Publications

• Characterization of the terephthalate degradation genes of Comamonas sp. strain E6.

  Sasoh M., Masai E., Ishibashi S., Hara H., Kamimura N., Miyauchi K., Fukuda M.

  We isolated Comamonas sp. strain E6, which utilizes terephthalate (TPA) as the sole carbon and energy source via the protocatechuate (PCA) 4,5-cleavage pathway. Two almost identical TPA degradation gene clusters, tphRICIA2IA3IBIA1I and tphRIICIIA2IIA3IIBIIA1II, were isolated from this strain. Base ... >> More

  We isolated Comamonas sp. strain E6, which utilizes terephthalate (TPA) as the sole carbon and energy source via the protocatechuate (PCA) 4,5-cleavage pathway. Two almost identical TPA degradation gene clusters, tphRICIA2IA3IBIA1I and tphRIICIIA2IIA3IIBIIA1II, were isolated from this strain. Based on amino acid sequence similarity, the genes tphR, tphC, tphA2, tphA3, tphB, and tphA1 were predicted to code, respectively, for an IclR-type transcriptional regulator, a periplasmic TPA binding receptor, the large subunit of the oxygenase component of TPA 1,2-dioxygenase (TPADO), the small subunit of the oxygenase component of TPADO, a 1,2-dihydroxy-3,5-cyclohexadiene-1,4-dicarboxylate (DCD) dehydrogenase, and a reductase component of TPADO. The growth of E6 on TPA was not affected by disruption of either tphA2I or tphA2II singly; however, the tphA2I tphA2II double mutant no longer grew on TPA, suggesting that both TPADO genes are involved in TPA degradation. Introduction of a plasmid carrying tphRIICIIA2IIA3IIBIIA1II conferred the TPA utilization phenotype on Comamonas testosteroni IAM 1152, which is able to grow on PCA but not on TPA. Disruption of either tphRII or tphCII on this plasmid resulted in the loss of the growth of IAM 1152 on TPA, suggesting that these genes are essential to convert TPA to PCA in E6. The genes tphA1II, tphA2II, tphA3II, and tphBII were expressed in Escherichia coli, and the resultant cell extracts containing TphA1II, TphA2II, and TphA3II converted TPA in the presence of NADPH into a product which was transformed to PCA by TphBII. On the basis of these results, TPADO was strongly suggested to be a two-component dioxygenase which consists of the terminal oxygenase component (TphA2 and TphA3) and the reductase (TphA1), and tphB codes for the DCD dehydrogenase. << Less

  Appl. Environ. Microbiol. 72:1825-1832(2006) [PubMed] [EuropePMC]

• Molecular analysis of isophthalate and terephthalate degradation by Comamonas testosteroni YZW-D.

  Wang Y.Z., Zhou Y., Zylstra G.J.

  Comamonas testosteroni YZW-D was isolated from Passaic River sediment for its ability to degrade isophthalate and terephthalate. Degradation of the two isomeric compounds proceeds via separately inducible catabolic pathways that converge at protocatechuate. Analysis of the catabolic pathways by wh ... >> More

  Comamonas testosteroni YZW-D was isolated from Passaic River sediment for its ability to degrade isophthalate and terephthalate. Degradation of the two isomeric compounds proceeds via separately inducible catabolic pathways that converge at protocatechuate. Analysis of the catabolic pathways by which these two isomers are degraded demonstrated that a cis-dihydrodiol intermediate is involved in both pathways. The genes for the conversion of isophthalate and terephthalate to protocatechuate were cloned on a single fragment of genomic DNA from C. testosteroni YZW-D. The two operons were located by subcloning and mutant complementation experiments. The regions coding for the two degradative pathways were sequenced. Analysis of the nucleotide sequence for the isophthalate degradation operon located genes for a dioxygenase, a transport protein, a cis-dihydrodiol dehydrogenase, and a reductase. Analysis of the nucleotide sequence for the terephthalate degradation operon located genes for a regulatory protein, a transport protein, a dioxygenase large subunit, a dioxygenase small subunit, a cis-dihydrodiol dehydrogenase, and a reductase. << Less

  Environ. Health Perspect. 103:9-12(1995) [PubMed] [EuropePMC]