Secondary alkylsulphatases in a strain of Comamonas terrigena.
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ABSTRACT:
SUBMITTER: Fitzgerald JW
PROVIDER: S-EPMC1165642 | biostudies-other | 1975 Aug
REPOSITORIES: biostudies-other
Similar Datasets
Project description:Extracts of the cells of Comamonas terrigena, grown under a variety of different conditions, contain two distinct, constitutive, NAD-dependent alcohol dehydrogenase enzymes that can be separated by polyacrylamide-gel electrophoresis. One of the enzymes exhibits activity towards D-alkan-2-ols and primary alcohols and the other is active towards L-alkan-2-ols, symmetrical secondary alcohols and probably other positional isomers of secondary alcohols of the L-configuration. Methods for the individual assay of the two enzymes have been developed and have been used to define some of their general properties. Most of the substrates for these enzymes would not support growth of C. terrigena under the experimental conditions used and were relatively poorly oxidized by resting cell suspensions.
| S-EPMC1162454 | biostudies-other
Project description:The availability of homogeneous samples of the potassium salts of L- and D-octan-2-yl sulphate has enabled the separation of the optically stereospecific CS1 and CS2 secondary alkysulphohydrolases from extracts of cells of Comamonas terrigena. The CS2 enzyme was purified to homogeneity, and an initial study was made of its general properties, specificity, cellular localization and relationship to the CS1 enzyme. The CS2 enzyme has a molecular weight of approx. 250000 and a subunit size of approx. 58000, indicating that the molecule is a tetramer. Under the experimental conditions used the enzyme appears to be specific for (+)-secondary alkyl sulphate esters with the sulphate group at C-2 and with a chain length of at least six carbons. Enzyme activity towards racemic C-2 sulphates increases with increasing chain length up to C10, and there is some indirect evidence to suggest that activity declines when that chain length is exceeded. Other indirect evidence confirms that the CS1 enzyme exhibits similar specificity, except that only (-)-isomers can serve as substrates. Both enzymes are present in broth-grown stationary-phase cells of C. terrigena in approximately equal amounts.
| S-EPMC1183720 | biostudies-other
Project description:A series of d-alkan-2-yl sulphate esters (C(7)-C(14)) were prepared by sulphation of the resolved parent alcohols by a method that entails complete retention of configuration. These sulphate esters were tested as substrates for the stereospecific CS2 secondary alkylsulphohydrolase of Comamonas terrigena. V(max.) reached a maximum with the C(9) compound, whereas logK(m) decreased linearly as the alkyl-chain length was increased from C(7) to C(14). A parallel series of l-alkan-2-yl sulphates was also prepared, and these esters, together with homologous series of primary alkyl sulphates and primary alkanesulphonates, were shown to be competitive inhibitors of the CS2 enzyme. For each series of compounds, logK(i) values decreased linearly with increasing alkyl-chain length. Plots of chain length against the standard free energy of binding (DeltaG(0)) of substrate and inhibitors to the CS2 enzyme showed that the standard free energy of association of a -CH(2)- group with the enzyme was 2.0-2.4kJ/mol for all classes of compound studied, indicating an important contribution from hydrophobic interactions to the overall binding. Plots for d-alkan-2-yl sulphate substrates and primary alkyl sulphate inhibitors were nearly coincident, suggesting that the overall interaction between a primary ester and the enzyme is the same as that between the isomeric secondary substrate and the enzyme. Plots for l-alkan-2-yl sulphate and alkanesulphonate inhibitors were very similar to each other, but were displaced by 1.5-3.0kJ/mol from that for substrate binding. This indicates that the binding of any one of these particular inhibitors involves one carbon atom fewer than the number involved in binding a substrate of the same chain length. These observations are discussed in terms of a three-point attachment of substrate to the enzyme involving the alkyl chain, sulphate group and the C-1 methyl group.
| S-EPMC1162237 | biostudies-other
Project description:Comamonas terrigena S00077 genome sequencing
| PRJNA632091 | ENA
Project description:Comamonas terrigena NBRC 13299 genome sequencing project
| PRJDB311 | ENA
Project description:In Comamonas testosteroni strain BR6020, metabolism of isovanillate (iVan; 3-hydroxy-4-methoxybenzoate), vanillate (Van; 4-hydroxy-3-methoxybenzoate), and veratrate (Ver; 3,4-dimethoxybenzoate) proceeds via protocatechuate (Pca; 3,4-dihydroxybenzoate). A 13.4-kb locus coding for the catabolic enzymes that channel the three substrates to Pca was cloned. O demethylation is mediated by the phthalate family oxygenases IvaA (converts iVan to Pca and Ver to Van) and VanA (converts Van to Pca and Ver to iVan). Reducing equivalents from NAD(P)H are transferred to the oxygenases by the class IA oxidoreductase IvaB. Studies using whole cells, cell extracts, and reverse transcriptase PCR showed that degradative activity and expression of vanA, ivaA, and ivaB are inducible. In succinate- and Pca-grown cells, there is negligible degradative activity towards Van, Ver, and iVan and little to no expression of vanA, ivaA, and ivaB. Growth on Van or Ver results in production of oxygenases with activity towards Van, Ver, and iVan and expression of vanA, ivaA, and ivaB. With iVan-grown cultures, ivaA and ivaB are expressed, and in assays with whole cells, production of the iVan oxygenase is observed, but there is little activity towards Van or Ver. In cell extracts, though, Ver metabolism is observed, which suggests that the system mediating iVan uptake in whole cells does not mediate Ver uptake.
| S-EPMC1482911 | biostudies-literature
Project description:The isophthalate (IPA) degradation gene cluster (iphACBDR) responsible for the conversion of IPA into protocatechuate (PCA) was isolated from Comamonas sp. strain E6, which utilizes phthalate isomers as sole carbon and energy sources via the PCA 4,5-cleavage pathway. Based on amino acid sequence similarity, the iphA, iphC, iphB, iphD, and iphR genes were predicted to code for an oxygenase component of IPA dioxygenase (IPADO), a periplasmic IPA binding receptor, a 1,2-dihydroxy-3,5-cyclohexadiene-1,5-dicarboxylate (1,5-DCD) dehydrogenase, a reductase component of IPADO, and an IclR-type transcriptional regulator, respectively. The iphACBDR genes constitute a single transcriptional unit, and transcription of the iph catabolic operon was induced during growth of E6 on IPA. The iphA, iphD, and iphB genes were expressed in Escherichia coli. Crude IphA and IphD converted IPA in the presence of NADPH into a product which was transformed to PCA by IphB. These results suggested that IPADO is a two-component dioxygenase that consists of a terminal oxygenase component (IphA) and a reductase component (IphD) and that iphB encodes the 1,5-DCD dehydrogenase. Disruption of iphA and iphB resulted in complete loss of growth of E6 on IPA. Inactivation of iphD significantly affected growth on IPA, and the iphC mutant did not grow on IPA at neutral pH. These results indicated that the iphACBD genes are essential for the catabolism of IPA in E6. Disruption of iphR resulted in faster growth of E6 on IPA, suggesting that iphR encodes a repressor for the iph catabolic operon. Promoter analysis of the operon supported this notion.
| S-EPMC2805221 | biostudies-literature
Project description: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.
| S-EPMC1393238 | biostudies-literature
Project description:Two almost identical gene clusters, tphR(I)C(I)A2(I)A3(I)B(I)A1(I) and tphR(II)C(II)A2(II)A3(II)B(II)A1(II), are responsible for the conversion of terephthalate (TPA) to protocatechuate in Comamonas sp. strain E6. In the present study, we investigated the transcriptional regulation of the tphR(II)C(II)A2(II)A3(II)B(II)A1(II) gene cluster. Reverse transcription-PCR analysis suggested that the tphR(II)C(II)A2(II)A3(II)B(II)A1(II) genes form two transcriptional units, the tphC(II)A2(II)A3(II)B(II)A1(II) catabolism operon and tphR(II), with the latter encoding an IclR-type transcriptional regulator (ITTR). The transcription start site of the tph(II) catabolism operon was mapped at 21 nucleotides upstream of the initiation codon of tphC(II). The lacZ transcriptional fusion experiments showed that tphR(II) encodes a transcriptional activator of the tph(II) catabolism operon and that TPA acts as an inducer. On the other hand, TphR(II) appeared to repress its own transcription regardless of the presence of TPA. The analysis of mutant derivatives of E6 indicated that tphR(II) is essential for the transcriptional activation of the tph(II) catabolism operon and the growth on TPA of a tph(I)-deficient derivative of E6. Purified His-tagged TphR(II) bound specifically to the tphR(II)-tphC(II) intergenic region containing a 21-bp inverted repeat sequence. Alignment of the inverted repeat sequences in the binding sites for TphR(II) and other members of ITTRs revealed highly conserved nucleotides. The substitution of conserved nucleotides resulted in significantly reduced TPA-dependent transcriptional activation from the tphC(II) promoter and reduced binding to His-tagged TphR(II). These results clearly indicate that the conserved nucleotides are required for the inducible expression of the tph(II) catabolism operon regulated by TphR(II).
| S-EPMC2937507 | biostudies-literature