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Mukherjee P, Agarwal S, Mallick SB, Dasgupta J. PAS domain of flagellar histidine kinase FlrB has a unique architecture and binds heme as a sensory ligand in an unconventional fashion. Structure 2024; 32:200-216.e5. [PMID: 38157857 DOI: 10.1016/j.str.2023.11.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 09/28/2023] [Accepted: 11/29/2023] [Indexed: 01/03/2024]
Abstract
Phosphorylation of the σ54-dependent transcription activator FlrC by the sensor histidine kinase FlrB is essential for flagellar synthesis of Vibrio cholerae. Despite that, the structure, sensory signal, and mechanistic basis of function of FlrB were elusive. Here, we report the crystal structure of the sensory PAS domain of FlrB in its functional dimeric state that exhibits a unique architecture. Series of biochemical/biophysical experiments on different constructs and mutants established that heme binds hydrophobically as sensory ligand in the shallow ligand-binding cleft of FlrB-PAS without axial coordination. Intriguingly, ATP binding to the C-terminal ATP-binding (CA) domain assists PAS domain to bind heme, vis-à-vis, heme binding to the PAS facilitates ATP binding to the CA domain. We hypothesize that synergistic binding of heme and ATP triggers conformational signaling in FlrB, leading to downstream flagellar gene transcription. Enhanced swimming motility of V. cholerae with increased heme uptake supports this proposition.
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Affiliation(s)
- Peeali Mukherjee
- Department of Biotechnology, St. Xavier's College (Autonomous), 30 Mother Teresa Sarani, Kolkata 700016, India
| | - Shubhangi Agarwal
- Department of Biotechnology, St. Xavier's College (Autonomous), 30 Mother Teresa Sarani, Kolkata 700016, India
| | - Sritapa Basu Mallick
- Department of Biotechnology, St. Xavier's College (Autonomous), 30 Mother Teresa Sarani, Kolkata 700016, India
| | - Jhimli Dasgupta
- Department of Biotechnology, St. Xavier's College (Autonomous), 30 Mother Teresa Sarani, Kolkata 700016, India.
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2
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Eilers K, Hoong Yam JK, Liu X, Goh YF, To KN, Paracuellos P, Morton R, Brizuela J, Hui Yong AM, Givskov M, Freibert SA, Bange G, Rice SA, Steinchen W, Filloux A. The dual GGDEF/EAL domain enzyme PA0285 is a Pseudomonas species housekeeping phosphodiesterase regulating early attachment and biofilm architecture. J Biol Chem 2024; 300:105659. [PMID: 38237678 PMCID: PMC10874727 DOI: 10.1016/j.jbc.2024.105659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 12/23/2023] [Accepted: 01/04/2024] [Indexed: 02/15/2024] Open
Abstract
Bacterial lifestyles depend on conditions encountered during colonization. The transition between planktonic and biofilm growth is dependent on the intracellular second messenger c-di-GMP. High c-di-GMP levels driven by diguanylate cyclases (DGCs) activity favor biofilm formation, while low levels were maintained by phosphodiesterases (PDE) encourage planktonic lifestyle. The activity of these enzymes can be modulated by stimuli-sensing domains such as Per-ARNT-Sim (PAS). In Pseudomonas aeruginosa, more than 40 PDE/DGC are involved in c-di-GMP homeostasis, including 16 dual proteins possessing both canonical DGC and PDE motifs, that is, GGDEF and EAL, respectively. It was reported that deletion of the EAL/GGDEF dual enzyme PA0285, one of five c-di-GMP-related enzymes conserved across all Pseudomonas species, impacts biofilms. PA0285 is anchored in the membrane and carries two PAS domains. Here, we confirm that its role is conserved in various P. aeruginosa strains and in Pseudomonas putida. Deletion of PA0285 impacts the early stage of colonization, and RNA-seq analysis suggests that expression of cupA fimbrial genes is involved. We demonstrate that the C-terminal portion of PA0285 encompassing the GGDEF and EAL domains binds GTP and c-di-GMP, respectively, but only exhibits PDE activity in vitro. However, both GGDEF and EAL domains are important for PA0285 PDE activity in vivo. Complementation of the PA0285 mutant strain with a copy of the gene encoding the C-terminal GGDEF/EAL portion in trans was not as effective as complementation with the full-length gene. This suggests the N-terminal transmembrane and PAS domains influence the PDE activity in vivo, through modulating the protein conformation.
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Affiliation(s)
- Kira Eilers
- CBRB Centre for Bacterial Resistance Biology, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Joey Kuok Hoong Yam
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
| | - Xianghui Liu
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
| | - Yu Fen Goh
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
| | - Ka-Ning To
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
| | - Patricia Paracuellos
- CBRB Centre for Bacterial Resistance Biology, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Richard Morton
- CBRB Centre for Bacterial Resistance Biology, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Jaime Brizuela
- CBRB Centre for Bacterial Resistance Biology, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Adeline Mei Hui Yong
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
| | - Michael Givskov
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore; Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Denmark
| | - Sven-Andreas Freibert
- Philipps University Marburg, Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Gert Bange
- Philipps University Marburg, Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany
| | - Scott A Rice
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore; Microbiomes for One Systems Health and Agriculture and Food, CSIRO, Westmead, New South Wales, Australia
| | - Wieland Steinchen
- Philipps University Marburg, Center for Synthetic Microbiology (SYNMIKRO), Marburg, Germany.
| | - Alain Filloux
- CBRB Centre for Bacterial Resistance Biology, Department of Life Sciences, Imperial College London, London, United Kingdom; Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore.
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Jin Z, Song D, Wang W, Feng L, Li Z, Chen H, Xiao X, Liu X. Synthesis and degradation of the cyclic dinucleotide messenger c-di-AMP in the hyperthermophilic archaeon Pyrococcus yayanosii. Protein Sci 2023; 32:e4829. [PMID: 37921047 PMCID: PMC10680344 DOI: 10.1002/pro.4829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 10/28/2023] [Accepted: 10/31/2023] [Indexed: 11/04/2023]
Abstract
Cyclic di-adenosine monophosphate (c-di-AMP) is a newly identified prokaryotic cyclic dinucleotide second messenger well elucidated in bacteria, while less studied in archaea. Here, we describe the enzymes involved in c-di-AMP metabolism in the hyperthermophilic archaeon Pyrococcus yayanosii. Our results demonstrate that c-di-AMP is synthesized from two molecules of ATP by diadenylate cyclase (DAC) and degraded into pApA and then to AMP by a DHH family phosphodiesterase (PDE). DAC can be activated by a wider variety of ions, using two conserved residues, D188 and E244, to coordinate divalent metal ions, which is different from bacterial CdaA and DisA. PDE possesses a broad substrate spectrum like bacterial DHH family PDEs but shows a stricter base selection between A and G in cyclic dinucleotides hydrolysis. PDE shows differences in substrate binding patches from bacterial counterparts. C-di-AMP was confirmed to exist in Thermococcus kodakarensis cells, and the deletion of the dac or pde gene supports that the synthesis and degradation of c-di-AMP are catalyzed by DAC and PDE, respectively. Our results provide a further understanding of the metabolism of c-di-AMP in archaea.
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Affiliation(s)
- Zheng Jin
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
- Instrumental analysis centerShanghai Jiao Tong UniversityShanghaiChina
| | - Dong Song
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
| | - Wei‐Wei Wang
- Shanghai Institute of Applied PhysicsChinese Academy of SciencesShanghaiChina
| | - Lei Feng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
| | - Zheng‐Xin Li
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
| | - Hai‐Feng Chen
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
- Joint International Research Laboratory of Metabolic & Developmental Sciences (Ministry of Education)Shanghai Jiao Tong UniversityShanghaiChina
| | - Xiang Xiao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
- State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghaiChina
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai)ZhuhaiGuangdongChina
| | - Xi‐Peng Liu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
- Joint International Research Laboratory of Metabolic & Developmental Sciences (Ministry of Education)Shanghai Jiao Tong UniversityShanghaiChina
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Lee VT, Sondermann H, Winkler WC. Nano-RNases: oligo- or dinucleases? FEMS Microbiol Rev 2022; 46:6677394. [PMID: 36026528 PMCID: PMC9779919 DOI: 10.1093/femsre/fuac038] [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: 09/23/2021] [Revised: 07/28/2022] [Accepted: 08/24/2022] [Indexed: 01/07/2023] Open
Abstract
Diribonucleotides arise from two sources: turnover of RNA transcripts (rRNA, tRNA, mRNA, and others) and linearization of cyclic-di-nucleotide signaling molecules. In both cases, there appears to be a requirement for a dedicated set of enzymes that will cleave these diribonucleotides into mononucleotides. The first enzyme discovered to mediate this activity is oligoribonuclease (Orn) from Escherichia coli. In addition to being the enzyme that cleaves dinucleotides and potentially other short oligoribonucleotides, Orn is also the only known exoribonuclease enzyme that is essential for E. coli, suggesting that removal of the shortest RNAs is an essential cellular function. Organisms naturally lacking the orn gene encode other nanoRNases (nrn) that can complement the conditional E. coli orn mutant. This review covers the history and recent advances in our understanding of these enzymes and their substrates. In particular, we focus on (i) the sources of diribonucleotides; (ii) the discovery of exoribonucleases; (iii) the structural features of Orn, NrnA/NrnB, and NrnC; (iv) the enzymatic activity of these enzymes against diribonucleotides versus other substrates; (v) the known physiological consequences of accumulation of linear dinucleotides; and (vi) outstanding biological questions for diribonucleotides and diribonucleases.
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Pathania M, Tosi T, Millership C, Hoshiga F, Morgan RML, Freemont PS, Gründling A. Structural basis for the inhibition of the Bacillus subtilis c-di-AMP cyclase CdaA by the phosphoglucomutase GlmM. J Biol Chem 2021; 297:101317. [PMID: 34678313 PMCID: PMC8573169 DOI: 10.1016/j.jbc.2021.101317] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 11/25/2022] Open
Abstract
Cyclic-di-adenosine monophosphate (c-di-AMP) is an important nucleotide signaling molecule that plays a key role in osmotic regulation in bacteria. c-di-AMP is produced from two molecules of ATP by proteins containing a diadenylate cyclase (DAC) domain. In Bacillus subtilis, the main c-di-AMP cyclase, CdaA, is a membrane-linked cyclase with an N-terminal transmembrane domain followed by the cytoplasmic DAC domain. As both high and low levels of c-di-AMP have a negative impact on bacterial growth, the cellular levels of this signaling nucleotide are tightly regulated. Here we investigated how the activity of the B. subtilis CdaA is regulated by the phosphoglucomutase GlmM, which has been shown to interact with the c-di-AMP cyclase. Using the soluble B. subtilis CdaACD catalytic domain and purified full-length GlmM or the GlmMF369 variant lacking the C-terminal flexible domain 4, we show that the cyclase and phosphoglucomutase form a stable complex in vitro and that GlmM is a potent cyclase inhibitor. We determined the crystal structure of the individual B. subtilis CdaACD and GlmM homodimers and of the CdaACD:GlmMF369 complex. In the complex structure, a CdaACD dimer is bound to a GlmMF369 dimer in such a manner that GlmM blocks the oligomerization of CdaACD and formation of active head-to-head cyclase oligomers, thus suggesting a mechanism by which GlmM acts as a cyclase inhibitor. As the amino acids at the CdaACD:GlmM interphase are conserved, we propose that the observed mechanism of inhibition of CdaA by GlmM may also be conserved among Firmicutes.
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Affiliation(s)
- Monisha Pathania
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Tommaso Tosi
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Charlotte Millership
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Fumiya Hoshiga
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Rhodri M L Morgan
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Paul S Freemont
- London Biofoundry, Imperial College Translation and Innovation Hub, White City Campus, London, United Kingdom; Section of Structural and Synthetic Biology, Department of Infectious Disease, Imperial College London, London, United Kingdom; UK Dementia Research Institute Centre for Care Research and Technology, Imperial College London, London, United Kingdom.
| | - Angelika Gründling
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom.
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Gonzaga de França Lopes L, Gouveia Júnior FS, Karine Medeiros Holanda A, Maria Moreira de Carvalho I, Longhinotti E, Paulo TF, Abreu DS, Bernhardt PV, Gilles-Gonzalez MA, Cirino Nogueira Diógenes I, Henrique Silva Sousa E. Bioinorganic systems responsive to the diatomic gases O2, NO, and CO: From biological sensors to therapy. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.214096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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7
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Gibhardt J, Heidemann JL, Bremenkamp R, Rosenberg J, Seifert R, Kaever V, Ficner R, Commichau FM. An extracytoplasmic protein and a moonlighting enzyme modulate synthesis of c-di-AMP in Listeria monocytogenes. Environ Microbiol 2020; 22:2771-2791. [PMID: 32250026 DOI: 10.1111/1462-2920.15008] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 03/17/2020] [Accepted: 03/31/2020] [Indexed: 01/06/2023]
Abstract
The second messenger cyclic di-AMP (c-di-AMP) is essential for growth of many bacteria because it controls osmolyte homeostasis. c-di-AMP can regulate the synthesis of potassium uptake systems in some bacteria and it also directly inhibits and activates potassium import and export systems, respectively. Therefore, c-di-AMP production and degradation have to be tightly regulated depending on the environmental osmolarity. The Gram-positive pathogen Listeria monocytogenes relies on the membrane-bound diadenylate cyclase CdaA for c-di-AMP production and degrades the nucleotide with two phosphodiesterases. While the enzymes producing and degrading the dinucleotide have been reasonably well examined, the regulation of c-di-AMP production is not well understood yet. Here we demonstrate that the extracytoplasmic regulator CdaR interacts with CdaA via its transmembrane helix to modulate c-di-AMP production. Moreover, we show that the phosphoglucosamine mutase GlmM forms a complex with CdaA and inhibits the diadenylate cyclase activity in vitro. We also found that GlmM inhibits c-di-AMP production in L. monocytogenes when the bacteria encounter osmotic stress. Thus, GlmM is the major factor controlling the activity of CdaA in vivo. GlmM can be assigned to the class of moonlighting proteins because it is active in metabolism and adjusts the cellular turgor depending on environmental osmolarity.
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Affiliation(s)
- Johannes Gibhardt
- Department of General Microbiology, Institute for Microbiology and Genetics, University of Goettingen, 37077, Göttingen, Germany.,FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, 01968, Senftenberg, Germany
| | - Jana L Heidemann
- Department of Molecular Structural Biology, Institute for Microbiology and Genetics, GZMB, University of Goettingen, 37077, Göttingen, Germany
| | - Rica Bremenkamp
- Department of General Microbiology, Institute for Microbiology and Genetics, University of Goettingen, 37077, Göttingen, Germany
| | - Jonathan Rosenberg
- Department of General Microbiology, Institute for Microbiology and Genetics, University of Goettingen, 37077, Göttingen, Germany
| | - Roland Seifert
- Institute of Pharmacology & Research Core Unit Metabolomics, Hannover Medical School, Hannover, Germany
| | - Volkhard Kaever
- Institute of Pharmacology & Research Core Unit Metabolomics, Hannover Medical School, Hannover, Germany
| | - Ralf Ficner
- Department of Molecular Structural Biology, Institute for Microbiology and Genetics, GZMB, University of Goettingen, 37077, Göttingen, Germany
| | - Fabian M Commichau
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, 01968, Senftenberg, Germany
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Gaudu P, Yamamoto Y, Jensen PR, Hammer K, Lechardeur D, Gruss A. Genetics of Lactococci. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0035-2018. [PMID: 31298208 PMCID: PMC10957224 DOI: 10.1128/microbiolspec.gpp3-0035-2018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Indexed: 11/20/2022] Open
Abstract
Lactococcus lactis is the best characterized species among the lactococci, and among the most consumed food-fermenting bacteria worldwide. Thanks to their importance in industrialized food production, lactococci are among the lead bacteria understood for fundamental metabolic pathways that dictate growth and survival properties. Interestingly, lactococci belong to the Streptococcaceae family, which includes food, commensal and virulent species. As basic metabolic pathways (e.g., respiration, metal homeostasis, nucleotide metabolism) are now understood to underlie virulence, processes elucidated in lactococci could be important for understanding pathogen fitness and synergy between bacteria. This chapter highlights major findings in lactococci and related bacteria, and covers five themes: distinguishing features of lactococci, metabolic capacities including the less known respiration metabolism in Streptococcaceae, factors and pathways modulating stress response and fitness, interbacterial dialogue via metabolites, and novel applications in health and biotechnology.
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Affiliation(s)
| | - Yuji Yamamoto
- Laboratory of Cellular Microbiology, School of Veterinary Medicine, Kitasato University, Towada, 034-8628, Aomori Japan
| | - Peter Ruhdal Jensen
- National Food Institute, Technical University of Denmark, DK-2800 Lyngby, Denmark
| | - Karin Hammer
- DTU Bioengineering, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
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The Second Messenger c-di-AMP Regulates Diverse Cellular Pathways Involved in Stress Response, Biofilm Formation, Cell Wall Homeostasis, SpeB Expression, and Virulence in Streptococcus pyogenes. Infect Immun 2019; 87:IAI.00147-19. [PMID: 30936159 DOI: 10.1128/iai.00147-19] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 03/25/2019] [Indexed: 02/07/2023] Open
Abstract
Cyclic di-AMP (c-di-AMP) is a recently discovered second messenger in bacteria. The cellular level of c-di-AMP in Streptococcus pyogenes is predicted to be controlled by the synthase DacA and two putative phosphodiesterases, GdpP and Pde2. To investigate the role of c-di-AMP in S. pyogenes, we generated null mutants in each of these proteins by gene deletion. Unlike those in other Gram-positive pathogens such as Staphylococcus aureus and Listeria monocytogenes, DacA in S. pyogenes was not essential for growth in rich media. The DacA null mutant presented a growth defect that manifested through an increased lag time, produced no detectable biofilm, and displayed increased susceptibility toward environmental stressors such as high salt, low pH, reactive oxygen radicals, and cell wall-targeting antibiotics, suggesting that c-di-AMP plays significant roles in crucial cellular processes involved in stress management. The Pde2 null mutant exhibited a lower growth rate and increased biofilm formation, and interestingly, these phenotypes were distinct from those of the null mutant of GdpP, suggesting that Pde2 and GdpP play distinctive roles in c-di-AMP signaling. DacA and Pde2 were critical to the production of the virulence factor SpeB and to the overall virulence of S. pyogenes, as both DacA and Pde2 null mutants were highly attenuated in a mouse model of subcutaneous infection. Collectively, these results show that c-di-AMP is an important global regulator and is required for a proper response to stress and for virulence in S. pyogenes, suggesting that its signaling pathway could be an attractive antivirulence drug target against S. pyogenes infections.
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Abstract
SIGNIFICANCE The molecule nitric oxide (NO) has been shown to regulate behaviors in bacteria, including biofilm formation. NO detection and signaling in bacteria is typically mediated by hemoproteins such as the bis-(3',5')-cyclic dimeric adenosine monophosphate-specific phosphodiesterase YybT, the transcriptional regulator dissimilative nitrate respiration regulator, or heme-NO/oxygen binding (H-NOX) domains. H-NOX domains are well-characterized primary NO sensors that are capable of detecting nanomolar NO and influencing downstream signal transduction in many bacterial species. However, many bacteria, including the human pathogen Pseudomonas aeruginosa, respond to nanomolar concentrations of NO but do not contain an annotated H-NOX domain, indicating the existence of an additional nanomolar NO-sensing protein (NosP). Recent Advances: A newly discovered bacterial hemoprotein called NosP may also act as a primary NO sensor in bacteria, in addition to, or in place of, H-NOX. NosP was first described as a regulator of a histidine kinase signal transduction pathway that is involved in biofilm formation in P. aeruginosa. CRITICAL ISSUES The molecular details of NO signaling in bacteria are still poorly understood. There are still many bacteria that are NO responsive but do encode either H-NOX or NosP domains in their genomes. Even among bacteria that encode H-NOX or NosP, many questions remain. FUTURE DIRECTIONS The molecular mechanisms of NO regulation in many bacteria remain to be established. Future studies are required to gain knowledge about the mechanism of NosP signaling. Advancements on structural and molecular understanding of heme-based sensors in bacteria could lead to strategies to alleviate or control bacterial biofilm formation or persistent biofilm-related infections.
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Affiliation(s)
| | - Lisa-Marie Nisbett
- 2 Graduate Program in Biochemistry and Structural Biology, Stony Brook University , Stony Brook, New York
| | - Bezalel Bacon
- 2 Graduate Program in Biochemistry and Structural Biology, Stony Brook University , Stony Brook, New York
| | - Elizabeth Boon
- 1 Department of Chemistry, Stony Brook University , Stony Brook, New York.,2 Graduate Program in Biochemistry and Structural Biology, Stony Brook University , Stony Brook, New York.,3 Institute of Chemical Biology and Drug Design, Stony Brook University , Stony Brook, New York
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Making and Breaking of an Essential Poison: the Cyclases and Phosphodiesterases That Produce and Degrade the Essential Second Messenger Cyclic di-AMP in Bacteria. J Bacteriol 2018; 201:JB.00462-18. [PMID: 30224435 DOI: 10.1128/jb.00462-18] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cyclic di-AMP is a second-messenger nucleotide that is produced by many bacteria and some archaea. Recent work has shown that c-di-AMP is unique among the signaling nucleotides, as this molecule is in many bacteria both essential on one hand and toxic upon accumulation on the other. Moreover, in bacteria, like Bacillus subtilis, c-di-AMP controls a biological process, potassium homeostasis, by binding both potassium transporters and riboswitch molecules in the mRNAs that encode the potassium transporters. In addition to the control of potassium homeostasis, c-di-AMP has been implicated in many cellular activities, including DNA repair, cell wall homeostasis, osmotic adaptation, biofilm formation, central metabolism, and virulence. c-di-AMP is synthesized and degraded by diadenylate cyclases and phosphodiesterases, respectively. In the diadenylate cyclases, one type of catalytic domain, the diadenylate cyclase (DAC) domain, is coupled to various other domains that control the localization, the protein-protein interactions, and the regulation of the enzymes. The phosphodiesterases have a catalytic core that consists either of a DHH/DHHA1 or of an HD domain. Recent findings on the occurrence, domain organization, activity control, and structural features of diadenylate cyclases and phosphodiesterases are discussed in this review.
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Gas Sensing and Signaling in the PAS-Heme Domain of the Pseudomonas aeruginosa Aer2 Receptor. J Bacteriol 2017; 199:JB.00003-17. [PMID: 28167524 DOI: 10.1128/jb.00003-17] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 01/31/2017] [Indexed: 12/22/2022] Open
Abstract
The Aer2 chemoreceptor from Pseudomonas aeruginosa contains a PAS sensing domain that coordinates b-type heme and signals in response to the binding of O2, CO, or NO. PAS-heme structures suggest that Aer2 uniquely coordinates heme via a His residue on a 310 helix (H234 on Eη), stabilizes O2 binding via a Trp residue (W283), and signals via both W283 and an adjacent Leu residue (L264). Ligand binding may displace L264 and reorient W283 for hydrogen bonding to the ligand. Here, we clarified the mechanisms by which Aer2-PAS binds heme, regulates ligand binding, and initiates conformational signaling. H234 coordinated heme, but additional hydrophobic residues in the heme cleft were also critical for stable heme binding. O2 appeared to be the native Aer2 ligand (dissociation constant [Kd ] of 16 μM). With one exception, mutants that bound O2 could signal, whereas many mutants that bound CO could not. W283 stabilized O2 binding but not CO binding, and it was required for signal initiation; W283 mutants that could not stabilize O2 were rapidly oxidized to Fe(III). W283F was the only Trp mutant that bound O2 with wild-type affinity. The size and nature of residue 264 was important for gas binding and signaling: L264W blocked O2 binding, L264A and L264G caused O2-mediated oxidation, and L264K formed a hexacoordinate heme. Our data suggest that when O2 binds to Aer2, L264 moves concomitantly with W283 to initiate the conformational signal. The signal then propagates from the PAS domain to regulate the C-terminal HAMP and kinase control domains, ultimately modulating a cellular response.IMPORTANCEPseudomonas aeruginosa is a ubiquitous environmental bacterium and opportunistic pathogen that infects multiple body sites, including the lungs of cystic fibrosis patients. P. aeruginosa senses and responds to its environment via four chemosensory systems. Three of these systems regulate biofilm formation, twitching motility, and chemotaxis. The role of the fourth system, Che2, is unclear but has been implicated in virulence. The Che2 system contains a chemoreceptor called Aer2, which contains a PAS sensing domain that binds heme and senses oxygen. Here, we show that Aer2 uses unprecedented mechanisms to bind O2 and initiate signaling. These studies provide both the first functional corroboration of the Aer2-PAS signaling mechanism previously proposed from structure as well as a signaling model for Aer2-PAS receptors.
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Fahmi T, Port GC, Cho KH. c-di-AMP: An Essential Molecule in the Signaling Pathways that Regulate the Viability and Virulence of Gram-Positive Bacteria. Genes (Basel) 2017; 8:E197. [PMID: 28783096 PMCID: PMC5575661 DOI: 10.3390/genes8080197] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 07/29/2017] [Accepted: 07/31/2017] [Indexed: 11/16/2022] Open
Abstract
Signal transduction pathways enable organisms to monitor their external environment and adjust gene regulation to appropriately modify their cellular processes. Second messenger nucleotides including cyclic adenosine monophosphate (c-AMP), cyclic guanosine monophosphate (c-GMP), cyclic di-guanosine monophosphate (c-di-GMP), and cyclic di-adenosine monophosphate (c-di-AMP) play key roles in many signal transduction pathways used by prokaryotes and/or eukaryotes. Among the various second messenger nucleotides molecules, c-di-AMP was discovered recently and has since been shown to be involved in cell growth, survival, and regulation of virulence, primarily within Gram-positive bacteria. The cellular level of c-di-AMP is maintained by a family of c-di-AMP synthesizing enzymes, diadenylate cyclases (DACs), and degradation enzymes, phosphodiesterases (PDEs). Genetic manipulation of DACs and PDEs have demonstrated that alteration of c-di-AMP levels impacts both growth and virulence of microorganisms. Unlike other second messenger molecules, c-di-AMP is essential for growth in several bacterial species as many basic cellular functions are regulated by c-di-AMP including cell wall maintenance, potassium ion homeostasis, DNA damage repair, etc. c-di-AMP follows a typical second messenger signaling pathway, beginning with binding to receptor molecules to subsequent regulation of downstream cellular processes. While c-di-AMP binds to specific proteins that regulate pathways in bacterial cells, c-di-AMP also binds to regulatory RNA molecules that control potassium ion channel expression in Bacillus subtilis. c-di-AMP signaling also occurs in eukaryotes, as bacterially produced c-di-AMP stimulates host immune responses during infection through binding of innate immune surveillance proteins. Due to its existence in diverse microorganisms, its involvement in crucial cellular activities, and its stimulating activity in host immune responses, c-di-AMP signaling pathway has become an attractive antimicrobial drug target and therefore has been the focus of intensive study in several important pathogens.
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Affiliation(s)
- Tazin Fahmi
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA.
| | - Gary C Port
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, MO 63110, USA.
- Elanco Animal Health, Natural Products Fermentation, Eli Lilly and Company, Indianapolis, IN 46285, USA.
| | - Kyu Hong Cho
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA.
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Pham TH, Liang ZX, Marcellin E, Turner MS. Replenishing the cyclic-di-AMP pool: regulation of diadenylate cyclase activity in bacteria. Curr Genet 2016; 62:731-738. [PMID: 27074767 DOI: 10.1007/s00294-016-0600-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 03/29/2016] [Accepted: 04/01/2016] [Indexed: 02/08/2023]
Abstract
Bacteria can sense environmental cues and alter their physiology accordingly through the use of signal transduction pathways involving second messenger nucleotides. One broadly conserved second messenger is cyclic-di-AMP (c-di-AMP) which regulates a range of processes including cell wall homeostasis, potassium uptake, DNA repair, fatty acid synthesis, biofilm formation and central metabolism in bacteria. The intracellular pool of c-di-AMP is maintained by the activities of diadenylate cyclase (DAC) and phosphodiesterase (PDE) enzymes, as well as possibly via c-di-AMP export. Whilst extracellular stimuli regulating c-di-AMP levels in bacteria are poorly understood, recent work has identified effector proteins which directly interact and alter the activity of DACs. These include the membrane bound CdaR and the phosphoglucosamine mutase GlmM which both bind directly to the membrane bound CdaA DAC and the recombination protein RadA which binds directly to the DNA binding DisA DAC. The genes encoding these multiprotein complexes are co-localised in many bacteria providing further support for their functional connection. The roles of GlmM in peptidoglycan synthesis and RadA in Holliday junction intermediate processing suggest that c-di-AMP synthesis by DACs will be responsive to these cellular activities. In addition to these modulatory interactions, permanent dysregulation of DAC activity due to suppressor mutations can occur during selection to overcome growth defects, rapid cell lysis and osmosensitivity. DACs have also been investigated as targets for the development of new antibiotics and several small compound inhibitors have recently been identified. This review aims to provide an overview of how c-di-AMP synthesis by DACs can be regulated.
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Affiliation(s)
- Thi Huong Pham
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD, Australia
| | - Zhao-Xun Liang
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, QLD, Australia
| | - Mark S Turner
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD, Australia.
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, QLD, Australia.
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15
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Huynh TN, Woodward JJ. Too much of a good thing: regulated depletion of c-di-AMP in the bacterial cytoplasm. Curr Opin Microbiol 2016; 30:22-29. [PMID: 26773214 DOI: 10.1016/j.mib.2015.12.007] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 12/14/2015] [Accepted: 12/15/2015] [Indexed: 01/11/2023]
Abstract
Bacteria that synthesize c-di-AMP also encode several mechanisms for controlling c-di-AMP levels within the cytoplasm. One major class of phosphodiesterases comprises GdpP and DhhP homologs, which degrade c-di-AMP into the linear molecule 5'-pApA or AMP by the DHH-DHHA1 domain. The other major class comprises PgpH homologs, which degrade c-di-AMP by the HD domain. Both GdpP and PgpH harbor sensory domains, likely to regulate c-di-AMP hydrolysis activity in response to signal input. As another possible mechanism for controlling cytoplasmic c-di-AMP levels, bacteria also secrete c-di-AMP via multidrug resistance transporters, as demonstrated for Listeria monocytogenes. Mutants that accumulate high c-di-AMP levels, by deletion of phosphodiesterases or multidrug resistance transporters, exhibit aberrant physiology, growth defects, and attenuated virulence in infection.
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Affiliation(s)
- TuAnh Ngoc Huynh
- Department of Microbiology, University of Washington, Seattle, WA, United States
| | - Joshua J Woodward
- Department of Microbiology, University of Washington, Seattle, WA, United States.
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16
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Zhu Y, Pham TH, Nhiep THN, Vu NMT, Marcellin E, Chakrabortti A, Wang Y, Waanders J, Lo R, Huston WM, Bansal N, Nielsen LK, Liang ZX, Turner MS. Cyclic-di-AMP synthesis by the diadenylate cyclase CdaA is modulated by the peptidoglycan biosynthesis enzyme GlmM in Lactococcus lactis. Mol Microbiol 2015; 99:1015-27. [PMID: 26585449 DOI: 10.1111/mmi.13281] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2015] [Indexed: 12/28/2022]
Abstract
The second messenger cyclic-di-adenosine monophosphate (c-di-AMP) plays important roles in growth, virulence, cell wall homeostasis, potassium transport and affects resistance to antibiotics, heat and osmotic stress. Most Firmicutes contain only one c-di-AMP synthesizing diadenylate cyclase (CdaA); however, little is known about signals and effectors controlling CdaA activity and c-di-AMP levels. In this study, a genetic screen was employed to identify components which affect the c-di-AMP level in Lactococcus. We characterized suppressor mutations that restored osmoresistance to spontaneous c-di-AMP phosphodiesterase gdpP mutants, which contain high c-di-AMP levels. Loss-of-function and gain-of-function mutations were identified in the cdaA and gdpP genes, respectively, which led to lower c-di-AMP levels. A mutation was also identified in the phosphoglucosamine mutase gene glmM, which is commonly located within the cdaA operon in bacteria. The glmM I154F mutation resulted in a lowering of the c-di-AMP level and a reduction in the key peptidoglycan precursor UDP-N-acetylglucosamine in L. lactis. C-di-AMP synthesis by CdaA was shown to be inhibited by GlmM(I154F) more than GlmM and GlmM(I154F) was found to bind more strongly to CdaA than GlmM. These findings identify GlmM as a c-di-AMP level modulating protein and provide a direct connection between c-di-AMP synthesis and peptidoglycan biosynthesis.
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Affiliation(s)
- Yan Zhu
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Thi Huong Pham
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia.,University of Science and Technology, The University of Danang, Da Nang, Vietnam
| | - Thi Hanh Nguyen Nhiep
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Ngoc Minh Thu Vu
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Esteban Marcellin
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland, Australia
| | - Alolika Chakrabortti
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Yuanliang Wang
- College of Food Science and Technology, Hunan Agricultural University, Changsha, Hunan Province, China
| | - Jennifer Waanders
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Raquel Lo
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Wilhelmina M Huston
- School of Life Sciences, University of Technology Sydney, Sydney, New South Wales, Australia
| | - Nidhi Bansal
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Lars K Nielsen
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland, Australia
| | - Zhao-Xun Liang
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Mark S Turner
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, Queensland, Australia.,Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, Queensland, Australia
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17
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Zheng C, Ma Y, Wang X, Xie Y, Ali MK, He J. Functional analysis of the sporulation-specific diadenylate cyclase CdaS in Bacillus thuringiensis. Front Microbiol 2015; 6:908. [PMID: 26441857 PMCID: PMC4568413 DOI: 10.3389/fmicb.2015.00908] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 08/19/2015] [Indexed: 01/03/2023] Open
Abstract
Cyclic di-AMP (c-di-AMP) is a recently discovered bacterial secondary messenger molecule, which is associated with various physiological functions. In the genus Bacillus, the intracellular level and turnover of c-di-AMP are mainly regulated by three diadenylate cyclases (DACs), including DisA, CdaA and CdaS, and two c-di-AMP-specific phosphodiesterases (GdpP and PgpH). In this study, we demonstrated that CdaS protein from B. thuringiensis is a hexameric DAC protein that can convert ATP or ADP to c-di-AMP in vitro and the N-terminal YojJ domain is essential for the DAC activity. Based on the markerless gene knock-out method, we demonstrated that the transcription of cdaS was initiated by the sporulation-specific sigma factor σ(H) and the deletion of cdaS significantly delayed sporulation and parasporal crystal formation. These findings contrast with similar experiments conducted using B. subtilis, wherein transcription of its cdaS was initiated by the sigma factor σ(G). Deletion of all the three DAC genes from a single strain was unsuccessful, suggesting that c-di-AMP is an indispensable molecule in B. thuringiensis. Phylogenetic analysis indicated increased diversity of CdaS in the B. cereus and B. subtilis Bacillus subgroups. In summary, this study identifies important aspects in the regulation of c-di-AMP in the genus Bacillus.
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Affiliation(s)
- Cao Zheng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University Wuhan, China
| | - Yang Ma
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University Wuhan, China
| | - Xun Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University Wuhan, China
| | - Yuqun Xie
- Key Laboratory of Fermentation Engineering (Ministry of Education), College of Bioengineering, Hubei University of Technology Wuhan, China
| | - Maria K Ali
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University Wuhan, China
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University Wuhan, China
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18
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Shimizu T, Huang D, Yan F, Stranava M, Bartosova M, Fojtíková V, Martínková M. Gaseous O2, NO, and CO in signal transduction: structure and function relationships of heme-based gas sensors and heme-redox sensors. Chem Rev 2015; 115:6491-533. [PMID: 26021768 DOI: 10.1021/acs.chemrev.5b00018] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Toru Shimizu
- †Department of Cell Biology and Genetics and Key Laboratory of Molecular Biology in High Cancer Incidence Coastal Chaoshan Area of Guangdong Higher Education Institutes, Shantou University Medical College, Shantou, Guangdong 515041, China
- ‡Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague 2 128 43, Czech Republic
- §Research Center for Compact Chemical System, National Institute of Advanced Industrial Science and Technology (AIST), Sendai 983-8551, Japan
| | - Dongyang Huang
- †Department of Cell Biology and Genetics and Key Laboratory of Molecular Biology in High Cancer Incidence Coastal Chaoshan Area of Guangdong Higher Education Institutes, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Fang Yan
- †Department of Cell Biology and Genetics and Key Laboratory of Molecular Biology in High Cancer Incidence Coastal Chaoshan Area of Guangdong Higher Education Institutes, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Martin Stranava
- ‡Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague 2 128 43, Czech Republic
| | - Martina Bartosova
- ‡Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague 2 128 43, Czech Republic
| | - Veronika Fojtíková
- ‡Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague 2 128 43, Czech Republic
| | - Markéta Martínková
- ‡Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague 2 128 43, Czech Republic
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19
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Commichau FM, Dickmanns A, Gundlach J, Ficner R, Stülke J. A jack of all trades: the multiple roles of the unique essential second messenger cyclic di-AMP. Mol Microbiol 2015; 97:189-204. [PMID: 25869574 DOI: 10.1111/mmi.13026] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/10/2015] [Indexed: 12/28/2022]
Abstract
Second messengers are key components of many signal transduction pathways. In addition to cyclic AMP, ppGpp and cyclic di-GMP, many bacteria use also cyclic di-AMP as a second messenger. This molecule is synthesized by distinct classes of diadenylate cyclases and degraded by phosphodiesterases. The control of the intracellular c-di-AMP pool is very important since both a lack of this molecule and its accumulation can inhibit growth of the bacteria. In many firmicutes, c-di-AMP is essential, making it the only known essential second messenger. Cyclic di-AMP is implicated in a variety of functions in the cell, including cell wall metabolism, potassium homeostasis, DNA repair and the control of gene expression. To understand the molecular mechanisms behind these functions, targets of c-di-AMP have been identified and characterized. Interestingly, c-di-AMP can bind both proteins and RNA molecules. Several proteins that interact with c-di-AMP are required to control the intracellular potassium concentration. In Bacillus subtilis, c-di-AMP also binds a riboswitch that controls the expression of a potassium transporter. Thus, c-di-AMP is the only known second messenger that controls a biological process by interacting with both a protein and the riboswitch that regulates its expression. Moreover, in Listeria monocytogenes c-di-AMP controls the activity of pyruvate carboxylase, an enzyme that is required to replenish the citric acid cycle. Here, we review the components of the c-di-AMP signaling system.
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Affiliation(s)
- Fabian M Commichau
- Department of General Microbiology, Georg-August-University Göttingen, Grisebachstr. 8, D-37077, Göttingen, Germany
| | - Achim Dickmanns
- Department of Molecular Structural Biology, Georg-August-University Göttingen, Justus-von-Liebig-Weg 11, D-37077, Göttingen, Germany
| | - Jan Gundlach
- Department of General Microbiology, Georg-August-University Göttingen, Grisebachstr. 8, D-37077, Göttingen, Germany
| | - Ralf Ficner
- Department of Molecular Structural Biology, Georg-August-University Göttingen, Justus-von-Liebig-Weg 11, D-37077, Göttingen, Germany
| | - Jörg Stülke
- Department of General Microbiology, Georg-August-University Göttingen, Grisebachstr. 8, D-37077, Göttingen, Germany
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Aono S. The Dos family of globin-related sensors using PAS domains to accommodate haem acting as the active site for sensing external signals. Adv Microb Physiol 2013; 63:273-327. [PMID: 24054799 DOI: 10.1016/b978-0-12-407693-8.00007-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Sensor proteins play crucial roles in maintaining homeostasis of cells by sensing changes in extra- and intracellular chemical and physical conditions to trigger biological responses. It has recently become clear that gas molecules function as signalling molecules in these biological regulatory systems responsible for transcription, chemotaxis, synthesis/hydrolysis of nucleotide second messengers, and other complex physiological processes. Haem-containing sensor proteins are widely used to sense gas molecules because haem can bind gas molecules reversibly. Ligand binding to the haem in the sensor proteins triggers conformational changes around the haem, which results in their functional regulation. Spectroscopic and crystallographic studies are essential to understand how these sensor proteins function in these biological regulatory systems. In this chapter, I discuss structural and functional relationships of haem-containing PAS and PAS-related families of the sensor proteins.
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