Publications

• Degradative pathways for p-toluenecarboxylate and p-toluenesulfonate and their multicomponent oxygenases in Comamonas testosteroni strains PSB-4 and T-2.

  Junker F., Saller E., Schlaefli Oppenberg H.R., Kroneck P.M., Leisinger T., Cook A.M.

  Three multicomponent oxygenases involved in the degradation of p-toluenesulfonate and p-toluenecarboxylate and the regulation of their synthesis have been examined in three strains (T-2, PSB-4 and TER-1) of Comamonas testosteroni. Strain T-2 utilizes p-toluenesulfonate as a source of carbon and en ... >> More

  Three multicomponent oxygenases involved in the degradation of p-toluenesulfonate and p-toluenecarboxylate and the regulation of their synthesis have been examined in three strains (T-2, PSB-4 and TER-1) of Comamonas testosteroni. Strain T-2 utilizes p-toluenesulfonate as a source of carbon and energy for growth via p-sulfobenzoate and protocatechuate, and p-toluenecarboxylate via terephthalate and protocatechuate, and has the unusual property of requiring the reductase (TsaB) of the toluenesulfonate methyl monooxygenase system (TsaMB) in an incompletely expressed sulfobenzoate dioxygenase system (PsbAC) [Schläfli Oppenberg, H.R., Chen, G., Leisinger, T. & Cook, A. M. (1995). Microbiology 141, 1891-1899]. The independently isolated C. testosteroni PSB-4 utilized only sulfobenzoate and terephthalate via protocatechuate. Mutant TER-1, derived from strain T-2, utilized only terephthalate via protocatechuate. We detected no enzymes of the pathway from toluenesulfonate to sulfobenzoate in strains PSB-4 and TER-1, and confirmed by PCR and Southern blot analysis that the genes (tsaMB) encoding toluenesulfonate monooxygenase were absent. We concluded that, in strain PSB-4, the regulatory unit encoding the genes for the conversion of toluenesulfonate to sulfobenzoate was missing, and that generation of mutant TER-1 involved deletion of this regulatory unit and of the regulatory unit encoding desulfonation of sulfobenzoate. The degradation of sulfobenzoate in strain PSB-4 was catalysed by a fully inducible sulfobenzoate dioxygenase system (PsbACPSB-4), which, after purification of the oxygenase component (PsbAPSB-4), turned out to be indistinguishable from the corresponding component from strain T-2 (PsbAT-2). Reductase PsbCPSB-4, which we could separate but not purify, was active with oxygenase PsbAPSB-4 and PsbAT-2. Oxygenase PsbAPSB-4 was shown by electron paramagnetic resonance spectroscopy to contain a Rieske [2Fe-2S] centre. The enzyme system oxygenating terephthalate was examined and the oxygenase component purified and characterized. The oxygenase component in strains T-2 (and mutant TER-1) and PSB-4 were indistinguishable. The reductase component, which we separated but failed to purify, was active with the oxygenase from all strains. Gains and losses of blocks of genes in evolution is discussed. << Less

  Microbiology 142:2419-2427(1996) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Characterization of the p-toluenesulfonate operon tsaMBCD and tsaR in Comamonas testosteroni T-2.

  Junker F., Kiewitz R., Cook A.M.

  Comamonas testosteroni T-2 uses a standard, if seldom examined, attack on an aromatic compound and oxygenates the side chain of p-toluenesulfonate (TS) (or p-toluenecarboxylate) to p-sulfobenzoate (or terephthalate) prior to complete oxidation. The expression of the first three catabolic enzymes i ... >> More

  Comamonas testosteroni T-2 uses a standard, if seldom examined, attack on an aromatic compound and oxygenates the side chain of p-toluenesulfonate (TS) (or p-toluenecarboxylate) to p-sulfobenzoate (or terephthalate) prior to complete oxidation. The expression of the first three catabolic enzymes in the pathway, the TS methyl-monooxygenase system (comprising reductase B and oxygenase M; TsaMB), p-sulfobenzyl alcohol dehydrogenase (TsaC), and p-sulfobenzaldehyde dehydrogenase (TsaD), is coregulated as regulatory unit R1 (H. R. Schlafli Oppenberg, G. Chen, T. Leisinger, and A. M. Cook, Microbiology [Reading] 141:1891-1899, 1995). The components of the oxygenase system were repurified, and the N-terminal amino acid sequences were confirmed and extended. An internal sequence of TsaM was obtained, and the identity of the [2Fe-2S] Rieske center was confirmed by electron paramagnetic resonance spectroscopy. We purified both dehydrogenases (TsaC and TsaD) and determined their molecular weights and N-terminal amino acid sequences. Oligonucleotides derived from the partial sequences of TsaM were used to identify cloned DNA from strain T-2, and about 6 kb of contiguous cloned DNA was sequenced. Regulatory unit R1 was presumed to represent a four-gene operon (tsaMBCD) which was regulated by the LysR-type regulator, TsaR, encoded by a deduced one-gene transcriptional unit. The genes for the inducible TS transport system were not at this locus. The oxygenase system was confirmed to be a class IA mononuclear iron oxygenase, and class IA can now be seen to have two evolutionary groups, the monooxygenases and the dioxygenases, though the divergence is limited to the oxygenase components. The alcohol dehydrogenase TsaC was confirmed to belong to the short-chain, zinc-independent dehydrogenases, and the aldehyde dehydrogenase TsaD was found to resemble several other aldehyde dehydrogenases. The operon and its putative regulator are compared with units of the TOL plasmid. << Less

  J. Bacteriol. 179:919-927(1997) [PubMed] [EuropePMC]