ATPase-coupled sulfate transmembrane transporter activity.
| 12835925 | Characterization and identification of genes essential for dimethyl sulfide utilization in Pseudomonas putida strain DS1.Endoh T, Kasuga K, Horinouchi M, Yoshida T, Habe H, Nojiri H, Omori T | Microbial dimethyl sulfide (DMS) conversion is thought to be involved in the global sulfur cycle. We isolated Pseudomonas putida strain DS1 from soil as a bacterium utilizing DMS as a sole sulfur source, and tried to elucidate the DMS conversion mechanism of strain DS1 at biochemical and genetic level. Strain DS1 oxidized DMS to dimethyl sulfone (DMSO(2)) via dimethyl sulfoxide, whereas the oxidation was repressed in the presence of sulfate, suggesting that a sulfate starvation response is involved in DMS utilization by strain DS1. Two of the five DMS-utilization-defective mutants isolated by transposon 5 (Tn 5) mutagenesis had a Tn 5 insertion in the ssuEADCBF operon, which has been reported to encode a two-component monooxygenase system (SsuED), an ABC-type transporter (SsuABC), and a small protein (SsuF), and also to play a key role in utilization of sulfonates and sulfate esters in another bacterium, P. putida strain S-313. Disruption of ssuD and SsuD enzymatic activity demonstrated that methanesulfonate is a metabolic intermediate of DMS and desulfonated by SsuD. Disruption of ssuC or ssuF also led to a DMS-utilization-defective phenotype. Another two mutants had a defect in a gene homologous to pa2354 from P. aeruginosa PAO1, which encodes a putative transcriptional regulator, while the remaining mutant had a defect in cysM encoding O-acetylserine (thiol)-lyase B. | 2003 | |
| 0 | 10781534 | Deletion analysis of the Escherichia coli taurine and alkanesulfonate transport systems.Eichhorn E, van der Ploeg JR, Leisinger T | The Escherichia coli tauABCD and ssuEADCB gene clusters are required for the utilization of taurine and alkanesulfonates as sulfur sources and are expressed only under conditions of sulfate or cysteine starvation. tauD and ssuD encode an alpha-ketoglutarate-dependent taurine dioxygenase and a reduced flavin mononucleotide-dependent alkanesulfonate monooxygenase, respectively. These enzymes are responsible for the desulfonation of taurine and alkanesulfonates. The amino acid sequences of SsuABC and TauABC exhibit similarity to those of components of the ATP-binding cassette transporter superfamily, suggesting that two uptake systems for alkanesulfonates are present in E. coli. Chromosomally located in-frame deletions of the tauABC and ssuABC genes were constructed in E. coli strain EC1250, and the growth properties of the mutants were studied to investigate the requirement for the TauABC and SsuABC proteins for growth on alkanesulfonates as sulfur sources. Complementation analysis of in-frame deletion mutants confirmed that the growth phenotypes obtained were the result of the in-frame deletions constructed. The range of substrates transported by these two uptake systems was largely reflected in the substrate specificities of the TauD and SsuD desulfonation systems. However, certain known substrates of TauD were transported exclusively by the SsuABC system. Mutants in which only formation of hybrid transporters was possible were unable to grow with sulfonates, indicating that the individual components of the two transport systems were not functionally exchangeable. The TauABCD and SsuEADCB systems involved in alkanesulfonate uptake and desulfonation thus are complementary to each other at the levels of both transport and desulfonation. | 2000 |
Eichhorn E , Van d P J R , Leisinger T . Deletion Analysis of the Escherichia coli Taurine and Alkanesulfonate Transport Systems[J]. Journal of Bacteriology, 2000, 182(10):2687-2695.