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Shafipour M, Mohammadzadeh A, Ghaemi EA, Mahmoodi P. PCR Development for Analysis of Some Type II Toxin-Antitoxin Systems, relJK, mazEF3, and vapBC3 Genes, in Mycobacterium tuberculosis and Mycobacterium bovis. Curr Microbiol 2024; 81:90. [PMID: 38311651 DOI: 10.1007/s00284-023-03599-0] [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: 10/14/2023] [Accepted: 12/22/2023] [Indexed: 02/06/2024]
Abstract
Toxin-Antitoxin (TA) systems are some small genetic modules in bacteria that play significant roles in resistance and tolerance development to antibiotics. Whole genome sequencing (WGS) is an effective method to analyze TA systems in pathogenic Mycobacteria. However, this study aimed to use a simple and inexpensive PCR-Sequencing approach to investigate the type II TA system. Using data from the WGS of Mycobacterium tuberculosis (M. tuberculosis) strain H37Rv and Mycobacterium bovis (M. bovis) strain BCG, primers specific to the relJK, mazEF3, and vapBC3 gene families were designed by Primer3 software. Following that, a total of 90 isolates were examined using the newly developed PCR assay, consisting of 64 M. tuberculosis and 26 M. bovis isolates, encompassing both 45 rifampin-sensitive and 45 rifampin-resistant strains. Finally, 28 isolates (including 14 rifampin-resistant isolates) were sent for sequencing, and their sequences were aligned and compared to the mentioned reference sequences. The amplicons size of mazEF3, relJK, and vapBC3 genes were 825, 875, and 934 bp, respectively. Furthermore, all tested isolates showed the specific amplicons for these TA families. To evaluate the specificity of the primers, PCR was performed on S. aureus and E.coli isolates. None of the examined samples had the desired amplicons. Therefore, the primers had acceptable specificity. The results indicated that the developed PCR-Sequencing approach can be used to effectively investigate certain types of TA systems. Considering high costs of WGS and difficulty in interpreting its results, such a simple and inexpensive method is beneficial in the evaluation of TA systems in Mycobacteria.
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Affiliation(s)
- Maryam Shafipour
- Department of Pathobiology, Faculty of Veterinary Medicine, Bu-Ali Sina University, Hamedan, Iran
| | - Abdolmajid Mohammadzadeh
- Department of Pathobiology, Faculty of Veterinary Medicine, Bu-Ali Sina University, Hamedan, Iran.
| | - Ezzat Allah Ghaemi
- Infectious Diseases Research Center, Golestan University of Medical Sciences, Gorgan, Iran
| | - Pezhman Mahmoodi
- Department of Pathobiology, Faculty of Veterinary Medicine, Bu-Ali Sina University, Hamedan, Iran
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2
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Chan WT, Garcillán-Barcia MP, Yeo CC, Espinosa M. Type II bacterial toxin-antitoxins: hypotheses, facts, and the newfound plethora of the PezAT system. FEMS Microbiol Rev 2023; 47:fuad052. [PMID: 37715317 PMCID: PMC10532202 DOI: 10.1093/femsre/fuad052] [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: 06/26/2023] [Revised: 08/24/2023] [Accepted: 09/07/2023] [Indexed: 09/17/2023] Open
Abstract
Toxin-antitoxin (TA) systems are entities found in the prokaryotic genomes, with eight reported types. Type II, the best characterized, is comprised of two genes organized as an operon. Whereas toxins impair growth, the cognate antitoxin neutralizes its activity. TAs appeared to be involved in plasmid maintenance, persistence, virulence, and defence against bacteriophages. Most Type II toxins target the bacterial translational machinery. They seem to be antecessors of Higher Eukaryotes and Prokaryotes Nucleotide-binding (HEPN) RNases, minimal nucleotidyltransferase domains, or CRISPR-Cas systems. A total of four TAs encoded by Streptococcus pneumoniae, RelBE, YefMYoeB, Phd-Doc, and HicAB, belong to HEPN-RNases. The fifth is represented by PezAT/Epsilon-Zeta. PezT/Zeta toxins phosphorylate the peptidoglycan precursors, thereby blocking cell wall synthesis. We explore the body of knowledge (facts) and hypotheses procured for Type II TAs and analyse the data accumulated on the PezAT family. Bioinformatics analyses showed that homologues of PezT/Zeta toxin are abundantly distributed among 14 bacterial phyla mostly in Proteobacteria (48%), Firmicutes (27%), and Actinobacteria (18%), showing the widespread distribution of this TA. The pezAT locus was found to be mainly chromosomally encoded whereas its homologue, the tripartite omega-epsilon-zeta locus, was found mostly on plasmids. We found several orphan pezT/zeta toxins, unaccompanied by a cognate antitoxin.
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Affiliation(s)
- Wai Ting Chan
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Maria Pilar Garcillán-Barcia
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-Consejo Superior de Investigaciones Científicas, C/Albert Einstein 22, PCTCAN, 39011 Santander, Spain
| | - Chew Chieng Yeo
- Centre for Research in Infectious Diseases and Biotechnology (CeRIDB), Faculty of Medicine
, Universiti Sultan Zainal Abidin, Jalan Sultan Mahumd, 20400 Kuala Terengganu, Malaysia
| | - Manuel Espinosa
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, 9, 28040 Madrid, Spain
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Schott S, Scheuer R, Ermoli F, Glatter T, Evguenieva-Hackenberg E, Diepold A. A ParDE toxin-antitoxin system is responsible for the maintenance of the Yersinia virulence plasmid but not for type III secretion-associated growth inhibition. Front Cell Infect Microbiol 2023; 13:1166077. [PMID: 37228670 PMCID: PMC10203498 DOI: 10.3389/fcimb.2023.1166077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 04/20/2023] [Indexed: 05/27/2023] Open
Abstract
Many Gram-negative pathogens utilize the type III secretion system (T3SS) to translocate virulence-promoting effector proteins into eukaryotic host cells. The activity of this system results in a severe reduction of bacterial growth and division, summarized as secretion-associated growth inhibition (SAGI). In Yersinia enterocolitica, the T3SS and related proteins are encoded on a virulence plasmid. We identified a ParDE-like toxin-antitoxin system on this virulence plasmid in genetic proximity to yopE, encoding a T3SS effector. Effectors are strongly upregulated upon activation of the T3SS, indicating a potential role of the ParDE system in the SAGI or maintenance of the virulence plasmid. Expression of the toxin ParE in trans resulted in reduced growth and elongated bacteria, highly reminiscent of the SAGI. Nevertheless, the activity of ParDE is not causal for the SAGI. T3SS activation did not influence ParDE activity; conversely, ParDE had no impact on T3SS assembly or activity itself. However, we found that ParDE ensures the presence of the T3SS across bacterial populations by reducing the loss of the virulence plasmid, especially under conditions relevant to infection. Despite this effect, a subset of bacteria lost the virulence plasmid and regained the ability to divide under secreting conditions, facilitating the possible emergence of T3SS-negative bacteria in late acute and persistent infections.
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Affiliation(s)
- Saskia Schott
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Robina Scheuer
- Department of Microbiology and Molecular Biology, Justus Liebig University Gießen, Gießen, Germany
| | - Francesca Ermoli
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Timo Glatter
- Core Facility for Mass spectrometry & Proteomics, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | | | - Andreas Diepold
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
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Kang SM. Mycobacterium tuberculosis Rv0229c Shows Ribonuclease Activity and Reveals Its Corresponding Role as Toxin VapC51. Antibiotics (Basel) 2023; 12:antibiotics12050840. [PMID: 37237743 DOI: 10.3390/antibiotics12050840] [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: 03/28/2023] [Revised: 04/24/2023] [Accepted: 04/27/2023] [Indexed: 05/28/2023] Open
Abstract
The VapBC system, which belongs to the type II toxin-antitoxin (TA) system, is the most abundant and widely studied system in Mycobacterium tuberculosis. The VapB antitoxin suppresses the activity of the VapC toxin through a stable protein-protein complex. However, under environmental stress, the balance between toxin and antitoxin is disrupted, leading to the release of free toxin and bacteriostatic state. This study introduces the Rv0229c, a putative VapC51 toxin, and aims to provide a better understanding of its discovered function. The structure of the Rv0229c shows a typical PIN-domain protein, exhibiting an β1-α1-α2-β2-α3-α4-β3-α5-α6-β4-α7-β5 topology. The structure-based sequence alignment showed four electronegative residues in the active site of Rv0229c, which is composed of Asp8, Glu42, Asp95, and Asp113. By comparing the active site with existing VapC proteins, we have demonstrated the justification for naming it VapC51 at the molecular level. In an in vitro ribonuclease activity assay, Rv0229c showed ribonuclease activity dependent on the concentration of metal ions such as Mg2+ and Mn2+. In addition, magnesium was found to have a greater effect on VapC51 activity than manganese. Through these structural and experimental studies, we provide evidence for the functional role of Rv0229c as a VapC51 toxin. Overall, this study aims to enhance our understanding of the VapBC system in M. tuberculosis.
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Affiliation(s)
- Sung-Min Kang
- College of Pharmacy, Duksung Women's University, Seoul 01369, Republic of Korea
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5
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Lee KY, Lee BJ. Dynamics-Based Regulatory Switches of Type II Antitoxins: Insights into New Antimicrobial Discovery. Antibiotics (Basel) 2023; 12:antibiotics12040637. [PMID: 37106997 PMCID: PMC10135005 DOI: 10.3390/antibiotics12040637] [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: 01/25/2023] [Revised: 03/20/2023] [Accepted: 03/22/2023] [Indexed: 04/29/2023] Open
Abstract
Type II toxin-antitoxin (TA) modules are prevalent in prokaryotes and are involved in cell maintenance and survival under harsh environmental conditions, including nutrient deficiency, antibiotic treatment, and human immune responses. Typically, the type II TA system consists of two protein components: a toxin that inhibits an essential cellular process and an antitoxin that neutralizes its toxicity. Antitoxins of type II TA modules typically contain the structured DNA-binding domain responsible for TA transcription repression and an intrinsically disordered region (IDR) at the C-terminus that directly binds to and neutralizes the toxin. Recently accumulated data have suggested that the antitoxin's IDRs exhibit variable degrees of preexisting helical conformations that stabilize upon binding to the corresponding toxin or operator DNA and function as a central hub in regulatory protein interaction networks of the type II TA system. However, the biological and pathogenic functions of the antitoxin's IDRs have not been well discussed compared with those of IDRs from the eukaryotic proteome. Here, we focus on the current state of knowledge about the versatile roles of IDRs of type II antitoxins in TA regulation and provide insights into the discovery of new antibiotic candidates that induce toxin activation/reactivation and cell death by modulating the regulatory dynamics or allostery of the antitoxin.
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Affiliation(s)
- Ki-Young Lee
- College of Pharmacy and Institute of Pharmaceutical Sciences, CHA University, Pocheon-si 11160, Republic of Korea
| | - Bong-Jin Lee
- College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
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6
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Achromobacter spp. prevalence and adaptation in cystic fibrosis lung infection. Microbiol Res 2022; 263:127140. [DOI: 10.1016/j.micres.2022.127140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 07/11/2022] [Accepted: 07/20/2022] [Indexed: 11/30/2022]
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Dai Z, Wu T, Xu S, Zhou L, Tang W, Hu E, Zhan L, Chen M, Yu G. Characterization of toxin-antitoxin systems from public sequencing data: A case study in Pseudomonas aeruginosa. Front Microbiol 2022; 13:951774. [PMID: 36051757 PMCID: PMC9424990 DOI: 10.3389/fmicb.2022.951774] [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] [Received: 05/24/2022] [Accepted: 07/15/2022] [Indexed: 11/13/2022] Open
Abstract
The toxin-antitoxin (TA) system is a widely distributed group of genetic modules that play important roles in the life of prokaryotes, with mobile genetic elements (MGEs) contributing to the dissemination of antibiotic resistance gene (ARG). The diversity and richness of TA systems in Pseudomonas aeruginosa, as one of the bacterial species with ARGs, have not yet been completely demonstrated. In this study, we explored the TA systems from the public genomic sequencing data and genome sequences. A small scale of genomic sequencing data in 281 isolates was selected from the NCBI SRA database, reassembling the genomes of these isolates led to the findings of abundant TA homologs. Furthermore, remapping these identified TA modules on 5,437 genome/draft genomes uncovers a great diversity of TA modules in P. aeruginosa. Moreover, manual inspection revealed several TA systems that were not yet reported in P. aeruginosa including the hok-sok, cptA-cptB, cbeA-cbtA, tomB-hha, and ryeA-sdsR. Additional annotation revealed that a large number of MGEs were closely distributed with TA. Also, 16% of ARGs are located relatively close to TA. Our work confirmed a wealth of TA genes in the unexplored P. aeruginosa pan-genomes, expanded the knowledge on P. aeruginosa, and provided methodological tips on large-scale data mining for future studies. The co-occurrence of MGE, ARG, and TA may indicate a potential interaction in their dissemination.
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8
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Cuthbert BJ, Hayes CS, Goulding CW. Functional and Structural Diversity of Bacterial Contact-Dependent Growth Inhibition Effectors. Front Mol Biosci 2022; 9:866854. [PMID: 35558562 PMCID: PMC9086364 DOI: 10.3389/fmolb.2022.866854] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/07/2022] [Indexed: 12/25/2022] Open
Abstract
Bacteria live in complex communities and environments, competing for space and nutrients. Within their niche habitats, bacteria have developed various inter-bacterial mechanisms to compete and communicate. One such mechanism is contact-dependent growth inhibition (CDI). CDI is found in many Gram-negative bacteria, including several pathogens. These CDI+ bacteria encode a CdiB/CdiA two-partner secretion system that delivers inhibitory toxins into neighboring cells upon contact. Toxin translocation results in the growth inhibition of closely related strains and provides a competitive advantage to the CDI+ bacteria. CdiB, an outer-membrane protein, secretes CdiA onto the surface of the CDI+ bacteria. When CdiA interacts with specific target-cell receptors, CdiA delivers its C-terminal toxin region (CdiA-CT) into the target-cell. CdiA-CT toxin proteins display a diverse range of toxic functions, such as DNase, RNase, or pore-forming toxin activity. CDI+ bacteria also encode an immunity protein, CdiI, that specifically binds and neutralizes its cognate CdiA-CT, protecting the CDI+ bacteria from auto-inhibition. In Gram-negative bacteria, toxin/immunity (CdiA-CT/CdiI) pairs have highly variable sequences and functions, with over 130 predicted divergent toxin/immunity complex families. In this review, we will discuss biochemical and structural advances made in the characterization of CDI. This review will focus on the diverse array of CDI toxin/immunity complex structures together with their distinct toxin functions. Additionally, we will discuss the most recent studies on target-cell recognition and toxin entry, along with the discovery of a new member of the CDI loci. Finally, we will offer insights into how these diverse toxin/immunity complexes could be harnessed to fight human diseases.
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Affiliation(s)
- Bonnie J. Cuthbert
- Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, United States
| | - Christopher S. Hayes
- Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
- Biomolecular Science and Engineering Program, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Celia W. Goulding
- Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, United States
- Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, United States
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9
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Mahmoudi M, Sadeghifard N, Maleki A, Yeo CC, Ghafourian S. relBE Toxin-antitoxin System as a Reliable Anti-biofilm Target in Pseudomonas aeruginosa. J Appl Microbiol 2022; 133:683-695. [PMID: 35445489 DOI: 10.1111/jam.15585] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 04/13/2022] [Accepted: 04/16/2022] [Indexed: 11/29/2022]
Abstract
AIMS The ability of the pathogenic bacterium Pseudomonas aeruginosa to produce biofilms has made it more difficult to treat its infections with current antibiotics. Several genes are involved in biofilm production, and toxin-antitoxin (TA) loci have been reported to be responsible for the regulation of biofilm-associated genes. This study was aimed at evaluating various TA loci in P. aeruginosa to find a reliable target in order to disrupt biofilm formation. METHODS AND RESULTS Thirty clinical isolates of P. aeruginosa were assessed for biofilm production as well as the presence of various TA loci in their genomes. The relBETA locus was present in all 30 P. aeruginosa isolates but its expression was not detectable in isolates that did not show biofilm production. Quantitative real-time -PCR (q-PCR) also demonstrated that the expression of relBE was higher in isolates with stronger biofilm-producing capability. Knocking out the relBE locus in one biofilm-producing P. aeruginosa isolate led to the cessation of biofilm-producing capacity in that isolate and eliminated the expression of ndvB, which is among the genes involved in biofilm production. CONCLUSIONS These results inferred the involvement of relBE TA locus in the regulation of biofilm production in P. aeruginosa and indicated the possibility of relBE as an anti-biofilm target for this pathogen.
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Affiliation(s)
- Mina Mahmoudi
- Department of Microbiology, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran
| | - Nourkhoda Sadeghifard
- Department of Microbiology, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran
| | - Abbas Maleki
- Department of Microbiology, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran
| | - Chew Chieng Yeo
- Faculty of Medicine, Biomedical Research Centre, Universiti Sultan Zainal Abidin, Kuala Terengganu, Malaysia
| | - Sobhan Ghafourian
- Department of Microbiology, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran
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10
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Sun H, Coussens NP, Danchik C, Wachsmuth LM, Henderson MJ, Patnaik S, Hall MD, Molinaro AL, Daines DA, Shen M. Discovery of Small-Molecule VapC1 Nuclease Inhibitors by Virtual Screening and Scaffold Hopping from an Atomic Structure Revealing Protein-Protein Interactions with a Native VapB1 Inhibitor. J Chem Inf Model 2022; 62:1249-1258. [PMID: 35103473 PMCID: PMC10041999 DOI: 10.1021/acs.jcim.1c01188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Nontypeable Haemophilus influenzae (NTHi) are clinically important Gram-negative bacteria that are responsible for various human mucosal diseases, including otitis media (OM). Recurrent OM caused by NTHi is common, and infections that recur less than 2 weeks following antimicrobial therapy are largely attributable to the recurrence of the same strain of bacteria. Toxin-antitoxin (TA) modules encoded by bacteria enable rapid responses to environmental stresses and are thought to facilitate growth arrest, persistence, and tolerance to antibiotics. The vapBC-1 locus of NTHi encodes a type II TA system, comprising the ribonuclease toxin VapC1 and its cognate antitoxin VapB1. The activity of VapC1 has been linked to the survival of NTHi during antibiotic treatment both in vivo and ex vivo. Therefore, inhibitors of VapC1 might serve as adjuvants to antibiotics, preventing NTHi from entering growth arrest and surviving; however, none have been reported to date. A truncated VapB1 peptide from a crystal structure of the VapBC-1 complex was used to generate pharmacophore queries to facilitate a scaffold hopping approach for the identification of small-molecule VapC1 inhibitors. The National Center for Advancing Translational Sciences small-molecule library was virtually screened using the shape-based method rapid overlay of chemical structures (ROCS), and the top-ranking hits were docked into the VapB1 binding pocket of VapC1. Two hundred virtual screening hits with the best docking scores were selected and tested in a biochemical VapC1 activity assay, which confirmed eight compounds as VapC1 inhibitors. An additional 60 compounds were selected with structural similarities to the confirmed VapC1 inhibitors, of which 20 inhibited VapC1 activity. Intracellular target engagement of five inhibitors was indicated by the destabilization of VapC1 within bacterial cells from a cellular thermal shift assay; however, no impact on bacterial growth was observed. Thus, this virtual screening and scaffold hopping approach enabled the discovery of VapC1 ribonuclease inhibitors that might serve as starting points for preclinical development.
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Affiliation(s)
- Hongmao Sun
- National Center for Advancing Translational Sciences (NCATS), 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Nathan P Coussens
- National Center for Advancing Translational Sciences (NCATS), 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Carina Danchik
- National Center for Advancing Translational Sciences (NCATS), 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Leah M Wachsmuth
- National Center for Advancing Translational Sciences (NCATS), 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Mark J Henderson
- National Center for Advancing Translational Sciences (NCATS), 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Samarjit Patnaik
- National Center for Advancing Translational Sciences (NCATS), 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Matthew D Hall
- National Center for Advancing Translational Sciences (NCATS), 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Ashley L Molinaro
- Office of the Dean, College of Sciences, Old Dominion University, Norfolk, Virginia 23529, United States
| | - Dayle A Daines
- Office of the Dean, College of Sciences, Old Dominion University, Norfolk, Virginia 23529, United States
| | - Min Shen
- National Center for Advancing Translational Sciences (NCATS), 9800 Medical Center Drive, Rockville, Maryland 20850, United States
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Manikandan P, Sandhya S, Nadig K, Paul S, Srinivasan N, Rothweiler U, Singh M. Identification, functional characterization, assembly and structure of ToxIN type III toxin-antitoxin complex from E. coli. Nucleic Acids Res 2022; 50:1687-1700. [PMID: 35018473 PMCID: PMC8860590 DOI: 10.1093/nar/gkab1264] [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: 05/16/2021] [Revised: 11/26/2021] [Accepted: 12/09/2021] [Indexed: 11/21/2022] Open
Abstract
Toxin–antitoxin (TA) systems are proposed to play crucial roles in bacterial growth under stress conditions such as phage infection. The type III TA systems consist of a protein toxin whose activity is inhibited by a noncoding RNA antitoxin. The toxin is an endoribonuclease, while the antitoxin consists of multiple repeats of RNA. The toxin assembles with the individual antitoxin repeats into a cyclic complex in which the antitoxin forms a pseudoknot structure. While structure and functions of some type III TA systems are characterized, the complex assembly process is not well understood. Using bioinformatics analysis, we have identified type III TA systems belonging to the ToxIN family across different Escherichia coli strains and found them to be clustered into at least five distinct clusters. Furthermore, we report a 2.097 Å resolution crystal structure of the first E. coli ToxIN complex that revealed the overall assembly of the protein-RNA complex. Isothermal titration calorimetry experiments showed that toxin forms a high-affinity complex with antitoxin RNA resulting from two independent (5′ and 3′ sides of RNA) RNA binding sites on the protein. These results further our understanding of the assembly of type III TA complexes in bacteria.
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Affiliation(s)
| | - Sankaran Sandhya
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru 560012, India
| | - Kavyashree Nadig
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru 560012, India
| | - Souradip Paul
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru 560012, India
| | | | - Ulli Rothweiler
- The Norwegian Structural Biology Centre, Department of Chemistry, The Arctic University of Norway, N-9037 Tromsø, Norway
| | - Mahavir Singh
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru 560012, India
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12
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Snead KJ, Moore LL, Bourne CR. ParD Antitoxin Hotspot Alters a Disorder-to-Order Transition upon Binding to Its Cognate ParE Toxin, Lessening Its Interaction Affinity and Increasing Its Protease Degradation Kinetics. Biochemistry 2022; 61:34-45. [PMID: 34914378 PMCID: PMC9805813 DOI: 10.1021/acs.biochem.1c00584] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Type-II toxin-antitoxin (TA) systems are comprised of two tightly interacting proteins, and operons encoding these systems have been identified throughout the genomes of bacteria. In contrast to secretion system effector-immunity pairs, TA systems must remain paired to protect the host cell from toxicity. Continual depletion of the antitoxin results in a shorter half-life than that of the toxin, though it is unclear if antitoxins can be effectively degraded when complexed with toxins. The current work probed the protein-protein interface of the PaParDE1 TA system, guided by an X-ray crystal structure, to determine contributions of antitoxin amino acids to interaction kinetics and affinity. These studies identified a "hotspot" position that alters the binding mode and resulting affinity (KD) from 152 pM for a 1:1 model for wild type to 25.5 and 626 nM for a 2:1 model with mutated antitoxin. This correlates with an altered induced secondary structure upon complexation with PaParE1 and increased kinetics of Lon protease digestion of the antitoxin despite the toxin presence. However, the decreased affinity at this hotspot was essentially reversed when the antitoxin dimerization region was deleted, yielding insights into complex interactions involved in the tight association. Removal of the antitoxin C-terminal seven amino acids, corresponding to the site of a disorder-to-order transition, completely prevents association. These studies combine to provide a model for the initiation of the TA interaction and highlight how manipulation of the sequence can impact the antitoxin disorder-to-order transition, weakening the affinity and resulting in increased antitoxin susceptibility to degradation.
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Affiliation(s)
- Kevin J. Snead
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
| | - Landon L. Moore
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States; Present Address: Department of Internal Medicine, Digestive Diseases and Nutrition Section, The University of Oklahoma Health Science Center, 800 Stanton L Young Blvd, Oklahoma City, OK 73104, USA
| | - Christina R. Bourne
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, United States
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13
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Kim DH, Kang SM, Baek SM, Yoon HJ, Jang DM, Kim H, Lee S, Lee BJ. OUP accepted manuscript. Nucleic Acids Res 2022; 50:2319-2333. [PMID: 35141752 PMCID: PMC8887465 DOI: 10.1093/nar/gkab1288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 12/15/2021] [Accepted: 12/17/2021] [Indexed: 11/24/2022] Open
Abstract
Staphylococcus aureus is a notorious and globally distributed pathogenic bacterium. New strategies to develop novel antibiotics based on intrinsic bacterial toxin–antitoxin (TA) systems have been recently reported. Because TA systems are present only in bacteria and not in humans, these distinctive systems are attractive targets for developing antibiotics with new modes of action. S. aureus PemIK is a type II TA system, comprising the toxin protein PemK and the labile antitoxin protein PemI. Here, we determined the crystal structures of both PemK and the PemIK complex, in which PemK is neutralized by PemI. Our biochemical approaches, including fluorescence quenching and polarization assays, identified Glu20, Arg25, Thr48, Thr49, and Arg84 of PemK as being important for RNase function. Our study indicates that the active site and RNA-binding residues of PemK are covered by PemI, leading to unique conformational changes in PemK accompanied by repositioning of the loop between β1 and β2. These changes can interfere with RNA binding by PemK. Overall, PemK adopts particular open and closed forms for precise neutralization by PemI. This structural and functional information on PemIK will contribute to the discovery and development of novel antibiotics in the form of peptides or small molecules inhibiting direct binding between PemI and PemK.
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Affiliation(s)
| | | | - Sung-Min Baek
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Hye-Jin Yoon
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Dong Man Jang
- Research Institute, National Cancer Center, Goyang, Gyeonggi 10408, Republic of Korea
| | - Hyoun Sook Kim
- Research Institute, National Cancer Center, Goyang, Gyeonggi 10408, Republic of Korea
| | - Sang Jae Lee
- Correspondence may also be addressed to Sang Jae Lee. Tel: +82 54 279 1490;
| | - Bong-Jin Lee
- To whom correspondence should be addressed. Tel: +82 2 880 7869;
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14
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Singh G, Yadav M, Ghosh C, Rathore JS. Bacterial toxin-antitoxin modules: classification, functions, and association with persistence. CURRENT RESEARCH IN MICROBIAL SCIENCES 2021; 2:100047. [PMID: 34841338 PMCID: PMC8610362 DOI: 10.1016/j.crmicr.2021.100047] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 07/04/2021] [Accepted: 07/05/2021] [Indexed: 11/24/2022] Open
Abstract
Ubiquitously present bacterial Toxin-Antitoxin (TA) modules consist of stable toxin associated with labile antitoxin. Classification of TAs modules based on inhibition of toxin through antitoxin in 8 different classes. Variety of specific toxin targets and the abundance of TA modules in various deadly pathogens. Specific role of TAs modules in conservation of the resistant genes, emergence of persistence & biofilm formation. Proposed antibacterial strategies involving TA modules for elimination of multi-drug resistance.
Toxin-antitoxin (TA) modules are ubiquitous gene loci among bacteria and are comprised of a toxin part and its cognate antitoxin part. Under normal physiological conditions, antitoxin counteracts the toxicity of the toxin whereas, during stress conditions, TA modules play a crucial role in bacterial physiology through involvement in the post-segregational killing, abortive infection, biofilms, and persister cell formation. Most of the toxins are proteinaceous that affect translation or DNA replication, although some other intracellular molecular targets have also been described. While antitoxins may be a protein or RNA, that generally neutralizes its cognate toxin by direct interaction or with the help of other signaling elements and thus helps in the TA module regulation. In this review, we have discussed the current state of the multifaceted TA (type I–VIII) modules by highlighting their classification and specific targets. We have also discussed the presence of TA modules in the various pathogens and their role in antibiotic persistence development as well as biofilm formation, by influencing the different cellular processes. In the end, assembling knowledge about ubiquitous TA systems from pathogenic bacteria facilitated us to propose multiple novel antibacterial strategies involving artificial activation of TA modules.
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Affiliation(s)
- Garima Singh
- School of Biotechnology, Gautam Buddha University, Greater Noida, Yamuna Expressway, Uttar Pradesh, India
| | - Mohit Yadav
- School of Biotechnology, Gautam Buddha University, Greater Noida, Yamuna Expressway, Uttar Pradesh, India
| | - Chaitali Ghosh
- Department of Zoology Gargi College, University of Delhi, New Delhi, India
| | - Jitendra Singh Rathore
- School of Biotechnology, Gautam Buddha University, Greater Noida, Yamuna Expressway, Uttar Pradesh, India
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15
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Abd El rahman A, El kholy Y, Shash RY. Correlation between mazEF Toxin-Antitoxin System Expression and Methicillin Susceptibility in Staphylococcus aureus and Its Relation to Biofilm-Formation. Microorganisms 2021; 9:microorganisms9112274. [PMID: 34835399 PMCID: PMC8618890 DOI: 10.3390/microorganisms9112274] [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: 10/20/2021] [Accepted: 10/27/2021] [Indexed: 11/16/2022] Open
Abstract
Methicillin resistance in Staphylococcus aureus has become prevalent globally. Moreover, biofilm-formation makes it more difficult to eradicate bacteria by antibiotics. The mazEF toxin-antitoxin system encodes for mazF, which acts as an endoribonuclease that cleaves cellular mRNAs at specific sequence motifs (ACA), and mazE, which opposes the mazF action. Our goal was to detect mazEF expression in methicillin-resistant S. aureus (MRSA) isolates compared with methicillin-sensitive S. aureus (MSSA) isolates and determine its relation to methicillin susceptibility as well as biofilm-formation. According to their susceptibility to cefoxitin disks, 100 S. aureus isolates obtained from patients admitted to Cairo University Hospitals were categorized into 50 MSSA and 50 MRSA according to their susceptibility to cefoxitin disks (30 µg). Antimicrobial susceptibility and biofilm-formation were investigated using the disk diffusion method and tissue culture plate method, respectively. Finally, using real-time PCR, mazEF expression was estimated and correlated to methicillin susceptibility and biofilm formation. Both MRSA and MSSA isolates showed the best sensitivity results with linezolid and gentamicin, where about 88% of MRSA isolates and 96% of MSSA isolates were sensitive to linezolid while 76% of MRSA isolates and 84% of MSSA isolates were sensitive to gentamicin. MRSA isolates were significantly more able to form biofilm than MSSA isolates (p-value = 0.037). The mazEF expression was significantly correlated to methicillin resistance in S. aureus (p-value < 0.001), but not to biofilm-formation.
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16
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Roussin M, Salcedo SP. NAD+-targeting by bacteria: an emerging weapon in pathogenesis. FEMS Microbiol Rev 2021; 45:6315328. [PMID: 34223888 DOI: 10.1093/femsre/fuab037] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 07/01/2021] [Indexed: 11/14/2022] Open
Abstract
Nicotinamide adenine dinucleotide (NAD+) is a major cofactor in redox reactions in all lifeforms. A stable level of NAD+ is vital to ensure cellular homeostasis. Some pathogens can modulate NAD+ metabolism to their advantage and even utilize or cleave NAD+ from the host using specialized effectors known as ADP-ribosyltransferase toxins and NADases, leading to energy store depletion, immune evasion, or even cell death. This review explores recent advances in the field of bacterial NAD+-targeting toxins, highlighting the relevance of NAD+ modulation as an emerging pathogenesis strategy. In addition, we discuss the role of specific NAD+-targeting toxins in niche colonization and bacterial lifestyle as components of Toxin/Antitoxin systems and key players in inter-bacterial competition. Understanding the mechanisms of toxicity, regulation, and secretion of these toxins will provide interesting leads in the search for new antimicrobial treatments in the fight against infectious diseases.
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Affiliation(s)
- Morgane Roussin
- Laboratory of Molecular Microbiology and Structural Biochemistry, Centre National de la Recherche Scientifique UMR5086, Université de Lyon, Lyon, France
| | - Suzana P Salcedo
- Laboratory of Molecular Microbiology and Structural Biochemistry, Centre National de la Recherche Scientifique UMR5086, Université de Lyon, Lyon, France
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17
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Identification and characterization of the type II toxin-antitoxin systems in the carbapenem-resistant Acinetobacterbaumannii. Microb Pathog 2021; 158:105052. [PMID: 34147586 DOI: 10.1016/j.micpath.2021.105052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 06/08/2021] [Accepted: 06/10/2021] [Indexed: 11/20/2022]
Abstract
Carbapenem -resistant A. baumannii (CRAB) is a major cause of both community-associated and nosocomial infections that are difficult to control and treat worldwide. Among different mediators of pathogenesis, toxin-antitoxin (TA) systems are emerging as the most prominent. The functional diversity and ubiquitous distribution in bacterial genomes are causing significant attention toward TA systems in bacteria. However, there is no enough information on the prevalence and identity of TA systems in CRAB clinical isolates. This study aimed to identify type II toxin-antitoxin systems in carbapenem-resistant A. baumannii (CRAB) isolates. A total of 80 A. baumannii isolates were collected from different clinical samples. Antibiotic resistance patterns of A. baumannii isolates were evaluated phenotypically and genetically. The frequency of type II TA genes was evaluated in CRAB isolates using PCR. Moreover, the expression level of the most prevalent TA encoding genes in some clinical isolates were evaluated by RT-qPCR. To determine whether the SplT and SplA are functional, the growth of E. coli BL21 cells (DE3/pLysS) harboring pET28a, pET28a-splTA, and pET28a-splT were analyzed by kill-rescue assay. All of the isolates were resistant to third generation of cephalosporins, ciprofloxacin and levofloxacin, whereas, 72%, 81% and 87% were resistant to amikacin, carbapenems and tetracycline, respectively. The cheTA in 47 isolates (72.5%) and splTA in 39 isolates (60%) of 65 isolates were the most common genes encoding type II TA among CRAB isolates. RT-qPCR demonstrated that cheTA and splTA transcripts are produced in the clinical isolates. There was a significant correlation between the presence of splTA genes and blaOXA-24 in CRAB isolates. Over-expression of the splT gene in E. coli results in inhibition of bacterial growth, whereas co-expression of splTA effectively restores the growth. This study presents the first identification of the type II TA systems among the carbapenem -resistant A. baumannii isolates, in Iran.
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18
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Chen R, Zhou J, Xie W. Mechanistic Insight into the Peptide Binding Modes to Two M. tb MazF Toxins. Toxins (Basel) 2021; 13:toxins13050319. [PMID: 33925254 PMCID: PMC8145246 DOI: 10.3390/toxins13050319] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 04/26/2021] [Accepted: 04/26/2021] [Indexed: 11/30/2022] Open
Abstract
Tuberculosis (TB) is a contagious disease caused by Mycobacterium tuberculosis (M. tb). It is regarded as a major health threat all over the world, mainly because of its high mortality and drug-resistant nature. Toxin-antitoxin (TA) systems are modules ubiquitously found in prokaryotic organisms, and the well-studied MazEF systems (MazE means “what is it?” in Hebrew) are implicated in the formation of “persister cells” in the M. tb pathogen. Here, we report cocrystal structures of M. tb MazF-mt1 and -mt9, two important MazF members responsible for specific mRNA and tRNA cleavages, respectively, in complexes with truncated forms of their cognate antitoxin peptides. These peptides bind to the toxins with comparable affinities to their full-length antitoxins, which would reduce the RNA-cleavage capacities of the toxins in vitro. After structural analysis of the binding modes, we systemically tested the influence of the substitutions of individual residues in the truncated MazE-mt9 peptide on its affinity. This study provides structural insight into the binding modes and the inhibition mechanisms between the MazE/F-mt TA pairs. More importantly, it contributes to the future design of peptide-based antimicrobial agents against TB and potentially relieves the drug-resistance problems by targeting novel M. tb proteins.
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Affiliation(s)
- Ran Chen
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory for Biocontrol, School of Life Sciences, The Sun Yat-Sen University, Guangzhou 510006, China; (R.C.); (J.Z.)
- Key Laboratory of Tropical Marine Bio-Resources 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, No.1119, Haibin Road, Nansha District, Guangzhou 511458, China
| | - Jie Zhou
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory for Biocontrol, School of Life Sciences, The Sun Yat-Sen University, Guangzhou 510006, China; (R.C.); (J.Z.)
| | - Wei Xie
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory for Biocontrol, School of Life Sciences, The Sun Yat-Sen University, Guangzhou 510006, China; (R.C.); (J.Z.)
- Correspondence:
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19
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Kahan R, Worm DJ, de Castro GV, Ng S, Barnard A. Modulators of protein-protein interactions as antimicrobial agents. RSC Chem Biol 2021; 2:387-409. [PMID: 34458791 PMCID: PMC8341153 DOI: 10.1039/d0cb00205d] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 01/27/2021] [Indexed: 12/12/2022] Open
Abstract
Protein-Protein interactions (PPIs) are involved in a myriad of cellular processes in all living organisms and the modulation of PPIs is already under investigation for the development of new drugs targeting cancers, autoimmune diseases and viruses. PPIs are also involved in the regulation of vital functions in bacteria and, therefore, targeting bacterial PPIs offers an attractive strategy for the development of antibiotics with novel modes of action. The latter are urgently needed to tackle multidrug-resistant and multidrug-tolerant bacteria. In this review, we describe recent developments in the modulation of PPIs in pathogenic bacteria for antibiotic development, including advanced small molecule and peptide inhibitors acting on bacterial PPIs involved in division, replication and transcription, outer membrane protein biogenesis, with an additional focus on toxin-antitoxin systems as upcoming drug targets.
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Affiliation(s)
- Rashi Kahan
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London 82 Wood Lane London W12 0BZ UK
| | - Dennis J Worm
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London 82 Wood Lane London W12 0BZ UK
| | - Guilherme V de Castro
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London 82 Wood Lane London W12 0BZ UK
| | - Simon Ng
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London 82 Wood Lane London W12 0BZ UK
| | - Anna Barnard
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London 82 Wood Lane London W12 0BZ UK
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20
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Kang SM, Moon H, Han SW, Kim BW, Kim DH, Kim BM, Lee BJ. Toxin-Activating Stapled Peptides Discovered by Structural Analysis Were Identified as New Therapeutic Candidates That Trigger Antibacterial Activity against Mycobacterium tuberculosis in the Mycobacterium smegmatis Model. Microorganisms 2021; 9:microorganisms9030568. [PMID: 33801872 PMCID: PMC8000039 DOI: 10.3390/microorganisms9030568] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 11/17/2022] Open
Abstract
The structure-function relationships of toxin-antitoxin (TA) systems from Mycobacterium tuberculosis have prompted the development of novel and effective antimicrobial agents that selectively target this organism. The artificial activation of toxins by peptide inhibitors can lead to the growth arrest and eventual death of bacterial cells. Optimizing candidate peptides by hydrocarbon α-helix stapling based on structural information from the VapBC TA system and in vitro systematic validation led to V26-SP-8, a VapC26 activator of M. tuberculosis. This compound exhibited highly enhanced activity and cell permeability owing to the stabilizing helical propensity of the peptide. These characteristics will increase its efficacy against multidrug-resistant tuberculosis and extensively drug-resistant tuberculosis. Similar approaches utilizing structural and biochemical information for new antibiotic targets opens a new era for developing TB therapies.
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Affiliation(s)
- Sung-Min Kang
- College of Pharmacy, Duksung Women’s University, Seoul 01369, Korea;
| | - Heejo Moon
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 08826, Korea; (H.M.); (B.W.K.)
| | - Sang-Woo Han
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea;
| | - Byeong Wook Kim
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 08826, Korea; (H.M.); (B.W.K.)
| | - Do-Hee Kim
- College of Pharmacy, Jeju National University, Jeju 63243, Korea;
- Interdisciplinary Graduate Program in Advanced Convergence Technology & Science, Jeju National University, Jeju 63243, Korea
| | - Byeong Moon Kim
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 08826, Korea; (H.M.); (B.W.K.)
- Correspondence: (B.M.K.); (B.-J.L.); Tel.: +82-2-880-6634 (B.M.K.); +82-2-880-7868 (B.-J.L.)
| | - Bong-Jin Lee
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea;
- Correspondence: (B.M.K.); (B.-J.L.); Tel.: +82-2-880-6634 (B.M.K.); +82-2-880-7868 (B.-J.L.)
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21
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Srivastava A, Pati S, Kaushik H, Singh S, Garg LC. Toxin-antitoxin systems and their medical applications: current status and future perspective. Appl Microbiol Biotechnol 2021; 105:1803-1821. [PMID: 33582835 DOI: 10.1007/s00253-021-11134-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 01/13/2021] [Accepted: 01/20/2021] [Indexed: 12/11/2022]
Abstract
Almost all bacteria synthesize two types of toxins-one for its survival by regulating different cellular processes and another as a strategy to interact with host cells for pathogenesis. Usually, "bacterial toxins" are contemplated as virulence factors that harm the host organism. However, toxins produced by bacteria, as a survival strategy against the host, also hamper its cellular processes. To overcome this, the bacteria have evolved with the production of a molecule, referred to as antitoxin, to negate the deleterious effect of the toxin against itself. The toxin and antitoxins are encoded by a two-component toxin-antitoxin (TA) system. The antitoxin, a protein or RNA, sequesters the toxins of the TA system for neutralization within the bacterial cell. In this review, we have described different TA systems of bacteria and their potential medical and biotechnological applications. It is of interest to note that while bacterial toxin-antitoxin systems have been well studied, the TA system in unicellular eukaryotes, though predicted by the investigators, have never been paid the desired attention. In the present review, we have also touched upon the TA system of eukaryotes identified to date. KEY POINTS: Bacterial toxins harm the host and also affect the bacterial cellular processes. The antitoxin produced by bacteria protect it from the toxin's harmful effects. The toxin-antitoxin systems can be targeted for various medical applications.
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Affiliation(s)
- Akriti Srivastava
- Department of Life Sciences, Shiv Nadar University, Gautam Buddha Nagar, Greater Noida, Uttar Pradesh, 201314, India
| | - Soumya Pati
- Department of Life Sciences, Shiv Nadar University, Gautam Buddha Nagar, Greater Noida, Uttar Pradesh, 201314, India
| | - Himani Kaushik
- Gene Regulation Laboratory, National Institute of Immunology, New Delhi, 110067, India
| | - Shailja Singh
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India.
| | - Lalit C Garg
- Gene Regulation Laboratory, National Institute of Immunology, New Delhi, 110067, India.
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22
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Rohde KH, Sorci L. The Prospective Synergy of Antitubercular Drugs With NAD Biosynthesis Inhibitors. Front Microbiol 2021; 11:634640. [PMID: 33584600 PMCID: PMC7873932 DOI: 10.3389/fmicb.2020.634640] [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: 11/28/2020] [Accepted: 12/23/2020] [Indexed: 11/29/2022] Open
Abstract
Given the upsurge of drug-resistant tuberculosis worldwide, there is much focus on developing novel drug combinations allowing shorter treatment duration and a lower toxicity profile. Nicotinamide adenine dinucleotide (NAD) biosynthesis targeting is acknowledged as a promising strategy to combat drug-susceptible, drug-resistant, and latent tuberculosis (TB) infections. In this review, we describe the potential synergy of NAD biosynthesis inhibitors with several TB-drugs in prospective novel combination therapy. Despite not directly targeting the essential NAD cofactor's biosynthesis, several TB prodrugs either require a NAD biosynthesis enzyme to be activated or form a toxic chemical adduct with NAD(H) itself. For example, pyrazinamide requires the action of nicotinamidase (PncA), often referred to as pyrazinamidase, to be converted into its active form. PncA is an essential player in NAD salvage and recycling. Since most pyrazinamide-resistant strains are PncA-defective, a combination with downstream NAD-blocking molecules may enhance pyrazinamide activity and possibly overcome the resistance mechanism. Isoniazid, ethionamide, and delamanid form NAD adducts in their active form, partly perturbing the redox cofactor metabolism. Indeed, NAD depletion has been observed in Mycobacterium tuberculosis (Mtb) during isoniazid treatment, and activation of the intracellular NAD phosphorylase MbcT toxin potentiates its effect. Due to the NAD cofactor's crucial role in cellular energy production, additional synergistic correlations of NAD biosynthesis blockade can be envisioned with bedaquiline and other drugs targeting energy-metabolism in mycobacteria. In conclusion, future strategies targeting NAD metabolism in Mtb should consider its potential synergy with current and other forthcoming TB-drugs.
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Affiliation(s)
- Kyle H. Rohde
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, United States
| | - Leonardo Sorci
- Division of Bioinformatics and Biochemistry, Department of Materials, Environmental Sciences and Urban Planning, Polytechnic University of Marche, Ancona, Italy
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23
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Mourenza Á, Gil JA, Mateos LM, Letek M. Novel Treatments and Preventative Strategies Against Food-Poisoning Caused by Staphylococcal Species. Pathogens 2021; 10:91. [PMID: 33498299 PMCID: PMC7909252 DOI: 10.3390/pathogens10020091] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/14/2021] [Accepted: 01/16/2021] [Indexed: 12/19/2022] Open
Abstract
Staphylococcal infections are a widespread cause of disease in humans. In particular, S. aureus is a major causative agent of infection in clinical medicine. In addition, these bacteria can produce a high number of staphylococcal enterotoxins (SE) that may cause food intoxications. Apart from S. aureus, many coagulase-negative Staphylococcus spp. could be the source of food contamination. Thus, there is an active research work focused on developing novel preventative interventions based on food supplements to reduce the impact of staphylococcal food poisoning. Interestingly, many plant-derived compounds, such as polyphenols, flavonoids, or terpenoids, show significant antimicrobial activity against staphylococci, and therefore these compounds could be crucial to reduce the incidence of food intoxication in humans. Here, we reviewed the most promising strategies developed to prevent staphylococcal food poisoning.
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Affiliation(s)
- Álvaro Mourenza
- Departamento de Biología Molecular, Área de Microbiología, Universidad de León, 24071 León, Spain; (Á.M.); (J.A.G.)
| | - José A. Gil
- Departamento de Biología Molecular, Área de Microbiología, Universidad de León, 24071 León, Spain; (Á.M.); (J.A.G.)
- Instituto de Biología Molecular, Genómica y Proteómica (INBIOMIC), Universidad de León, 24071 León, Spain
| | - Luis M. Mateos
- Departamento de Biología Molecular, Área de Microbiología, Universidad de León, 24071 León, Spain; (Á.M.); (J.A.G.)
- Instituto de Biología Molecular, Genómica y Proteómica (INBIOMIC), Universidad de León, 24071 León, Spain
| | - Michal Letek
- Departamento de Biología Molecular, Área de Microbiología, Universidad de León, 24071 León, Spain; (Á.M.); (J.A.G.)
- Instituto de Desarrollo Ganadero y Sanidad Animal (INDEGSAL), Universidad de León, 24071 León, Spain
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24
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Veschetti L, Sandri A, Patuzzo C, Melotti P, Malerba G, Lleò MM. Mobilome Analysis of Achromobacter spp. Isolates from Chronic and Occasional Lung Infection in Cystic Fibrosis Patients. Microorganisms 2021; 9:microorganisms9010130. [PMID: 33430044 PMCID: PMC7826576 DOI: 10.3390/microorganisms9010130] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/23/2020] [Accepted: 01/04/2021] [Indexed: 12/22/2022] Open
Abstract
Achromobacter spp. is an opportunistic pathogen that can cause lung infections in patients with cystic fibrosis (CF). Although a variety of mobile genetic elements (MGEs) carrying antimicrobial resistance genes have been identified in clinical isolates, little is known about the contribution of Achromobacter spp. mobilome to its pathogenicity. To provide new insights, we performed bioinformatic analyses of 54 whole genome sequences and investigated the presence of phages, insertion sequences (ISs), and integrative and conjugative elements (ICEs). Most of the detected phages were previously described in other pathogens and carried type II toxin-antitoxin systems as well as other pathogenic genes. Interestingly, the partial sequence of phage Bcep176 was found in all the analyzed Achromobacter xylosoxidans genome sequences, suggesting the integration of this phage in an ancestor strain. A wide variety of IS was also identified either inside of or in proximity to pathogenicity islands. Finally, ICEs carrying pathogenic genes were found to be widespread among our isolates and seemed to be involved in transfer events within the CF lung. These results highlight the contribution of MGEs to the pathogenicity of Achromobacter species, their potential to become antimicrobial targets, and the need for further studies to better elucidate their clinical impact.
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Affiliation(s)
- Laura Veschetti
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (L.V.); (C.P.); (G.M.)
| | - Angela Sandri
- Department of Diagnostics and Public Health, Microbiology Section, University of Verona, 37134 Verona, Italy;
| | - Cristina Patuzzo
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (L.V.); (C.P.); (G.M.)
| | - Paola Melotti
- Cystic Fibrosis Center, Azienda Ospedaliera Universitaria Integrata Verona, 37126 Verona, Italy;
| | - Giovanni Malerba
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (L.V.); (C.P.); (G.M.)
| | - Maria M. Lleò
- Department of Diagnostics and Public Health, Microbiology Section, University of Verona, 37134 Verona, Italy;
- Correspondence:
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25
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Av Sá LGD, Silva CRD, de A Neto JB, Cândido TM, de Oliveira LC, do Nascimento FB, Barroso FD, da Silva LJ, de Mesquita JR, de Moraes MO, Cavalcanti BC, Júnior HV. Etomidate inhibits the growth of MRSA and exhibits synergism with oxacillin. Future Microbiol 2020; 15:1611-1619. [PMID: 33215536 DOI: 10.2217/fmb-2020-0078] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Aim: The purpose of this study was to evaluate the antimicrobial activity of the anesthetic etomidate against strains of MRSA and biofilms. Materials & methods: The antibacterial effect of etomidate was assessed by the broth microdilution method. To investigate the probable action mechanism of the compound flow cytometry techniques were used. Results: MRSA strains showed MIC equal to 500 and 1000 μg/ml of etomidate. Four-fifths (80%) of the tested MRSA strains demonstrated synergistic effect with oxacillin. Etomidate also showed activity against MRSA biofilm at concentration of 250 μg/ml. Cytometric analysis revealed that the cells treated with etomidate leading to cell death, probably by apoptosis. Conclusion: Etomidate showed antibacterial activity against MRSA.
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Affiliation(s)
- Lívia G do Av Sá
- Department of Clinical & Toxicological Analysis, School of Pharmacy, Laboratory of Bioprospection in Antimicrobial Molecules (LABIMAN), Federal University of Ceará, Fortaleza, CE, Brazil.,Drug Research & Development Center, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Cecília R da Silva
- Department of Clinical & Toxicological Analysis, School of Pharmacy, Laboratory of Bioprospection in Antimicrobial Molecules (LABIMAN), Federal University of Ceará, Fortaleza, CE, Brazil.,Drug Research & Development Center, Federal University of Ceará, Fortaleza, CE, Brazil
| | - João B de A Neto
- Department of Clinical & Toxicological Analysis, School of Pharmacy, Laboratory of Bioprospection in Antimicrobial Molecules (LABIMAN), Federal University of Ceará, Fortaleza, CE, Brazil.,Drug Research & Development Center, Federal University of Ceará, Fortaleza, CE, Brazil.,University Center Christus, Fortaleza, CE, Brazil
| | - Thiago M Cândido
- Department of Clinical & Toxicological Analysis, School of Pharmacy, Laboratory of Bioprospection in Antimicrobial Molecules (LABIMAN), Federal University of Ceará, Fortaleza, CE, Brazil.,Drug Research & Development Center, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Leilson C de Oliveira
- Department of Clinical & Toxicological Analysis, School of Pharmacy, Laboratory of Bioprospection in Antimicrobial Molecules (LABIMAN), Federal University of Ceará, Fortaleza, CE, Brazil.,Drug Research & Development Center, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Francisca Bsa do Nascimento
- Department of Clinical & Toxicological Analysis, School of Pharmacy, Laboratory of Bioprospection in Antimicrobial Molecules (LABIMAN), Federal University of Ceará, Fortaleza, CE, Brazil.,Drug Research & Development Center, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Fátima Dd Barroso
- Department of Clinical & Toxicological Analysis, School of Pharmacy, Laboratory of Bioprospection in Antimicrobial Molecules (LABIMAN), Federal University of Ceará, Fortaleza, CE, Brazil.,Drug Research & Development Center, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Lisandra J da Silva
- Department of Clinical & Toxicological Analysis, School of Pharmacy, Laboratory of Bioprospection in Antimicrobial Molecules (LABIMAN), Federal University of Ceará, Fortaleza, CE, Brazil.,Drug Research & Development Center, Federal University of Ceará, Fortaleza, CE, Brazil
| | | | - Manoel O de Moraes
- Drug Research & Development Center, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Bruno C Cavalcanti
- Drug Research & Development Center, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Hélio Vn Júnior
- Department of Clinical & Toxicological Analysis, School of Pharmacy, Laboratory of Bioprospection in Antimicrobial Molecules (LABIMAN), Federal University of Ceará, Fortaleza, CE, Brazil.,Drug Research & Development Center, Federal University of Ceará, Fortaleza, CE, Brazil
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26
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Kang SM, Jin C, Kim DH, Lee Y, Lee BJ. Structural and Functional Study of the Klebsiella pneumoniae VapBC Toxin-Antitoxin System, Including the Development of an Inhibitor That Activates VapC. J Med Chem 2020; 63:13669-13679. [PMID: 33146528 DOI: 10.1021/acs.jmedchem.0c01118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Klebsiella pneumoniae is one of the most critical opportunistic pathogens. TA systems are promising drug targets because they are related to the survival of bacterial pathogens. However, structural information on TA systems in K. pneumoniae remains lacking; therefore, it is necessary to explore this information for the development of antibacterial agents. Here, we present the first crystal structure of the VapBC complex from K. pneumoniae at a resolution of 2.00 Å. We determined the toxin inhibitory mechanism of the VapB antitoxin through an Mg2+ switch, in which Mg2+ is displaced by R79 of VapB. This inhibitory mechanism of the active site is a novel finding and the first to be identified in a bacterial TA system. Furthermore, inhibitors, including peptides and small molecules, that activate the VapC toxin were discovered and investigated. These inhibitors can act as antimicrobial agents by disrupting the VapBC complex and activating VapC. Our comprehensive investigation of the K. pneumoniae VapBC system will help elucidate an unsolved conundrum in VapBC systems and develop potential antimicrobial agents.
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Affiliation(s)
- Sung-Min Kang
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Chenglong Jin
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea
| | - Do-Hee Kim
- College of Pharmacy, Jeju National University, Jeju 63243, Korea.,Interdisciplinary Graduate Program in Advanced Convergence Technology & Science, Jeju National University, Jeju 63243, Korea
| | - Yuno Lee
- Korea Chemical Bank, Korea Research Institute of Chemical Technology, Daejeon 34114, Korea
| | - Bong-Jin Lee
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Korea
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27
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Kang SM, Moon H, Han SW, Kim DH, Kim BM, Lee BJ. Structure-Based De Novo Design of Mycobacterium Tuberculosis VapC-Activating Stapled Peptides. ACS Chem Biol 2020; 15:2493-2498. [PMID: 32840352 DOI: 10.1021/acschembio.0c00492] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Toxin-antitoxin (TA) systems have been considered essential factors for bacterial survival. During our drug development program aimed against tuberculosis (TB), we discovered certain peptides that mimic the binding of the VapBC30 complex, leading to the arrest of bacterial cell growth and eventually cell death. Herein, we optimized these candidate peptides based on a hydrocarbon stapling strategy and performed biological in vitro evaluations. The V30-SP-8 peptide successfully penetrated Mycobacterium smegmatis cell membranes and exerted bactericidal activity at a minimum inhibitory concentration that inhibited 50% of the isolates (MIC50) < 6.25 μM. With the aid of structural and biochemical information for the VapBC30 TA system from M. tuberculosis, we suggest potential antimicrobial agents that could provide a platform to establish a novel antibacterial strategy. Reflecting the limited number of therapeutic agents targeting TA systems, we believe that this study not only provides chemical tools for exploring the biological events relevant to TA systems but also opens a new gateway toward TB drug discovery.
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Affiliation(s)
- Sung-Min Kang
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Heejo Moon
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Sang-Woo Han
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Do-Hee Kim
- College of Pharmacy, Jeju National University, Jeju 63243, Republic of Korea
- Interdisciplinary Graduate Program in Advanced Convergence Technology & Science, Jeju National University, Jeju, 63243 Republic of Korea
| | - Byeong Moon Kim
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Bong-Jin Lee
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
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28
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Fujitani H, Momiuchi K, Ishii K, Nomachi M, Kikuchi S, Ushiki N, Sekiguchi Y, Tsuneda S. Genomic and Physiological Characteristics of a Novel Nitrite-Oxidizing Nitrospira Strain Isolated From a Drinking Water Treatment Plant. Front Microbiol 2020; 11:545190. [PMID: 33042056 PMCID: PMC7522533 DOI: 10.3389/fmicb.2020.545190] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 08/24/2020] [Indexed: 11/13/2022] Open
Abstract
Nitrite-oxidizing bacteria (NOB) catalyze the second step of nitrification, which is an important process of the biogeochemical nitrogen cycle and is exploited extensively as a biological nitrogen removal process. Members of the genus Nitrospira are often identified as the dominant NOB in a diverse range of natural and artificial environments. Additionally, a number of studies examining the distribution, abundance, and characterization of complete ammonia oxidation (comammox) Nitrospira support the ecological importance of the genus Nitrospira. However, niche differentiation between nitrite-oxidizing Nitrospira and comammox Nitrospira remains unknown due to a lack of pure cultures. In this study, we report the isolation, physiology, and genome of a novel nitrite-oxidizing Nitrospira strain isolated from a fixed-bed column at a drinking water treatment plant. Continuous feeding of ammonia led to the enrichment of Nitrospira-like cells, as well as members of ammonia-oxidizing genus Nitrosomonas. Subsequently, a microcolony sorting technique was used to isolate a novel nitrite-oxidizing Nitrospira strain. Sequences of strains showing the growth of microcolonies in microtiter plates were checked. Consequently, the most abundant operational taxonomic unit (OTU) exhibited high sequence similarity with Nitrospira japonica (98%) at the 16S rRNA gene level. The two other Nitrospira OTUs shared over 99% sequence similarities with N. japonica and Nitrospira sp. strain GC86. Only one strain identified as Nitrospira was successfully subcultivated and designated as Nitrospira sp. strain KM1 with high sequence similarity with N. japonica (98%). The half saturation constant for nitrite and the maximum nitrite oxidation rate of strain KM1 were orders of magnitude lower than the published data of other known Nitrospira strains; moreover, strain KM1 was more sensitive to free ammonia compared with previously isolated Nitrospira strains. Therefore, the new Nitrospira strain appears to be better adapted to oligotrophic environments compared with other known non-marine nitrite oxidizers. The complete genome of strain KM1 was 4,509,223 bp in length and contained 4,318 predicted coding sequences. Average nucleotide identities between strain KM1 and known cultured Nitrospira genome sequences are 76.7-78.4%, suggesting at least species-level novelty of the strain in the Nitrospira lineage II. These findings broaden knowledge of the ecophysiological diversity of nitrite-oxidizing Nitrospira.
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Affiliation(s)
- Hirotsugu Fujitani
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan.,Research Organization for Nano & Life Innovation, Waseda University, Tokyo, Japan
| | - Kengo Momiuchi
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan
| | - Kento Ishii
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan
| | - Manami Nomachi
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan
| | - Shuta Kikuchi
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan
| | - Norisuke Ushiki
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan
| | - Yuji Sekiguchi
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Satoshi Tsuneda
- Research Organization for Nano & Life Innovation, Waseda University, Tokyo, Japan.,Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan
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29
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Targeting Type II Toxin-Antitoxin Systems as Antibacterial Strategies. Toxins (Basel) 2020; 12:toxins12090568. [PMID: 32899634 PMCID: PMC7551001 DOI: 10.3390/toxins12090568] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 08/31/2020] [Accepted: 08/31/2020] [Indexed: 12/13/2022] Open
Abstract
The identification of novel targets for antimicrobial agents is crucial for combating infectious diseases caused by evolving bacterial pathogens. Components of bacterial toxin–antitoxin (TA) systems have been recognized as promising therapeutic targets. These widespread genetic modules are usually composed of two genes that encode a toxic protein targeting an essential cellular process and an antitoxin that counteracts the activity of the toxin. Uncontrolled toxin expression may elicit a bactericidal effect, so they may be considered “intracellular molecular bombs” that can lead to elimination of their host cells. Based on the molecular nature of antitoxins and their mode of interaction with toxins, TA systems have been classified into six groups. The most prevalent are type II TA systems. Due to their ubiquity among clinical isolates of pathogenic bacteria and the essential processes targeted, they are promising candidates for the development of novel antimicrobial strategies. In this review, we describe the distribution of type II TA systems in clinically relevant human pathogens, examine how these systems could be developed as the targets for novel antibacterials, and discuss possible undesirable effects of such therapeutic intervention, such as the induction of persister cells, biofilm formation and toxicity to eukaryotic cells.
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30
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Zaveri A, Wang R, Botella L, Sharma R, Zhu L, Wallach JB, Song N, Jansen RS, Rhee KY, Ehrt S, Schnappinger D. Depletion of the DarG antitoxin in Mycobacterium tuberculosis triggers the DNA-damage response and leads to cell death. Mol Microbiol 2020; 114:641-652. [PMID: 32634279 PMCID: PMC7689832 DOI: 10.1111/mmi.14571] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/28/2020] [Accepted: 07/01/2020] [Indexed: 01/01/2023]
Abstract
Of the ~80 putative toxin-antitoxin (TA) modules encoded by the bacterial pathogen Mycobacterium tuberculosis (Mtb), three contain antitoxins essential for bacterial viability. One of these, Rv0060 (DNA ADP-ribosyl glycohydrolase, DarGMtb ), functions along with its cognate toxin Rv0059 (DNA ADP-ribosyl transferase, DarTMtb ), to mediate reversible DNA ADP-ribosylation (Jankevicius et al., 2016). We demonstrate that DarTMtb -DarGMtb form a functional TA pair and essentiality of darGMtb is dependent on the presence of darTMtb , but simultaneous deletion of both darTMtb -darGMtb does not alter viability of Mtb in vitro or in mice. The antitoxin, DarGMtb , forms a cytosolic complex with DNA-repair proteins that assembles independently of either DarTMtb or interaction with DNA. Depletion of DarGMtb alone is bactericidal, a phenotype that is rescued by expression of an orthologous antitoxin, DarGTaq , from Thermus aquaticus. Partial depletion of DarGMtb triggers a DNA-damage response and sensitizes Mtb to drugs targeting DNA metabolism and respiration. Induction of the DNA-damage response is essential for Mtb to survive partial DarGMtb -depletion and leads to a hypermutable phenotype.
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Affiliation(s)
- Anisha Zaveri
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Ruojun Wang
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Laure Botella
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Ritu Sharma
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Linnan Zhu
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Joshua B Wallach
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Naomi Song
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Robert S Jansen
- Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Kyu Y Rhee
- Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Sabine Ehrt
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Dirk Schnappinger
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
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31
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Jahanshahi S, Li Y. An Effective Method for Quantifying RNA Expression of IbsC-SibC, a Type I Toxin-Antitoxin System in Escherichia coli. Chembiochem 2020; 21:3120-3130. [PMID: 32516493 DOI: 10.1002/cbic.202000280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/04/2020] [Indexed: 01/28/2023]
Abstract
Toxin and antitoxin (TA) systems are small genetic modules consisting of a toxin protein and an RNA or protein antitoxin. It is difficult to study their functions in a large part due to the lack of effective methods to study toxin RNAs, which usually exist at exceptionally low levels. Herein, we describe a sensitive reverse transcription quantitative PCR (RT-qPCR) method that is able to quantitate such RNA species. The method was directed at detection of the toxin mRNA of the ibsC-sibC TA pair, and its high specificity was validated by sequencing. The approach was used to determine relative expression of the IbsC and SibC RNAs at different cell-growth phases; this revealed an expression pattern that cannot be explained by the prevailing notion of growth stasis by the toxin and rescue by the antitoxin. The usefulness of the method was further showcased by the determination of average cellular copy numbers of the IbsC-SibC RNAs in wild-type E. coli cells and RNA abundance in E. coli cells engineered with extra copies of the ibsC-sibC genes. With a robust method to quantitate cellular small RNAs at very low concentrations, we are now equipped to study the expression of TA systems under different conditions to gain useful insights about their functions.
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Affiliation(s)
- Shahrzad Jahanshahi
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, DeGroote School of Medicine, School of Biomedical Engineering, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4 K1, Canada
| | - Yingfu Li
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, DeGroote School of Medicine, School of Biomedical Engineering, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4 K1, Canada
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32
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Multi-Stress Induction of the Mycobacterium tuberculosis MbcTA Bactericidal Toxin-Antitoxin System. Toxins (Basel) 2020; 12:toxins12050329. [PMID: 32429486 PMCID: PMC7291234 DOI: 10.3390/toxins12050329] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/13/2020] [Accepted: 05/14/2020] [Indexed: 11/16/2022] Open
Abstract
MbcTA is a type II toxin/antitoxin (TA) system of Mycobacterium tuberculosis. The MbcT toxin triggers mycobacterial cell death in vitro and in vivo through the phosphorolysis of the essential metabolite NAD+ and its bactericidal activity is neutralized by physical interaction with its cognate antitoxin MbcA. Therefore, the MbcTA system appears as a promising target for the development of novel therapies against tuberculosis, through the identification of compounds able to antagonize or destabilize the MbcA antitoxin. Here, the expression of the mbcAT operon and its regulation were investigated. A dual fluorescent reporter system was developed, based on an integrative mycobacterial plasmid that encodes a constitutively expressed reporter, serving as an internal standard for monitoring mycobacterial gene expression, and an additional reporter, dependent on the promoter under investigation. This system was used both in M. tuberculosis and in the fast growing model species Mycobacterium smegmatis to: (i) assess the autoregulation of mbcAT; (ii) perform a genetic dissection of the mbcA promoter/operator region; and (iii) explore the regulation of mbcAT transcription from the mbcA promoter (PmbcA) in a variety of stress conditions, including in vivo in mice and in macrophages.
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33
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Safari F, Sharifi M, Farajnia S, Akbari B, Karimi Baba Ahmadi M, Negahdaripour M, Ghasemi Y. The interaction of phages and bacteria: the co-evolutionary arms race. Crit Rev Biotechnol 2019; 40:119-137. [PMID: 31793351 DOI: 10.1080/07388551.2019.1674774] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Since the dawn of life, bacteria and phages are locked in a constant battle and both are perpetually changing their tactics to overcome each other. Bacteria use various strategies to overcome the invading phages, including adsorption inhibition, restriction-modification (R/E) systems, CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated proteins) systems, abortive infection (Abi), etc. To counteract, phages employ intelligent tactics for the nullification of bacterial defense systems, such as accessing host receptors, evading R/E systems, and anti-CRISPR proteins. Intense knowledge about the details of these defense pathways is the basis for their broad utilities in various fields of research from microbiology to biotechnology. Hence, in this review, we discuss some strategies used by bacteria to inhibit phage infections as well as phage tactics to circumvent bacterial defense systems. In addition, the application of these strategies will be described as a lesson learned from bacteria and phage combats. The ecological factors that affect the evolution of bacterial immune systems is the other issue represented in this review.
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Affiliation(s)
- Fatemeh Safari
- Diagnostic Laboratory Sciences and Technology Research Center, School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran.,Department of Medical Biotechnology, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mehrdad Sharifi
- Department of Emergency Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Safar Farajnia
- Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Bahman Akbari
- Department of Medical Biotechnology, School of Medical Sciences, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | | | - Manica Negahdaripour
- Pharmaceutical Sciences Research Center, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Younes Ghasemi
- Pharmaceutical Sciences Research Center, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran.,Department of Pharmaceutical Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
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34
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Farhadi T, Hashemian SM, Farhadi Z. In Silico Designing of Peptidomimetics Enhancing Endoribonucleolytic Activities of Acinetobacter MazF Toxin as the Novel Anti-bacterial Candidates. Int J Pept Res Ther 2019. [DOI: 10.1007/s10989-019-09908-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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35
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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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36
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Deep A, Tiwari P, Agarwal S, Kaundal S, Kidwai S, Singh R, Thakur KG. Structural, functional and biological insights into the role of Mycobacterium tuberculosis VapBC11 toxin-antitoxin system: targeting a tRNase to tackle mycobacterial adaptation. Nucleic Acids Res 2019; 46:11639-11655. [PMID: 30329074 PMCID: PMC6265470 DOI: 10.1093/nar/gky924] [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: 07/25/2018] [Accepted: 10/04/2018] [Indexed: 01/10/2023] Open
Abstract
Toxin–antitoxin (TA) systems are involved in diverse physiological processes in prokaryotes, but their exact role in Mycobacterium tuberculosis (Mtb) virulence and in vivo stress adaptation has not been extensively studied. Here, we demonstrate that the VapBC11 TA module is essential for Mtb to establish infection in guinea pigs. RNA-sequencing revealed that overexpression of VapC11 toxin results in metabolic slowdown, suggesting that modulation of the growth rate is an essential strategy for in vivo survival. Interestingly, overexpression of VapC11 resulted in the upregulation of chromosomal TA genes, suggesting the existence of highly coordinated crosstalk among TA systems. In this study, we also present the crystal structure of the VapBC11 heterooctameric complex at 1.67 Å resolution. Binding kinetic studies suggest that the binding affinities of toxin–substrate and toxin–antitoxin interactions are comparable. We used a combination of structural studies, molecular docking, mutational analysis and in vitro ribonuclease assays to enhance our understanding of the mode of substrate recognition by the VapC11 toxin. Furthermore, we have also designed peptide-based inhibitors to target VapC11 ribonuclease activity. Taken together, we propose that the structure-guided design of inhibitors against in vivo essential ribonucleases might be a novel strategy to hasten clearance of intracellular Mtb.
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Affiliation(s)
- Amar Deep
- Structural Biology Laboratory, G. N. Ramachandran Protein Centre, Council of Scientific and Industrial Research-Institute of Microbial Technology (CSIR-IMTECH), Chandigarh 160036, India
| | - Prabhakar Tiwari
- Tuberculosis Research Laboratory, Vaccine and Infectious Disease Research Centre, Translational Health Science and Technology Institute, NCR-Biotech Science Cluster, 3rd Milestone, Faridabad Gurgaon Expressway, Faridabad 121001, India
| | - Sakshi Agarwal
- Tuberculosis Research Laboratory, Vaccine and Infectious Disease Research Centre, Translational Health Science and Technology Institute, NCR-Biotech Science Cluster, 3rd Milestone, Faridabad Gurgaon Expressway, Faridabad 121001, India
| | - Soni Kaundal
- Structural Biology Laboratory, G. N. Ramachandran Protein Centre, Council of Scientific and Industrial Research-Institute of Microbial Technology (CSIR-IMTECH), Chandigarh 160036, India
| | - Saqib Kidwai
- Tuberculosis Research Laboratory, Vaccine and Infectious Disease Research Centre, Translational Health Science and Technology Institute, NCR-Biotech Science Cluster, 3rd Milestone, Faridabad Gurgaon Expressway, Faridabad 121001, India
| | - Ramandeep Singh
- Tuberculosis Research Laboratory, Vaccine and Infectious Disease Research Centre, Translational Health Science and Technology Institute, NCR-Biotech Science Cluster, 3rd Milestone, Faridabad Gurgaon Expressway, Faridabad 121001, India
| | - Krishan G Thakur
- Structural Biology Laboratory, G. N. Ramachandran Protein Centre, Council of Scientific and Industrial Research-Institute of Microbial Technology (CSIR-IMTECH), Chandigarh 160036, India
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In Silico Insight into the Dominant Type II Toxin–Antitoxin Systems and Clp Proteases in Listeria monocytogenes and Designation of Derived Peptides as a Novel Approach to Interfere with this System. Int J Pept Res Ther 2019. [DOI: 10.1007/s10989-019-09868-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Paul P, Sahu BR, Suar M. Plausible role of bacterial toxin-antitoxin system in persister cell formation and elimination. Mol Oral Microbiol 2019; 34:97-107. [PMID: 30891951 DOI: 10.1111/omi.12258] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 02/22/2019] [Accepted: 03/16/2019] [Indexed: 12/11/2022]
Abstract
Although, a large proportion of pathogenic bacteria gets eliminated from hosts after antibiotic treatment, a fraction of population confronts against such effects and undergoes growth arrest to form persisters. Persistence in bacteria is a dormant physiological state where cells escape the effects of antimicrobials as well as other host immune defences without any genetic mutations. The state of dormancy is achieved through various complex phenomena and it is known that a gene pair named as toxin-antitoxin (TA) acts as a key player of persister cell formation where the toxin is activated either stochastically or after an environmental insult, thereby silencing the physiological processes. However, the controversial role of TA modules in persister cell formation has also been documented with reasonable clarity. Persisters may revert back from state of quiescence and regrow when conditions become favourable for their propagation. Therefore, the elimination of dormant bacteria is crucial, and currently, research interest is highly focussed on developing several antipersister strategies that may kill persister bacteria by targeting different molecules. It is worth examining these targets to develop appropriate therapeutic interventions against bacterial infections and it is believed that earmarking TA system can be a novel approach for resuscitation of persisters. In this review, we discussed the role of TA modules in mediating persistence with highlighting on the debatable issues regarding contribution of these modules in dormant bacteria formation. Furthermore, we discussed if these modules in bacteria can be targeted for successful elimination of dormant persister cells.
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Affiliation(s)
- Prajita Paul
- School of Biotechnology, KIIT (Deemed to be University), Bhubaneswar, India
| | - Bikash R Sahu
- School of Biotechnology, KIIT (Deemed to be University), Bhubaneswar, India
| | - Mrutyunjay Suar
- School of Biotechnology, KIIT (Deemed to be University), Bhubaneswar, India
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Freire DM, Gutierrez C, Garza-Garcia A, Grabowska AD, Sala AJ, Ariyachaokun K, Panikova T, Beckham KSH, Colom A, Pogenberg V, Cianci M, Tuukkanen A, Boudehen YM, Peixoto A, Botella L, Svergun DI, Schnappinger D, Schneider TR, Genevaux P, de Carvalho LPS, Wilmanns M, Parret AHA, Neyrolles O. An NAD + Phosphorylase Toxin Triggers Mycobacterium tuberculosis Cell Death. Mol Cell 2019; 73:1282-1291.e8. [PMID: 30792174 PMCID: PMC6436930 DOI: 10.1016/j.molcel.2019.01.028] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 11/13/2018] [Accepted: 01/18/2019] [Indexed: 01/13/2023]
Abstract
Toxin-antitoxin (TA) systems regulate fundamental cellular processes in bacteria and represent potential therapeutic targets. We report a new RES-Xre TA system in multiple human pathogens, including Mycobacterium tuberculosis. The toxin, MbcT, is bactericidal unless neutralized by its antitoxin MbcA. To investigate the mechanism, we solved the 1.8 Å-resolution crystal structure of the MbcTA complex. We found that MbcT resembles secreted NAD+-dependent bacterial exotoxins, such as diphtheria toxin. Indeed, MbcT catalyzes NAD+ degradation in vitro and in vivo. Unexpectedly, the reaction is stimulated by inorganic phosphate, and our data reveal that MbcT is a NAD+ phosphorylase. In the absence of MbcA, MbcT triggers rapid M. tuberculosis cell death, which reduces mycobacterial survival in macrophages and prolongs the survival of infected mice. Our study expands the molecular activities employed by bacterial TA modules and uncovers a new class of enzymes that could be exploited to treat tuberculosis and other infectious diseases.
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Affiliation(s)
- Diana Mendes Freire
- European Molecular Biology Laboratory, Hamburg Unit, Notkestraße 85, 22607 Hamburg, Germany
| | - Claude Gutierrez
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, 31400 Toulouse, France
| | - Acely Garza-Garcia
- Mycobacterial Metabolism and Antibiotic Research Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Anna D Grabowska
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, 31400 Toulouse, France
| | - Ambre J Sala
- Laboratoire de Microbiologie et Génétique Moléculaires, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 118 route de Narbonne, 31400 Toulouse, France
| | - Kanchiyaphat Ariyachaokun
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, 31400 Toulouse, France
| | - Terezie Panikova
- European Molecular Biology Laboratory, Hamburg Unit, Notkestraße 85, 22607 Hamburg, Germany
| | - Katherine S H Beckham
- European Molecular Biology Laboratory, Hamburg Unit, Notkestraße 85, 22607 Hamburg, Germany
| | - André Colom
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, 31400 Toulouse, France
| | - Vivian Pogenberg
- European Molecular Biology Laboratory, Hamburg Unit, Notkestraße 85, 22607 Hamburg, Germany
| | - Michele Cianci
- European Molecular Biology Laboratory, Hamburg Unit, Notkestraße 85, 22607 Hamburg, Germany
| | - Anne Tuukkanen
- European Molecular Biology Laboratory, Hamburg Unit, Notkestraße 85, 22607 Hamburg, Germany
| | - Yves-Marie Boudehen
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, 31400 Toulouse, France
| | - Antonio Peixoto
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, 31400 Toulouse, France
| | - Laure Botella
- Department of Microbiology and Immunology, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA
| | - Dmitri I Svergun
- European Molecular Biology Laboratory, Hamburg Unit, Notkestraße 85, 22607 Hamburg, Germany
| | - Dirk Schnappinger
- Department of Microbiology and Immunology, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA
| | - Thomas R Schneider
- European Molecular Biology Laboratory, Hamburg Unit, Notkestraße 85, 22607 Hamburg, Germany
| | - Pierre Genevaux
- Laboratoire de Microbiologie et Génétique Moléculaires, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, 118 route de Narbonne, 31400 Toulouse, France
| | - Luiz Pedro Sorio de Carvalho
- Mycobacterial Metabolism and Antibiotic Research Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Matthias Wilmanns
- European Molecular Biology Laboratory, Hamburg Unit, Notkestraße 85, 22607 Hamburg, Germany; University Hamburg Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20246 Hamburg, Germany
| | - Annabel H A Parret
- European Molecular Biology Laboratory, Hamburg Unit, Notkestraße 85, 22607 Hamburg, Germany.
| | - Olivier Neyrolles
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 205 route de Narbonne, 31400 Toulouse, France.
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A Systematic Overview of Type II and III Toxin-Antitoxin Systems with a Focus on Druggability. Toxins (Basel) 2018; 10:toxins10120515. [PMID: 30518070 PMCID: PMC6315513 DOI: 10.3390/toxins10120515] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 11/29/2018] [Accepted: 11/30/2018] [Indexed: 02/07/2023] Open
Abstract
Toxin-antitoxin (TA) systems are known to play various roles in physiological processes, such as gene regulation, growth arrest and survival, in bacteria exposed to environmental stress. Type II TA systems comprise natural complexes consisting of protein toxins and antitoxins. Each toxin and antitoxin participates in distinct regulatory mechanisms depending on the type of TA system. Recently, peptides designed by mimicking the interfaces between TA complexes showed its potential to activate the activity of toxin by competing its binding counterparts. Type II TA systems occur more often in pathogenic bacteria than in their nonpathogenic kin. Therefore, they can be possible drug targets, because of their high abundance in some pathogenic bacteria, such as Mycobacterium tuberculosis. In addition, recent bioinformatic analyses have shown that type III TA systems are highly abundant in the intestinal microbiota, and recent clinical studies have shown that the intestinal microbiota is linked to inflammatory diseases, obesity and even several types of cancer. We therefore focused on exploring the putative relationship between intestinal microbiota-related human diseases and type III TA systems. In this paper, we review and discuss the development of possible druggable materials based on the mechanism of type II and type III TA system.
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In Silico Derived Peptides for Inhibiting the Toxin–Antitoxin Systems of Mycobacterium tuberculosis: Basis for Developing Peptide-Based Therapeutics. Int J Pept Res Ther 2018. [DOI: 10.1007/s10989-018-9792-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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42
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Równicki M, Pieńko T, Czarnecki J, Kolanowska M, Bartosik D, Trylska J. Artificial Activation of Escherichia coli mazEF and hipBA Toxin-Antitoxin Systems by Antisense Peptide Nucleic Acids as an Antibacterial Strategy. Front Microbiol 2018; 9:2870. [PMID: 30534121 PMCID: PMC6275173 DOI: 10.3389/fmicb.2018.02870] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 11/08/2018] [Indexed: 12/14/2022] Open
Abstract
The search for new, non-standard targets is currently a high priority in the design of new antibacterial compounds. Bacterial toxin-antitoxin systems (TAs) are genetic modules that encode a toxin protein that causes growth arrest by interfering with essential cellular processes, and a cognate antitoxin, which neutralizes the toxin activity. TAs have no human analogs, are highly abundant in bacterial genomes, and therefore represent attractive alternative targets for antimicrobial drugs. This study demonstrates how artificial activation of Escherichia coli mazEF and hipBA toxin-antitoxin systems using sequence-specific antisense peptide nucleic acid oligomers is an innovative antibacterial strategy. The growth arrest observed in E. coli resulted from the inhibition of translation of the antitoxins by the antisense oligomers. Furthermore, two other targets, related to the activities of mazEF and hipBA, were identified as promising sites of action for antibacterials. These results show that TAs are susceptible to sequence-specific antisense agents and provide a proof-of-concept for their further exploitation in antimicrobial strategies.
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Affiliation(s)
- Marcin Równicki
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Warsaw, Poland
| | - Tomasz Pieńko
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Department of Drug Chemistry, Faculty of Pharmacy with the Laboratory Medicine Division, Medical University of Warsaw, Warsaw, Poland
| | - Jakub Czarnecki
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
- Unit of Bacterial Genome Plasticity, Department of Genomes and Genetics, Pasteur Institute, Paris, France
| | - Monika Kolanowska
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Genomic Medicine, Medical University of Warsaw, Warsaw, Poland
| | - Dariusz Bartosik
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Joanna Trylska
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
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Paul P, Verma S, Kumar Panda P, Jaiswal S, Sahu BR, Suar M. Molecular insight to influential role of Hha–TomB toxin–antitoxin system for antibacterial activity of biogenic silver nanoparticles. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2018; 46:S572-S584. [DOI: 10.1080/21691401.2018.1503598] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Prajita Paul
- School of Biotechnology, KIIT University, Bhubaneswar, India
| | - SureshK. Verma
- School of Biotechnology, KIIT University, Bhubaneswar, India
| | - Pritam Kumar Panda
- Division of Pediatric Hematology and Oncology, University Children’s Hospital, University of Freiburg, Freiburg, Germany
| | - Sangeeta Jaiswal
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan Health System, Ann Arbor, MI, USA
| | - Bikash R. Sahu
- School of Biotechnology, KIIT University, Bhubaneswar, India
| | - Mrutyunjay Suar
- School of Biotechnology, KIIT University, Bhubaneswar, India
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Kalani BS, Irajian G, Lotfollahi L, Abdollahzadeh E, Razavi S. Putative type II toxin-antitoxin systems in Listeria monocytogenes isolated from clinical, food, and animal samples in Iran. Microb Pathog 2018; 122:19-24. [DOI: 10.1016/j.micpath.2018.06.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 04/28/2018] [Accepted: 06/01/2018] [Indexed: 10/14/2022]
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Fei Q, Gao EB, Liu B, Wei Y, Ning D. A Toxin-Antitoxin System VapBC15 from Synechocystis sp. PCC 6803 Shows Distinct Regulatory Features. Genes (Basel) 2018; 9:E173. [PMID: 29561797 PMCID: PMC5924515 DOI: 10.3390/genes9040173] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 03/13/2018] [Accepted: 03/15/2018] [Indexed: 12/26/2022] Open
Abstract
Type II toxin-antitoxin (TA) systems play important roles in bacterial stress survival by regulating cell growth or death. They are highly abundant in cyanobacteria yet remain poorly characterized. Here, we report the identification and regulation of a putative type II TA system from Synechocystis PCC6803, VapBC15. The VapBC15 system is encoded by the chromosomal operon vapBC15. Exogenous expression of VapC15 dramatically arrested cell growth of Escherichia coli and reduced the numbers of colony-forming units (CFU). The VapC15 toxicity could be which was counteracted neutralized by simultaneous or delayed production of VapB15. Biochemical analysis demonstrated the formation of VapB15-VapC15 complexes by the physical interaction between VapB15 and VapC15. Notably, the VapB15 antitoxin up-regulated the transcription of the vapBC15 operon by directly binding to the promoter region, and the VapC15 toxin abolished the up-regulatory effect by destabilizing the binding. Moreover, VapB15 can be degraded by the proteases Lons and ClpXP2s from Synechocystis PCC6803, thus activating the latent toxicity of VapBC15. These findings suggest that VapBC15 represents a genuine TA system that utilizes a distinct mechanism to regulate toxin activity.
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Affiliation(s)
- Qian Fei
- CAS Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - E-Bin Gao
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China.
| | - Biao Liu
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China.
| | - Yao Wei
- Huai'an Research Center, Institute of Hydrobiology, Chinese Academy of Sciences, Huai'an 223005, China.
| | - Degang Ning
- CAS Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
- Huai'an Research Center, Institute of Hydrobiology, Chinese Academy of Sciences, Huai'an 223005, China.
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46
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Kang SM, Kim DH, Lee KY, Park SJ, Yoon HJ, Lee SJ, Im H, Lee BJ. Functional details of the Mycobacterium tuberculosis VapBC26 toxin-antitoxin system based on a structural study: insights into unique binding and antibiotic peptides. Nucleic Acids Res 2017; 45:8564-8580. [PMID: 28575388 PMCID: PMC5737657 DOI: 10.1093/nar/gkx489] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 05/25/2017] [Indexed: 11/16/2022] Open
Abstract
Toxin-antitoxin (TA) systems are essential for bacterial persistence under stressful conditions. In particular, Mycobacterium tuberculosis express VapBC TA genes that encode the stable VapC toxin and the labile VapB antitoxin. Under normal conditions, these proteins interact to form a non-toxic TA complex, but the toxin is activated by release from the antitoxin in response to unfavorable conditions. Here, we present the crystal structure of the M. tuberculosis VapBC26 complex and show that the VapC26 toxin contains a pilus retraction protein (PilT) N-terminal (PIN) domain that is essential for ribonuclease activity and that, the VapB26 antitoxin folds into a ribbon-helix-helix DNA-binding motif at the N-terminus. The active site of VapC26 is sterically blocked by the flexible C-terminal region of VapB26. The C-terminal region of free VapB26 adopts an unfolded conformation but forms a helix upon binding to VapC26. The results of RNase activity assays show that Mg2+ and Mn2+ are essential for the ribonuclease activity of VapC26. As shown in the nuclear magnetic resonance spectra, several residues of VapB26 participate in the specific binding to the promoter region of the VapBC26 operon. In addition, toxin-mimicking peptides were designed that inhibit TA complex formation and thereby increase toxin activity, providing a novel approach to the development of new antibiotics.
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Affiliation(s)
- Sung-Min Kang
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Gwanak-gu, Seoul 151-742, Republic of Korea
| | - Do-Hee Kim
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Gwanak-gu, Seoul 151-742, Republic of Korea
| | - Ki-Young Lee
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Gwanak-gu, Seoul 151-742, Republic of Korea
| | - Sung Jean Park
- College of Pharmacy, Gachon University, 534-2 Yeonsu-dong, Yeonsu-gu, Incheon 406-799, Republic of Korea
| | - Hye-Jin Yoon
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 151-742, Republic of Korea
| | - Sang Jae Lee
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Gwanak-gu, Seoul 151-742, Republic of Korea
| | - Hookang Im
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Gwanak-gu, Seoul 151-742, Republic of Korea
| | - Bong-Jin Lee
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Gwanak-gu, Seoul 151-742, Republic of Korea
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Klimina KM, Poluektova EU, Danilenko VN. Bacterial toxin–antitoxin systems: Properties, functional significance, and possibility of use (Review). APPL BIOCHEM MICRO+ 2017. [DOI: 10.1134/s0003683817050076] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Shidore T, Triplett LR. Toxin-Antitoxin Systems: Implications for Plant Disease. ANNUAL REVIEW OF PHYTOPATHOLOGY 2017; 55:161-179. [PMID: 28525308 DOI: 10.1146/annurev-phyto-080516-035559] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Toxin-antitoxin (TA) systems are gene modules that are ubiquitous in free-living prokaryotes. Diverse in structure, cellular function, and fitness roles, TA systems are defined by the presence of a toxin gene that suppresses bacterial growth and a toxin-neutralizing antitoxin gene, usually encoded in a single operon. Originally viewed as DNA maintenance modules, TA systems are now thought to function in many roles, including bacterial stress tolerance, virulence, phage defense, and biofilm formation. However, very few studies have investigated the significance of TA systems in the context of plant-microbe interactions. This review discusses the potential impact and application of TA systems in plant-associated bacteria, guided by insights gained from animal-pathogenic model systems.
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Affiliation(s)
- T Shidore
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511:
| | - L R Triplett
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511:
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Ramisetty BCM, Santhosh RS. Endoribonuclease type II toxin-antitoxin systems: functional or selfish? MICROBIOLOGY-SGM 2017; 163:931-939. [PMID: 28691660 DOI: 10.1099/mic.0.000487] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Most bacterial genomes have multiple type II toxin-antitoxin systems (TAs) that encode two proteins which are referred to as a toxin and an antitoxin. Toxins inhibit a cellular process, while the interaction of the antitoxin with the toxin attenuates the toxin's activity. Endoribonuclease-encoding TAs cleave RNA in a sequence-dependent fashion, resulting in translational inhibition. To account for their prevalence and retention by bacterial genomes, TAs are credited with clinically significant phenomena, such as bacterial programmed cell death, persistence, biofilms and anti-addiction to plasmids. However, the programmed cell death and persistence hypotheses have been challenged because of conceptual, methodological and/or strain issues. In an alternative view, chromosomal TAs seem to be retained by virtue of addiction at two levels: via a poison-antidote combination (TA proteins) and via transcriptional reprogramming of the downstream core gene (due to integration). Any perturbation in the chromosomal TA operons could cause fitness loss due to polar effects on the downstream genes and hence be detrimental under natural conditions. The endoribonucleases encoding chromosomal TAs are most likely selfish DNA as they are retained by bacterial genomes, even though TAs do not confer a direct advantage via the TA proteins. TAs are likely used by various replicons as 'genetic arms' that allow the maintenance of themselves and associated genetic elements. TAs seem to be the 'selfish arms' that make the best use of the 'arms race' between bacterial genomes and plasmids.
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Namouchi A, Cimino M, Favre-Rochex S, Charles P, Gicquel B. Phenotypic and genomic comparison of Mycobacterium aurum and surrogate model species to Mycobacterium tuberculosis: implications for drug discovery. BMC Genomics 2017; 18:530. [PMID: 28705154 PMCID: PMC5508667 DOI: 10.1186/s12864-017-3924-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 07/05/2017] [Indexed: 12/18/2022] Open
Abstract
Background Tuberculosis (TB) is caused by Mycobacterium tuberculosis and represents one of the major challenges facing drug discovery initiatives worldwide. The considerable rise in bacterial drug resistance in recent years has led to the need of new drugs and drug regimens. Model systems are regularly used to speed-up the drug discovery process and circumvent biosafety issues associated with manipulating M. tuberculosis. These include the use of strains such as Mycobacterium smegmatis and Mycobacterium marinum that can be handled in biosafety level 2 facilities, making high-throughput screening feasible. However, each of these model species have their own limitations. Results We report and describe the first complete genome sequence of Mycobacterium aurum ATCC23366, an environmental mycobacterium that can also grow in the gut of humans and animals as part of the microbiota. This species shows a comparable resistance profile to that of M. tuberculosis for several anti-TB drugs. The aims of this study were to (i) determine the drug resistance profile of a recently proposed model species, Mycobacterium aurum, strain ATCC23366, for anti-TB drug discovery as well as Mycobacterium smegmatis and Mycobacterium marinum (ii) sequence and annotate the complete genome sequence of this species obtained using Pacific Bioscience technology (iii) perform comparative genomics analyses of the various surrogate strains with M. tuberculosis (iv) discuss how the choice of the surrogate model used for drug screening can affect the drug discovery process. Conclusions We describe the complete genome sequence of M. aurum, a surrogate model for anti-tuberculosis drug discovery. Most of the genes already reported to be associated with drug resistance are shared between all the surrogate strains and M. tuberculosis. We consider that M. aurum might be used in high-throughput screening for tuberculosis drug discovery. We also highly recommend the use of different model species during the drug discovery screening process. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3924-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Amine Namouchi
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, P.O. Box 1066, Blindern NO-0316, Oslo, Norway.
| | - Mena Cimino
- Unit of Mycobacterial genetics, Institut Pasteur, 25-28, rue du Docteur Roux, 75724, Paris, Cedex 15, France
| | - Sandrine Favre-Rochex
- Unit of Mycobacterial genetics, Institut Pasteur, 25-28, rue du Docteur Roux, 75724, Paris, Cedex 15, France
| | - Patricia Charles
- Unit of Mycobacterial genetics, Institut Pasteur, 25-28, rue du Docteur Roux, 75724, Paris, Cedex 15, France
| | - Brigitte Gicquel
- Unit of Mycobacterial genetics, Institut Pasteur, 25-28, rue du Docteur Roux, 75724, Paris, Cedex 15, France.
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