Identification of cis-diols as intermediates in the oxidation of aromatic acids by a strain of Pseudomonas putida that contains a TOL plasmid.
Pseudomonas putida BG1 was isolated from soil by enrichment with p-toluate and selection for growth with p-xylene. Other hydrocarbons that served as growth substrates were toluene, m-xylene, 3-ethyltoluene, and 1,2,4-trimethylbenzene. The enzymes responsible for growth on these substrates are encoded by a large plasmid with properties similar to those of TOL plasmids isolated from other strains of Pseudomonas. Treatment of P. putida BG1 with nitrosoguanidine led to the isolation of a mutant strain which, when grown with fructose, oxidized both p-xylene and p-toluate to (-)-cis-1,2-dihydroxy-4-methylcyclohexa-3,5-diene-1-carboxylic acid (cis-p-toluate diol). The structure of the diol was determined by conventional chemical techniques including identification of the products formed by acid-catalyzed dehydration and characterization of a methyl ester derivative. The cis-relative stereochemistry of the hydroxyl groups was determined by the isolation and characterization of an isopropylidene derivative. p-Xylene-grown cells contained an inducible NAD+-dependent dehydrogenase which formed catechols from cis-p-toluate diol and the analogous acid diols formed from the other hydrocarbon substrates listed above. The catechols were converted to meta ring fission products by an inducible catechol-2,3-dioxygenase which was partially purified from p-xylene-grown cells of P. putida BG1.
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D001565:Benzoates / Q000378:metabolism*; D002396:Catechols / Q000378:metabolism; D004587:Electrophoresis, Agar Gel; D005947:Glucose / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D010957:Plasmids; D011549:Pseudomonas / Q000235:genetics / Q000378:metabolism*; D014050:Toluene / Q000031:analogs & derivatives / Q000378:metabolism; D014992:Xylenes / Q000378:metabolism
D001565:Benzoates; D002396:Catechols; D014992:Xylenes; C018599:4-methylcatechol; D014050:Toluene; C029719:3-ethyltoluene; C009504:4-toluic acid; D005947:Glucose