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Naraki S, Igimi S, Sasaki Y. NADH peroxidase plays a crucial role in consuming H 2O 2 in Lactobacillus casei IGM394. BIOSCIENCE OF MICROBIOTA, FOOD AND HEALTH 2020; 39:45-56. [PMID: 32328400 PMCID: PMC7162690 DOI: 10.12938/bmfh.19-027] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 12/05/2019] [Indexed: 12/17/2022]
Abstract
The facultative anaerobic bacterium Lactobacillus casei IGM394 is used as a host for drug delivery systems, and it exhibits the same growth rate under aerobic and anaerobic
conditions. L. casei strains carry several genes that facilitate oxygen and reactive oxygen species (ROS) tolerance in their genomes, but their complete functions have not
been uncovered. To clarify the oxygen and ROS tolerance mechanisms of L. casei IGM394, we constructed 23 deficient mutants targeting genes that confer oxidative stress
resistance. Significantly decreased growth and high H2O2 accumulation were observed in the NADH peroxidase gene-mutated strain (Δnpr) compared with the
findings in the wild type. The H2O2 degradation capacity of Δnpr revealed that NADH peroxidase is a major H2O2-degrading enzyme
in L. casei IGM394. Interestingly, ΔohrR, a mutant deficient in the organic hydroperoxide (OhrA) repressor, exhibited higher H2O2
resistance than the wild-type strain. Increased Npr expression and H2O2 degradation ability were observed in ΔohrR, further supporting the importance
of OhrA to ROS tolerance mechanisms. The other mutants did not exhibit altered growth rates, although some mutants had higher growth in the presence of oxygen. From these results, it is
presumed that L. casei IGM394 has multiple oxygen tolerance mechanisms and that the loss of a single gene does not alter the growth rate because of the presence of
complementary mechanisms. Contrarily, the H2O2 tolerance mechanism is solely dependent on NADH peroxidase in L. casei IGM394.
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Affiliation(s)
- Shingo Naraki
- Agricultural Chemistry, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
| | - Shizunobu Igimi
- Agricultural Chemistry, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | - Yasuko Sasaki
- Agricultural Chemistry, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
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Barth C, Weiss MC, Roettger M, Martin WF, Unden G. Origin and phylogenetic relationships of [4Fe-4S]-containing O 2 sensors of bacteria. Environ Microbiol 2018; 20:4567-4586. [PMID: 30225854 DOI: 10.1111/1462-2920.14411] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 09/10/2018] [Indexed: 11/28/2022]
Abstract
The advent of environmental O2 about 2.5 billion years ago forced microbes to metabolically adapt and to develop mechanisms for O2 sensing. Sensing of O2 by [4Fe-4S]2+ to [2Fe-2S]2+ cluster conversion represents an ancient mechanism that is used by FNREc (Escherichia coli), FNRBs (Bacillus subtilis), NreBSa (Staphylococcus aureus) and WhiB3Mt (Mycobacterium tuberculosis). The phylogenetic relationship of these sensors was investigated. FNREc homologues are restricted to the proteobacteria and a few representatives from other phyla. Homologues of FNRBs and NreBSa are located within the bacilli, of WhiB3 within the actinobacteria. Archaea contain no homologues. The data reveal no similarity between the FNREc , FNRBs , NreBSa and WhiB3 sensor families on the sequence and structural levels. These O2 sensor families arose independently in phyla that were already present at the time O2 appeared, their members were subsequently distributed by lateral gene transfer. The chemistry of [4Fe-4S] and [2Fe-2S] cluster formation and interconversion appears to be shared by the sensor protein families. The type of signal output is, however, family specific. The homologues of FNREc and NreBSa vary with regard to the number of Cys residues that coordinate the cluster. It is suggested that the variants derive from lateral gene transfer and gained other functions.
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Affiliation(s)
- C Barth
- Microbiology and Wine Research, Institute for Molecular Physiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - M C Weiss
- Institute for Molecular Evolution, Heinrich Heine University of Düsseldorf, Düsseldorf, Germany
| | - M Roettger
- Institute for Molecular Evolution, Heinrich Heine University of Düsseldorf, Düsseldorf, Germany
| | - W F Martin
- Institute for Molecular Evolution, Heinrich Heine University of Düsseldorf, Düsseldorf, Germany
| | - G Unden
- Microbiology and Wine Research, Institute for Molecular Physiology, Johannes Gutenberg University Mainz, Mainz, Germany
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High-Resolution X-Ray Structures of Two Functionally Distinct Members of the Cyclic Amide Hydrolase Family of Toblerone Fold Enzymes. Appl Environ Microbiol 2017; 83:AEM.03365-16. [PMID: 28235873 DOI: 10.1128/aem.03365-16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 02/15/2017] [Indexed: 01/28/2023] Open
Abstract
The Toblerone fold was discovered recently when the first structure of the cyclic amide hydrolase, AtzD (a cyanuric acid hydrolase), was elucidated. We surveyed the cyclic amide hydrolase family, finding a strong correlation between phylogenetic distribution and specificity for either cyanuric acid or barbituric acid. One of six classes (IV) could not be tested due to a lack of expression of the proteins from it, and another class (V) had neither cyanuric acid nor barbituric acid hydrolase activity. High-resolution X-ray structures were obtained for a class VI barbituric acid hydrolase (1.7 Å) from a Rhodococcus species and a class V cyclic amide hydrolase (2.4 Å) from a Frankia species for which we were unable to identify a substrate. Both structures were homologous with the tetrameric Toblerone fold enzyme AtzD, demonstrating a high degree of structural conservation within the cyclic amide hydrolase family. The barbituric acid hydrolase structure did not contain zinc, in contrast with early reports of zinc-dependent activity for this enzyme. Instead, each barbituric acid hydrolase monomer contained either Na+ or Mg2+, analogous to the structural metal found in cyanuric acid hydrolase. The Frankia cyclic amide hydrolase contained no metal but instead formed unusual, reversible, intermolecular vicinal disulfide bonds that contributed to the thermal stability of the protein. The active sites were largely conserved between the three enzymes, differing at six positions, which likely determine substrate specificity.IMPORTANCE The Toblerone fold enzymes catalyze an unusual ring-opening hydrolysis with cyclic amide substrates. A survey of these enzymes shows that there is a good correlation between physiological function and phylogenetic distribution within this family of enzymes and provide insights into the evolutionary relationships between the cyanuric acid and barbituric acid hydrolases. This family of enzymes is structurally and mechanistically distinct from other enzyme families; however, to date the structure of just two, physiologically identical, enzymes from this family has been described. We present two new structures: a barbituric acid hydrolase and an enzyme of unknown function. These structures confirm that members of the CyAH family have the unusual Toblerone fold, albeit with some significant differences.
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FlpS, the FNR-Like Protein of Streptococcus suis Is an Essential, Oxygen-Sensing Activator of the Arginine Deiminase System. Pathogens 2016; 5:pathogens5030051. [PMID: 27455333 PMCID: PMC5039431 DOI: 10.3390/pathogens5030051] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 07/07/2016] [Accepted: 07/14/2016] [Indexed: 11/17/2022] Open
Abstract
Streptococcus (S.) suis is a zoonotic pathogen causing septicemia and meningitis in pigs and humans. During infection S. suis must metabolically adapt to extremely diverse environments of the host. CcpA and the FNR family of bacterial transcriptional regulators are important for metabolic gene regulation in various bacteria. The role of CcpA in S. suis is well defined, but the function of the FNR-like protein of S. suis, FlpS, is yet unknown. Transcriptome analyses of wild-type S. suis and a flpS mutant strain suggested that FlpS is involved in the regulation of the central carbon, arginine degradation and nucleotide metabolism. However, isotopologue profiling revealed no substantial changes in the core carbon and amino acid de novo biosynthesis. FlpS was essential for the induction of the arcABC operon of the arginine degrading pathway under aerobic and anaerobic conditions. The arcABC-inducing activity of FlpS could be associated with the level of free oxygen in the culture medium. FlpS was necessary for arcABC-dependent intracellular bacterial survival but redundant in a mice infection model. Based on these results, we propose that the core function of S. suis FlpS is the oxygen-dependent activation of the arginine deiminase system.
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Akyol I. Proteomics analysis of the Flp regulon in Lactococcus lactis subsp. cremoris. Electrophoresis 2013; 34:2218-28. [PMID: 23712609 DOI: 10.1002/elps.201300002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 03/30/2013] [Accepted: 04/03/2013] [Indexed: 11/09/2022]
Abstract
Lactococcus lactis subsp. cremoris MG1363 genome sequence was completed and encodes two flp genes flpA and flpB. Research carried out has suggested that the flpB proteins are transcriptional regulators that respond to the environmental oxygen level. A variety of flp deletion mutant strains with single and double mutation were created. Wild-type (MG1363) and its flp(-) derivatives were compared by 2DE to identify changes in protein intensity under different aerobic/anaerobic growth conditions. In total, 416 ± 20 and 444 ± 32 protein spots were quantified from anaerobic and aerobic cells, respectively, on pH 4-7 gels. Forty-five protein spots that changed were excised from 2DE gel, digested with trypsin and identified from their MALDI-TOF MS Peptide Mass Fingerprint. A variety of proteins were affected by the flp mutations and oxygen level. Some proteins were controlled by FlpA and FlpB independently and some required both FlpA and B for regulation. The identified proteins that are regulated by the Flp proteins can be grouped by biochemical function. These groups are oxidative stress, electron transfer, sugars, cell wall, ABC transporters, arginine metabolism, and pyrimidine biosynthesis pathway.
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Affiliation(s)
- Ismail Akyol
- Department of Agricultural Biotechnology, Faculty of Agriculture, Kahramanmaras Sutcu Imam University, Kahramanmaras, Turkey.
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de Jong A, Hansen ME, Kuipers OP, Kilstrup M, Kok J. The transcriptional and gene regulatory network of Lactococcus lactis MG1363 during growth in milk. PLoS One 2013; 8:e53085. [PMID: 23349698 PMCID: PMC3547956 DOI: 10.1371/journal.pone.0053085] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 11/27/2012] [Indexed: 11/18/2022] Open
Abstract
In the present study we examine the changes in the expression of genes of Lactococcus lactis subspecies cremoris MG1363 during growth in milk. To reveal which specific classes of genes (pathways, operons, regulons, COGs) are important, we performed a transcriptome time series experiment. Global analysis of gene expression over time showed that L. lactis adapted quickly to the environmental changes. Using upstream sequences of genes with correlated gene expression profiles, we uncovered a substantial number of putative DNA binding motifs that may be relevant for L. lactis fermentative growth in milk. All available novel and literature-derived data were integrated into network reconstruction building blocks, which were used to reconstruct and visualize the L. lactis gene regulatory network. This network enables easy mining in the chrono-transcriptomics data. A freely available website at http://milkts.molgenrug.nl gives full access to all transcriptome data, to the reconstructed network and to the individual network building blocks.
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Affiliation(s)
- Anne de Jong
- Department of Molecular Genetics, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Groningen, The Netherlands
| | - Morten E. Hansen
- Center for Systems Microbiology, Institute of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - Oscar P. Kuipers
- Department of Molecular Genetics, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Groningen, The Netherlands
| | - Mogens Kilstrup
- Center for Systems Microbiology, Institute of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - Jan Kok
- Department of Molecular Genetics, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Groningen, The Netherlands
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7
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Unden G, Nilkens S, Singenstreu M. Bacterial sensor kinases using Fe-S cluster binding PAS or GAF domains for O2 sensing. Dalton Trans 2012; 42:3082-7. [PMID: 23138661 DOI: 10.1039/c2dt32089d] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
[4Fe-4S](2+) clusters are used by very diverse types of bacterial sensors for response to oxygen, including DNA-binding proteins of the CRP/FNR family and sensor kinases like NreB. In NreB the cluster is bound by an input domain of the PAS type. The [4Fe-4S](2+) cluster of NreB responds to O(2) by degradation to a [2Fe-2S](2+) cluster which is labile and decomposes. NreB constitutes together with AirS the NreB/AirS family of bacterial sensor kinases that contain PAS or GAF domains for binding of [4Fe-4S](2+) or [2Fe-2S](2+) clusters and oxygen sensing. The NreB/AirS family is related to the FixL sensor kinases that use hemeB binding PAS domains for oxygen sensing.
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Affiliation(s)
- Gottfried Unden
- Institute for Microbiology and Wine Research, University of Mainz, Mainz, Germany.
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Michelon D, Abraham S, Ebel B, De Coninck J, Husson F, Feron G, Gervais P, Cachon R. Contribution of exofacial thiol groups in the reducing activity of Lactococcus lactis. FEBS J 2010; 277:2282-90. [PMID: 20423456 DOI: 10.1111/j.1742-4658.2010.07644.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lactococcus lactis can decrease the redox potential at pH 7 (E(h7)) from 200 to -200 mV in oxygen free Man-Rogosa-Sharpe media. Neither the consumption of oxidizing compounds or the release of reducing compounds during lactic acid fermentation were involved in the decrease in E(h7) by the bacteria. Thiol groups located on the bacterial cell surface appear to be the main components that are able to establish a greater exchange current between the Pt electrode and the bacteria. After the final E(h7) (-200 mV) was reached, only thiol-reactive reagents could restore the initial E(h7) value. Inhibition of the proton motive force showed no effect on maintaining the final E(h7) value. These results suggest that maintaining the exofacial thiol (-SH) groups in a reduced state does not depend on an active mechanism. Thiol groups appear to be displayed by membrane proteins or cell wall-bound proteins and may participate in protecting cells against oxidative stress.
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Affiliation(s)
- D Michelon
- Laboratoire de Génie des Procédés Microbiologiques et Alimentaires, AgroSup Dijon, Université de Bourgogne, Dijon, France
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9
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Mesa S, Reutimann L, Fischer HM, Hennecke H. Posttranslational control of transcription factor FixK2, a key regulator for the Bradyrhizobium japonicum-soybean symbiosis. Proc Natl Acad Sci U S A 2009; 106:21860-5. [PMID: 19955406 PMCID: PMC2799828 DOI: 10.1073/pnas.0908097106] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2009] [Indexed: 12/23/2022] Open
Abstract
Rhizobial FixK-like proteins play essential roles in activating genes for endosymbiotic life in legume root nodules, such as genes for micro-oxic respiration. In the facultative soybean symbiont, Bradyrhizobium japonicum, the FixK(2) protein is the key player in a complex regulatory network. The fixK(2) gene itself is activated by the 2-component regulatory system FixLJ in response to a moderate decrease of the oxygen tension, and the FixK(2) protein distributes and amplifies this response to the level of approximately 200 target genes. Unlike other members of the cAMP receptor protein family, to which FixK(2) belongs, the FixK(2) protein does not appear to be modulated by small effector molecules. Here, we show that a critical, single cysteine residue (C183) near the DNA-binding domain of FixK(2) confers sensitivity to oxidizing agents and reactive oxygen species. Oxidation-dependent inactivation occurs not only in vitro, as shown with cell-free transcription assays, but also in vivo, as shown by microarray-assisted transcriptome analysis of the FixK(2) regulon. The oxidation mechanism may involve a reversible dimerization by intermolecular disulfide-bridge formation and a direct, irreversible oxidation at the cysteine thiol, depending on the oxidizing agent. Mutational exchange of C183 to alanine renders FixK(2) resistant to oxidation, yet allows full activity, shown again both in vitro and in vivo. We hypothesize that posttranslational modification by reactive oxygen species is a means to counterbalance the cellular pool of active FixK(2), which would otherwise fill unrestrictedly through FixLJ-dependent synthesis.
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Affiliation(s)
- Socorro Mesa
- ETH, Institute of Microbiology, CH-8093 Zürich, Switzerland
| | | | | | - Hauke Hennecke
- ETH, Institute of Microbiology, CH-8093 Zürich, Switzerland
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Müllner M, Hammel O, Mienert B, Schlag S, Bill E, Unden G. A PAS domain with an oxygen labile [4Fe-4S](2+) cluster in the oxygen sensor kinase NreB of Staphylococcus carnosus. Biochemistry 2009; 47:13921-32. [PMID: 19102705 DOI: 10.1021/bi8014086] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The cytoplasmic histidine sensor kinase NreB of Staphylococcus carnosus responds to O(2) and controls together with the response regulator NreC the expression of genes of nitrate/nitrite respiration. nreBC homologous genes were found in Staphylococcus strains and Bacillus clausii, and a modified form was found in some Lactobacillus strains. NreB contains a sensory domain with similarity to heme B binding PAS domains. Anaerobically prepared NreB of S. carnosus exhibited a (diamagnetic) [4Fe-4S](2+) cluster when assessed by Mossbauer spectroscopy. Upon reaction with air, the cluster was degraded with a half-life of approximately 2.5 min. No significant amounts of Mossbauer or EPR detectable intermediates were found during the decay, but magnetic Mossbauer spectra revealed formation of diamagnetic [2Fe-2S](2+) clusters. After extended exposure to air, NreB was devoid of a FeS cluster. Photoreduction with deazaflavin produced small amounts of [4Fe-4S](+), which were degraded subsequently. The magnetically perturbed Mossbauer spectrum of the [4Fe-4S](2+) cluster corroborated the S = 0 spin state and revealed uniform electric field gradient tensors of the iron sites, suggesting full delocalization of the valence electrons and binding of each of the Fe ions by four S ligands, including the ligand to the protein. Mutation of each of the four Cys residues inactivated NreB function in vivo in accordance with their role as ligands. [4Fe-4S](2+) cluster-containing NreB had high kinase activity. Exposure to air decreased the kinase activity and content of the [4Fe-4S](2+) cluster with similar half-lives. We conclude that the sensory domain of NreB represents a new type of PAS domain containing a [4Fe-4S](2+) cluster for sensing and function.
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Affiliation(s)
- Martin Müllner
- Institut fur Mikrobiologie and Weinforschung, Universitat Mainz, Becherweg 15, 55099 Mainz, Germany
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Lithgow JK, Haider F, Roberts IS, Green J. Alternate SlyA and H-NS nucleoprotein complexes control hlyE expression in Escherichia coli K-12. Mol Microbiol 2007; 66:685-98. [PMID: 17892462 PMCID: PMC2156107 DOI: 10.1111/j.1365-2958.2007.05950.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Haemolysin E is a cytolytic pore-forming toxin found in several Escherichia coli and Salmonella enterica strains. Expression of hlyE is repressed by the global regulator H-NS (histone-like nucleoid structuring protein), but can be activated by the regulator SlyA. Expression of a chromosomal hlyE–lacZ fusion in an E. coli slyA mutant was reduced to 60% of the wild-type level confirming a positive role for SlyA. DNase I footprint analysis revealed the presence of two separate SlyA binding sites, one located upstream, the other downstream of the hlyE transcriptional start site. These sites overlap AT-rich H-NS binding sites. Footprint and gel shift data showed that whereas H-NS prevented binding of RNA polymerase (RNAP) at the hlyE promoter (PhlyE), SlyA allowed binding of RNAP, but inhibited binding of H-NS. Accordingly, in vitro transcription analyses showed that addition of SlyA protein relieved H-NS-mediated repression of hlyE. Based on these observations a model for SlyA/H-NS regulation of hlyE expression is proposed in which the relative concentrations of SlyA and H-NS govern the nature of the nucleoprotein complexes formed at PhlyE. When H-NS is dominant RNAP binding is inhibited and hlyE expression is silenced; when SlyA is dominant H-NS binding is inhibited allowing RNAP access to the promoter facilitating hlyE transcription.
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Affiliation(s)
- James K Lithgow
- Department of Molecular Biology and Biotechnology, The University of SheffieldWestern Bank, Sheffield S10 2TN, UK.
| | - Fouzia Haider
- Department of Molecular Biology and Biotechnology, The University of SheffieldWestern Bank, Sheffield S10 2TN, UK.
| | - Ian S Roberts
- 1.800 Stopford Building, Faculty of Life Sciences, University of ManchesterOxford Road, Manchester M13 9PT, UK.
| | - Jeffrey Green
- Department of Molecular Biology and Biotechnology, The University of SheffieldWestern Bank, Sheffield S10 2TN, UK.
- For correspondence. E-mail ; Tel. (+44) 114 222 4403; Fax (+44) 0114 222 2800
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Gruening P, Fulde M, Valentin-Weigand P, Goethe R. Structure, regulation, and putative function of the arginine deiminase system of Streptococcus suis. J Bacteriol 2006; 188:361-9. [PMID: 16385025 PMCID: PMC1347268 DOI: 10.1128/jb.188.2.361-369.2006] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2005] [Accepted: 10/27/2005] [Indexed: 11/20/2022] Open
Abstract
Streptococcus suis is an important cause of infectious diseases in young pigs. Little is known about the virulence factors or protective antigens of S. suis. Recently, we have identified two proteins of the arginine deiminase system (ADS) of S. suis, which were temperature induced and expressed on the streptococcal surface (N. Winterhoff, R. Goethe, P. Gruening, M. Rohde, H. Kalisz, H. E. Smith, and P. Valentin-Weigand, J. Bacteriol. 184:6768-6776, 2002). In the present study, we analyzed the complete ADS of S. suis. Due to their homologies to the recently published S. gordonii ADS genes, the genes for arginine deiminase, ornithine carbamoyl-transferase, and carbamate kinase, which were previously designated adiS, octS, and ckS, respectively, were renamed arcA, arcB, and arcC, respectively. Our data revealed that arcA, arcB, and arcC of the S. suis ADS are transcribed from an operon (arcABC operon). Additionally, putative ADS-associated genes were cloned and sequenced which, however, did not belong to the arcABC operon. These were the flpS gene upstream of the arcABC operon with homology to the flp transcription regulator of S. gordonii and the arcD, arcT, arcH, and argR genes downstream of the arcABC operon with high homologies to a putative arginine-ornithine antiporter, a putative dipeptidase of S. gordonii, a putative beta-N-acetylhexosaminidase of S. pneumoniae, and a putative arginine repressor of S. gordonii, respectively. The transcriptional start point of the arcABC operon was determined, and promoter analysis provided evidence that multiple factors contribute to the regulation of the ADS. Thus, a putative binding site for a transcription regulator of the Crp/Fnr family, an ArgR-binding site, and two cis-acting catabolite response elements were identified in the promoter-operator region of the operon. Consistent with this, we could demonstrate that the ADS of S. suis is inducible by arginine and reduced O2 tension and subject to carbon catabolite repression. Furthermore, comparing an arcA knockout mutant in which expression of the three operon-encoded proteins was abolished with the parental wild-type strain showed that the arcABC operon of S. suis contributes to survival under acidic conditions.
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Affiliation(s)
- Petra Gruening
- Institut fuer Mikrobiologie, Zentrum fuer Infektionsmedizin, Tieraerztliche Hochschule Hannover, Bischofsholer Damm 15, 30173 Hannover, Germany
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13
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Stillman TJ, Upadhyay M, Norte VA, Sedelnikova SE, Carradus M, Tzokov S, Bullough PA, Shearman CA, Gasson MJ, Williams CH, Artymiuk PJ, Green J. The crystal structures of Lactococcus lactis MG1363 Dps proteins reveal the presence of an N-terminal helix that is required for DNA binding. Mol Microbiol 2005; 57:1101-12. [PMID: 16091047 DOI: 10.1111/j.1365-2958.2005.04757.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dps proteins play a major role in the protection of bacterial DNA from damage by reactive oxygen species. Previous studies have implicated the extended lysine-containing N-terminal regions of Dps subunits in DNA binding, but this part of the structure has not previously been observed crystallographically. Here the structures of two Dps proteins (DpsA and DpsB) from Lactococcus lactis MG1363 reveal for the first time the presence of an N-terminal alpha helix that extends from the core of the Dps subunit. Consequently, the N-terminal helices are displayed in parallel pairs on the exterior of the dodecameric Dps assemblies. Both DpsA and DpsB bind DNA. Deletion of the DpsA N-terminal helix impaired DNA binding. The N-terminal Lys residues of Escherichia coli Dps have been implicated in DNA binding. Replacement of the lactococcal DpsA Lys residues 9, 15 and 16 by Glu did not inhibit DNA binding. However, DNA binding was inhibited by EDTA, suggesting a role for cations in DNA binding. In contrast to E. coli, Bacillus brevis and Mycobacterium smegmatis Dps:DNA complexes, in which DNA interacts with crystalline Dps phases, L. lactis DNA:Dps complexes appeared as non-crystalline aggregates of protein and DNA in electron micrographs.
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Affiliation(s)
- Timothy J Stillman
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, Firth Court, Western Bank, University of Sheffield, Sheffield S10 2TN, UK
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14
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Kamps A, Achebach S, Fedtke I, Unden G, Götz F. Staphylococcal NreB: an O(2)-sensing histidine protein kinase with an O(2)-labile iron-sulphur cluster of the FNR type. Mol Microbiol 2004; 52:713-23. [PMID: 15101978 DOI: 10.1111/j.1365-2958.2004.04024.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The nreABC (nitrogen regulation) operon encodes a new staphylococcal two-component regulatory system that controls dissimilatory nitrate/nitrite reduction in response to oxygen. Unlike other two-component sensors NreB is a cytosolic protein with four N-terminal cysteine residues. It was shown that both the NreB-cysteine cluster and Fe ions are required for function. Isolated NreB was converted to the active form by incubation with cysteine desulphurase, ferrous ions and cysteine. This activation is typical for FeS-containing proteins and was reversed by oxygen. During reconstitution an absorption band at 420 nm and a yellow-brownish colour (typical for an FNR-type iron-sulphur cluster formation) developed. After alkylation of thiol groups in NreB and in the cysteine mutant NreB(C62S) almost no iron-sulphur cluster was incorporated; both findings corroborated the importance of the cysteine residues. Comparison of the kinase activity of (i). the reconstituted (ii). the unreconstituted, and (iii). the unreconstituted and deferrated NreB-His indicated that NreB kinase activity depended on iron availability and was greatly enhanced by reconstitution. NreB is the first direct oxygen-sensing protein described in staphylococci so far. Reconstituted NreB contains 4-8 acid-labile Fe and sulphide ions per NreB which is in agreement with the presence of 1-2 iron-sulphur [4Fe-4S](2+) clusters of the FNR-type. Unlike FNR, NreB does not act directly as transcriptional activator, but transfers the phosphoryl group to the response regulator NreC.
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Affiliation(s)
- Annegret Kamps
- Mikrobielle Genetik, Universität Tübingen, D-72076 Tübingen, Germany
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Buhrke T, Lenz O, Porthun A, Friedrich B. The H2-sensing complex of Ralstonia eutropha: interaction between a regulatory [NiFe] hydrogenase and a histidine protein kinase. Mol Microbiol 2004; 51:1677-89. [PMID: 15009894 DOI: 10.1111/j.1365-2958.2003.03933.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two [NiFe] hydrogenases enable the proteobacterium Ralstonia eutropha H16 to grow on molecular hydrogen as the sole energy source. A third [NiFe] hydrogenase (RH) acts as an H2 sensor in a multiple component signal transduction chain that controls hydrogenase gene transcription. The RH forms a dimeric heterodimer (HoxBC)2 in which HoxC contains the H2-sensing active site and HoxB the electron-transferring components including an organic, not yet identified redox cofactor. This oligomer forms a tight complex with the histidine protein kinase HoxJ. Both the sensor and the kinase were analysed by mutagenesis for functional domains that are instrumental in H2 signal transmission. A mutant deleted for a C-terminal peptide of 55 amino acids in HoxB lost its H2-sensing ability but still catalysed H2 oxidation. The mutant protein failed to form the dimeric heterodimer and a complex with HoxJ. The organic redox cofactor was no longer detectable in the truncated sensor. H2 sensing was also abolished by deletion of the PAS domain of HoxJ, indicating that this domain is involved in signal transduction. A truncated version of HoxJ consisting of only the input domain of the kinase was still capable of forming a complex with the RH. Mass determination of the purified HoxJ protein revealed that the kinase forms a homotetramer. The unique oligomeric structure of the H2-sensing complex with respect to its regulatory function is discussed.
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Affiliation(s)
- Thorsten Buhrke
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Chausseestr 117, 10115 Berlin, Germany
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Dong Y, Chen YYM, Burne RA. Control of expression of the arginine deiminase operon of Streptococcus gordonii by CcpA and Flp. J Bacteriol 2004; 186:2511-4. [PMID: 15060059 PMCID: PMC412168 DOI: 10.1128/jb.186.8.2511-2514.2004] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Streptococcus gordonii DL1, inactivation of the ccpA gene and a gene encoding an Fnr-like protein (Flp) demonstrated that CcpA was essential for carbohydrate catabolite repression and that Flp was required for optimal expression and anaerobic induction of the arginine deiminase system.
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Affiliation(s)
- Yiqian Dong
- Department of Oral Biology, University of Florida, Gainesville, Florida 32610, USA
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17
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Vido K, Le Bars D, Mistou MY, Anglade P, Gruss A, Gaudu P. Proteome analyses of heme-dependent respiration in Lactococcus lactis: involvement of the proteolytic system. J Bacteriol 2004; 186:1648-57. [PMID: 14996795 PMCID: PMC355967 DOI: 10.1128/jb.186.6.1648-1657.2004] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sugar fermentation was long considered the sole means of energy metabolism available to lactic acid bacteria. We recently showed that metabolism of Lactococcus lactis shifts progressively from fermentation to respiration during growth when oxygen and heme are available. To provide insights into this phenomenon, we compared the proteomic profiles of L. lactis under fermentative and respiratory growth conditions in rich medium. We identified 21 proteins whose levels differed significantly between these conditions. Two major groups of proteins were distinguished, one involved in carbon metabolism and the second in nitrogen metabolism. Unexpectedly, enzymes of the proteolytic system (PepO1 and PepC) which are repressed in rich medium in fermentation growth were induced under respiratory conditions despite the availability of free amino acids. A triple mutant (dtpT dtpP oppA) deficient in oligopeptide transport displayed normal respiration, showing that increased proteolytic activity is not an absolute requirement for respiratory metabolism. Transcriptional analysis confirmed that pepO1 is induced under respiration-permissive conditions. This induction was independent of CodY, the major regulator of proteolytic functions in L. lactis. We also observed that pepO1 induction is redox sensitive. In a codY mutant, pepO1 expression was increased twofold in aeration and eightfold in respiration-permissive conditions compared to static conditions. These observations suggest that new regulators activate proteolysis in L. lactis, which help to maintain the energetic needs of L. lactis during respiration.
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Affiliation(s)
- Karin Vido
- Unité de Recherches Laitières et Génétique Appliquée, Institut National de la Recherche Agronomique, Domaine de Vilvert, 78352 Jouy en Josas, France
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18
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Körner H, Sofia HJ, Zumft WG. Phylogeny of the bacterial superfamily of Crp-Fnr transcription regulators: exploiting the metabolic spectrum by controlling alternative gene programs. FEMS Microbiol Rev 2003; 27:559-92. [PMID: 14638413 DOI: 10.1016/s0168-6445(03)00066-4] [Citation(s) in RCA: 325] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The Crp-Fnr regulators, named after the first two identified members, are DNA-binding proteins which predominantly function as positive transcription factors, though roles of repressors are also important. Among over 1200 proteins with an N-terminally located nucleotide-binding domain similar to the cyclic adenosine monophosphate (cAMP) receptor protein, the distinctive additional trait of the Crp-Fnr superfamily is a C-terminally located helix-turn-helix motif for DNA binding. From a curated database of 369 family members exhibiting both features, we provide a protein tree of Crp-Fnr proteins according to their phylogenetic relationships. This results in the assembly of the regulators ArcR, CooA, CprK, Crp, Dnr, FixK, Flp, Fnr, FnrN, MalR, NnrR, NtcA, PrfA, and YeiL and their homologs in distinct clusters. Lead members and representatives of these groups are described, placing emphasis on the less well-known regulators and target processes. Several more groups consist of sequence-derived proteins of unknown physiological roles; some of them are tight clusters of highly similar members. The Crp-Fnr regulators stand out in responding to a broad spectrum of intracellular and exogenous signals such as cAMP, anoxia, the redox state, oxidative and nitrosative stress, nitric oxide, carbon monoxide, 2-oxoglutarate, or temperature. To accomplish their roles, Crp-Fnr members have intrinsic sensory modules allowing the binding of allosteric effector molecules, or have prosthetic groups for the interaction with the signal. The regulatory adaptability and structural flexibility represented in the Crp-Fnr scaffold has led to the evolution of an important group of physiologically versatile transcription factors.
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Affiliation(s)
- Heinz Körner
- Lehrstuhl für Mikrobiologie, Universität Karlsruhe, PF 6980, D-76128 Karlsruhe, Germany
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Fernández M, Kleerebezem M, Kuipers OP, Siezen RJ, van Kranenburg R. Regulation of the metC-cysK operon, involved in sulfur metabolism in Lactococcus lactis. J Bacteriol 2002; 184:82-90. [PMID: 11741847 PMCID: PMC134770 DOI: 10.1128/jb.184.1.82-90.2002] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sulfur metabolism in gram-positive bacteria is poorly characterized. Information on the molecular mechanisms of regulation of genes involved in sulfur metabolism is limited, and no regulator genes have been identified. Here we describe the regulation of the lactococcal metC-cysK operon, encoding a cystathionine beta-lyase (metC) and cysteine synthase (cysK). Its expression was shown to be negatively affected by high concentrations of cysteine, methionine, and glutathione in the culture medium, while sulfur limitation resulted in a high level of expression. Other sulfur sources tested showed no significant effect on metC-cysK gene expression. In addition we found that O-acetyl-l-serine, the substrate of cysteine synthase, was an inducer of the metC-cysK operon. Using a random mutagenesis approach, we identified two genes, cmbR and cmbT, involved in regulation of metC-cysK expression. The cmbT gene is predicted to encode a transport protein, but its precise role in regulation remains unclear. Disruption of cmbT resulted in a two- to threefold reduction of metC-cysK transcription. A 5.7-kb region containing the cmbR gene was cloned and sequenced. The encoded CmbR protein is homologous to the LysR family of regulator proteins and is an activator of the metC-cysK operon. In analogy to CysB from Escherichia coli, we propose that CmbR requires acetylserine to be able to bind the activation sites and subsequently activate transcription of the metC-cysK operon.
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Affiliation(s)
- María Fernández
- Wageningen Centre for Food Sciences, Wageningen, and Department of Flavour, Nutrition and Ingredients, NIZO Food Research, Ede, The Netherlands
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Green J, Scott C, Guest JR. Functional versatility in the CRP-FNR superfamily of transcription factors: FNR and FLP. Adv Microb Physiol 2001; 44:1-34. [PMID: 11407111 DOI: 10.1016/s0065-2911(01)44010-0] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The cAMP receptor protein (CRP; sometimes known as CAP, the catabolite gene activator protein) and the fumarate and nitrate reduction regulator (FNR) of Escherichia coli are founder members of an expanding superfamily of structurally related transcription factors. The archetypal CRP structural fold provides a very versatile mechanism for transducing environmental and metabolic signals to the transcription machinery. It allows different functional specificities at the sensory, DNA-recognition and RNA-polymerase-interaction levels to be 'mixed and matched' in order to create a diverse range of transcription factors tailored to respond to particular physiological conditions. This versatility is clearly illustrated by comparing the properties of the CRP, FNR and FLP (FNR-like protein) regulators. At the sensory level, the basic structural fold has been adapted in FNR and FLP by the acquisition in the N-terminal region of different combinations of cysteine or other residues; which bestow oxygen/redox sensing mechanisms that are poised according to the oxidative stress thresholds affecting the metabolism of specific bacteria. At the DNA-recognition level, discrimination between distinct but related DNA targets is mediated by amino acid sequence modifications in the conserved core contact between the DNA-recognition helix and target DNA. And, at the level of RNA-polymerase-interaction, different combinations of three discrete regions contacting the polymerase (the activating regions) are used for polymerase recruitment and promoting transcription.
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Affiliation(s)
- J Green
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
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Scott C, Rawsthorne H, Upadhyay M, Shearman CA, Gasson MJ, Guest JR, Green J. Zinc uptake, oxidative stress and the FNR-like proteins of Lactococcus lactis. FEMS Microbiol Lett 2000; 192:85-9. [PMID: 11040433 DOI: 10.1111/j.1574-6968.2000.tb09363.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Lactococcus lactis ssp. cremoris MG1363 contains two FNR homologues, FlpA and FlpB, encoded by the distal genes of two paralogous operons (orfX(A/B)-orfY(A/B)-flpA/B). An flpA flpB double mutant strain is hypersensitive to hydrogen peroxide and has a depleted intracellular Zn(II) pool. The phenotypes of the flp mutant strains suggest that FlpA and FlpB control the expression of high and low affinity ATP-dependent Zn(II) uptake systems, respectively. Plate tests revealed that expression from a orfX(B)::lac reporter was activated by Cd(II), consistent with other Zn(II)-regulated systems. The link between a failure to acquire Zn(II) and hypersensitivity to oxidative stress suggests that Zn(II) may be required to protect vulnerable protein thiols from oxidation.
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Affiliation(s)
- C Scott
- Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield, UK
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