المؤلفون: Felux AK; Department of Biology, University of Konstanz, Konstanz, Germany., Denger K, Weiss M, Cook AM, Schleheck D

المصدر: Journal of bacteriology [J Bacteriol] 2013 Jun; Vol. 195 (12), pp. 2921-30. Date of Electronic Publication: 2013 Apr 19.

نوع المنشور: Journal Article; Research Support, Non-U.S. Gov't

بيانات الدورية: Publisher: American Society for Microbiology Country of Publication: United States NLM ID: 2985120R Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1098-5530 (Electronic) Linking ISSN: 00219193 NLM ISO Abbreviation: J Bacteriol Subsets: MEDLINE

مواضيع طبية MeSH: Metabolic Networks and Pathways*, Acetaldehyde/*metabolism , Acetates/*metabolism , Paracoccus denitrificans/*growth & development , Paracoccus denitrificans/*metabolism , Taurine/*analogs & derivatives, Escherichia coli/genetics ; Gene Expression ; Models, Biological ; Recombinant Proteins/genetics ; Recombinant Proteins/isolation & purification ; Recombinant Proteins/metabolism ; Taurine/metabolism

مستخلص: Hypotaurine (HT; 2-aminoethane-sulfinate) is known to be utilized by bacteria as a sole source of carbon, nitrogen, and energy for growth, as is taurine (2-aminoethane-sulfonate); however, the corresponding HT degradation pathway has remained undefined. Genome-sequenced Paracoccus denitrificans PD1222 utilized HT (and taurine) quantitatively for heterotrophic growth and released the HT sulfur as sulfite (and sulfate) and HT nitrogen as ammonium. Enzyme assays with cell extracts suggested that an HT-inducible HT:pyruvate aminotransferase (Hpa) catalyzes the deamination of HT in an initial reaction step. Partial purification of the Hpa activity and peptide fingerprinting-mass spectrometry (PF-MS) identified the Hpa candidate gene; it encoded an archetypal taurine:pyruvate aminotransferase (Tpa). The same gene product was identified via differential PAGE and PF-MS, as was the gene of a strongly HT-inducible aldehyde dehydrogenase (Adh). Both genes were overexpressed in Escherichia coli. The overexpressed, purified Hpa/Tpa showed HT:pyruvate-aminotransferase activity. Alanine, acetaldehyde, and sulfite were identified as the reaction products but not sulfinoacetaldehyde; the reaction of Hpa/Tpa with taurine yielded sulfoacetaldehyde, which is stable. The overexpressed, purified Adh oxidized the acetaldehyde generated during the Hpa reaction to acetate in an NAD(+)-dependent reaction. Based on these results, the following degradation pathway for HT in strain PD1222 can be depicted. The identified aminotransferase converts HT to sulfinoacetaldehyde, which desulfinates spontaneously to acetaldehyde and sulfite; the inducible aldehyde dehydrogenase oxidizes acetaldehyde to yield acetate, which is metabolized, and sulfite, which is excreted.

المؤلفون: Krejčík Z; Department of Biology, University of Konstanz, 78457 Constance, Germany., Schleheck D, Hollemeyer K, Cook AM

المصدر: Archives of microbiology [Arch Microbiol] 2012 Oct; Vol. 194 (10), pp. 857-63. Date of Electronic Publication: 2012 May 16.

نوع المنشور: Journal Article; Research Support, Non-U.S. Gov't

بيانات الدورية: Publisher: Springer-Verlag Country of Publication: Germany NLM ID: 0410427 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1432-072X (Electronic) Linking ISSN: 03028933 NLM ISO Abbreviation: Arch Microbiol Subsets: MEDLINE

مواضيع طبية MeSH: Acetaldehyde/*analogs & derivatives , Acinetobacter/*metabolism , Bacterial Proteins/*genetics , Bacterial Proteins/*metabolism , Multigene Family/*genetics , Taurine/*metabolism, Acetaldehyde/metabolism ; Acinetobacter/genetics ; Acinetobacter/growth & development ; Molecular Sequence Data ; Nitrogen/metabolism

مستخلص: Acinetobacter calcoaceticus SW1, under nitrogen limitation, assimilates the nitrogen moiety of taurine (2-aminoethanesulfonate) inducibly and excretes sulfoacetaldehyde, a product of taurine dehydrogenase (TauXY). BLAST searches of newly available genome sequences using the TauXY sequences revealed a 5-gene cluster, tauRXYPI, in Acinetobacter radioresistens SH164. We hypothesized that tauXYPI (HMPREF0018_00717-HMPREF0018_00720) encodes proteins that are orthologs of the undefined pathway from strain SW1, and that tauR (HMPREF0018_00716) encodes the relevant transcriptional regulator. Strain SH164 excreted sulfoacetaldehyde from taurine during growth. TauXY activity was expressed inducibly. Reverse transcription PCR showed that the tauRXYPI genes were transcribed inducibly. This allowed the conclusions that (i) TauP (currently annotated as permease GabP [TC 2.A.3]) is a taurine permease, and (ii) TauI (currently annotated as DUF6 drug/metabolite exporter [TC 2.A.7]) is a sulfoacetaldehyde exporter. The presumably equifunctional cluster tauRXYPI was then found in strain SW1. TauP is the third recognized taurine uptake system, and TauI is the third postulated class of sulfonate exporters, in bacteria.

المؤلفون: Weinitschke S; Department of Biology, The University of Konstanz, D-78457 Konstanz, Germany., Hollemeyer K, Kusian B, Bowien B, Smits TH, Cook AM

المصدر: The Journal of biological chemistry [J Biol Chem] 2010 Nov 12; Vol. 285 (46), pp. 35249-54. Date of Electronic Publication: 2010 Aug 06.

نوع المنشور: Journal Article; Research Support, Non-U.S. Gov't

بيانات الدورية: Publisher: Elsevier Inc. on behalf of American Society for Biochemistry and Molecular Biology Country of Publication: United States NLM ID: 2985121R Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1083-351X (Electronic) Linking ISSN: 00219258 NLM ISO Abbreviation: J Biol Chem Subsets: MEDLINE

مواضيع طبية MeSH: Acetaldehyde/*analogs & derivatives , Acetates/*metabolism , Bacterial Proteins/*metabolism , Cupriavidus necator/*metabolism, Acetaldehyde/chemistry ; Acetaldehyde/metabolism ; Acetates/chemistry ; Acetyl Coenzyme A/metabolism ; Adenosine Monophosphate/chemistry ; Adenosine Monophosphate/metabolism ; Adenosine Triphosphate/chemistry ; Adenosine Triphosphate/metabolism ; Aldehyde Oxidoreductases/genetics ; Aldehyde Oxidoreductases/metabolism ; Bacterial Proteins/genetics ; Coenzyme A Ligases/genetics ; Coenzyme A Ligases/metabolism ; Cupriavidus necator/genetics ; Cupriavidus necator/growth & development ; Electrophoresis, Polyacrylamide Gel ; Gene Expression Regulation, Bacterial ; Membrane Transport Proteins/genetics ; Membrane Transport Proteins/metabolism ; Molecular Structure ; Mutation ; NADP/chemistry ; NADP/metabolism ; Operon ; Reverse Transcriptase Polymerase Chain Reaction ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Sulfates/chemistry ; Sulfates/metabolism ; Transcription Factors/genetics ; Transcription Factors/metabolism

مستخلص: Bacterial degradation of sulfoacetate, a widespread natural product, proceeds via sulfoacetaldehyde and requires a considerable initial energy input. Whereas the fate of sulfoacetaldehyde in Cupriavidus necator (Ralstonia eutropha) H16 is known, the pathway from sulfoacetate to sulfoacetaldehyde is not. The genome sequence of the organism enabled us to hypothesize that the inducible pathway, which initiates sau (sulfoacetate utilization), involved a four-gene cluster (sauRSTU; H16_A2746 to H16_A2749). The sauR gene, divergently orientated to the other three genes, probably encodes the transcriptional regulator of the presumed sauSTU operon, which is subject to inducible transcription. SauU was tentatively identified as a transporter of the major facilitator superfamily, and SauT was deduced to be a sulfoacetate-CoA ligase. SauT was a labile protein, but it could be separated and shown to generate AMP and an unknown, labile CoA-derivative from sulfoacetate, CoA, and ATP. This unknown compound, analyzed by MALDI-TOF-MS, had a relative molecular mass of 889.7, which identified it as protonated sulfoacetyl-CoA (calculated 889.6). SauS was deduced to be sulfoacetaldehyde dehydrogenase (acylating). The enzyme was purified 175-fold to homogeneity and characterized. Peptide mass fingerprinting confirmed the sauS locus (H16_A2747). SauS converted sulfoacetyl-CoA and NADPH to sulfoacetaldehyde, CoA, and NADP(+), thus confirming the hypothesis.

المؤلفون: Denger K; Department of Biology, University of Konstanz, D-78457 Konstanz, Germany., Mayer J, Buhmann M, Weinitschke S, Smits TH, Cook AM

المصدر: Journal of bacteriology [J Bacteriol] 2009 Sep; Vol. 191 (18), pp. 5648-56. Date of Electronic Publication: 2009 Jul 06.

نوع المنشور: Journal Article; Research Support, Non-U.S. Gov't

بيانات الدورية: Publisher: American Society for Microbiology Country of Publication: United States NLM ID: 2985120R Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1098-5530 (Electronic) Linking ISSN: 00219193 NLM ISO Abbreviation: J Bacteriol Subsets: MEDLINE

مواضيع طبية MeSH: Acetaldehyde/*analogs & derivatives , Acetyltransferases/*metabolism , Cysteic Acid/*metabolism , Lactates/*metabolism , Lyases/*metabolism , Rhodobacteraceae/*enzymology , Sulfates/*metabolism, Acetaldehyde/metabolism ; Bacterial Proteins/genetics ; Bacterial Proteins/metabolism ; Culture Media ; Gene Expression Regulation, Bacterial ; Lyases/genetics ; Rhodobacteraceae/genetics ; Rhodobacteraceae/growth & development ; Rhodobacteraceae/metabolism

مستخلص: Data from the genome sequence of the aerobic, marine bacterium Roseovarius nubinhibens ISM were interpreted such that 3-sulfolactate would be degraded as a sole source of carbon and energy for growth via a novel bifurcated pathway including two known desulfonative enzymes, sulfoacetaldehyde acetyltransferase (EC 2.3.3.15) (Xsc) and cysteate sulfo-lyase (EC 4.4.1.25) (CuyA). Strain ISM utilized sulfolactate quantitatively with stoichiometric excretion of the sulfonate sulfur as sulfate. A combination of enzyme assays, analytical chemistry, enzyme purification, peptide mass fingerprinting, and reverse transcription-PCR data supported the presence of an inducible, tripartite sulfolactate uptake system (SlcHFG), and a membrane-bound sulfolactate dehydrogenase (SlcD) which generated 3-sulfopyruvate, the point of bifurcation. 3-Sulfopyruvate was in part decarboxylated by 3-sulfopyruvate decarboxylase (EC 4.1.1.79) (ComDE), which was purified. The sulfoacetaldehyde that was formed was desulfonated by Xsc, which was identified, and the acetyl phosphate was converted to acetyl-coenzyme A by phosphate acetyltransferase (Pta). The other portion of the 3-sulfopyruvate was transaminated to (S)-cysteate, which was desulfonated by CuyA, which was identified. The sulfite that was formed was presumably exported by CuyZ (TC 9.B.7.1.1 in the transport classification system), and a periplasmic sulfite dehydrogenase is presumed. Bioinformatic analyses indicated that transporter SlcHFG is rare but that SlcD is involved in three different combinations of pathways, the bifurcated pathway shown here, via CuyA alone, and via Xsc alone. This novel pathway involves ComDE in biodegradation, whereas it was discovered in the biosynthesis of coenzyme M. The different pathways of desulfonation of sulfolactate presumably represent final steps in the biodegradation of sulfoquinovose (and exudates derived from it) in marine and aquatic environments.

المؤلفون: Krejcík Z; Department of Biology, The University, 78457, Constance, Germany., Denger K, Weinitschke S, Hollemeyer K, Paces V, Cook AM, Smits TH

المصدر: Archives of microbiology [Arch Microbiol] 2008 Aug; Vol. 190 (2), pp. 159-68. Date of Electronic Publication: 2008 May 28.

نوع المنشور: Journal Article; Research Support, Non-U.S. Gov't

بيانات الدورية: Publisher: Springer-Verlag Country of Publication: Germany NLM ID: 0410427 Publication Model: Print-Electronic Cited Medium: Print ISSN: 0302-8933 (Print) Linking ISSN: 03028933 NLM ISO Abbreviation: Arch Microbiol Subsets: MEDLINE

مواضيع طبية MeSH: Acetaldehyde/*analogs & derivatives , Bacterial Proteins/*isolation & purification , Nitrogen/*metabolism , Oceanospirillaceae/*enzymology , Oxidoreductases/*isolation & purification , Oxidoreductases/*metabolism , Taurine/*metabolism, Acetaldehyde/metabolism ; Bacterial Proteins/chemistry ; Bacterial Proteins/genetics ; Bacterial Proteins/metabolism ; Gene Expression Regulation, Bacterial ; Molecular Sequence Data ; Molecular Weight ; Oceanospirillaceae/genetics ; Oceanospirillaceae/growth & development ; Oceanospirillaceae/metabolism ; Oxidoreductases/chemistry ; Oxidoreductases/genetics ; Taurine/analogs & derivatives ; Transcription, Genetic

مستخلص: Taurine (2-aminoethanesulfonate) is a widespread natural product whose nitrogen moiety was recently shown to be assimilated by bacteria, usually with excretion of an organosulfonate via undefined novel pathways; other data involve transcriptional regulator TauR in taurine metabolism. A screen of genome sequences for TauR with the BLAST algorithm allowed the hypothesis that the marine gammaproteobacterium Neptuniibacter caesariensis MED92 would inducibly assimilate taurine-nitrogen and excrete sulfoacetate. The pathway involved an ABC transporter (TauABC), taurine:pyruvate aminotransferase (Tpa), a novel sulfoacetaldehyde dehydrogenase (SafD) and exporter(s) of sulfoacetate (SafE) (DUF81). Ten candidate genes in two clusters involved three sets of paralogues (for TauR, Tpa and SafE). Inducible Tpa and SafD were detected in cell extracts. SafD was purified 600-fold to homogeneity in two steps. The monomer had a molecular mass of 50 kDa (SDS-PAGE); data from gel filtration chromatography indicated a tetrameric native protein. SafD was specific for sulfoacetaldehyde with a K (m)-value of 0.12 mM. The N-terminal amino acid sequence of SafD confirmed the identity of the safD gene. The eight pathway genes were transcribed inducibly, which indicated expression of the whole hypothetical pathway. We presume that this pathway is one source of sulfoacetate in nature, where this compound is dissimilated by many bacteria.

المؤلفون: Weinitschke S; Department of Biology, The University, D-78457 Konstanz, Germany., von Rekowski KS; Department of Biology, The University, D-78457 Konstanz, Germany., Denger K; Department of Biology, The University, D-78457 Konstanz, Germany., Cook AM; Department of Biology, The University, D-78457 Konstanz, Germany.

المصدر: Microbiology (Reading, England) [Microbiology (Reading)] 2005 Apr; Vol. 151 (Pt 4), pp. 1285-1290.

نوع المنشور: Journal Article; Research Support, Non-U.S. Gov't

بيانات الدورية: Publisher: Microbiology Society Country of Publication: England NLM ID: 9430468 Publication Model: Print Cited Medium: Print ISSN: 1350-0872 (Print) Linking ISSN: 13500872 NLM ISO Abbreviation: Microbiology (Reading) Subsets: MEDLINE

مواضيع طبية MeSH: Acetaldehyde/*analogs & derivatives , Acetaldehyde/*metabolism , Acinetobacter calcoaceticus/*metabolism , Taurine/*metabolism, Acetaldehyde/analysis ; Acinetobacter calcoaceticus/genetics ; Acinetobacter calcoaceticus/growth & development ; Molecular Sequence Data ; Oxidoreductases Acting on CH-NH Group Donors/metabolism ; RNA, Bacterial/genetics ; RNA, Ribosomal, 16S/genetics ; Rhodopseudomonas/metabolism ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

مستخلص: Eighteen enrichment cultures with taurine (2-aminoethanesulfonate) as the sole source of combined nitrogen under aerobic conditions were all successful, and 24 pure cultures were obtained. Only three of the cultures yielded an inorganic product, sulfate, from the sulfonate moiety of taurine, and the others were presumed to yield organosulfonates. Sulfoacetate, known from Rhodopseudomonas palustris CGA009 under these conditions, was not detected in any culture, but sulfoacetaldehyde (as a hydrazone derivative) was tentatively detected in the outgrown medium of nine isolates. The compound was stable under these conditions and the identification was confirmed by MALDI-TOF-MS. Most sulfoacetaldehyde-releasing isolates were determined to be strains of Acinetobacter calcoaceticus, and a representative organism, strain SW1, was chosen for further work. A quantitative enzymic determination of sulfoacetaldehyde and its bisulfite addition complex was developed: it involved the NAD-coupled sulfoacetaldehyde dehydrogenase from R. palustris. A. calcoaceticus SW1 utilized taurine quantitatively and concomitantly with growth in, for example, an adipate-salts medium, and the release of sulfoacetaldehyde was stoichiometric. The deamination reaction involved a taurine dehydrogenase. Enrichment cultures to explore the possible release of organophosphonates from the analogous substrate, 2-aminoethanephosphonate, led to 33 isolates, all of which released inorganic phosphate quantitatively.

المؤلفون: Denger K; Fachbereich Biologie der Universität Konstanz, 78457 Konstanz, Germany., Weinitschke S, Hollemeyer K, Cook AM

المصدر: Archives of microbiology [Arch Microbiol] 2004 Oct; Vol. 182 (2-3), pp. 254-8. Date of Electronic Publication: 2004 Aug 31.

نوع المنشور: Journal Article; Research Support, Non-U.S. Gov't

بيانات الدورية: Publisher: Springer-Verlag Country of Publication: Germany NLM ID: 0410427 Publication Model: Print-Electronic Cited Medium: Print ISSN: 0302-8933 (Print) Linking ISSN: 03028933 NLM ISO Abbreviation: Arch Microbiol Subsets: MEDLINE

مواضيع طبية MeSH: Acetaldehyde/*analogs & derivatives , Acetates/*metabolism , Rhodopseudomonas/*metabolism , Taurine/*metabolism, Acetaldehyde/metabolism ; Acetates/analysis ; Aldehyde Oxidoreductases/metabolism ; Betaine-Aldehyde Dehydrogenase ; Sulfates/metabolism

مستخلص: Genes thought to encode (a) the regulator of taurine catabolism under carbon-limiting or nitrogen-limiting conditions and (b) taurine dehydrogenase were found in the genome of Rhodopseudomonas palustris. The organism utilized taurine quantitatively as a sole source of nitrogen (but not of carbon) for aerobic and photoheterotrophic growth. No sulfate was released, and the C-sulfonate bond was recovered stoichiometrically as sulfoacetate, which was identified by mass spectrometry. An inducible sulfoacetaldehyde dehydrogenase was detected. R. palustris thus contains a pathway to generate a natural product that was previously believed to be formed solely from sulfoquinovose.

المؤلفون: Denger K; Department of Biological Sciences, The University, D-78457 Konstanz, Germany., Ruff J; Department of Biological Sciences, The University, D-78457 Konstanz, Germany., Schleheck D; Department of Biological Sciences, The University, D-78457 Konstanz, Germany., Cook AM; Department of Biological Sciences, The University, D-78457 Konstanz, Germany.

المصدر: Microbiology (Reading, England) [Microbiology (Reading)] 2004 Jun; Vol. 150 (Pt 6), pp. 1859-1867.

نوع المنشور: Journal Article; Research Support, Non-U.S. Gov't

بيانات الدورية: Publisher: Microbiology Society Country of Publication: England NLM ID: 9430468 Publication Model: Print Cited Medium: Print ISSN: 1350-0872 (Print) Linking ISSN: 13500872 NLM ISO Abbreviation: Microbiology (Reading) Subsets: MEDLINE

مواضيع طبية MeSH: Acetaldehyde/*analogs & derivatives , Acetaldehyde/*metabolism , Acetyltransferases/*genetics , Carbon/*metabolism , Nitrogen/*metabolism , Rhodococcus/*enzymology , Sulfur/*metabolism , Taurine/*metabolism, Acetyltransferases/metabolism ; Bacterial Proteins/genetics ; Bacterial Proteins/metabolism ; Gene Expression Regulation, Bacterial ; Molecular Sequence Data ; Rhodococcus/genetics ; Rhodococcus/growth & development ; Sequence Analysis, DNA

مستخلص: The Gram-positive bacteria Rhodococcus opacus ISO-5 and Rhodococcus sp. RHA1 utilized taurine (2-aminoethanesulfonate) as the sole source of carbon or of nitrogen or of sulfur for growth. Different gene clusters and enzymes were active under these different metabolic situations. Under carbon- or nitrogen-limited conditions three enzymes were induced, though to different levels: taurine-pyruvate aminotransferase (Tpa), alanine dehydrogenase (Ald) and sulfoacetaldehyde acetyltransferase (Xsc). The specific activities of these enzymes in R. opacus ISO-5 were sufficient to explain the growth rates under the different conditions. These three enzymes were purified and characterized, and the nature of each reaction was confirmed. Analyses of the genome of Rhodococcus sp. RHA1 revealed a gene cluster, tauR-ald-tpa, putatively encoding regulation and oxidation of taurine, located 20 kbp from the xsc gene and separate from two candidate phosphotransacetylase (pta) genes, as well as many candidate ABC transporters (tauBC). PCR primers allowed the amplification and sequencing of the tauR-ald-tpa gene cluster and the xsc gene in R. opacus ISO-5. The N-terminal sequences of the three tested proteins matched the derived amino acid sequences of the corresponding genes. The sequences of the four genes found in each Rhodococcus strain shared high degrees of identity (>95 % identical positions). RT-PCR studies proved transcription of the xsc gene when taurine was the source of carbon or of nitrogen. Under sulfur-limited conditions no xsc mRNA was generated and no Xsc was detected. Taurine dioxygenase (TauD), the enzyme catalysing the anticipated desulfonative reaction when taurine sulfur is assimilated, was presumed to be present because oxygen-dependent taurine disappearance was demonstrated with taurine-grown cells only. A putative tauD gene (with three other candidates) was detected in strain ISO-5. Regulation of the different forms of metabolism of taurine remains to be elucidated.

المؤلفون: Brüggemann C; Department of Biology, The University, D-78457 Konstanz, Germany., Denger K; Department of Biology, The University, D-78457 Konstanz, Germany., Cook AM; Department of Biology, The University, D-78457 Konstanz, Germany., Ruff J; Department of Biology, The University, D-78457 Konstanz, Germany.

المصدر: Microbiology (Reading, England) [Microbiology (Reading)] 2004 Apr; Vol. 150 (Pt 4), pp. 805-816.

نوع المنشور: Journal Article; Research Support, Non-U.S. Gov't

بيانات الدورية: Publisher: Microbiology Society Country of Publication: England NLM ID: 9430468 Publication Model: Print Cited Medium: Print ISSN: 1350-0872 (Print) Linking ISSN: 13500872 NLM ISO Abbreviation: Microbiology (Reading) Subsets: MEDLINE

مواضيع طبية MeSH: Multigene Family*, Acetaldehyde/*analogs & derivatives , Bacterial Proteins/*genetics , Isethionic Acid/*metabolism , Paracoccus denitrificans/*enzymology , Taurine/*metabolism, Acetaldehyde/metabolism ; Acetyltransferases/genetics ; Acetyltransferases/metabolism ; Bacterial Proteins/metabolism ; Molecular Sequence Data ; Oxidoreductases/genetics ; Oxidoreductases/metabolism ; Oxidoreductases Acting on CH-NH Group Donors/genetics ; Oxidoreductases Acting on CH-NH Group Donors/metabolism ; Paracoccus denitrificans/genetics ; Paracoccus denitrificans/growth & development ; Phosphate Acetyltransferase/genetics ; Phosphate Acetyltransferase/metabolism ; Rhodobacteraceae/enzymology ; Rhodobacteraceae/genetics ; Sequence Analysis, DNA

مستخلص: Growth of the alpha-proteobacterium Paracoccus denitrificans NKNIS with taurine or isethionate as sole source of carbon involves sulfoacetaldehyde acetyltransferase (Xsc), which is presumably encoded by an xsc gene in subgroup 3, none of whose gene products has been characterized. The genome of the alpha-proteobacterium Rhodobacter sphaeroides 2.4.1 was interpreted to contain a nine-gene cluster encoding the inducible dissimilation of taurine, and this deduced pathway included a regulator, a tripartite ATP-independent transporter, taurine dehydrogenase (TDH; presumably TauXY) as well as Xsc (subgroup 3), a hypothetical protein and phosphate acetyltransferase (Pta). A similar cluster was found in P. denitrificans NKNIS, in contrast to an analogous cluster encoding an ATP-binding cassette transporter in Paracoccus pantotrophus. Inducible TDH, Xsc and Pta were found in extracts of taurine-grown cells of strain NKNIS. TDH oxidized taurine to sulfoacetaldehyde and ammonium ion with cytochrome c as electron acceptor. Whereas Xsc and Pta were soluble enzymes, TDH was located in the particulate fraction, where inducible proteins with the expected masses of TauXY (14 and 50 kDa, respectively) were detected by SDS-PAGE. Xsc and Pta were separated by anion-exchange chromatography. Xsc was effectively pure; the molecular mass of the subunit (64 kDa) and the N-terminal amino acid sequence confirmed the identification of the xsc gene. Inducible isethionate dehydrogenase (IDH), Xsc and Pta were assayed in extracts of isethionate-grown cells of strain NKNIS. IDH was located in the particulate fraction, oxidized isethionate to sulfoacetaldehyde with cytochrome c as electron acceptor and correlated with the expression of a 62 kDa protein. Strain NKNIS excreted sulfite and sulfate during growth with a sulfonate and no sulfite dehydrogenase was detected. There is considerable biochemical, genetic and regulatory complexity in the degradation of these simple molecules.

المؤلفون: Ruff J; Department of Biology, University of Konstanz, D-78457 Konstanz, Germany., Denger K, Cook AM

المصدر: The Biochemical journal [Biochem J] 2003 Jan 15; Vol. 369 (Pt 2), pp. 275-85.

نوع المنشور: Journal Article; Research Support, Non-U.S. Gov't

بيانات الدورية: Publisher: Published by Portland Press on behalf of the Biochemical Society Country of Publication: England NLM ID: 2984726R Publication Model: Print Cited Medium: Print ISSN: 0264-6021 (Print) Linking ISSN: 02646021 NLM ISO Abbreviation: Biochem J Subsets: MEDLINE

مواضيع طبية MeSH: Alcaligenes*/enzymology , Alcaligenes*/genetics , Genes, Bacterial*, Acetaldehyde/*analogs & derivatives , Acetaldehyde/*metabolism , Acetyltransferases/*isolation & purification , Organophosphates/*metabolism , Taurine/*metabolism, Acetyltransferases/chemistry ; Acetyltransferases/genetics ; Acetyltransferases/metabolism ; Amino Acid Sequence ; Binding Sites ; Cell-Free System ; Molecular Sequence Data ; Molecular Structure ; Multigene Family ; Sequence Alignment

مستخلص: The facultatively anaerobic bacterium Alcaligenes defragrans NKNTAU was found to oxidize taurine (2-aminoethanesulphonate) with nitrate as the terminal electron acceptor. Taurine was transaminated to 2-sulphoacetaldehyde. This was not converted into sulphite and acetate by a "sulphoacetaldehyde sulpho-lyase" (EC 4.4.1.12), but into sulphite and acetyl phosphate, which was identified by three methods. The enzyme, which required the addition of phosphate, thiamin diphosphate and Mg(2+) ions for activity, was renamed sulphoacetaldehyde acetyltransferase (Xsc; EC 2.3.1.-). Inducible Xsc was expressed at high levels, and a three-step 11-fold purification yielded an essentially homogeneous soluble protein, which was a homotetramer in its native form; the molecular mass of the subunit was found to be between about 63 kDa (SDS/PAGE) and 65.3 kDa (matrix-assisted laser-desorption ionization-time-of-flight MS). The N-terminal and two internal amino acid sequences were determined, and PCR primers were generated. The xsc gene was amplified and sequenced; the derived molecular mass of the processed protein was 65.0 kDa. The downstream gene presumably encoded the inducible phosphate acetyltransferase (Pta) found in crude extracts. The desulphonative enzymes ("EC 4.4.1.12") from Achromobacter xylosoxidans NCIMB 10751 and Desulfonispora thiosulfatigenes GKNTAU were shown to be Xscs. We detected at least three subclasses of xsc in Proteobacteria and in Gram-positive bacteria, and they comprised a distinct group within the acetohydroxyacid synthase supergene family. Genome sequencing data revealed xsc genes in Burkholderia fungorum (80% sequence identity) and Sinorhizobium meliloti (61%) with closely linked pta genes. Different patterns of regulation for the transport and dissimilation of taurine were hypothesized for S. meliloti and B. fungorum.