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At least 19 recordsLinked to original sources
PubMed2000

Deletion analysis of the Escherichia coli taurine and alkanesulfonate transport systems.

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.

ATP-Binding Cassette Transporters↗
PubMed2001

Alkanesulfonate degradation by novel strains of Achromobacter xylosoxidans, Tsukamurella wratislaviensis and Rhodococcus sp., and evidence for an ethanesulfonate monooxygenase in A. xylosoxidans strain AE4.

Novel isolates of Achromobacter xylosoxidans, Tsukamurella wratislaviensis and a Rhodococcus sp. are described. These grew with short-chain alkanesulfonates as their sole source of carbon and energy. T. wratislaviensis strain SB2 grew well with C(3)-C(6) linear alkanesulfonates, isethionate and taurine, Rhodococcus sp. strain CB1 used C(3)-C(10) linear alkanesulfonates, taurine and cysteate, but neither strain grew with ethanesulfonate. In contrast, A. xylosoxidans strain AE4 grew well with ethanesulfonate, making it the first bacterium to be described which can grow with this compound. It also grew with unsubstituted C(3)-C(5) alkanesulfonates and isethionate. Hydrolysis was excluded as a mechanism for alkanesulfonate metabolism in these strains; and evidence is given for a diversity of uptake and desulfonatase systems. We provide evidence for an initial monooxygenase-dependent desulfonation in the metabolism of ethanesulfonate and propanesulfonate by A. xylosoxidans strain AE4.

Actinomycetales↗
PubMed2005

Altered mechanism of the alkanesulfonate FMN reductase with the monooxygenase enzyme.

The two-component alkanesulfonate monooxygenase system from Escherichia coli is comprised of an FMN reductase (SsuE) and a monooxygenase enzyme (SsuD) that together catalyze the oxidation of alkanesulfonate to the corresponding aldehyde and sulfite products. To determine the effects of protein interactions on catalysis, the steady-state kinetic parameters for SsuE were determined in single-enzyme assays and in the presence of the monooxygenase enzyme and alkanesulfonate substrate. In single-enzyme kinetic assays, SsuE followed an ordered sequential mechanism, with NADPH as the first substrate to bind and NADP+ as the last product to dissociate. However, in the presence of SsuD and octanesulfonate the kinetic mechanism of SsuE is altered to a rapid equilibrium ordered mechanism, and the Km value for FMN is increased 10-fold. These results suggest that both the SsuD enzyme and alkanesulfonate substrate are required to ensure that the FMN reductase reaction proceeds to form the ternary complex with the subsequent generation of reduced flavin transfer.

Base Sequence↗
PubMed1991

Some cytotoxicological aspects of ethyl and fluoroethyl alkanesulfonates in Escherichia coli: role of fluorine substitution.

Several fluoroethyl derivatives of alkanesulfonates and N-nitrosourea were tested for cytotoxicity and mutagenicity in E. coli K12 AB1157. Cytotoxicity was potentiated by fluorine substitution in the alkyl moiety of the ethylating agents. Mutagenicity was strongly suppressed by fluorine substitution in the alkanesulfonates, but not in the N-nitrosourea. The capacity to induce the SOS repair network was suppressed, as was mutagenicity, in alkanesulfonates, but not in N-nitrosourea. The potentiating effect of fluorine on the cytotoxicity of alkanesulfonates seems to be due to an as yet unknown killing mechanism. An appreciable suppressive effect on the mutagenicity and the SOS induction is worth notice for the biological role of fluorine substitution in alkylating agents.

Alkylating Agents↗
PubMedDate not supplied

Linear alkanesulfonates as carbon and energy sources for gram-positive and gram-negative bacteria.

Several bacteria from soil and rainwater samples were enriched and isolated with propanesulfonate or butanesulfonate as sole carbon and energy source. Most of the strains isolated utilized nonsubstituted alkanesulfonates with a chain length of C3-C6 and the substituted sulfonates taurine and isethionate as carbon and energy source. A gram-positive isolate, P40, and a gram-negative isolate, P53, were characterized in more detail. Phylogenetic analysis grouped strain P40 within group IV of the genus Rhodococcus and showed a close relationship with Rhodococcus opacus. After phylogenetic and physiological analyses, strain P53 was identified as Comamonas acidovorans. Both bacteria also utilized a wide range of sulfonates as sulfur source. Strain P40, but not strain P53, released sulfite into the medium during dissimilation of sulfonated compounds. Cell-free extracts of strain P53 exhibited high sulfite oxidase activity [2.34 U (mg protein)-1] when assayed with ferricyanide, but not with cytochrome c. Experiments with whole-cell suspensions of both strains showed that the ability to dissimilate 1-propanesulfonate was specifically induced during growth on this substrate and was not present in cells grown on propanol, isethionate or taurine. Whole-cell suspensions of both strains accumulated acetone when oxidizing the non-growth substrate 2-propanesulfonate. Strain P40 cells also accumulated sulfite under these conditions. Stoichiometric measurements with 2-propanesulfonate as substrate in oxygen electrode experiments indicate that the nonsubstituted alkanesulfonates were degraded by a monooxygenase. When strain P53 grew with nonsubstituted alkanesulfonates as carbon and energy source, cells expressed high amounts of yellow pigments, supporting the proposition that an oxygenase containing iron sulfur centres or flavins was involved in their degradation.

Acinetobacter↗
PubMed1999

Characterization of a two-component alkanesulfonate monooxygenase from Escherichia coli.

The Escherichia coli ssuEADCB gene cluster is required for the utilization of alkanesulfonates as sulfur sources, and is expressed under conditions of sulfate or cysteine starvation. The SsuD and SsuE proteins were overexpressed and characterized. SsuE was purified to homogeneity as an N-terminal histidine-tagged fusion protein. Native SsuE was a homodimeric enzyme of M(r) 58,400, which catalyzed an NAD(P)H-dependent reduction of FMN, but it was also able to reduce FAD or riboflavin. The SsuD protein was purified to >98% purity using cation exchange, anion exchange, and hydrophobic interaction chromatography. The pure enzyme catalyzed the conversion of pentanesulfonic acid to sulfite and pentaldehyde and was able to desulfonate a wide range of sulfonated substrates including C-2 to C-10 unsubstituted linear alkanesulfonates, substituted ethanesulfonic acids and sulfonated buffers. SsuD catalysis was absolutely dependent on FMNH(2) and oxygen, and was maximal for SsuE/SsuD molar ratios of 2.1 to 4.2 in 10 mM Tris-HCl, pH 9.1. Native SsuD was a homotetrameric enzyme of M(r) 181,000. These results demonstrate that SsuD is a broad range FMNH(2)-dependent monooxygenase catalyzing the oxygenolytic conversion of alkanesulfonates to sulfite and the corresponding aldehydes. SsuE is the FMN reducing enzyme providing SsuD with FMNH(2).

Alkanesulfonates↗
PubMed2002

Crystal structure of Escherichia coli alkanesulfonate monooxygenase SsuD.

The FMNH(2)-dependent alkanesulfonate monooxygenase SsuD catalyzes the conversion of alkanesulfonates to the corresponding aldehyde and sulfite. The enzyme allows Escherichia coli to use a wide range of alkanesulfonates as sulfur sources for growth when sulfate or cysteine are not available. The structure of SsuD was solved using the multiwavelength anomalous dispersion method from only four ordered selenium sites per asymmetric unit (one site per 20,800 Da). The final model includes 328 of 380 amino acid residues and was refined to an R-factor of 23.5% (R(free)=27.5%) at 2.3A resolution. The X-ray crystal structure of SsuD shows a homotetrameric state for the enzyme, each subunit being composed of a TIM-barrel fold enlarged by four insertion regions that contribute to intersubunit interactions. SsuD is structurally related to a bacterial luciferase and an archaeal coenzyme F(420)-dependent reductase in spite of a low level of sequence identity with these enzymes. The structural relationship is not limited to the beta-barrel region; it includes most but not all extension regions and shows distinct properties for the SsuD TIM-barrel. A likely substrate-binding site is postulated on the basis of the SsuD structure presented here, results from earlier biochemical studies, and structure relatedness to bacterial luciferase. SsuD is related to other FMNH(2)-dependent monooxygenases that show distant sequence relationship to luciferase. Thus, the structure reported here provides a model for enzymes belonging to this family and suggests that they might all fold as TIM-barrel proteins.

Amino Acid Sequence↗
PubMed1992

Liquid chromatographic separation of alkanesulfonate and alkyl sulfate surfactants: effect of ionic strength.

The retention of alkanesulfonate and alkyl sulfate surfactants, which was determined on a reversed stationary phase as a function of mobile-phase ionic strength, is consistent with a double-layer type interaction at the stationary-phase surface. Increasing the mobile-phase ionic strength not only increases retention but also improves resolution because peak widths are significantly reduced. The type of cation provided by the ionic strength salt also enhances retention, reduces peak width, and improves resolution. Lithium hydroxide is an ideal electrolyte for the separation of multicomponent mixtures of alkanesulfonate and alkyl sulfate surfactants. When the column effluent is passed through a postcolumn anion micromembrane suppressor, the conductivity due to the electrolyte is minimized and conductivity detection is sensitive, yielding a detection limit of about 0.3 nmol of injected analyte for a 3:1 signal:noise ratio. Multicomponent alkanesulfonate and alkyl sulfate mixtures from C2 to C18 are baseline resolved by using a mobile-phase gradient whereby CH3CN concentration increases and LiOH concentration decreases.

Chromatography, Liquid↗
PubMed1978

Comparative mutagenicity of alkylsulfate and alkanesulfonate derivatives in Chinese hamster ovary cells.

Mutation induction and cell killing produced by selected alkylsulfates and alkanesulfonates have been quantitated using the Chinese hamster ovary/hypoxanthine--guanine phosphoribosyl transferase (CHO/HGPRT) system. Dose--response relationships of cytotoxicity and mutagenicity are presented for two alkylsulfates [dimethylsulfate (DMS), diethylsulfate (DES)] and three alkyl alkanesulfonates [methyl methanesulfonate (MMS), ethyl methanesulfonate (EMS), and isopropyl methanesulfonate (iPMS)]. Under the experimental conditions employed, cytotoxicity decreased with the size of the alkyl group. DMS was more toxic than DES, and MMS was more toxic than EMS and iPMS. All agents produced linear dose--response of mutation induction: DMS was more mutagenic than DES, and MMS was more mutagenic than EMS and iPMS based on mutants induced per unit mutagen concentration. However, the following relative mutagenic potency was observed when comparisons were made at 10% survival: DES greater than DMS; EMS greater than MMS greater than iPMS.

Cell Line↗
PubMed2005

Smectic liquid crystals from supramolecular guanidinium alkanesulfonates.

The thermotropic polymorphism of a series of guanidinium alkanesulfonates (6 < or = n < or = 18) was investigated by optical microscopy and differential scanning calorimetry. Hydrogen bonding was analyzed by infrared spectroscopy. Molecular volumes were measured by dilatometry. The structure of the crystal, smectic A, and ordered smectic phases observed were studied by X-ray diffraction and utilized to prove that the supramolecular arrangement of the molecules in the crystal survives in the smectic phases at high temperature.

Alkanesulfonates↗
PubMed2005

Crystallization and preliminary X-ray crystallographic studies of the alkanesulfonate FMN reductase from Escherichia coli.

The alkanesulfonate FMN reductase (SsuE) from Escherichia coli catalyzes the reduction of FMN by NADPH to provide reduced flavin for the monooxygenase (SsuD) enzyme. The vapor-diffusion technique yielded single crystals that grow as hexagonal rods and diffract to 2.9 A resolution using synchrotron X-ray radiation. The protein crystallizes in the primitive hexagonal space group P622. The SsuE protein lacks any cysteine or methionine residues owing to the role of the SsuE enzyme in the acquisition of sulfur during sulfate starvation. Therefore, substitution of two leucine residues (Leu114 and Leu165) to methionine was performed to obtain selenomethionine-containing SsuE for MAD phasing. The selenomethionine derivative of SsuE has been expressed and purified and crystals of the protein have been obtained with and without bound FMN. These preliminary studies should lead to the structure solution of SsuE. It is anticipated that this new protein structure will provide detailed structural information on specific active-site regions of the protein and insight into the mechanism of flavin reduction and transfer of reduced flavin.

Alkanesulfonates↗
PubMed1984

Epiandrosterone- and dehydroepiandrosterone-3 beta-alkanesulfonates as inhibitors of mouse glucose-6-phosphate dehydrogenase activity.

3 beta-Alkanesulfonates of dehydroepiandrosterone, 16 alpha-bromodehydroepiandrosterone, epiandrosterone, and 16 alpha-bromoepiandrosterone were prepared in 54-95% yield via the reaction of long chain alkanesulfonyl chlorides with the corresponding dehydroepiandrosterone, and epiandrosterone analogues. These compounds inhibit mouse glucose-6-phosphate dehydrogenase activity.

Androsterone↗
PubMed1999

Desulfonation of propanesulfonic acid by comamonas acidovorans strain P53: evidence for an alkanesulfonate sulfonatase and an atypical sulfite dehydrogenase

Evidence is presented for the presence in propanesulfonate-grown Comamonas acidovorans strain P53 of a cytoplasmically located sulfonatase that does not sediment at 100,000 x g. This enzyme catalysed the sulfonate-dependent oxidation of NADH or NADPH, indicating a monooxygenase that effects the addition of molecular oxygen to C(3)-C(6) 1-alkanesulfonates. Enzyme activity was proportional to protein concentration only above approximately 2 mg cytoplasmic fraction protein ml(-1), suggesting that the sulfonatase is a multicomponent enzyme, possibly comparable with methanesulfonate monooxygenase. Enzyme activity was strongly inhibited by divalent metal-chelating agents, but was insensitive to cyanide and azide. Sulfite released from sulfonates by Comamonas acidovorans was oxidized by an unusual sulfite dehydrogenase. This was purified approximately 230-fold and was shown to have a molecular mass of 74.4 kDa, comprising two or more subunits. The enzyme activity was specific in vitro for ferricyanide as an electron acceptor and, unlike other bacterial sulfite dehydrogenases, did not contain native cytochrome c or reduce added cytochrome c. It was a basic protein, insensitive to chloride and sulfate, and exhibited a K(m) for sulfite of approximately 45 &mgr;M.

Journal Article↗
PubMed2006

Expanding the scope of sulfur-centered Arbuzov rearrangement in diethyl/di-n-propyl sulfite for the synthesis of mixed-ligand di-n-butyltin alkanesulfonates.

A one-pot reaction between di-n-butyltin oxide and diethyl/di-n-propyl sulfite in the presence of an equimolar amount of alkyl iodide proceeds via sulfur-centered Arbuzov rearrangement to afford the corresponding di-n-butyltin (alkoxy)alkanesulfonates n-Bu2Sn(OR')OS(O)2R [R = R' = Et (1), n-Pr (2); R = Me, R' = Et (3), n-Pr (4)]. The compounds 1 and 3 react with methylphosphonic acid under mild conditions to give [n-Bu2Sn(OS(O)2R)OP(O)(OH)Me]n [R = Et (5), Me (6), respectively].

Journal Article↗
PubMed2006

Detection of protein-protein interactions in the alkanesulfonate monooxygenase system from Escherichia coli.

The two-component alkanesulfonate monooxygenase system utilizes reduced flavin as a substrate to catalyze a unique desulfonation reaction during times of sulfur starvation. The importance of protein-protein interactions in the mechanism of flavin transfer was analyzed in these studies. The results from affinity chromatography and cross-linking experiments support the formation of a stable complex between the flavin mononucleotide (FMN) reductase (SsuE) and monooxygenase (SsuD). Interactions between the two proteins do not lead to overall conformational changes in protein structure, as indicated by the results from circular dichroism spectroscopy in the far-UV region. However, subtle changes in the flavin environment of FMN-bound SsuE that occur in the presence of SsuD were identified by circular dichroism spectroscopy in the visible region. These data are supported by the results from fluorescent spectroscopy experiments, where a dissociation constant of 0.0022 +/- 0.0010 muM was obtained for the binding of SsuE to SsuD. Based on these studies, the stoichiometry for protein-protein interactions is proposed to involve a 1:1 monomeric association of SsuE with SsuD.

Escherichia coli↗
PubMed1987

Renal tubular secretion of the alkanesulfonate 2,3-dimercapto-1-propanesulfonate.

The in vivo tubular secretion and metabolism of 2,3-dimercapto-1-propanesulfonate (DMPS) was examined in the chicken by use of the Sperber technique. Infusion of DMPS into the renal portal circulation of the chicken at rates equal to or less than 7.5 mumol X min-1 X kg body wt-1, resulted in a tubular excretion ratio of 0.5 for DMPS with 90% of the infused DMPS excreted in the urine unchanged. Renal tubular secretion accounted for approximately 90% of the total DMPS excreted into the urine during the infusion of DMPS at a rate of 0.75 mumol X min-1 X kg-1. The secretion of DMPS was saturable and was inhibited by p-aminohippurate (PAH), probenecid, and heptanesulfonate. Taurine (2-aminoethanesulfonate), isethionate (2-hydroxyethanesulfonate), and 2-mercaptoethanesulfonate had no effect on the secretion of DMPS or PAH. Renal tubular secretion may explain several pharmacological characteristics previously reported for DMPS, including the selective removal of heavy metals from the kidney.

Alkanesulfonates↗