1
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Fraikin N, Van Melderen L. Single-cell evidence for plasmid addiction mediated by toxin-antitoxin systems. Nucleic Acids Res 2024; 52:1847-1859. [PMID: 38224456 PMCID: PMC10899753 DOI: 10.1093/nar/gkae018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 12/22/2023] [Accepted: 01/03/2024] [Indexed: 01/16/2024] Open
Abstract
Toxin-antitoxin (TA) systems are small selfish genetic modules that increase vertical stability of their replicons. They have long been thought to stabilize plasmids by killing cells that fail to inherit a plasmid copy through a phenomenon called post-segregational killing (PSK) or addiction. While this model has been widely accepted, no direct observation of PSK was reported in the literature. Here, we devised a system that enables visualization of plasmid loss and PSK at the single-cell level using meganuclease-driven plasmid curing. Using the ccd system, we show that cells deprived of a ccd-encoding plasmid show hallmarks of DNA damage, i.e. filamentation and induction of the SOS response. Activation of ccd triggered cell death in most plasmid-free segregants, although some intoxicated cells were able to resume growth, showing that PSK-induced damage can be repaired in a SOS-dependent manner. Damage induced by ccd activates resident lambdoid prophages, which potentiate the killing effect of ccd. The loss of a model plasmid containing TA systems encoding toxins presenting various molecular mechanisms induced different morphological changes, growth arrest and loss of viability. Our experimental setup enables further studies of TA-induced phenotypes and suggests that PSK is a general mechanism for plasmid stabilization by TA systems.
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Affiliation(s)
- Nathan Fraikin
- Bacterial Genetics and Physiology, Department of Molecular Biology, Faculté des Sciences, Université Libre de Bruxelles (ULB), 6041 Gosselies, Belgium
| | - Laurence Van Melderen
- Bacterial Genetics and Physiology, Department of Molecular Biology, Faculté des Sciences, Université Libre de Bruxelles (ULB), 6041 Gosselies, Belgium
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2
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Ardissone S, Greub G. The Chlamydia-related Waddlia chondrophila encodes functional type II toxin-antitoxin systems. Appl Environ Microbiol 2024; 90:e0068123. [PMID: 38214519 PMCID: PMC10880633 DOI: 10.1128/aem.00681-23] [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: 04/25/2023] [Accepted: 11/13/2023] [Indexed: 01/13/2024] Open
Abstract
Bacterial toxin-antitoxin (TA) systems are widespread in chromosomes and plasmids of free-living microorganisms, but only a few have been identified in obligate intracellular species. We found seven putative type II TA modules in Waddlia chondrophila, a Chlamydia-related species that is able to infect a very broad series of eukaryotic hosts, ranging from protists to mammalian cells. The RNA levels of Waddlia TA systems are significantly upregulated by iron starvation and novobiocin, but they are not affected by antibiotics such as β-lactams and glycopeptides, which suggests different mechanisms underlying stress responses. Five of the identified TA modules, including HigBA1 and MazEF1, encoded on the Waddlia cryptic plasmid, proved to be functional when expressed in a heterologous host. TA systems have been associated with the maintenance of mobile genetic elements, bacterial defense against bacteriophages, and persistence upon exposure to adverse conditions. As their RNA levels are upregulated upon exposure to adverse conditions, Waddlia TA modules may be involved in survival to stress. Moreover, as Waddlia can infect a wide range of hosts including free-living amoebae, TA modules could also represent an innate immunity system to fight against bacteriophages and other microorganisms with which Waddlia has to share its replicative niche.IMPORTANCEThe response to adverse conditions, such as exposure to antibiotics, nutrient starvation and competition with other microorganisms, is essential for the survival of a bacterial population. TA systems are modules composed of two elements, a toxic protein and an antitoxin (protein or RNA) that counteracts the toxin. Although many aspects of TA biological functions still await to be elucidated, TAs have often been implicated in bacterial response to stress, including the response to nutrient starvation, antibiotic treatment and bacteriophage infection. TAs are ubiquitous in free-living bacteria but rare in obligate intracellular species such as chlamydiae. We identified functional TA systems in Waddlia chondrophila, a chlamydial species with a strikingly broad host range compared to other chlamydiae. Our work contributes to understand how obligate intracellular bacteria react to adverse conditions that might arise from competition with other viruses/bacteria for the same replicative niche and would threaten their ability to replicate.
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Affiliation(s)
- Silvia Ardissone
- Institute of Microbiology, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Gilbert Greub
- Institute of Microbiology, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
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3
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Lin S, Guo Y, Huang Z, Tang K, Wang X. Comparative Genomic Analysis of Cold-Water Coral-Derived Sulfitobacter faviae: Insights into Their Habitat Adaptation and Metabolism. Mar Drugs 2023; 21:md21050309. [PMID: 37233503 DOI: 10.3390/md21050309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/15/2023] [Accepted: 05/17/2023] [Indexed: 05/27/2023] Open
Abstract
Sulfitobacter is one of the major sulfite-oxidizing alphaproteobacterial groups and is often associated with marine algae and corals. Their association with the eukaryotic host cell may have important ecological contexts due to their complex lifestyle and metabolism. However, the role of Sulfitobacter in cold-water corals remains largely unexplored. In this study, we explored the metabolism and mobile genetic elements (MGEs) in two closely related Sulfitobacter faviae strains isolated from cold-water black corals at a depth of ~1000 m by comparative genomic analysis. The two strains shared high sequence similarity in chromosomes, including two megaplasmids and two prophages, while both contained several distinct MGEs, including prophages and megaplasmids. Additionally, several toxin-antitoxin systems and other types of antiphage elements were also identified in both strains, potentially helping Sulfitobacter faviae overcome the threat of diverse lytic phages. Furthermore, the two strains shared similar secondary metabolite biosynthetic gene clusters and genes involved in dimethylsulfoniopropionate (DMSP) degradation pathways. Our results provide insight into the adaptive strategy of Sulfitobacter strains to thrive in ecological niches such as cold-water corals at the genomic level.
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Affiliation(s)
- Shituan Lin
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yunxue Guo
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
| | - Zixian Huang
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kaihao Tang
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 511458, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
| | - Xiaoxue Wang
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 511458, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
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4
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Wachter S, Cockrell DC, Miller HE, Virtaneva K, Kanakabandi K, Darwitz B, Heinzen RA, Beare PA. The endogenous Coxiella burnetii plasmid encodes a functional toxin-antitoxin system. Mol Microbiol 2022; 118:744-764. [PMID: 36385554 PMCID: PMC10098735 DOI: 10.1111/mmi.15001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/25/2022] [Accepted: 11/08/2022] [Indexed: 11/18/2022]
Abstract
Coxiella burnetii is the causative agent of Q fever. All C. burnetii isolates encode either an autonomously replicating plasmid (QpH1, QpDG, QpRS, or QpDV) or QpRS-like chromosomally integrated plasmid sequences. The role of the ORFs present in these sequences is unknown. Here, the role of the ORFs encoded on QpH1 was investigated. Using a new C. burnetii shuttle vector (pB-TyrB-QpH1ori), we cured the C. burnetii Nine Mile Phase II strain of QpH1. The ΔQpH1 strain grew normally in axenic media but had a significant growth defect in Vero cells, indicating QpH1 was important for C. burnetii virulence. We developed an inducible CRISPR interference system to examine the role of individual QpH1 plasmid genes. CRISPRi of cbuA0027 resulted in significant growth defects in axenic media and THP-1 cells. The cbuA0028/cbuA0027 operon encodes CBUA0028 (ToxP) and CBUA0027 (AntitoxP), which are homologous to the HigB2 toxin and HigA2 antitoxin, respectively, from Vibrio cholerae. Consistent with toxin-antitoxin systems, overexpression of toxP resulted in a severe intracellular growth defect that was rescued by co-expression of antitoxP. ToxP inhibited protein translation. AntitoxP bound the toxP promoter (PtoxP) and ToxP, with the resulting complex binding also PtoxP. In summary, our data indicate that C. burnetii maintains an autonomously replicating plasmid because of a plasmid-based toxin-antitoxin system.
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Affiliation(s)
- Shaun Wachter
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA.,Vaccine and Infectious Disease Organization, Saskatoon, Saskatchewan, Canada
| | - Diane C Cockrell
- Vector-Pathogen-Host Interaction unit, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | | | - Kimmo Virtaneva
- Genomics Research Section, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Kishore Kanakabandi
- Genomics Research Section, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Benjamin Darwitz
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Robert A Heinzen
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Paul A Beare
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA.,Genomics Research Section, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
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5
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Mahdizadeh SJ, Pålsson E, Carlesso A, Chevet E, Eriksson LA. QM/MM Well-Tempered Metadynamics Study of the Mechanism of XBP1 mRNA Cleavage by Inositol Requiring Enzyme 1α RNase. J Chem Inf Model 2022; 62:4247-4260. [PMID: 35960929 PMCID: PMC9472280 DOI: 10.1021/acs.jcim.2c00735] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A range of in silico methodologies were herein employed to study the unconventional XBP1 mRNA cleavage mechanism performed by the unfolded protein response (UPR) mediator Inositol Requiring Enzyme 1α (IRE1). Using Protein-RNA molecular docking along with a series of extensive restrained/unrestrained atomistic molecular dynamics (MD) simulations, the dynamical behavior of the system was evaluated and a reliable model of the IRE1/XBP1 mRNA complex was constructed. From a series of well-converged quantum mechanics molecular mechanics well-tempered metadynamics (QM/MM WT-MetaD) simulations using the Grimme dispersion interaction corrected semiempirical parametrization method 6 level of theory (PM6-D3) and the AMBER14SB-OL3 force field, the free energy profile of the cleavage mechanism was determined, along with intermediates and transition state structures. The results show two distinct reaction paths based on general acid-general base type mechanisms, with different activation energies that perfectly match observations from experimental mutagenesis data. The study brings unique atomistic insights into the cleavage mechanism of XBP1 mRNA by IRE1 and clarifies the roles of the catalytic residues H910 and Y892. Increased understanding of the details in UPR signaling can assist in the development of new therapeutic agents for its modulation.
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Affiliation(s)
- Sayyed Jalil Mahdizadeh
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Göteborg, Sweden
| | - Emil Pålsson
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Göteborg, Sweden
| | - Antonio Carlesso
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Göteborg, Sweden.,Faculty of Biomedical Sciences, Euler Institute, Università della Svizzera Italiana (USI),, Lugano 6904, Switzerland.,Department of Pharmacology, Sahlgrenska Academy, University of Gothenburg, 405 30 Göteborg, Sweden
| | - Eric Chevet
- INSERM U1242, University of Rennes 1, 35000 Rennes, France.,Centre Eugène Marquis, 35000 Rennes, France
| | - Leif A Eriksson
- Department of Chemistry and Molecular Biology, University of Gothenburg, 405 30 Göteborg, Sweden
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6
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Mansour M, Giudice E, Xu X, Akarsu H, Bordes P, Guillet V, Bigot DJ, Slama N, D'urso G, Chat S, Redder P, Falquet L, Mourey L, Gillet R, Genevaux P. Substrate recognition and cryo-EM structure of the ribosome-bound TAC toxin of Mycobacterium tuberculosis. Nat Commun 2022; 13:2641. [PMID: 35552387 PMCID: PMC9098466 DOI: 10.1038/s41467-022-30373-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 04/27/2022] [Indexed: 11/16/2022] Open
Abstract
Toxins of toxin-antitoxin systems use diverse mechanisms to control bacterial growth. Here, we focus on the deleterious toxin of the atypical tripartite toxin-antitoxin-chaperone (TAC) system of Mycobacterium tuberculosis, whose inhibition requires the concerted action of the antitoxin and its dedicated SecB-like chaperone. We show that the TAC toxin is a bona fide ribonuclease and identify exact cleavage sites in mRNA targets on a transcriptome-wide scale in vivo. mRNA cleavage by the toxin occurs after the second nucleotide of the ribosomal A-site codon during translation, with a strong preference for CCA codons in vivo. Finally, we report the cryo-EM structure of the ribosome-bound TAC toxin in the presence of native M. tuberculosis cspA mRNA, revealing the specific mechanism by which the TAC toxin interacts with the ribosome and the tRNA in the P-site to cleave its mRNA target. Toxin-antitoxin systems are widespread in bacteria. Here the authors present structures of M. tuberculosis HigBTAC alone and bound to the ribosome in the presence of native cspA mRNA, shedding light on its mechanism of translation inhibition.
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Affiliation(s)
- Moise Mansour
- Laboratoire de Microbiologie et de Génétique Moléculaires, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Emmanuel Giudice
- Institut de Génétique et Développement de Rennes (IGDR), UMR6290, Université de Rennes, CNRS, Rennes, France
| | - Xibing Xu
- Laboratoire de Microbiologie et de Génétique Moléculaires, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Hatice Akarsu
- Department of Biology, University of Fribourg & Swiss Institute of Bioinformatics, Fribourg, Switzerland.,Institute of Veterinary Bacteriology, University of Bern, Bern, Switzerland
| | - Patricia Bordes
- Laboratoire de Microbiologie et de Génétique Moléculaires, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Valérie Guillet
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Donna-Joe Bigot
- Laboratoire de Microbiologie et de Génétique Moléculaires, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France.,Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Nawel Slama
- Laboratoire de Microbiologie et de Génétique Moléculaires, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Gaetano D'urso
- Institut de Génétique et Développement de Rennes (IGDR), UMR6290, Université de Rennes, CNRS, Rennes, France
| | - Sophie Chat
- Institut de Génétique et Développement de Rennes (IGDR), UMR6290, Université de Rennes, CNRS, Rennes, France
| | - Peter Redder
- Laboratoire de Microbiologie et de Génétique Moléculaires, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Laurent Falquet
- Department of Biology, University of Fribourg & Swiss Institute of Bioinformatics, Fribourg, Switzerland
| | - Lionel Mourey
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Reynald Gillet
- Institut de Génétique et Développement de Rennes (IGDR), UMR6290, Université de Rennes, CNRS, Rennes, France.
| | - Pierre Genevaux
- Laboratoire de Microbiologie et de Génétique Moléculaires, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France.
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7
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Abstract
Toxin-antitoxin systems are widespread in bacterial genomes. They are usually composed of two elements: a toxin that inhibits an essential cellular process and an antitoxin that counteracts its cognate toxin. In the past decade, a number of new toxin-antitoxin systems have been described, bringing new growth inhibition mechanisms to light as well as novel modes of antitoxicity. However, recent advances in the field profoundly questioned the role of these systems in bacterial physiology, stress response and antimicrobial persistence. This shifted the paradigm of the functions of toxin-antitoxin systems to roles related to interactions between hosts and their mobile genetic elements, such as viral defence or plasmid stability. In this Review, we summarize the recent progress in understanding the biology and evolution of these small genetic elements, and discuss how genomic conflicts could shape the diversification of toxin-antitoxin systems.
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8
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Richardson W, Kang GW, Lee HJ, Kwon KM, Kim S, Kim HJ. Chasing the structural diversity of the transcription regulator Mycobacterium tuberculosis HigA2. IUCRJ 2021; 8:823-832. [PMID: 34584743 PMCID: PMC8420761 DOI: 10.1107/s2052252521007715] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 07/28/2021] [Indexed: 06/13/2023]
Abstract
Transcription factors are the primary regulators of gene expression and recognize specific DNA sequences under diverse physiological conditions. Although they are vital for many important cellular processes, it remains unclear when and how transcription factors and DNA interact. The antitoxin from a toxin-antitoxin system is an example of negative transcriptional autoregulation: during expression of the cognate toxin it is suppressed through binding to a specific DNA sequence. In the present study, the antitoxin HigA2 from Mycobacterium tuberculosis M37Rv was structurally examined. The crystal structure of M. tuberculosis HigA2 comprises three sections: an N-terminal autocleavage region, an α-helix bundle which contains an HTH motif, and a C-terminal β-lid. The N-terminal region is responsible for toxin binding, but was shown to cleave spontaneously in its absence. The HTH motif performs a key role in DNA binding, with the C-terminal β-lid influencing the interaction by mediating the distance between the motifs. However, M. tuberculosis HigA2 exhibits a unique coordination of the HTH motif and no DNA-binding activity is detected. Three crystal structures of M. tuberculosis HigA2 show a flexible alignment of the HTH motif, which implies that the motif undergoes structural rearrangement to interact with DNA. This study reveals the molecular mechanisms of how transcription factors interact with partner proteins or DNA.
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Affiliation(s)
- William Richardson
- Centre for Biomolecular Sciences, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom
| | - Gyun Won Kang
- College of Pharmacy, Woosuk University, Wanju 55338, Republic of Korea
| | - Hee Joong Lee
- College of Pharmacy, Woosuk University, Wanju 55338, Republic of Korea
| | - Kang Mu Kwon
- College of Pharmacy, Woosuk University, Wanju 55338, Republic of Korea
| | - Saron Kim
- College of Pharmacy, Woosuk University, Wanju 55338, Republic of Korea
| | - Hyo Jung Kim
- Centre for Biomolecular Sciences, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom
- College of Pharmacy, Woosuk University, Wanju 55338, Republic of Korea
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9
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Characterisation of Early Positive mcr-1 Resistance Gene and Plasmidome in Escherichia coli Pathogenic Strains Associated with Variable Phylogroups under Colistin Selection. Antibiotics (Basel) 2021; 10:antibiotics10091041. [PMID: 34572623 PMCID: PMC8466100 DOI: 10.3390/antibiotics10091041] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/19/2021] [Accepted: 08/23/2021] [Indexed: 01/08/2023] Open
Abstract
An antibiotic susceptibility monitoring programme was conducted from 2004 to 2010, resulting in a collection of 143 Escherichia coli cultured from bovine faecal samples (diarrhoea) and milk-aliquots (mastitis). The isolates were subjected to whole-genome sequencing and were distributed in phylogroups A, B1, B2, C, D, E, and G with no correlation for particular genotypes with pathotypes. In fact, the population structure showed that the strains belonging to the different phylogroups matched broadly to ST complexes; however, the isolates are randomly associated with the diseases, highlighting the necessity to investigate the virulence factors more accurately in order to identify the mechanisms by which they cause disease. The antimicrobial resistance was assessed phenotypically, confirming the genomic prediction on three isolates that were resistant to colistin, although one isolate was positive for the presence of the gene mcr-1 but susceptible to colistin. To further characterise the genomic context, the four strains were sequenced by using a single-molecule long read approach. Genetic analyses indicated that these four isolates harboured complex and diverse plasmids encoding not only antibiotic resistant genes (including mcr-1 and bla) but also virulence genes (siderophore, ColV, T4SS). A detailed description of the plasmids of these four E. coli strains, which are linked to bovine mastitis and diarrhoea, is presented for the first time along with the characterisation of the predicted antibiotic resistance genes. The study highlighted the diversity of incompatibility types encoding complex antibiotic resistance elements such as Tn6330, ISEcp1, Tn6029, and IS5075. The mcr-1 resistance determinant was identified in IncHI2 plasmids pCFS3273-1 and pCFS3292-1, thus providing some of the earliest examples of mcr-1 reported in Europe, and these sequences may be a representative of the early mcr-1 plasmidome characterisation in the EU/EEA.
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10
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Kang S, Jin C, Kim D, Park SJ, Han S, Lee B. Structure-based design of peptides that trigger Streptococcus pneumoniae cell death. FEBS J 2021; 288:1546-1564. [PMID: 32770723 PMCID: PMC7984235 DOI: 10.1111/febs.15514] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 06/30/2020] [Accepted: 08/06/2020] [Indexed: 01/08/2023]
Abstract
Toxin-antitoxin (TA) systems regulate key cellular functions in bacteria. Here, we report a unique structure of the Streptococcus pneumoniae HigBA system and a novel antimicrobial agent that activates HigB toxin, which results in mRNA degradation as an antibacterial strategy. In this study, protein structure-based peptides were designed and successfully penetrated the S. pneumoniae cell membrane and exerted bactericidal activity. This result represents the time during which inhibitors triggered S. pneumoniae cell death via the TA system. This discovery is a remarkable milestone in the treatment of antibiotic-resistant S. pneumoniae, and the mechanism of bactericidal activity is completely different from those of current antibiotics. Furthermore, we found that the HigBA complex shows a crossed-scissor interface with two intermolecular β-sheets at both the N and C termini of the HigA antitoxin. Our biochemical and structural studies provided valuable information regarding the transcriptional regulation mechanisms associated with the structural variability of HigAs. Our in vivo study also revealed the potential catalytic residues of HigB and their functional relationships. An inhibition study with peptides additionally proved that peptide binding may allosterically inhibit HigB activity. Overall, our results provide insights into the molecular basis of HigBA TA systems in S. pneumoniae, which can be applied for the development of new antibacterial strategies. DATABASES: Structural data are available in the PDB database under the accession number 6AF4.
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Affiliation(s)
- Sung‐Min Kang
- Research Institute of Pharmaceutical Sciences, College of PharmacySeoul National UniversityGwanak‐guSeoulKorea
| | - Chenglong Jin
- Research Institute of Pharmaceutical Sciences, College of PharmacySeoul National UniversityGwanak‐guSeoulKorea
| | - Do‐Hee Kim
- College of PharmacyJeju National UniversityJejuKorea
- Interdisciplinary Graduate Program in Advanced Convergence Technology & ScienceJeju National UniversityJejuKorea
| | - Sung Jean Park
- Gachon Institute of Pharmaceutical Sciences, College of PharmacyGachon UniversityIncheonKorea
| | - Sang‐Woo Han
- Research Institute of Pharmaceutical Sciences, College of PharmacySeoul National UniversityGwanak‐guSeoulKorea
| | - Bong‐Jin Lee
- Research Institute of Pharmaceutical Sciences, College of PharmacySeoul National UniversityGwanak‐guSeoulKorea
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11
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McGillick J, Ames JR, Murphy T, Bourne CR. A YoeB toxin cleaves both RNA and DNA. Sci Rep 2021; 11:3592. [PMID: 33574407 PMCID: PMC7878887 DOI: 10.1038/s41598-021-82950-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 01/20/2021] [Indexed: 11/17/2022] Open
Abstract
Type II toxin-antitoxin systems contain a toxin protein, which mediates diverse interactions within the bacterial cell when it is not bound by its cognate antitoxin protein. These toxins provide a rich source of evolutionarily-conserved tertiary folds that mediate diverse catalytic reactions. These properties make toxins of interest in biotechnology applications, and studies of the catalytic mechanisms continue to provide surprises. In the current work, our studies on a YoeB family toxin from Agrobacterium tumefaciens have revealed a conserved ribosome-independent non-specific nuclease activity. We have quantified the RNA and DNA cleavage activity, revealing they have essentially equivalent dose-dependence while differing in requirements for divalent cations and pH sensitivity. The DNA cleavage activity is as a nickase for any topology of double-stranded DNA, as well as cleaving single-stranded DNA. AtYoeB is able to bind to double-stranded DNA with mid-micromolar affinity. Comparison of the ribosome-dependent and -independent reactions demonstrates an approximate tenfold efficiency imparted by the ribosome. This demonstrates YoeB toxins can act as non-specific nucleases, cleaving both RNA and DNA, in the absence of being bound within the ribosome.
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Affiliation(s)
- Julia McGillick
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, 73019, USA.,GENEiQ, Dallas, TX, USA
| | - Jessica R Ames
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, 73019, USA.,School of Physics, University of Bristol, Bristol, England
| | - Tamiko Murphy
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, 73019, USA.,Baylor College of Medicine, Houston, TX, USA
| | - Christina R Bourne
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, 73019, USA.
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12
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Abstract
Bacterial endoribonuclease toxins belong to a protein family that inhibits bacterial growth by degrading mRNA or rRNA sequences. The toxin genes are organized in pairs with its cognate antitoxins in the chromosome and thus the activities of the toxins are antagonized by antitoxin proteins or RNAs during active translation. In response to a variety of cellular stresses, the endoribonuclease toxins appear to be released from antitoxin molecules via proteolytic cleavage of antitoxin proteins or preferential degradation of antitoxin RNAs and cleave a diverse range of mRNA or rRNA sequences in a sequence-specific or codon-specific manner, resulting in various biological phenomena such as antibiotic tolerance and persister cell formation. Given that substrate specificity of each endoribonuclease toxin is determined by its structure and the composition of active site residues, we summarize the biology, structure, and substrate specificity of the updated bacterial endoribonuclease toxins.
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Affiliation(s)
- Yoontak Han
- Department of Life Sciences, Korea University, Seoul 02481, Korea
| | - Eun-Jin Lee
- Department of Life Sciences, Korea University, Seoul 02481, Korea
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13
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Klimkaitė L, Armalytė J, Skerniškytė J, Sužiedėlienė E. The Toxin-Antitoxin Systems of the Opportunistic Pathogen Stenotrophomonas maltophilia of Environmental and Clinical Origin. Toxins (Basel) 2020; 12:E635. [PMID: 33019620 PMCID: PMC7650669 DOI: 10.3390/toxins12100635] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/22/2020] [Accepted: 09/25/2020] [Indexed: 12/16/2022] Open
Abstract
Stenotrophomonas maltophilia is a ubiquitous environmental bacterium that has recently emerged as a multidrug-resistant opportunistic pathogen causing bloodstream, respiratory, and urinary tract infections. The connection between the commensal environmental S. maltophilia and the opportunistic pathogen strains is still under investigation. Bacterial toxin-antitoxin (TA) systems have been previously associated with pathogenic traits, such as biofilm formation and resistance to antibiotics, which are important in clinical settings. The same species of the bacterium can possess various sets of TAs, possibly influencing their overall stress response. While the TA systems of other important opportunistic pathogens have been researched, nothing is known about the TA systems of S. maltophilia. Here, we report the identification and characterization of S. maltophilia type II TA systems and their prevalence in the isolates of clinical and environmental origins. We found 49 putative TA systems by bioinformatic analysis in S. maltophilia genomes. Despite their even spread in sequenced S. maltophilia genomes, we observed that relBE, hicAB, and previously undescribed COG3832-ArsR operons were present solely in clinical S. maltophilia isolates collected in Lithuania, while hipBA was more frequent in the environmental ones. The kill-rescue experiments in Escherichia coli proved higBA, hicAB, and relBE systems to be functional TA modules. Together with different TA profiles, the clinical S. maltophilia isolates exhibited stronger biofilm formation, increased antibiotic, and serum resistance compared to environmental isolates. Such tendencies suggest that certain TA systems could be used as indicators of virulence traits.
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Affiliation(s)
| | - Julija Armalytė
- Institute of Biosciences, Life Sciences Center, Vilnius University, LT-1025 Vilnius, Lithuania; (L.K.); (J.S.)
| | | | - Edita Sužiedėlienė
- Institute of Biosciences, Life Sciences Center, Vilnius University, LT-1025 Vilnius, Lithuania; (L.K.); (J.S.)
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14
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Evaluating the Potential for Cross-Interactions of Antitoxins in Type II TA Systems. Toxins (Basel) 2020; 12:toxins12060422. [PMID: 32604745 PMCID: PMC7354431 DOI: 10.3390/toxins12060422] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 01/21/2023] Open
Abstract
The diversity of Type-II toxin–antitoxin (TA) systems in bacterial genomes requires tightly controlled interaction specificity to ensure protection of the cell, and potentially to limit cross-talk between toxin–antitoxin pairs of the same family of TA systems. Further, there is a redundant use of toxin folds for different cellular targets and complexation with different classes of antitoxins, increasing the apparent requirement for the insulation of interactions. The presence of Type II TA systems has remained enigmatic with respect to potential benefits imparted to the host cells. In some cases, they play clear roles in survival associated with unfavorable growth conditions. More generally, they can also serve as a “cure” against acquisition of highly similar TA systems such as those found on plasmids or invading genetic elements that frequently carry virulence and resistance genes. The latter model is predicated on the ability of these highly specific cognate antitoxin–toxin interactions to form cross-reactions between chromosomal antitoxins and invading toxins. This review summarizes advances in the Type II TA system models with an emphasis on antitoxin cross-reactivity, including with invading genetic elements and cases where toxin proteins share a common fold yet interact with different families of antitoxins.
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15
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Ames JR, McGillick J, Murphy T, Reddem E, Bourne CR. Identifying a Molecular Mechanism That Imparts Species-Specific Toxicity to YoeB Toxins. Front Microbiol 2020; 11:959. [PMID: 32528435 PMCID: PMC7256200 DOI: 10.3389/fmicb.2020.00959] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 04/21/2020] [Indexed: 11/24/2022] Open
Abstract
The ribosome-dependent E. coli (Ec) mRNase toxin YoeB has been demonstrated to protect cells during thermal stress. Agrobacterium tumefaciens (At), a plant pathogen, also encodes a YoeB toxin. Initial studies indicated that AtYoeB does not impact the growth of Ec, but its expression is toxic to the native host At. The current work examines this species-specific effect. We establish the highly similar structure and function of Ec and AtYoeB toxins, including the ability of the AtYoeB toxin to inhibit Ec ribosomes in vitro. Comparison of YoeB sequences and structures highlights a four-residue helix between β-strands 2 and 3 that interacts with mRNA bases within the ribosome. This helix sequence is varied among YoeB toxins, and this variation correlates with bacterial classes of proteobacteria. When the four amino acid sequence of this helix is transplanted from EcYoeB onto AtYoeB, the resulting chimera gains toxicity to Ec cells and lessens toxicity to At cells. The reverse is also true, such that EcYoeB with the AtYoeB helix sequence is less toxic to Ec and gains toxicity to At cultures. We suggest this helix sequence directs mRNA sequence-specific degradation, which varies among proteobacterial classes, and thus controls growth inhibition and YoeB toxicity.
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Affiliation(s)
- Jessica R Ames
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, United States
| | - Julia McGillick
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, United States
| | - Tamiko Murphy
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, United States
| | - Eswar Reddem
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, United States
| | - Christina R Bourne
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, United States
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16
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Jurėnas D, Van Melderen L. The Variety in the Common Theme of Translation Inhibition by Type II Toxin-Antitoxin Systems. Front Genet 2020; 11:262. [PMID: 32362907 PMCID: PMC7180214 DOI: 10.3389/fgene.2020.00262] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 03/05/2020] [Indexed: 12/12/2022] Open
Abstract
Type II Toxin–antitoxin (TA) modules are bacterial operons that encode a toxic protein and its antidote, which form a self-regulating genetic system. Antitoxins put a halter on toxins in many ways that distinguish different types of TA modules. In type II TA modules, toxin and antitoxin are proteins that form a complex which physically sequesters the toxin, thereby preventing its toxic activity. Type II toxins inhibit various cellular processes, however, the translation process appears to be their favorite target and nearly every step of this complex process is inhibited by type II toxins. The structural features, enzymatic activities and target specificities of the different toxin families are discussed. Finally, this review emphasizes that the structural folds presented by these toxins are not restricted to type II TA toxins or to one particular cellular target, and discusses why so many of them evolved to target translation as well as the recent developments regarding the role(s) of these systems in bacterial physiology and evolution.
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Affiliation(s)
- Dukas Jurėnas
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie de la Méditerranée, CNRS, Aix-Marseille Université, Marseille, France
| | - Laurence Van Melderen
- Cellular and Molecular Microbiology, Faculté des Sciences, Université libre de Bruxelles, Gosselies, Belgium
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17
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Liu Y, Gao Z, Liu G, Geng Z, Dong Y, Zhang H. Structural Insights Into the Transcriptional Regulation of HigBA Toxin-Antitoxin System by Antitoxin HigA in Pseudomonas aeruginosa. Front Microbiol 2020; 10:3158. [PMID: 32038588 PMCID: PMC6987408 DOI: 10.3389/fmicb.2019.03158] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 12/30/2019] [Indexed: 12/21/2022] Open
Abstract
HigB-HigA is a bacterial toxin-antitoxin (TA) system in which the antitoxin HigA can mask the endoribonuclease activity of toxin HigB and repress the transcription of the TA operon by binding to its own promoter region. The opportunistic pathogen Pseudomonas aeruginosa HigBA (PaHigBA) is closely associated with the pathogenicity by reducing the production of multiple virulence factors and biofilm formation. However, the molecular mechanism underlying HigBA TA operon transcription by PaHigA remains elusive. Here, we report the crystal structure of PaHigA binding to the promoter region of higBA operon containing two identical palindromic sequences at 3.14 Å resolution. The promoter DNA is bound by two cooperative dimers to essentially encircle the intact palindrome region. The helix-turn-helix (HTH) motifs from the two dimers insert into the major grooves of the DNA at the opposite sides. The DNA adopts a canonical B-DNA conformation and all the hydrogen bonds between protein and DNA are mediated by the DNA phosphate backbone. A higher resolution structure of PaHigA-DNA complex at 2.50 Å further revealed three water molecules bridged the DNA-binding interface and mediated the interactions between the bases of palindromic sequences and PaHigA (Thr40, Asp43, and Arg49). Structure-based mutagenesis confirmed these residues are essential for the specific DNA-binding ability of PaHigA. Our structure-function studies therefore elucidated the cooperative dimer-dimer transcription repression mechanism, and may help to understand the regulation of multiple virulence factors by PaHigA in P. aeruginosa.
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Affiliation(s)
- Ying Liu
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China
| | - Zengqiang Gao
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China
| | - Guangfeng Liu
- National Center for Protein Science Shanghai, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, China
| | - Zhi Geng
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China
| | - Yuhui Dong
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Heng Zhang
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China
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18
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Kurylo CM, Parks MM, Juette MF, Zinshteyn B, Altman RB, Thibado JK, Vincent CT, Blanchard SC. Endogenous rRNA Sequence Variation Can Regulate Stress Response Gene Expression and Phenotype. Cell Rep 2020; 25:236-248.e6. [PMID: 30282032 PMCID: PMC6312700 DOI: 10.1016/j.celrep.2018.08.093] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 08/16/2018] [Accepted: 08/30/2018] [Indexed: 11/30/2022] Open
Abstract
Prevailing dogma holds that ribosomes are uniform in composition and function. Here, we show that nutrient limitation-induced stress in E. coli changes the relative expression of rDNA operons to alter the rRNA composition within the actively translating ribosome pool. The most upregulated operon encodes the unique 16S rRNA, rrsH, distinguished by conserved sequence variation within the small ribosomal subunit. rrsH-bearing ribosomes affect the expression of functionally coherent gene sets and alter the levels of the RpoS sigma factor, the master regulator of the general stress response. These impacts are associated with phenotypic changes in antibiotic sensitivity, biofilm formation, and cell motility and are regulated by stress response proteins, RelA and RelE, as well as the metabolic enzyme and virulence-associated protein, AdhE. These findings establish that endogenously encoded, naturally occurring rRNA sequence variation can modulate ribosome function, central aspects of gene expression regulation, and cellular physiology. Most organisms encode multiple, distinct copies of rRNA genes, rendering the composition of the ribosome pool intrinsically heterogeneous. Here, Kurylo et al. show that nutrient limitation in E. coli upregulates the expression of ribosomes bearing conserved sequence variation in 16S rRNA that can regulate gene expression and phenotype.
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Affiliation(s)
- Chad M Kurylo
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - Matthew M Parks
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - Manuel F Juette
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - Boris Zinshteyn
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Roger B Altman
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - Jordana K Thibado
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - C Theresa Vincent
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Scott C Blanchard
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA; Tri-Institutional Training Program in Chemical Biology, Weill Cornell Medicine, New York, NY, USA.
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19
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Pavelich IJ, Maehigashi T, Hoffer ED, Ruangprasert A, Miles SJ, Dunham CM. Monomeric YoeB toxin retains RNase activity but adopts an obligate dimeric form for thermal stability. Nucleic Acids Res 2019; 47:10400-10413. [PMID: 31501867 PMCID: PMC6821326 DOI: 10.1093/nar/gkz760] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 08/13/2019] [Accepted: 08/21/2019] [Indexed: 11/30/2022] Open
Abstract
Chromosomally-encoded toxin-antitoxin complexes are ubiquitous in bacteria and regulate growth through the release of the toxin component typically in a stress-dependent manner. Type II ribosome-dependent toxins adopt a RelE-family RNase fold and inhibit translation by degrading mRNAs while bound to the ribosome. Here, we present biochemical and structural studies of the Escherichia coli YoeB toxin interacting with both a UAA stop and an AAU sense codon in pre- and post-mRNA cleavage states to provide insights into possible mRNA substrate selection. Both mRNAs undergo minimal changes during the cleavage event in contrast to type II ribosome-dependent RelE toxin. Further, the 16S rRNA decoding site nucleotides that monitor the mRNA in the aminoacyl(A) site adopt different orientations depending upon which toxin is present. Although YoeB is a RelE family member, it is the sole ribosome-dependent toxin that is dimeric. We show that engineered monomeric YoeB is active against mRNAs bound to both the small and large subunit. However, the stability of monomeric YoeB is reduced ∼20°C, consistent with potential YoeB activation during heat shock in E. coli as previously demonstrated. These data provide a molecular basis for the ability of YoeB to function in response to thermal stress.
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Affiliation(s)
- Ian J Pavelich
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, GA 30322, USA.,Department of Chemistry, Emory University, Atlanta, GA 30322, USA
| | - Tatsuya Maehigashi
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Eric D Hoffer
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, GA 30322, USA
| | | | - Stacey J Miles
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Christine M Dunham
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.,Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, GA 30322, USA
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20
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Ames JR, Muthuramalingam M, Murphy T, Najar FZ, Bourne CR. Expression of different ParE toxins results in conserved phenotypes with distinguishable classes of toxicity. Microbiologyopen 2019; 8:e902. [PMID: 31309747 PMCID: PMC6813445 DOI: 10.1002/mbo3.902] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 06/12/2019] [Accepted: 06/18/2019] [Indexed: 01/10/2023] Open
Abstract
Toxin–antitoxin (TA) systems are found on both chromosomes and plasmids. These systems are unique in that they can confer both fatal and protective effects on bacterial cells—a quality that could potentially be harnessed given further understanding of these TA mechanisms. The current work focuses on the ParE subfamily, which is found throughout proteobacteria and has a sequence identity on average of approximately 12% (similarity at 30%–80%). Our aim is to evaluate the equivalency of chromosomally derived ParE toxin activity depending on its bacterial species of origin. Nine ParE toxins were analyzed, originating from six different bacterial species. Based on the resulting toxicity, three categories can be established: ParE toxins that do not exert toxicity under the experimental conditions, toxins that exert toxicity within the first four hours, and those that exert toxicity only after 10–12 hr of exposure. All tested ParE toxins produce a cellular morphologic change from rods to filaments, consistent with disruption of DNA topology. Analysis of the distribution of filamented cells within a population reveals a correlation between the extent of filamentation and toxicity. No membrane septation is visible along the length of the cell filaments, whereas aberrant lipid blebs are evident. Potent ParE‐mediated toxicity is also correlated with a hallmark signature of abortive DNA replication, consistent with the inhibition of DNA gyrase.
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Affiliation(s)
- Jessica R Ames
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
| | | | - Tamiko Murphy
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
| | - Fares Z Najar
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
| | - Christina R Bourne
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
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21
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Guo Y, Sun C, Li Y, Tang K, Ni S, Wang X. Antitoxin HigA inhibits virulence gene mvfR expression in Pseudomonas aeruginosa. Environ Microbiol 2019; 21:2707-2723. [PMID: 30882983 DOI: 10.1111/1462-2920.14595] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 03/07/2019] [Accepted: 03/17/2019] [Indexed: 01/14/2023]
Abstract
Toxin/antitoxin (TA) systems are ubiquitous in bacteria and archaea and participate in biofilm formation and stress responses. The higBA locus of the opportunistic pathogen Pseudomonas aeruginosa encodes a type II TA system. Previous work found that the higBA operon is cotranscribed and that HigB toxin regulates biofilm formation and virulence expression. In this study, we demonstrate that HigA antitoxin is produced at a higher level than HigB and that higA mRNA is expressed separately from a promoter inside higB during the late stationary phase. Critically, HigA represses the expression of mvfR, which is an important virulence-related regulator, by binding to a conserved HigA palindrome (5'-TTAAC GTTAA-3') in the mvfR promoter, and the binding of HigB to HigA derepresses this process. During the late stationary phase, excess HigA represses the expression of mvfR and higBA. However, in the presence of aminoglycoside antibiotics where Lon protease is activated, the degradation of HigA by Lon increases P. aeruginosa virulence by simultaneously derepressing mvfR and higB transcription. Therefore, this study reveals that the antitoxin of the P. aeruginosa TA system is integrated into the key virulence regulatory network of the host and functions as a transcriptional repressor to control the production of virulence factors.
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Affiliation(s)
- Yunxue Guo
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Chenglong Sun
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.,University of Chinese Academy of Sciences, Beijing, China.,Basic Medical School of Guizhou University of Traditional Chinese Medicine, Guiyang, China
| | - Yangmei Li
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Kaihao Tang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Songwei Ni
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Xiaoxue Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.,University of Chinese Academy of Sciences, Beijing, China
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22
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Schureck MA, Meisner J, Hoffer ED, Wang D, Onuoha N, Ei Cho S, Lollar P, Dunham CM. Structural basis of transcriptional regulation by the HigA antitoxin. Mol Microbiol 2019; 111:1449-1462. [PMID: 30793388 DOI: 10.1111/mmi.14229] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2019] [Indexed: 01/16/2023]
Abstract
Bacterial toxin-antitoxin systems are important factors implicated in growth inhibition and plasmid maintenance. Type II toxin-antitoxin pairs are regulated at the transcriptional level by the antitoxin itself. Here, we examined how the HigA antitoxin regulates the expression of the Proteus vulgaris higBA toxin-antitoxin operon from the Rts1 plasmid. The HigBA complex adopts a unique architecture suggesting differences in its regulation as compared to classical type II toxin-antitoxin systems. We find that the C-terminus of the HigA antitoxin is required for dimerization and transcriptional repression. Further, the HigA structure reveals that the C terminus is ordered and does not transition between disorder-to-order states upon toxin binding. HigA residue Arg40 recognizes a TpG dinucleotide in higO2, an evolutionary conserved mode of recognition among prokaryotic and eukaryotic transcription factors. Comparison of the HigBA and HigA-higO2 structures reveals the distance between helix-turn-helix motifs of each HigA monomer increases by ~4 Å in order to bind to higO2. Consistent with these data, HigBA binding to each operator is twofold less tight than HigA alone. Together, these data show the HigB toxin does not act as a co-repressor suggesting potential novel regulation in this toxin-antitoxin system.
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Affiliation(s)
- Marc A Schureck
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Jeffrey Meisner
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Eric D Hoffer
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Dongxue Wang
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Nina Onuoha
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Shein Ei Cho
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Pete Lollar
- Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Atlanta, GA, 30322, USA.,Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Christine M Dunham
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA
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23
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Talavera A, Tamman H, Ainelo A, Konijnenberg A, Hadži S, Sobott F, Garcia-Pino A, Hõrak R, Loris R. A dual role in regulation and toxicity for the disordered N-terminus of the toxin GraT. Nat Commun 2019; 10:972. [PMID: 30814507 PMCID: PMC6393540 DOI: 10.1038/s41467-019-08865-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 01/31/2019] [Indexed: 11/09/2022] Open
Abstract
Bacterial toxin-antitoxin (TA) modules are tightly regulated to maintain growth in favorable conditions or growth arrest during stress. A typical regulatory strategy involves the antitoxin binding and repressing its own promoter while the toxin often acts as a co-repressor. Here we show that Pseudomonas putida graTA-encoded antitoxin GraA and toxin GraT differ from other TA proteins in the sense that not the antitoxin but the toxin possesses a flexible region. GraA auto-represses the graTA promoter: two GraA dimers bind cooperatively at opposite sides of the operator sequence. Contrary to other TA modules, GraT is a de-repressor of the graTA promoter as its N-terminal disordered segment prevents the binding of the GraT2A2 complex to the operator. Removal of this region restores operator binding and abrogates Gr aT toxicity. GraTA represents a TA module where a flexible region in the toxin rather than in the antitoxin controls operon expression and toxin activity. The Pseudomonas putida toxin GraT and antitoxin GraA form a type II toxin-antoxin module. Here the authors present the crystal structures of the GraA dimer, GraTA and GraA-DNA complexes and show that GraT contains a functionally important N-terminal intrinsic disordered region that prevents the binding of the GraTA complex to the operator.
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Affiliation(s)
- Ariel Talavera
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, B-1050, Brussel, Belgium. .,Molecular Recognition Unit, Structural Biology Research Center, Vlaams Instituut voor Biotechnologie, B-1050, Brussel, Belgium.
| | - Hedvig Tamman
- Institute of Molecular and Cell Biology, University of Tartu, 51010, Tartu, Estonia
| | - Andres Ainelo
- Institute of Molecular and Cell Biology, University of Tartu, 51010, Tartu, Estonia
| | - Albert Konijnenberg
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, B-1050, Brussel, Belgium.,Molecular Recognition Unit, Structural Biology Research Center, Vlaams Instituut voor Biotechnologie, B-1050, Brussel, Belgium.,Biomolecular and Analytical Mass Spectrometry Group, Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, B-2020, Antwerpen, Belgium
| | - San Hadži
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, B-1050, Brussel, Belgium.,Department of Physical Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000, Ljubljana, Slovenia
| | - Frank Sobott
- Biomolecular and Analytical Mass Spectrometry Group, Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, B-2020, Antwerpen, Belgium.,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK.,School of Molecular and Cellular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Abel Garcia-Pino
- Biologie Structurale et Biophysique, Institut de Biologie et de Médecine Moléculaires, Université Libre de Bruxelles, B-6041, Gosselies, Belgium
| | - Rita Hõrak
- Institute of Molecular and Cell Biology, University of Tartu, 51010, Tartu, Estonia
| | - Remy Loris
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, B-1050, Brussel, Belgium. .,Molecular Recognition Unit, Structural Biology Research Center, Vlaams Instituut voor Biotechnologie, B-1050, Brussel, Belgium.
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Yoon WS, Seok SH, Won HS, Cho T, Lee SJ, Seo MD. Structural changes of antitoxin HigA from Shigella flexneri by binding of its cognate toxin HigB. Int J Biol Macromol 2019; 130:99-108. [PMID: 30797012 DOI: 10.1016/j.ijbiomac.2019.02.111] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/19/2019] [Accepted: 02/19/2019] [Indexed: 11/17/2022]
Abstract
In toxin-antitoxin systems, many antitoxin proteins that neutralize their cognate toxin proteins also bind to DNA to repress transcription, and the DNA-binding affinity of the antitoxin is affected by its toxin. We solved crystal structures of the antitoxin HigA (apo-SfHigA) and its complex with the toxin HigB (SfHigBA) from Shigella flexneri. The apo-SfHigA shows a distinctive V-shaped homodimeric conformation with sequestered N-domains having a novel fold. SfHigBA appears as a heterotetramer formed by N-terminal dimerization of SfHigB-bound SfHigA molecules. The conformational change in SfHigA upon SfHigB binding is mediated by rigid-body movements of its C-domains, which accompanied an overall conformational change from wide V-shaped to narrow V-shaped dimer. Consequently, the two putative DNA-binding helices (α7 in each subunit) are repositioned to a conformation more compatible with canonical homodimeric DNA-binding proteins containing HTH motifs. Collectively, this study demonstrates a conformational change in an antitoxin protein, which occurs upon toxin binding and is responsible for regulating antitoxin DNA binding.
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Affiliation(s)
- Won-Su Yoon
- Department of Molecular Science and Technology, Ajou University, Suwon, Gyeonggi 16499, Republic of Korea; College of Pharmacy and Research Institute of Pharmaceutical Science and Technology (RIPST), Ajou University, Suwon, Gyeonggi 16499, Republic of Korea
| | - Seung-Hyeon Seok
- College of Pharmacy and Research Institute of Pharmaceutical Science and Technology (RIPST), Ajou University, Suwon, Gyeonggi 16499, Republic of Korea
| | - Hyung-Sik Won
- Department of Biotechnology, Research Institute (RIBHS) and College of Biomedical & Health Science, Konkuk University, Chungju, Chungbuk 27478, Republic of Korea
| | - Taehwan Cho
- Department of Molecular Science and Technology, Ajou University, Suwon, Gyeonggi 16499, Republic of Korea; College of Pharmacy and Research Institute of Pharmaceutical Science and Technology (RIPST), Ajou University, Suwon, Gyeonggi 16499, Republic of Korea
| | - Sang Jae Lee
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 37673, Republic of Korea
| | - Min-Duk Seo
- Department of Molecular Science and Technology, Ajou University, Suwon, Gyeonggi 16499, Republic of Korea; College of Pharmacy and Research Institute of Pharmaceutical Science and Technology (RIPST), Ajou University, Suwon, Gyeonggi 16499, Republic of Korea.
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25
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Muthuramalingam M, White JC, Murphy T, Ames JR, Bourne CR. The toxin from a ParDE toxin-antitoxin system found in Pseudomonas aeruginosa offers protection to cells challenged with anti-gyrase antibiotics. Mol Microbiol 2019; 111:441-454. [PMID: 30427086 PMCID: PMC6368863 DOI: 10.1111/mmi.14165] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/25/2018] [Indexed: 12/13/2022]
Abstract
Toxin-antitoxin systems are mediators of diverse activities in bacterial physiology. For the ParE-type toxins, their reported role of gyrase inhibition utilized during plasmid-segregation killing indicates they are toxic. However, their location throughout chromosomes leads to questions about function, including potential non-toxic outcomes. The current study has characterized a ParDE system from the opportunistic human pathogen Pseudomonas aeruginosa (Pa). We identified a protective function for this ParE toxin, PaParE, against effects of quinolone and other antibiotics. However, higher concentrations of PaParE are themselves toxic to cells, indicating the phenotypic outcome can vary based on its concentration. Our assays confirmed PaParE inhibition of gyrase-mediated supercoiling of DNA with an IC50 value in the low micromolar range, a species-specificity that resulted in more efficacious inhibition of Escherichia coli derived gyrase versus Pa gyrase, and overexpression in the absence of antitoxin yielded an expected filamentous morphology with multi-foci nucleic acid material. Additional data revealed that the PaParE toxin is monomeric and interacts with dimeric PaParD antitoxin with a KD in the lower picomolar range, yielding a heterotetramer. This work provides novel insights into chromosome-encoded ParE function, whereby its expression can impart partial protection to cultures from selected antibiotics.
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Affiliation(s)
- Meenakumari Muthuramalingam
- The University of Oklahoma, Department of Chemistry and BiochemistryNorman73019OKUSA
- Present address:
Department of Pharmaceutical ChemistryUniversity of KansasLawrence66047 KSUSA
| | - John C. White
- The University of Oklahoma, Department of Chemistry and BiochemistryNorman73019OKUSA
| | - Tamiko Murphy
- The University of Oklahoma, Department of Chemistry and BiochemistryNorman73019OKUSA
| | - Jessica R. Ames
- The University of Oklahoma, Department of Chemistry and BiochemistryNorman73019OKUSA
| | - Christina R. Bourne
- The University of Oklahoma, Department of Chemistry and BiochemistryNorman73019OKUSA
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Zhang Y, Xia B, Li M, Shi J, Long Y, Jin Y, Bai F, Cheng Z, Jin S, Wu W. HigB Reciprocally Controls Biofilm Formation and the Expression of Type III Secretion System Genes through Influencing the Intracellular c-di-GMP Level in Pseudomonas aeruginosa. Toxins (Basel) 2018; 10:toxins10110424. [PMID: 30355991 PMCID: PMC6265988 DOI: 10.3390/toxins10110424] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/21/2018] [Accepted: 10/22/2018] [Indexed: 11/16/2022] Open
Abstract
Toxin-antitoxin (TA) systems play important roles in bacteria persister formation. Increasing evidence demonstrate the roles of TA systems in regulating virulence factors in pathogenic bacteria. The toxin HigB in Pseudomonas aeruginosa contributes to persister formation and regulates the expression of multiple virulence factors and biofilm formation. However, the regulatory mechanism remains elusive. In this study, we explored the HigB mediated regulatory pathways. We demonstrate that HigB decreases the intracellular level of c-di-GMP, which is responsible for the increased expression of the type III secretion system (T3SS) genes and repression of biofilm formation. By analyzing the expression levels of the known c-di-GMP metabolism genes, we find that three c-di-GMP hydrolysis genes are up regulated by HigB, namely PA2133, PA2200 and PA3825. Deletion of the three genes individually or simultaneously diminishes the HigB mediated regulation on the expression of T3SS genes and biofilm formation. Therefore, our results reveal novel functions of HigB in P. aeruginosa.
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Affiliation(s)
- Yueying Zhang
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Bin Xia
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Mei Li
- Meishan Product Quality Supervision and Inspection Institute and National Pickle Quality Inspection Center, Meishan 620000, China.
| | - Jing Shi
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Yuqing Long
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Fang Bai
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Shouguang Jin
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA.
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China.
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27
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Zoledowska S, Motyka-Pomagruk A, Sledz W, Mengoni A, Lojkowska E. High genomic variability in the plant pathogenic bacterium Pectobacterium parmentieri deciphered from de novo assembled complete genomes. BMC Genomics 2018; 19:751. [PMID: 30326842 PMCID: PMC6192338 DOI: 10.1186/s12864-018-5140-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Accepted: 10/03/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pectobacterium parmentieri is a newly established species within the plant pathogenic family Pectobacteriaceae. Bacteria belonging to this species are causative agents of diseases in economically important crops (e.g. potato) in a wide range of different environmental conditions, encountered in Europe, North America, Africa, and New Zealand. Severe disease symptoms result from the activity of P. parmentieri virulence factors, such as plant cell wall degrading enzymes. Interestingly, we observe significant phenotypic differences among P. parmentieri isolates regarding virulence factors production and the abilities to macerate plants. To establish the possible genomic basis of these differences, we sequenced 12 genomes of P. parmentieri strains (10 isolated in Poland, 2 in Belgium) with the combined use of Illumina and PacBio approaches. De novo genome assembly was performed with the use of SPAdes software, while annotation was conducted by NCBI Prokaryotic Genome Annotation Pipeline. RESULTS The pan-genome study was performed on 15 genomes (12 de novo assembled and three reference strains: P. parmentieri CFBP 8475T, P. parmentieri SCC3193, P. parmentieri WPP163). The pan-genome includes 3706 core genes, a high number of accessory (1468) genes, and numerous unique (1847) genes. We identified the presence of well-known genes encoding virulence factors in the core genome fraction, but some of them were located in the dispensable genome. A significant fraction of horizontally transferred genes, virulence-related gene duplications, as well as different CRISPR arrays were found, which can explain the observed phenotypic differences. Finally, we found also, for the first time, the presence of a plasmid in one of the tested P. parmentieri strains isolated in Poland. CONCLUSIONS We can hypothesize that a large number of the genes in the dispensable genome and significant genomic variation among P. parmentieri strains could be the basis of the potential wide host range and widespread diffusion of P. parmentieri. The obtained data on the structure and gene content of P. parmentieri strains enabled us to speculate on the importance of high genomic plasticity for P. parmentieri adaptation to different environments.
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Affiliation(s)
- S Zoledowska
- Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - A Motyka-Pomagruk
- Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - W Sledz
- Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - A Mengoni
- Department of Biology, University of Florence, Sesto Fiorentino, Florence, Italy
| | - E Lojkowska
- Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland.
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28
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Belasco JG. Death by translation: ribosome-assisted degradation of mRNA by endonuclease toxins. FEBS Lett 2017. [PMID: 28649728 DOI: 10.1002/1873-3468.12715] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Joel G Belasco
- Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, New York, NY, USA.,Department of Microbiology, New York University School of Medicine, NY, USA
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29
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Li M, Long Y, Liu Y, Liu Y, Chen R, Shi J, Zhang L, Jin Y, Yang L, Bai F, Jin S, Cheng Z, Wu W. HigB of Pseudomonas aeruginosa Enhances Killing of Phagocytes by Up-Regulating the Type III Secretion System in Ciprofloxacin Induced Persister Cells. Front Cell Infect Microbiol 2016; 6:125. [PMID: 27790409 PMCID: PMC5064212 DOI: 10.3389/fcimb.2016.00125] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 09/27/2016] [Indexed: 12/01/2022] Open
Abstract
Bacterial persister cells are dormant and highly tolerant to lethal antibiotics, which are believed to be the major cause of recurring and chronic infections. Activation of toxins of bacterial toxin-antitoxin systems inhibits bacterial growth and plays an important role in persister formation. However, little is known about the overall gene expression profile upon toxin activation. More importantly, how the dormant bacterial persisters evade host immune clearance remains poorly understood. Here we demonstrate that a Pseudomonas aeruginosa toxin-antitoxin system HigB-HigA is required for the ciprofloxacin induced persister formation. Transcriptome analysis of a higA::Tn mutant revealed up regulation of type III secretion systems (T3SS) genes. Overexpression of HigB increased the expression of T3SS genes as well as bacterial cytotoxicity. We further demonstrate that wild type bacteria that survived ciprofloxacin treatment contain higher levels of T3SS proteins and display increased cytotoxicity to macrophage compared to vegetative bacterial cells. These results suggest that P. aeruginosa accumulates T3SS proteins during persister formation, which can protect the persister cells from host clearance by efficiently killing host immune cells.
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Affiliation(s)
- Mei Li
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Yuqing Long
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Ying Liu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Yang Liu
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University Singapore, Singapore
| | - Ronghao Chen
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Jing Shi
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Lu Zhang
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Liang Yang
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological UniversitySingapore, Singapore; School of Biological Sciences, Division of Structural Biology and Biochemistry, Nanyang Technological UniversitySingapore, Singapore
| | - Fang Bai
- State Key Laboratory of Medicinal Chemical Biology and College of Pharmacy and Life Sciences, Nankai University Tianjin, China
| | - Shouguang Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai UniversityTianjin, China; Department of Molecular Genetics and Microbiology, College of Medicine, University of FloridaGainesville, FL, USA
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University Tianjin, China
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30
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Yang J, Zhou K, Liu P, Dong Y, Gao Z, Zhang J, Liu Q. Structural insight into the E. coli HigBA complex. Biochem Biophys Res Commun 2016; 478:1521-7. [DOI: 10.1016/j.bbrc.2016.08.131] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 08/23/2016] [Indexed: 12/16/2022]
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