Cometabolism of 3-methylbenzoate and methylcatechols by a 3-chlorobenzoate utilizingPseudomonas: Accumulation of (+)-2,5-dihydro-4-methyl-and (+)-2,5-dihydro-2-methyl-5-oxo-furan-2-acetic acid

Knackmuss, Hans‐Joachim; Hellwig, M.; Lackner, Helmut; Otting, Walter

doi:10.1007/bf01278610

Cited by 80 publications

(67 citation statements)

References 5 publications

(7 reference statements)

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“…For 4-and 5-methylsalicylate, transformation by enzymes of this cluster results in the formation of 4-methylmuconolactone (Fig. 4), a compound previously described as a dead-end product in Pseudomonas strains (8,25). Transformation of this compound in C. necator JMP134 (39) and R. rhodochrous N75 (6), is catalyzed by a 4-methylmuconolactone methylisomerase transforming 4-into 3-methylmuconolactone (7,43).…”

Section: Discussionmentioning

confidence: 91%

“…The proteobacterial pathway for catechol degradation is not suited for the degradation of chlorosubstituted or methylsubstituted catechols. Methylcatechols, when channeled into the intradiol pathway, are transformed into methylsubstituted muconolactones as dead-end products (8,25). Enzymes involved in 4-methylmuconolactone degradation have thus far been characterized only from Rhodococcus rhodochrous N75 and Cupriavidus necator JMP134 and comprise a 4-methylmuconolactone 4-methylisomerase, forming 3-methylmuconolactone, as a key enzyme (7,13,43).…”

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confidence: 99%

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A Gene Cluster Involved in Degradation of Substituted Salicylates viaorthoCleavage inPseudomonassp. Strain MT1 Encodes Enzymes Specifically Adapted for Transformation of 4-Methylcatechol and 3-Methylmuconate

et al. 2007

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Pseudomonas sp. strain MT1 has recently been reported to degrade 4-and 5-chlorosalicylate by a pathway assumed to consist of a patchwork of reactions comprising enzymes of the 3-oxoadipate pathway. Genes encoding the initial steps in the degradation of salicylate and substituted derivatives were now localized and sequenced. One of the gene clusters characterized (sal) showed a novel gene arrangement, with salA, encoding a salicylate 1-hydroxylase, being clustered with salCD genes, encoding muconate cycloisomerase and catechol 1,2-dioxygenase, respectively, and was expressed during growth on salicylate and chlorosalicylate. A second gene cluster (cat), exhibiting the typical catRBCA arrangement of genes of the catechol branch of the 3-oxoadipate pathway in Pseudomonas strains, was expressed during growth on salicylate. Despite their high sequence similarities with isoenzymes encoded by the cat gene cluster, the catechol 1,2-dioxygenase and muconate cycloisomerase encoded by the sal cluster showed unusual kinetic properties. Enzymes were adapted for turnover of 4-chlorocatechol and 3-chloromuconate; however, 4-methylcatechol and 3-methylmuconate were identified as the preferred substrates. Investigation of the substrate spectrum identified 4-and 5-methylsalicylate as growth substrates, which were effectively converted by enzymes of the sal cluster into 4-methylmuconolactone, followed by isomerization to 3-methylmuconolactone. The function of the sal gene cluster is therefore to channel both chlorosubstituted and methylsubstituted salicylates into a catechol ortho cleavage pathway, followed by dismantling of the formed substituted muconolactones through specific pathways.

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Section: Discussionmentioning

confidence: 91%

mentioning

confidence: 99%

A Gene Cluster Involved in Degradation of Substituted Salicylates viaorthoCleavage inPseudomonassp. Strain MT1 Encodes Enzymes Specifically Adapted for Transformation of 4-Methylcatechol and 3-Methylmuconate

et al. 2007

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“…Because or biochemical and genetic in· activation of mela-cleavage activities provoked by 3-chlo roca techols, ch 10roaro ma tics-degradin g populations lose their ability to utilize methylaromatics (5). As a consequence of acdimatisation to chloroaromatics, methy1catechols are subject to unproductive ortho-cleavage with accumulation of methyl-substituted 4-carboxymethyl-but·2-en-I,4-olides as dead-end metabolites (6,7].…”

Section: Introducfionmentioning

confidence: 99%

Modified ortho-cleavage pathway in Alcaligenes eutrophus JMP134 for the degradation of 4-methylcatechol

Pieper¹

1985

FEMS Microbiology Letters

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“….0]octane (1-methylbislactone), and 3-methyl-cis,cis-muconate were prepared as previously described (1,4,6).…”

Section: Materials-(4s)-4-methylmuconolactonementioning

confidence: 99%

“…Ortho-cleavage of 4-methylcatechol typically results in the formation of 4-methylmuconolactone (4-ML) 2 as a dead-end product (1,3,4).…”

mentioning

confidence: 99%

Crystal Structure and Catalytic Mechanism of 4-Methylmuconolactone Methylisomerase

Marín

Heinz

Pieper

et al. 2009

Journal of Biological Chemistry

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When methyl-substituted aromatic compounds are degraded via ortho (intradiol)-cleavage of 4-methylcatechol, the dead-end metabolite 4-methylmuconolactone (4-ML) is formed. Degradation of 4-ML has only been described in few bacterial species, including Pseudomonas reinekei MT1. The isomerization of 4-ML to 3-methylmuconolactone (3-ML) is the first step required for the mineralization of 4-ML and is catalyzed by an enzyme termed 4-methylmuconolactone methylisomerase (MLMI). We identified the gene encoding MLMI in P. reinekei MT1 and solved the crystal structures of MLMI in complex with 3-ML at 1.4-Å resolution, with 4-ML at 1.9-Å resolution and with a MES buffer molecule at 1.45-Å resolution. MLMI exhibits a ferredoxin-like fold and assembles as a tight functional homodimeric complex. We were able to assign the active site clefts of MLMI from P. reinekei MT1 and of the homologous MLMI from Cupriavidus necator JMP134, which has previously been crystallized in a structural genomics project. Kinetic and structural analysis of wild-type MLMI and variants created by site-directed mutagenesis indicate Tyr-39 and His-26 to be the most probable catalytic residues. The previously proposed involvement of Cys-67 in covalent catalysis can now be excluded. Residue His-52 was found to be important for substrate affinity, with only marginal effect on catalytic activity. Based on these results, a novel catalytic mechanism for the isomerization of 4-ML to 3-ML by MLMI, involving a bislactonic intermediate, is proposed. This broadens the knowledge about the diverse group of proteins exhibiting a ferredoxin-like fold.

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Cometabolism of 3-methylbenzoate and methylcatechols by a 3-chlorobenzoate utilizingPseudomonas: Accumulation of (+)-2,5-dihydro-4-methyl-and (+)-2,5-dihydro-2-methyl-5-oxo-furan-2-acetic acid

Cited by 80 publications

References 5 publications

A Gene Cluster Involved in Degradation of Substituted Salicylates viaorthoCleavage inPseudomonassp. Strain MT1 Encodes Enzymes Specifically Adapted for Transformation of 4-Methylcatechol and 3-Methylmuconate

A Gene Cluster Involved in Degradation of Substituted Salicylates viaorthoCleavage inPseudomonassp. Strain MT1 Encodes Enzymes Specifically Adapted for Transformation of 4-Methylcatechol and 3-Methylmuconate

Modified ortho-cleavage pathway in Alcaligenes eutrophus JMP134 for the degradation of 4-methylcatechol

Crystal Structure and Catalytic Mechanism of 4-Methylmuconolactone Methylisomerase

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