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Zhao Q, Yao F, Li W, Liu S, Bi S. Identification of a dCache-type chemoreceptor in Campylobacter jejuni that specifically mediates chemotaxis towards methyl pyruvate. Front Microbiol 2024; 15:1400284. [PMID: 38784811 PMCID: PMC11111895 DOI: 10.3389/fmicb.2024.1400284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 04/25/2024] [Indexed: 05/25/2024] Open
Abstract
The foodborne pathogenic bacterium Campylobacter jejuni utilizes chemotaxis to assist in the colonization of host niches. A key to revealing the relationship among chemotaxis and pathogenicity is the discovery of signaling molecules perceived by the chemoreceptors. The C. jejuni chemoreceptor Tlp11 is encoded by the highly infective C. jejuni strains. In the present study, we report that the dCache-type ligand-binding domain (LBD) of C. jejuni ATCC 33560 Tlp11 binds directly to novel ligands methyl pyruvate, toluene, and quinoline using the same pocket. Methyl pyruvate elicits a strong chemoattractant response, while toluene and quinoline function as the antagonists without triggering chemotaxis. The sensory LBD was used to control heterologous proteins by constructing chimeras, indicating that the signal induced by methyl pyruvate is transmitted across the membrane. In addition, bioinformatics and experiments revealed that the dCache domains with methyl pyruvate-binding sites and ability are widely distributed in the order Campylobacterales. This is the first report to identify the class of dCache chemoreceptors that bind to attractant methyl pyruvate and antagonists toluene and quinoline. Our research provides a foundation for understanding the chemotaxis and virulence of C. jejuni and lays a basis for the control of this foodborne pathogen.
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Affiliation(s)
- Qi Zhao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Fulian Yao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Wei Li
- Department of Clinical Laboratory, Qilu Hospital, Shandong University, Jinan, China
| | - Shuangjiang Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
- State Key Laboratory of Microbial Resources, and Environmental Microbiology Research Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Shuangyu Bi
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
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Emergence of an Auxin Sensing Domain in Plant-Associated Bacteria. mBio 2023; 14:e0336322. [PMID: 36602305 PMCID: PMC9973260 DOI: 10.1128/mbio.03363-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Bacteria have evolved a sophisticated array of signal transduction systems that allow them to adapt their physiology and metabolism to changing environmental conditions. Typically, these systems recognize signals through dedicated ligand binding domains (LBDs) to ultimately trigger a diversity of physiological responses. Nonetheless, an increasing number of reports reveal that signal transduction receptors also bind antagonists to inhibit responses mediated by agonists. The mechanisms by which antagonists block the downstream signaling cascade remain largely unknown. To advance our knowledge in this field, we used the LysR-type transcriptional regulator AdmX as a model. AdmX activates the expression of an antibiotic biosynthetic cluster in the rhizobacterium Serratia plymuthica. AdmX specifically recognizes the auxin phytohormone indole-3-acetic acid (IAA) and its biosynthetic intermediate indole-3-pyruvic acid (IPA) as signals. However, only IAA, but not IPA, was shown to regulate antibiotic production in S. plymuthica. Here, we report the high-resolution structures of the LBD of AdmX in complex with IAA and IPA. We found that IAA and IPA compete for binding to AdmX. Although IAA and IPA binding does not alter the oligomeric state of AdmX, IPA binding causes a higher degree of compactness in the protein structure. Molecular dynamics simulations revealed significant differences in the binding modes of IAA and IPA by AdmX, and the inspection of the three-dimensional structures evidenced differential agonist- and antagonist-mediated structural changes. Key residues for auxin binding were identified and an auxin recognition motif defined. Phylogenetic clustering supports the recent evolutionary emergence of this motif specifically in plant-associated enterobacteria. IMPORTANCE Although antagonists were found to bind different bacterial signal transduction receptors, we are still at the early stages of understanding the molecular details by which these molecules exert their inhibitory effects. Here, we provide insight into the structural changes resulting from the binding of an agonist and an antagonist to a sensor protein. Our data indicate that agonist and antagonist recognition is characterized by small conformational differences in the LBDs that can be efficiently transmitted to the output domain to modulate the final response. LBDs are subject to strong selective pressures and are rapidly evolving domains. An increasing number of reports support the idea that environmental factors drive the evolution of sensor domains. Given the recent evolutionary history of AdmX homologs, as well as their narrow phyletic distribution within plant-associated bacteria, our results are in accordance with a plant-mediated evolutionary process that resulted in the emergence of receptor proteins that specifically sense auxin phytohormones.
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Aukema KG, Bygd MD, Tassoulas LJ, Richman JE, Wackett LP. Fluoro-recognition: New in vivo fluorescent assay for toluene dioxygenase probing induction by and metabolism of polyfluorinated compounds. Environ Microbiol 2022; 24:5202-5216. [PMID: 36054238 PMCID: PMC9828342 DOI: 10.1111/1462-2920.16187] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 08/30/2022] [Indexed: 01/12/2023]
Abstract
The present study examined the regulatory and metabolic response of the aromatic degrader Pseudomonas putida F1 and its tod operon, controlling toluene degradation, to fluorinated aromatic and aliphatic compounds. The tod operon is upregulated by inducer binding to the TodS sensing domain of a two-component regulator. The induced enzymes include toluene dioxygenase that initiates catabolic assimilation of benzenoid hydrocarbons. Toluene dioxygenase was shown to oxidize 6-fluoroindole to a meta-stable fluorescent product, 6-fluoroindoxyl. The fluorescent output allowed monitoring relative levels of tod operon induction in whole cells using microtiter well plates. Mono- and polyfluorinated aromatic compounds were shown to induce toluene dioxygenase, in some cases to a greater extent than compounds serving as growth substrates. Compounds that are oxidized by toluene dioxygenase and undergoing defluorination were shown to induce their own metabolism. 1,2,4-Trifluorobenzene caused significant induction and computational modelling indicated productive binding to the TodS sensor domain of the TodST regulator. Toluene dioxygenase also showed preferential binding of 1,2,4-trifluorobenzene such that defluorination was favoured. Fluorinated aliphatic compounds were shown to induce toluene dioxygenase. An aliphatic ether with seven fluorine atoms, 1,1,1,2-tetrafluoro-2-trifluoromethoxy-4-iodobutane (TTIB), was an excellent inducer of toluene dioxygenase activity and shown to undergo transformation in cultures of P. putida F1.
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Affiliation(s)
- Kelly G. Aukema
- Department of Biochemistry, Molecular Biology and Biophysics and Biotechnology InstituteUniversity of Minnesota, Twin CitiesMinnesotaUSA
| | - Madison D. Bygd
- Department of Biochemistry, Molecular Biology and Biophysics and Biotechnology InstituteUniversity of Minnesota, Twin CitiesMinnesotaUSA
| | - Lambros J. Tassoulas
- Department of Biochemistry, Molecular Biology and Biophysics and Biotechnology InstituteUniversity of Minnesota, Twin CitiesMinnesotaUSA
| | - Jack E. Richman
- Department of Biochemistry, Molecular Biology and Biophysics and Biotechnology InstituteUniversity of Minnesota, Twin CitiesMinnesotaUSA
| | - Lawrence P. Wackett
- Department of Biochemistry, Molecular Biology and Biophysics and Biotechnology InstituteUniversity of Minnesota, Twin CitiesMinnesotaUSA
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Mukherjee M, Geeta A, Ghosh S, Prusty A, Dutta S, Sarangi AN, Behera S, Adhikary SP, Tripathy S. Genome Analysis Coupled With Transcriptomics Reveals the Reduced Fitness of a Hot Spring Cyanobacterium Mastigocladus laminosus UU774 Under Exogenous Nitrogen Supplement. Front Microbiol 2022; 13:909289. [PMID: 35847102 PMCID: PMC9284123 DOI: 10.3389/fmicb.2022.909289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/20/2022] [Indexed: 11/13/2022] Open
Abstract
The present study focuses on the stress response of a filamentous, AT-rich, heterocystous cyanobacterium Mastigocladus laminosus UU774, isolated from a hot spring, Taptapani, located in the eastern part of India. The genome of UU774 contains an indispensable fragment, scaffold_38, of unknown origin that is implicated during severe nitrogen and nutrition stress. Prolonged exposure to nitrogen compounds during starvation has profound adverse effects on UU774, leading to loss of mobility, loss of ability to fight pathogens, reduced cell division, decreased nitrogen-fixing ability, reduced ability to form biofilms, reduced photosynthetic and light-sensing ability, and reduced production of secreted effectors and chromosomal toxin genes, among others. Among genes showing extreme downregulation when grown in a medium supplemented with nitrogen with the fold change > 5 are transcriptional regulator gene WalR, carbonic anhydrases, RNA Polymerase Sigma F factor, fimbrial protein, and twitching mobility protein. The reduced expression of key enzymes involved in the uptake of phosphate and enzymes protecting oxygen-sensitive nitrogenases is significant during the presence of nitrogen. UU774 is presumed to withstand heat by overexpressing peptidases that may be degrading abnormally folded proteins produced during heat. The absence of a key gene responsible for heterocyst pattern formation, patS, and an aberrant hetN without a functional motif probably lead to the formation of a chaotic heterocyst pattern in UU774. We suggest that UU774 has diverged from Fischerella sp. PCC 9339, another hot spring species isolated in the United States.
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Affiliation(s)
- Mayuri Mukherjee
- Computational Genomics Lab, Structural Biology and Bioinformatics Division, CSIR Indian Institute of Chemical Biology, Kolkata, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Aribam Geeta
- Computational Genomics Lab, Structural Biology and Bioinformatics Division, CSIR Indian Institute of Chemical Biology, Kolkata, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Samrat Ghosh
- Computational Genomics Lab, Structural Biology and Bioinformatics Division, CSIR Indian Institute of Chemical Biology, Kolkata, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Asharani Prusty
- Computational Genomics Lab, Structural Biology and Bioinformatics Division, CSIR Indian Institute of Chemical Biology, Kolkata, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Subhajeet Dutta
- Computational Genomics Lab, Structural Biology and Bioinformatics Division, CSIR Indian Institute of Chemical Biology, Kolkata, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
| | - Aditya Narayan Sarangi
- Computational Genomics Lab, Structural Biology and Bioinformatics Division, CSIR Indian Institute of Chemical Biology, Kolkata, India
| | - Smrutisanjita Behera
- Computational Genomics Lab, Structural Biology and Bioinformatics Division, CSIR Indian Institute of Chemical Biology, Kolkata, India
| | | | - Sucheta Tripathy
- Computational Genomics Lab, Structural Biology and Bioinformatics Division, CSIR Indian Institute of Chemical Biology, Kolkata, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India
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Moratti CF, Scott C, Coleman NV. Synthetic Biology Approaches to Hydrocarbon Biosensors: A Review. Front Bioeng Biotechnol 2022; 9:804234. [PMID: 35083206 PMCID: PMC8784404 DOI: 10.3389/fbioe.2021.804234] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/09/2021] [Indexed: 12/12/2022] Open
Abstract
Monooxygenases are a class of enzymes that facilitate the bacterial degradation of alkanes and alkenes. The regulatory components associated with monooxygenases are nature's own hydrocarbon sensors, and once functionally characterised, these components can be used to create rapid, inexpensive and sensitive biosensors for use in applications such as bioremediation and metabolic engineering. Many bacterial monooxygenases have been identified, yet the regulation of only a few of these have been investigated in detail. A wealth of genetic and functional diversity of regulatory enzymes and promoter elements still remains unexplored and unexploited, both in published genome sequences and in yet-to-be-cultured bacteria. In this review we examine in detail the current state of research on monooxygenase gene regulation, and on the development of transcription-factor-based microbial biosensors for detection of alkanes and alkenes. A new framework for the systematic characterisation of the underlying genetic components and for further development of biosensors is presented, and we identify focus areas that should be targeted to enable progression of more biosensor candidates to commercialisation and deployment in industry and in the environment.
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Affiliation(s)
- Claudia F. Moratti
- School of Life and Environmental Science, Faculty of Science, University of Sydney, Sydney, NSW, Australia
- CSIRO Synthetic Biology Future Science Platform, Canberra, ACT, Australia
| | - Colin Scott
- CSIRO Synthetic Biology Future Science Platform, Canberra, ACT, Australia
| | - Nicholas V. Coleman
- School of Life and Environmental Science, Faculty of Science, University of Sydney, Sydney, NSW, Australia
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6
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Matilla MA, Velando F, Monteagudo-Cascales E, Krell T. Flagella, Chemotaxis and Surface Sensing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:185-221. [DOI: 10.1007/978-3-031-08491-1_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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7
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Matilla MA, Velando F, Martín-Mora D, Monteagudo-Cascales E, Krell T. A catalogue of signal molecules that interact with sensor kinases, chemoreceptors and transcriptional regulators. FEMS Microbiol Rev 2021; 46:6356564. [PMID: 34424339 DOI: 10.1093/femsre/fuab043] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 08/10/2021] [Indexed: 12/12/2022] Open
Abstract
Bacteria have evolved many different signal transduction systems that sense signals and generate a variety of responses. Generally, most abundant are transcriptional regulators, sensor histidine kinases and chemoreceptors. Typically, these systems recognize their signal molecules with dedicated ligand-binding domains (LBDs), which, in turn, generate a molecular stimulus that modulates the activity of the output module. There are an enormous number of different LBDs that recognize a similarly diverse set of signals. To give a global perspective of the signals that interact with transcriptional regulators, sensor kinases and chemoreceptors, we manually retrieved information on the protein-ligand interaction from about 1,200 publications and 3D structures. The resulting 811 proteins were classified according to the Pfam family into 127 groups. These data permit a delineation of the signal profiles of individual LBD families as well as distinguishing between families that recognize signals in a promiscuous manner and those that possess a well-defined ligand range. A major bottleneck in the field is the fact that the signal input of many signaling systems is unknown. The signal repertoire reported here will help the scientific community design experimental strategies to identify the signaling molecules for uncharacterised sensor proteins.
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Affiliation(s)
- Miguel A Matilla
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain
| | - Félix Velando
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain
| | - David Martín-Mora
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain
| | - Elizabet Monteagudo-Cascales
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain
| | - Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain
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8
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Phale PS, Malhotra H, Shah BA. Degradation strategies and associated regulatory mechanisms/features for aromatic compound metabolism in bacteria. ADVANCES IN APPLIED MICROBIOLOGY 2020; 112:1-65. [PMID: 32762865 DOI: 10.1016/bs.aambs.2020.02.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
As a result of anthropogenic activity, large number of recalcitrant aromatic compounds have been released into the environment. Consequently, microbial communities have adapted and evolved to utilize these compounds as sole carbon source, under both aerobic and anaerobic conditions. The constitutive expression of enzymes necessary for metabolism imposes a heavy energy load on the microbe which is overcome by arrangement of degradative genes as operons which are induced by specific inducers. The segmentation of pathways into upper, middle and/or lower operons has allowed microbes to funnel multiple compounds into common key aromatic intermediates which are further metabolized through central carbon pathway. Various proteins belonging to diverse families have evolved to regulate the transcription of individual operons participating in aromatic catabolism. These proteins, complemented with global regulatory mechanisms, carry out the regulation of aromatic compound metabolic pathways in a concerted manner. Additionally, characteristics like chemotaxis, preferential utilization, pathway compartmentalization and biosurfactant production confer an advantage to the microbe, thus making bioremediation of the aromatic pollutants more efficient and effective.
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Affiliation(s)
- Prashant S Phale
- Department of Biosciences and Bioengineering, Indian Institute of Technology-Bombay, Mumbai, India.
| | - Harshit Malhotra
- Department of Biosciences and Bioengineering, Indian Institute of Technology-Bombay, Mumbai, India
| | - Bhavik A Shah
- Department of Biosciences and Bioengineering, Indian Institute of Technology-Bombay, Mumbai, India
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9
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Abstract
We report the entire process underlying the NicR2 regulatory mechanism from association between free NicR2 and two promoters to dissociation of the NicR2-promoter complex. NicR2 can bind to another promoter, Pspm, which controls expression of nicotine-degrading genes that are not controlled by the Phsp promoter. We identified specific nucleotides of the Pspm promoter responsible for NicR2 binding. HSP was further demonstrated as an antagonist, which prevents the binding of NicR2 to the Pspm and Phsp promoters, by locking NicR2 in the derepression conformation. The competition between NicR2 and RNA polymerase is essential to initiate transcription of nicotine-degrading genes. This study extends our understanding of molecular mechanisms in biodegradation of environmental pollutants and toxicants. Nicotine, a toxic and addictive alkaloid from tobacco, is an environmental pollutant in areas near cigarette production facilities. Over the last decade, our group has studied, in depth, the pyrrolidine pathway of nicotine degradation in Pseudomonas putida S16. However, little is known regarding whole mechanism(s) regulating transcription of the nicotine degradation pathway gene cluster. In the present study, we comprehensively elucidate an overall view of the NicR2-mediated two-step mechanism regulating 3-succinoyl-pyridine (SP) biotransformation, which involves the association of free NicR2 with two promoters and the dissociation of NicR2 from the NicR2-promoter complex. NicR2 can bind to another promoter, Pspm, and regulate expression of the nicotine-degrading genes in the middle of nic2 gene cluster, which are not controlled by the previously reported Phsp promoter. We identified the function of the inverted repeat bases on the two promoters responsible for NicR2 binding and found out that the –35/–10 motif for RNA polymerase is overlapped by the NicR2 binding site. We clarify the exact role of 6-hydroxy-3-succinoyl-pyridine (HSP), which acts as an antagonist and may prevent binding of free NicR2 to the promoters but cannot release NicR2 from the promoters. Finally, a regulatory model is proposed, which consists of three parts: the interaction between NicR2 and two promoters (Pspm and Phsp), the interaction between NicR2 and two effectors (HSP and SP), and the interaction between NicR2 and RNA polymerase.
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Blázquez B, Carmona M, Díaz E. Transcriptional Regulation of the Peripheral Pathway for the Anaerobic Catabolism of Toluene and m-Xylene in Azoarcus sp. CIB. Front Microbiol 2018; 9:506. [PMID: 29623071 PMCID: PMC5874301 DOI: 10.3389/fmicb.2018.00506] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 03/06/2018] [Indexed: 11/17/2022] Open
Abstract
Alkylbenzenes, such as toluene and m-xylene, are an important class of contaminant hydrocarbons that are widespread and tend to accumulate in subsurface anoxic environments. The peripheral pathway for the anaerobic oxidation of toluene in bacteria consists of an initial activation catalyzed by a benzylsuccinate synthase (encoded by bss genes), and a subsequent modified β-oxidation of benzylsuccinate to benzoyl-CoA and succinyl-CoA (encoded by bbs genes). We have shown here that the bss and bbs genes, which are located within an integrative and conjugative element, are essential for anaerobic degradation of toluene but also for m-xylene oxidation in the denitrifying beta-proteobacterium Azoarcus sp. CIB. New insights into the transcriptional organization and regulation of a complete gene cluster for anaerobic catabolism of toluene/m-xylene in a single bacterial strain are presented. The bss and bbs genes are transcriptionally coupled into two large convergent catabolic operons driven by the PbssD and PbbsA promoters, respectively, whose expression is inducible when cells grow anaerobically in toluene or m-xylene. An adjacent tdiSR operon driven by the PtdiS promoter encodes a putative two-component regulatory system. TdiR behaves as a transcriptional activator of the PbssD, PbbsA, and PtdiS promoters, being benzylsuccinate/(3-methyl)benzylsuccinate, rather than toluene/m-xylene, the inducers that may trigger the TdiS-mediated activation of TdiR. In addition to the TdiSR-based specific control, the expression of the bss and bbs genes in Azoarcus sp. CIB is under an overimposed regulation that depends on certain environmental factors, such as the presence/absence of oxygen or the availability of preferred carbon sources (catabolite repression). This work paves the way for future strategies toward the reliable assessment of microbial activity in toluene/m-xylene contaminated environments.
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Affiliation(s)
- Blas Blázquez
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Manuel Carmona
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Eduardo Díaz
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, Madrid, Spain
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11
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The activity of the C4-dicarboxylic acid chemoreceptor of Pseudomonas aeruginosa is controlled by chemoattractants and antagonists. Sci Rep 2018; 8:2102. [PMID: 29391435 PMCID: PMC5795001 DOI: 10.1038/s41598-018-20283-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 01/15/2018] [Indexed: 11/10/2022] Open
Abstract
Chemotaxis toward organic acids has been associated with colonization fitness and virulence and the opportunistic pathogen Pseudomonas aeruginosa exhibits taxis toward several tricarboxylic acid intermediates. In this study, we used high-throughput ligand screening and isothermal titration calorimetry to demonstrate that the ligand binding domain (LBD) of the chemoreceptor PA2652 directly recognizes five C4-dicarboxylic acids with KD values ranging from 23 µM to 1.24 mM. In vivo experimentation showed that three of the identified ligands act as chemoattractants whereas two of them behave as antagonists by inhibiting the downstream chemotaxis signalling cascade. In vitro and in vivo competition assays showed that antagonists compete with chemoattractants for binding to PA2652-LBD, thereby decreasing the affinity for chemoattractants and the subsequent chemotactic response. Two chemosensory pathways encoded in the genome of P. aeruginosa, che and che2, have been associated to chemotaxis but we found that only the che pathway is involved in PA2652-mediated taxis. The receptor PA2652 is predicted to contain a sCACHE LBD and analytical ultracentrifugation analyses showed that PA2652-LBD is dimeric in the presence and the absence of ligands. Our results indicate the feasibility of using antagonists to interfere specifically with chemotaxis, which may be an alternative strategy to fight bacterial pathogens.
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12
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Alvarez AF, Barba-Ostria C, Silva-Jiménez H, Georgellis D. Organization and mode of action of two component system signaling circuits from the various kingdoms of life. Environ Microbiol 2016; 18:3210-3226. [DOI: 10.1111/1462-2920.13397] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 05/17/2016] [Accepted: 05/23/2016] [Indexed: 11/26/2022]
Affiliation(s)
- Adrian F. Alvarez
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México; 04510 México City, México
| | - Carlos Barba-Ostria
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México; 04510 México City, México
| | - Hortencia Silva-Jiménez
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México; 04510 México City, México
| | - Dimitris Georgellis
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México; 04510 México City, México
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13
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Koh S, Hwang J, Guchhait K, Lee EG, Kim SY, Kim S, Lee S, Chung JM, Jung HS, Lee SJ, Ryu CM, Lee SG, Oh TK, Kwon O, Kim MH. Molecular Insights into Toluene Sensing in the TodS/TodT Signal Transduction System. J Biol Chem 2016; 291:8575-90. [PMID: 26903514 PMCID: PMC4861429 DOI: 10.1074/jbc.m116.718841] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Indexed: 11/17/2022] Open
Abstract
TodS is a sensor kinase that responds to various monoaromatic compounds, which either cause an agonistic or antagonistic effect on phosphorylation of its cognate response regulator TodT, and controls tod operon expression in Pseudomonas putida strains. We describe a molecular sensing mechanism of TodS that is activated in response to toluene. The crystal structures of the TodS Per-Arnt-Sim (PAS) 1 sensor domain (residues 43–164) and its complex with toluene (agonist) or 1,2,4-trimethylbenzene (antagonist) show a typical β2α3β3 PAS fold structure (residues 45–149), forming a hydrophobic ligand-binding site. A signal transfer region (residues 150–163) located immediately after the canonical PAS fold may be intrinsically flexible and disordered in both apo-PAS1 and antagonist-bound forms and dramatically adapt an α-helix upon toluene binding. This structural change in the signal transfer region is proposed to result in signal transmission to activate the TodS/TodT two-component signal transduction system. Site-directed mutagenesis and β-galactosidase assays using a P. putida reporter strain system verified the essential residues involved in ligand sensing and signal transfer and suggest that the Phe46 residue acts as a ligand-specific switch.
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Affiliation(s)
- Serry Koh
- From the Infection and Immunity Research Center,
| | | | - Koushik Guchhait
- From the Infection and Immunity Research Center, the Biosystems and Bioengineering Program, University of Science and Technology, Daejeon 305-350, Korea
| | - Eun-Gyeong Lee
- the Biosystems and Bioengineering Program, University of Science and Technology, Daejeon 305-350, Korea the Biochemicals and Synthetic Biology Research Center, and
| | - Sang-Yoon Kim
- the Biochemicals and Synthetic Biology Research Center, and
| | - Sujin Kim
- the Biochemicals and Synthetic Biology Research Center, and
| | - Sangmin Lee
- the Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chuncheon, Gangwon-do 200-701, Korea, and
| | - Jeong Min Chung
- the Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chuncheon, Gangwon-do 200-701, Korea, and
| | - Hyun Suk Jung
- the Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chuncheon, Gangwon-do 200-701, Korea, and
| | - Sang Jun Lee
- From the Infection and Immunity Research Center, the Biosystems and Bioengineering Program, University of Science and Technology, Daejeon 305-350, Korea
| | - Choong-Min Ryu
- the Biosystems and Bioengineering Program, University of Science and Technology, Daejeon 305-350, Korea the Molecular Phytobacteriology Laboratory, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Korea
| | - Seung-Goo Lee
- the Biosystems and Bioengineering Program, University of Science and Technology, Daejeon 305-350, Korea the Biochemicals and Synthetic Biology Research Center, and
| | - Tae-Kwang Oh
- From the Infection and Immunity Research Center, the Biosystems and Bioengineering Program, University of Science and Technology, Daejeon 305-350, Korea
| | - Ohsuk Kwon
- the Biosystems and Bioengineering Program, University of Science and Technology, Daejeon 305-350, Korea the Biochemicals and Synthetic Biology Research Center, and
| | - Myung Hee Kim
- From the Infection and Immunity Research Center, the Biosystems and Bioengineering Program, University of Science and Technology, Daejeon 305-350, Korea
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Styrene is sensed by the N-terminal PAS sensor domain of StyS, a double sensor kinase from the styrene-degrading bacterium Pseudomonas fluorescens ST. ANN MICROBIOL 2014. [DOI: 10.1007/s13213-014-0931-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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15
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Silva-Jiménez H, Ortega Á, García-Fontana C, Ramos JL, Krell T. Multiple signals modulate the activity of the complex sensor kinase TodS. Microb Biotechnol 2014; 8:103-15. [PMID: 24986263 PMCID: PMC4321377 DOI: 10.1111/1751-7915.12142] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 05/22/2014] [Accepted: 06/07/2014] [Indexed: 11/28/2022] Open
Abstract
The reason for the existence of complex sensor kinases is little understood but thought to lie in the capacity to respond to multiple signals. The complex, seven-domain sensor kinase TodS controls in concert with the TodT response regulator the expression of the toluene dioxygenase pathway in Pseudomonas putida F1 and DOT-T1E. We have previously shown that some aromatic hydrocarbons stimulate TodS activity whereas others behave as antagonists. We show here that TodS responds in addition to the oxidative agent menadione. Menadione but no other oxidative agent tested inhibited TodS activity in vitro and reduced PtodX expression in vivo. The menadione signal is incorporated by a cysteine-dependent mechanism. The mutation of the sole conserved cysteine of TodS (C320) rendered the protein insensitive to menadione. We evaluated the mutual opposing effects of toluene and menadione on TodS autophosphorylation. In the presence of toluene, menadione reduced TodS activity whereas toluene did not stimulate activity in the presence of menadione. It was shown by others that menadione increases expression of glucose metabolism genes. The opposing effects of menadione on glucose and toluene metabolism may be partially responsible for the interwoven regulation of both catabolic pathways. This work provides mechanistic detail on how complex sensor kinases integrate different types of signal molecules.
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Affiliation(s)
- Hortencia Silva-Jiménez
- Department of Environmental Protection, Consejo Superior de Investigaciones Científicas, Estación Experimental del Zaidín, C/ Prof. Albareda 1, Granada, 18008, Spain
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16
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Krell T, Lacal J, García-Fontana C, Silva-Jiménez H, Rico-Jiménez M, Lugo AC, Darias JAR, Ramos JL. Characterization of molecular interactions using isothermal titration calorimetry. Methods Mol Biol 2014; 1149:193-203. [PMID: 24818906 DOI: 10.1007/978-1-4939-0473-0_16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Isothermal titration calorimetry (ITC) is based on a simple titration of one ligand with another and the small heat changes caused by the molecular interaction are detected. From one ITC experiment the complete set of thermodynamic parameters of binding including association and dissociation constants as well as changes in enthalpy, entropy, and free energy can be derived. Using this technique almost any type of molecular interaction can be analyzed. Both ligands are in solution, and there is no need for their chemical derivatization. There are no limits as to the choice of the analysis buffer, and the analysis temperature can be set between 4 and 80 °C. This technique has been primarily applied to study the interaction between various proteins of Pseudomonas with small molecule ligands. In addition, ITC has been used to study the binding of Pseudomonas proteins to target DNA fragments.
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Affiliation(s)
- Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, C/Prof. Albareda 1, 18008, Granada, Spain,
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17
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Josenhans C, Jung K, Rao CV, Wolfe AJ. A tale of two machines: a review of the BLAST meeting, Tucson, AZ, 20-24 January 2013. Mol Microbiol 2013; 91:6-25. [PMID: 24125587 DOI: 10.1111/mmi.12427] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2013] [Indexed: 01/06/2023]
Abstract
Since its inception, Bacterial Locomotion and Signal Transduction (BLAST) meetings have been the place to exchange and share the latest developments in the field of bacterial signal transduction and motility. At the 12th BLAST meeting, held last January in Tucson, AZ, researchers from all over the world met to report and discuss progress in diverse aspects of the field. The majority of these advances, however, came at the level of atomic level structures and their associated mechanisms. This was especially true of the biological machines that sense and respond to environmental changes.
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Affiliation(s)
- Christine Josenhans
- Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Carl-Neuberg Strasse 1, 30625, Hannover, Germany
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18
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Lacal J, Reyes-Darias JA, García-Fontana C, Ramos JL, Krell T. Tactic responses to pollutants and their potential to increase biodegradation efficiency. J Appl Microbiol 2012; 114:923-33. [PMID: 23163356 DOI: 10.1111/jam.12076] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 11/07/2012] [Accepted: 11/11/2012] [Indexed: 11/26/2022]
Abstract
A significant number of bacterial strains are able to use toxic aromatic hydrocarbons as carbon and energy sources. In a number of cases, the evolution of the corresponding degradation pathway was accompanied by the evolution of tactic behaviours either towards or away from these toxic carbon sources. Reports are reviewed which show that a chemoattraction to heterogeneously distributed aromatic pollutants increases the bioavailability of these compounds and their biodegradation efficiency. An extreme form of chemoattraction towards aromatic pollutants, termed 'hyperchemotaxis', was described for Pseudomonas putida DOT-T1E, which is based on the action of the plasmid-encoded McpT chemoreceptor. Cells with this phenotype were found of being able to approach and of establishing contact with undiluted crude oil samples. Although close McpT homologues are found on other degradation plasmids, the sequence of their ligand-binding domains does not share significant similarity with that of NahY, the other characterized chemoreceptor for aromatic hydrocarbons. This may suggest the existence of at least two families of chemoreceptors for aromatic pollutants. The use of receptor chimers comprising the ligand-binding region of McpT for biosensing purposes is discussed.
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Affiliation(s)
- J Lacal
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
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