enzyme)
 85 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This report describes the isolation and preliminary characterization of a 5.0-kilobase-pair (kbp) EcoRI DNA restriction fragment carrying the catBCDE genes from Acinetobacter calcoaceticus. The respective genes encode enzymes that catalyze four consecutive reactions in the catechol branch of the beta-ketoadipate pathway: catB, muconate lactonizing enzyme (EC 5.5.1.1); catC, muconolactone isomerase (EC 5.3.3.4); catD, beta-ketoadipate enol-lactone hydrolase (EC 3.1.1.24); and catE, beta-ketoadipate succinyl-coenzyme A transferase (EC 2.8.3.6). In A. calcoaceticus, pcaDE genes encode products with the same enzyme activities as those encoded by the respective catDE genes. In Pseudomonas putida, the requirements for both catDE and pcaDE genes are met by a single set of genes, designated pcaDE. A P. putida mutant with a dysfunctional pcaE gene was used to select a recombinant pKT230 plasmid carrying the 5.0-kbp EcoRI restriction fragment containing the A. calcoaceticus catE structural gene. The recombinant plasmid, pAN1, complemented P. putida mutants with lesions in catB, catC, pcaD, and pcaE genes; the complemented activities were expressed constitutively in the recombinant P. putida strains. After introduction into Escherichia coli, the pAN1 plasmid expressed the activities constitutively but at much lower levels that those found in the P. putida transformants or in fully induced cultures of A. calcoaceticus or P. putida. When placed under the control of a lac promoter on a recombinant pUC13 plasmid in E. coli, the A. calcoaceticus restriction fragment expressed catBCDE activities at levels severalfold higher than those found in fully induced cultures of A. calcoaceticus. Thus there is no translational barrier to expression of the A. calcoaceticus genes at high levels in E. coli. The genetic origin of the cloned catBCDE genes was demonstrated by the fact that the 5.0-kbp EcoRI restriction fragment hybridized with a corresponding fragment from wild-type A. calcoaceticus DNA. This fragment was missing in DNA from an A. calcoaceticus mutant in which the cat genes had been removed by deletion. The properties of the cloned fragment demonstrate physical linkage of the catBCDE genes and suggest that they are coordinately transcribed.
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PMID:Cloning and expression of Acinetobacter calcoaceticus catBCDE genes in Pseudomonas putida and Escherichia coli. 300 31

A 9.9-kilobase (kb) BamHI restriction endonuclease fragment encoding the catA and catBC gene clusters was selected from a gene bank of the Pseudomonas aeruginosa PAO1c chromosome. The catA, catB, and catC genes encode enzymes that catalyze consecutive reactions in the catechol branch of the beta-ketoadipate pathway: catA, catechol-1,2-dioxygenase (EC 1.13.11.1); catB, muconate lactonizing enzyme (EC 5.5.1.1); and catC, muconolactone isomerase (EC 5.3.3.4). A recombinant plasmid, pRO1783, which contains the 9.9-kb BamHI restriction fragment complemented P. aeruginosa mutants with lesions in the catA, catB, or catC gene; however, this fragment of chromosomal DNA did not contain any other catabolic genes which had been placed near the catA or catBC cluster based on cotransducibility of the loci. Restriction mapping, deletion subcloning, and complementation analysis showed that the order of the genes on the cloned chromosomal DNA fragment is catA, catB, catC. The catBC genes are tightly linked and are transcribed from a single promoter that is on the 5' side of the catB gene. The catA gene is approximately 3 kb from the catBC genes. The cloned P. aeruginosa catA, catB, and catC genes were expressed at basal levels in blocked mutants of Pseudomonas putida and did not exhibit an inducible response. These observations suggest positive regulation of the P. aeruginosa catA and catBC cluster, the absence of a positive regulatory element from pRO1783, and the inability of the P. putida regulatory gene product to induce expression of the P. aeruginosa catA, catB, and catC genes.
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PMID:Cloning and expression of the catA and catBC gene clusters from Pseudomonas aeruginosa PAO. 313 26

Enolase or 2-phospho-D-glycerate hydrolase catalyses the dehydration of 2-phosphoglycerate to phosphoenolpyruvate, which in turn is converted by pyruvate kinase to pyruvate. We describe here the crystallographic determination of the structure of yeast enolase at high resolution (2.25 A) and an analysis of the structural homology between enolase, pyruvate kinase and triose phosphate isomerase. Each of the two subunits of enolase forms two distinctive domains. The larger domain (residues 143-420) is a regular 8-fold beta/alpha-barrel, as first found in triose phosphate isomerase, and later in pyruvate kinase and 11 other functionally different enzymes. An analysis of the molecular geometries of enolase and pyruvate kinase based on the roughly 8-fold symmetry of the barrel showed a structural homology better than expected for proteins related by convergent evolution. We argue that enolase and pyruvate kinase have evolved from a common ancestral multifunctional enzyme which could process phosphoenolpyruvate in both directions along the glycolytic pathway. There is structural and sequence evidence that muconate lactonizing enzyme later evolved from enolase.
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PMID:Crystal structure of enolase indicates that enolase and pyruvate kinase evolved from a common ancestor. 337 14

Cultures of Caulobacter crescentus were found to grow on a variety of aromatic compounds. Degradation of benzoate, p-hydroxybenzoate, and phenol was found to occur via beta-ketoadipate. The induction of degradative enzymes such as benzoate 1,2-dioxygenase, the ring cleavage enzyme catechol 1,2-dioxygenase, and cis, cis-muconate lactonizing enzyme appeared similar to the control mechanism present in Pseudomonas spp. Both benzoate 1,2-dioxygenase and catechol 1,2-dioxygenase had stringent specificities, as revealed by their action toward substituted benzoates and substituted catechols, respectively.
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PMID:Metabolism of aromatic compounds by Caulobacter crescentus. 357 Nov 58

The enzyme, cis,cis-muconate lactonizing enzyme I (MLEI; EC 5.5.1.1), has been proposed to play a key role in the beta-ketoadipate pathway of benzoate degradation. A 10.2-kb EcoRI fragment isolated from a Pseudomonas putida genomic library complemented a mutant deficient in this enzyme. The MLEI coding gene, catB, was localized to a 1.6-kb fragment which was sequenced by the dideoxy chain termination method. MLEI was purified 25-fold from crude extracts of benzoate-grown P. putida PRS2015 harboring the cloned catB gene. Purified MLEI was greater than 95% homogeneous as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The subunit Mr was 40,000 which was in close agreement with the nucleotide sequence data. N-terminal sequence analysis of purified MLEI protein agreed with the N terminus predicted by the nucleotide sequence. Comparison of the nucleotide and amino acid sequences for catB with the corresponding sequences of the clcB gene (K.L. Ngai, B.F., D.K. Chatterjee, L.N. Ornston, and A.M.C., unpublished), whose gene product catalyzes the analogous reaction in 3-chlorobenzoate degradation, showed significant homology. These results suggest that catB and clcB have diverged from a common ancestral gene.
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PMID:Cloning and complete nucleotide sequence determination of the catB gene encoding cis,cis-muconate lactonizing enzyme. 360 43

The crystal structure of muconate lactonizing enzyme has been solved at 3 A resolution, and an unambiguous alpha-carbon backbone chain trace made. The enzyme contains three domains; the central domain is a parallel-stranded alpha-beta barrel, which has previously been reported in six other enzymes, including triose phosphate isomerase and pyruvate kinase. One novel feature of this enzyme is that its alpha-beta barrel has only seven parallel alpha-helices around the central core of eight parallel beta-strands; all other known alpha-beta barrels contain eight such helices. The N-terminal (alpha + beta) and C-terminal domains cover the cleft where the eighth helix would be. The active site of muconate lactonizing enzyme has been found by locating the manganese ion that is essential for catalytic activity, and by binding and locating an inhibitor, alpha-ketoglutarate. The active site lies in a cleft between the N-terminal and barrel domains; when the active sites of muconate lactonizing enzyme and triose phosphate isomerase are superimposed, barrel-strand 1 of triose phosphate isomerase is aligned with barrel-strand 3 of muconate lactonizing enzyme. This implies that structurally homologous active-site residues in the two enzymes are carried on different parts of the primary sequence; the ancestral gene would had to have been transposed during its evolution to the modern proteins, which seems unlikely. Therefore, these two enzymes may be related by convergent, rather than divergent, evolution.
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PMID:Crystal structure of muconate lactonizing enzyme at 3 A resolution. 361

Protocatechuate is a universal growth substrate for members of the family Rhizobiaceae, and these bacteria utilize the aromatic compound via the beta-ketoadipate pathway. This report describes transcriptional controls exercised by different subgroups of the Rhizobiaceae over five enzymes that catalyze consecutive reactions in the pathway: protocatechuate oxygenase (EC 1.13.11.3), beta-carboxy-cis,cis-muconate lactonizing enzyme (EC 5.5.1.2), gamma-carboxymuconolactone decarboxylase (EC 4.1.1.44), beta-ketoadipate enol-lactone hydrolase (EC 3.1.1.24), and beta-ketoadipate succinyl-coenzyme A transferase (EC 2.8.3.6). All five enzymes were inducible in the fast-growing strains Agrobacterium rhizogenes, Agrobacterium tumefaciens, Rhizobium fredii, Rhizobium meliloti, Rhizobium leguminosarum, and Rhizobium trifolii. Specific activities in induced cells ranged from 5- to 100-fold greater than those found in uninduced cells. In contrast to the fast-growing strains and members of every other microbial taxon examined to date, the slow-growing Bradyrhizobium japonicum and cowpea Bradyrhizobium spp. constitutively expressed four of the five enzymes; protocatechuate oxygenase was the only inducible enzyme in this group. The slow-growing strains included different DNA homology groups, so it appears likely that constitutive expression of the four enzymes is a common trait in the bradyrhizobia. This property points to the importance of aromatic compounds and aromatic catabolites in the nutrition of these organisms.
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PMID:Enzymes of the beta-ketoadipate pathway are inducible in Rhizobium and Agrobacterium spp. and constitutive in Bradyrhizobium spp. 394 Oct 43

We have obtained crystals of Pseudomonas putida muconate lactonizing enzyme. They diffract to better than 2.4 A resolution and have two monomers in the asymmetric unit, related by a non-crystallographic 2-fold axis. The cell dimensions are 139.3 A X 139.3 A X 84.1 A, and the space group is I4. The electron density map at 6.5 A resolution shows that the enzyme is an octamer with D4 symmetry.
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PMID:Crystal structure of muconate lactonizing enzyme at 6.5 A resolution. 399 46

Cell extracts were prepared from Trichosporon cutaneum grown with phenol or p-cresol, and activities were assayed for enzymes catalyzing conversion of these two carbon sources into 3-ketoadipate (beta-ketoadipate) and 3-keto-4-methyladipate, respectively. When activities of each enzyme were expressed as a ratio, the rate for methyl-substituted substrate being divided by that for the unsubstituted substrate, it was apparent that p-cresol-grown cells elaborated pairs of enzymes for hydroxylation, dioxygenation, and delactonization. One enzyme of each pair was more active against its methyl-substituted substrate, and the other was more active against its unsubstituted substrate. Column chromatography was used to separate two hydroxylase activities and also 1,2-dioxygenase activities; the catechol 1,2-dioxygenases were further purified to electrophoretic homogeneity. Extracts of phenol-grown cells contained only those enzymes in this group that were more active against unsubstituted substrates. In contrast, whether cells were grown with phenol or p-cresol, only one muconate cycloisomerase (lactonizing enzyme) was elaborated which was more active against 3-methyl-cis,cis-muconate than against cis,cis-muconate; in this respect it differed from a cycloisomerase of another strain of T. cutaneum which has been characterized. The cycloisomerase was purified from both phenol-grown and p-cresol-grown cells, and some characteristics were determined.
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PMID:Enzymology of the beta-ketoadipate pathway in Trichosporon cutaneum. 404 Sep 5

A number of spontaneous mutant strains of Pseudomonas putida, obtained by repeated selection for inability to grow with cis,cis-muconate, have been shown to carry deletions in catB, the structural gene for muconate lactonizing enzyme. These strains have been employed for deletion mapping of the genetic region containing catB and catC (the structural gene for muconolactone isomerase, the synthesis of which is coordinate with that of muconate lactonizing enzyme). All deletions that overlap mutant sites located on the left side of the genetic map, as well as the point mutations in that region, lead to a pleiotropic loss of both catB and catC activities. We propose that this region to the left of catB has a regulatory function. Although the details of regulation at the molecular level are unclear, our data indicate that catB and catC may well be controlled by a mechanism unlike any yet described by workers on enteric bacteria.
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PMID:Genetic control of enzyme induction in the -ketoadipate pathway of Pseudomonas putida: deletion mapping of cat mutations. 462 87


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