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Nielsen MR, Brodersen DE. Structural Variations and Rearrangements in Bacterial Type II Toxin-Antitoxin Systems. Subcell Biochem 2024; 104:245-267. [PMID: 38963490 DOI: 10.1007/978-3-031-58843-3_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Bacteria encode a wide range of survival and immunity systems, including CRISPR-Cas, restriction-modification systems, and toxin-antitoxin systems involved in defence against bacteriophages, as well as survival during challenging growth conditions or exposure to antibiotics. Toxin-antitoxin (TA) systems are small two- or three-gene cassettes consisting of a metabolic regulator (the "toxin") and its associated antidote (the "antitoxin"), which also often functions as a transcriptional regulator. TA systems are widespread in the genomes of pathogens but are also present in commensal bacterial species and on plasmids. For mobile elements such as plasmids, TA systems play a role in maintenance, and increasing evidence now points to roles of chromosomal toxin-antitoxin systems in anti-phage defence. Moreover, the widespread occurrence of toxin-antitoxin systems in the genomes of pathogens has been suggested to relate to survival during host infection as well as in persistence during antibiotic treatment. Upon repeated exposure to antibiotics, TA systems have been shown to acquire point mutations as well as more dramatic rearrangements such as in-frame deletions with potential relevance for bacterial survival and pathogenesis. In this review, we present an overview of the known functional and structural consequences of mutations and rearrangements arising in bacterial toxin-antitoxin systems and discuss their relevance for survival and persistence of pathogenic species.
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Affiliation(s)
| | - Ditlev E Brodersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark.
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2
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Jian T, Su Q, Liu Y, Seoh HK, Houghton JE, Tai PC, Huang X. Structure-Based Virtual Screening of Helicobacter pylori SecA Inhibitors. IEEE Trans Nanobioscience 2023; 22:933-942. [PMID: 37030876 DOI: 10.1109/tnb.2023.3259946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2023]
Abstract
The human bacterial pathogen Helicobacter pylori causes a range of gastric diseases. The killing rate of Helicobacter pylori is declining year by year because of high antibiotics resistance. It is urgent to develop new target and novel anti- Helicobacter pylori drugs. As an "energy pump" for bacterial cells, SecA is essential for bacterial growth and drives bacterial protein transmembrane transport, moreover SecA is absent in mammals, all of which nominate SecA as an attractive antimicrobial target. Here, we provided a structure-based virtual screening method to screen the 3D-diversity natural-product-like screening library against SecA for novel anti- Helicobacter pylori inhibitors with novel scaffolds. In this study, homology modeling was used to construct the three-dimensional structure of Helicobacter pylori SecA. Two rounds of molecular docking were then used to find new small-molecule inhibitors of SecA, identifying six lead candidates that maintained key interactions with the binding pocket. After that, molecular dynamics simulations were used to explore more accurate ligand-receptor binding modes in states close to natural conditions. Encouragingly, all six compounds were relatively stable during the simulation. Apart from that the binding free energy calculation based on MM/PBSA demonstrated favorable results of < -13.642 kcal/mol. Finally, ADME-T analysis indicated that these compounds were also sufficiently druggable. All six compounds can be well combined with the crystal structure, which further facilitate the development of SecA inhibitors and lead compounds against Helicobacter pylori.
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3
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Shaibullah S, Shuhaimi N, Ker DS, Mohd-Sharif N, Ho KL, Teh AH, Waterman J, Tang TH, Wong RR, Nathan S, Mohamed R, Ng MJ, Fung SY, Jonet MA, Firdaus-Raih M, Ng CL. Structural and functional analyses of Burkholderia pseudomallei BPSL1038 reveal a Cas-2/VapD nuclease sub-family. Commun Biol 2023; 6:920. [PMID: 37684342 PMCID: PMC10491678 DOI: 10.1038/s42003-023-05265-4] [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: 12/04/2021] [Accepted: 08/21/2023] [Indexed: 09/10/2023] Open
Abstract
Burkholderia pseudomallei is a highly versatile pathogen with ~25% of its genome annotated to encode hypothetical proteins. One such hypothetical protein, BPSL1038, is conserved across seven bacterial genera and 654 Burkholderia spp. Here, we present a 1.55 Å resolution crystal structure of BPSL1038. The overall structure folded into a modified βαββαβα ferredoxin fold similar to known Cas2 nucleases. The Cas2 equivalent catalytic aspartate (D11) pairs are conserved in BPSL1038 although B. pseudomallei has no known CRISPR associated system. Functional analysis revealed that BPSL1038 is a nuclease with endonuclease activity towards double-stranded DNA. The DNase activity is divalent ion independent and optimum at pH 6. The concentration of monovalent ions (Na+ and K+) is crucial for nuclease activity. An active site with a unique D11(X20)SST motif was identified and proposed for BPSL1038 and its orthologs. Structure modelling indicates the catalytic role of the D11(X20)SST motif and that the arginine residues R10 and R30 may interact with the nucleic acid backbone. The structural similarity of BPSL1038 to Cas2 proteins suggests that BPSL1038 may represent a sub-family of nucleases that share a common ancestor with Cas2.
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Affiliation(s)
- Sofiyah Shaibullah
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, UKM Bangi, 43600, Selangor, Malaysia
| | - Nurshahirah Shuhaimi
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, UKM Bangi, 43600, Selangor, Malaysia
| | - De-Sheng Ker
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, UKM Bangi, 43600, Selangor, Malaysia
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
| | - Nurhikmah Mohd-Sharif
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, UKM Bangi, 43600, Selangor, Malaysia
| | - Kok Lian Ho
- Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, UPM Serdang, 43400, Selangor, Malaysia
| | - Aik-Hong Teh
- Centre for Chemical Biology, Universiti Sains Malaysia, Bayan Lepas, 11900, Penang, Malaysia
| | - Jitka Waterman
- Diamond Light Source, Harwell Science & Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - Thean-Hock Tang
- Advanced Medical and Dental Institute, Universiti Sains Malaysia, Pulau Pinang, Malaysia
| | - Rui-Rui Wong
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, UKM Bangi, 43600, Selangor, Malaysia
- Faculty of Health and Life Sciences, Inti International University, Persiaran Perdana, BBN, Nilai, 71800, Negeri Sembilan, Malaysia
| | - Sheila Nathan
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, UKM Bangi, 43600, Selangor, Malaysia
| | - Rahmah Mohamed
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, UKM Bangi, 43600, Selangor, Malaysia
| | - Min Jia Ng
- Medicinal Mushroom Research Group (MMRG), Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Shin-Yee Fung
- Medicinal Mushroom Research Group (MMRG), Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Mohd Anuar Jonet
- Malaysia Genome and Vaccine Institute, National Institutes of Biotechnology Malaysia (NIBM), Jalan Bangi, Kajang, 43000, Selangor, Malaysia
| | - Mohd Firdaus-Raih
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, UKM Bangi, 43600, Selangor, Malaysia
- Department of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, UKM Bangi, 43600, Selangor, Malaysia
| | - Chyan Leong Ng
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, UKM Bangi, 43600, Selangor, Malaysia.
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4
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Yee WX, Yasir M, Turner AK, Baker DJ, Cehovin A, Tang CM. Evolution, persistence, and host adaption of a gonococcal AMR plasmid that emerged in the pre-antibiotic era. PLoS Genet 2023; 19:e1010743. [PMID: 37186602 DOI: 10.1371/journal.pgen.1010743] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 05/25/2023] [Accepted: 04/14/2023] [Indexed: 05/17/2023] Open
Abstract
Plasmids are diverse extrachromosomal elements significantly contributing to interspecies dissemination of antimicrobial resistance (AMR) genes. However, within clinically important bacteria, plasmids can exhibit unexpected narrow host ranges, a phenomenon that has scarcely been examined. Here we show that pConj is largely restricted to the human-specific pathogen, Neisseria gonorrhoeae. pConj can confer tetracycline resistance and is central to the dissemination of other AMR plasmids. We tracked pConj evolution from the pre-antibiotic era 80 years ago to the modern day and demonstrate that, aside from limited gene acquisition and loss events, pConj is remarkably conserved. Notably, pConj has remained prevalent in gonococcal populations despite cessation of tetracycline use, thereby demonstrating pConj adaptation to its host. Equally, pConj imposes no measurable fitness costs and is stably inherited by the gonococcus. Its maintenance depends on the co-operative activity of plasmid-encoded Toxin:Antitoxin (TA) and partitioning systems rather than host factors. An orphan VapD toxin encoded on pConj forms a split TA with antitoxins expressed from an ancestral co-resident plasmid or a horizontally-acquired chromosomal island, potentially explaining pConj's limited distribution. Finally, ciprofloxacin can induce loss of this highly stable plasmid, reflecting epidemiological evidence of transient local falls in pConj prevalence when fluoroquinolones were introduced to treat gonorrhoea.
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Affiliation(s)
- Wearn-Xin Yee
- Sir William Dunn School of Pathology, University of Oxford, OXFORD, United Kingdom
| | | | | | | | - Ana Cehovin
- Sir William Dunn School of Pathology, University of Oxford, OXFORD, United Kingdom
| | - Christoph M Tang
- Sir William Dunn School of Pathology, University of Oxford, OXFORD, United Kingdom
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5
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Wang JY, Pausch P, Doudna JA. Structural biology of CRISPR-Cas immunity and genome editing enzymes. Nat Rev Microbiol 2022; 20:641-656. [PMID: 35562427 DOI: 10.1038/s41579-022-00739-4] [Citation(s) in RCA: 58] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/11/2022] [Indexed: 12/20/2022]
Abstract
CRISPR-Cas systems provide resistance against foreign mobile genetic elements and have a wide range of genome editing and biotechnological applications. In this Review, we examine recent advances in understanding the molecular structures and mechanisms of enzymes comprising bacterial RNA-guided CRISPR-Cas immune systems and deployed for wide-ranging genome editing applications. We explore the adaptive and interference aspects of CRISPR-Cas function as well as open questions about the molecular mechanisms responsible for genome targeting. These structural insights reflect close evolutionary links between CRISPR-Cas systems and mobile genetic elements, including the origins and evolution of CRISPR-Cas systems from DNA transposons, retrotransposons and toxin-antitoxin modules. We discuss how the evolution and structural diversity of CRISPR-Cas systems explain their functional complexity and utility as genome editing tools.
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Affiliation(s)
- Joy Y Wang
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA
| | - Patrick Pausch
- VU LSC-EMBL Partnership for Genome Editing Technologies, Life Sciences Center, Vilnius University, Vilnius, Lithuania.
| | - Jennifer A Doudna
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA.
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA.
- Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA, USA.
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA, USA.
- MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Gladstone Institutes, University of California, San Francisco, San Francisco, CA, USA.
- Gladstone-UCSF Institute of Genomic Immunology, San Francisco, CA, USA.
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6
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Anand V, Prabhakaran HS, Gogoi P, Kanaujia SP, Kumar M. Structural and functional characterization of Cas2 of CRISPR-Cas subtype I-C lacking the CRISPR component. Front Mol Biosci 2022; 9:988569. [PMID: 36172044 PMCID: PMC9510766 DOI: 10.3389/fmolb.2022.988569] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 08/08/2022] [Indexed: 11/29/2022] Open
Abstract
The genome of pathogenic Leptospira interrogans serovars (Copenhageni and Lai) are predicted to have CRISPR-Cas of subtypes I-B and I-C. Cas2, one of the core Cas proteins, has a crucial role in adaptive defense against foreign nucleic acids. However, subtype I-C lacks the CRISPR element at its loci essential for RNA-mediated adaptive immunity against foreign nucleic acids. The reason for sustaining the expense of cas genes are unknown in the absence of a CRISPR array. Thus, Cas2C was chosen as a representative Cas protein from two well-studied serovars of Leptospira to address whether it is functional. In this study, the recombinant Cas2C of Leptospira serovars Copenhageni (rLinCas2C, 12 kDa) and Lai (rLinCas2C_Lai, 8.6 kDa) were overexpressed and purified. Due to natural frameshift mutation in the cas2c gene of serovar Lai, rLinCas2C_Lai was overexpressed and purified as a partially translated protein. Nevertheless, the recombinant Cas2C from each serovar exhibited metal-dependent DNase and metal-independent RNase activities. The crystal structure of rLinCas2C obtained at the resolution of 2.60 Å revealed the protein is in apostate conformation and contains N- (1–71 amino acids) and C-terminal (72–90 amino acids) regions, with the former possessing a ferredoxin fold. Substitution of the conserved residues (Tyr7, Asp8, Arg33, and Phe39) with alanine and deletion of Loop L2 resulted in compromised DNase activity. On the other hand, a moderate reduction in RNase activity was evident only in selective rLinCas2C mutants. Overall, in the absence of an array, the observed catalytic activity of Cas2C may be required for biological processes distinct from the CRISPR-Cas-associated function.
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Affiliation(s)
| | | | | | | | - Manish Kumar
- *Correspondence: Shankar Prasad Kanaujia, ; Manish Kumar,
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7
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Bourne CR. Bacterial Growth Mindset: Structural Plasticity in Defense Systems. Structure 2021; 29:97-98. [PMID: 33545061 DOI: 10.1016/j.str.2021.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this issue of Structure, Bertelsen et al. determine the three-dimensional structures of the Haemophilus influenzae VapD toxin, a Cas-2 homolog, with and without its cognate neutralizing antitoxin, VapX, that together comprise a toxin-antitoxin system. These reveal a unique stoichiometry, with two VapD toxins neutralized simultaneously by one VapX antitoxin.
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Affiliation(s)
- Christina R Bourne
- University of Oklahoma, Department of Chemistry and Biochemistry, Norman, OK 73019, USA.
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8
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Krzyżek P. Toxin-Antitoxin Systems - A New Player in Morphological Transformation of Antibiotic-Exposed Helicobacter pylori? Front Cell Infect Microbiol 2021; 11:670677. [PMID: 33981631 PMCID: PMC8108984 DOI: 10.3389/fcimb.2021.670677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 04/06/2021] [Indexed: 11/13/2022] Open
Affiliation(s)
- Paweł Krzyżek
- Department of Microbiology, Faculty of Medicine, Wroclaw Medical University, Wroclaw, Poland
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9
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De Bruyn P, Girardin Y, Loris R. Prokaryote toxin-antitoxin modules: Complex regulation of an unclear function. Protein Sci 2021; 30:1103-1113. [PMID: 33786944 PMCID: PMC8138530 DOI: 10.1002/pro.4071] [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: 02/26/2021] [Revised: 03/29/2021] [Accepted: 03/30/2021] [Indexed: 12/29/2022]
Abstract
Toxin–antitoxin (TA) modules are small operons in bacteria and archaea that encode a metabolic inhibitor (toxin) and a matching regulatory protein (antitoxin). While their biochemical activities are often well defined, their biological functions remain unclear. In Type II TA modules, the most common class, both toxin and antitoxin are proteins, and the antitoxin inhibits the biochemical activity of the toxin via complex formation with the toxin. The different TA modules vary significantly regarding structure and biochemical activity. Both regulation of protein activity by the antitoxin and regulation of transcription can be highly complex and sometimes show striking parallels between otherwise unrelated TA modules. Interplay between the multiple levels of regulation in the broader context of the cell as a whole is most likely required for optimum fine‐tuning of these systems. Thus, TA modules can go through great lengths to prevent activation and to reverse accidental activation, in agreement with recent in vivo data. These complex mechanisms seem at odds with the lack of a clear biological function.
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Affiliation(s)
- Pieter De Bruyn
- VIB-VUB Center for Structural Biology, Vrije Universiteit Brussel and Vlaams Instituut voor Biotechnologie, Brussels, Belgium
| | - Yana Girardin
- VIB-VUB Center for Structural Biology, Vrije Universiteit Brussel and Vlaams Instituut voor Biotechnologie, Brussels, Belgium
| | - Remy Loris
- VIB-VUB Center for Structural Biology, Vrije Universiteit Brussel and Vlaams Instituut voor Biotechnologie, Brussels, Belgium
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10
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Abstract
In life's constant battle for survival, it takes one to kill but two to conquer. Toxin-antitoxin or toxin-antidote (TA) elements are genetic dyads that cheat the laws of inheritance to guarantee their transmission to the next generation. This seemingly simple genetic arrangement—a toxin linked to its antidote—is capable of quickly spreading and persisting in natural populations. TA elements were first discovered in bacterial plasmids in the 1980s and have recently been characterized in fungi, plants, and animals, where they underlie genetic incompatibilities and sterility in crosses between wild isolates. In this review, we provide a unified view of TA elements in both prokaryotic and eukaryotic organisms and highlight their similarities and differences at the evolutionary, genetic, and molecular levels. Finally, we propose several scenarios that could explain the paradox of the evolutionary origin of TA elements and argue that these elements may be key evolutionary players and that the full scope of their roles is only beginning to be uncovered.
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Affiliation(s)
- Alejandro Burga
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), 1030 Vienna, Austria
| | - Eyal Ben-David
- Department of Human Genetics, Department of Biological Chemistry, and Howard Hughes Medical Institute, University of California, Los Angeles, California 90095, USA
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, The Hebrew University School of Medicine, Jerusalem 91120, Israel
| | - Leonid Kruglyak
- Department of Human Genetics, Department of Biological Chemistry, and Howard Hughes Medical Institute, University of California, Los Angeles, California 90095, USA
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11
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Cehovin A, Jolley KA, Maiden MCJ, Harrison OB, Tang CM. Association of Neisseria gonorrhoeae Plasmids With Distinct Lineages and The Economic Status of Their Country of Origin. J Infect Dis 2020; 222:1826-1836. [PMID: 32163577 PMCID: PMC7653084 DOI: 10.1093/infdis/jiaa003] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 01/09/2020] [Indexed: 12/29/2022] Open
Abstract
Plasmids are vehicles for horizontal gene transfer between bacteria, and in Neisseria gonorrhoeae plasmids can mediate high-level antimicrobial resistance (AMR). Using genomic and phylogenetic analyses, we show that plasmids are widespread in a collection of 3724 gonococcal isolates from 56 countries, and characterized the conjugative, β-lactamase and cryptic plasmids. We found that variants of the conjugative plasmid (which can mediate tetracycline resistance) and the β-lactamase plasmid expressing TEM-135 are associated with distinct gonococcal lineages. Furthermore, AMR plasmids are significantly more prevalent in gonococci from less wealthy countries, highlighting the need for further studies. More than 94% of gonococci possess the cryptic plasmid, with its absence correlated with the presence of a novel chromosomal type IV secretion system. Our results reveal the extent of plasmid-mediated AMR in the gonococcus, particularly in less wealthy countries, where diagnostic and therapeutic options can be limited, and highlight the risk of their global spread.
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Affiliation(s)
- Ana Cehovin
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Keith A Jolley
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | | | - Odile B Harrison
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Christoph M Tang
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
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12
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Rapid growth inhibitory activity of a YafQ-family endonuclease toxin of the Helicobacter pylori tfs4 integrative and conjugative element. Sci Rep 2020; 10:18171. [PMID: 33097748 PMCID: PMC7584586 DOI: 10.1038/s41598-020-72063-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 08/07/2020] [Indexed: 12/19/2022] Open
Abstract
Prokaryotic and archaeal chromosomes encode a diversity of toxin–antitoxin (TA) systems that contribute to a variety of stress-induced cellular processes in addition to stability and maintenance of mobile elements. Here, we find DinJ-YafQ family TA systems to be broadly distributed amongst diverse phyla, consistent with other ParE/RelE superfamily TAs, but more unusually occurring as a multiplicity of species-specific subtypes. In the gastric pathogen Helicobacter pylori we identify six distinct subtypes, of which three are predominantly associated with the mobilome, including the disease-associated integrative and conjugative element (ICE), tfs4. Whereas, the ICE-encoded proteins have characteristic features of DinJ-YafQ family Type II TA systems in general, the toxin component is distinguished by a broad metal-ion-dependent endonuclease activity with specificity for both RNA and DNA. We show that the remarkably rapid growth inhibitory activity of the ICE toxin is a correlate of a C-terminal lysine doublet which likely augments catalytic activity by increasing the positive electrostatic potential in the vicinity of the conserved active site. Our collective results reveal a structural feature of an ICE TA toxin that influences substrate catalysis and toxin function which may be relevant to specific TA-mediated responses in diverse genera of bacteria.
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13
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Structural Basis for Toxin Inhibition in the VapXD Toxin-Antitoxin System. Structure 2020; 29:139-150.e3. [PMID: 33096014 DOI: 10.1016/j.str.2020.10.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 08/21/2020] [Accepted: 09/30/2020] [Indexed: 02/07/2023]
Abstract
Bacterial type II toxin-antitoxin (TA) modules encode a toxic protein that downregulates metabolism and a specific antitoxin that binds and inhibits the toxin during normal growth. In non-typeable Haemophilus influenzae, a common cause of infections in humans, the vapXD locus was found to constitute a functional TA module and contribute to pathogenicity; however, the mode of action of VapD and the mechanism of inhibition by the VapX antitoxin remain unknown. Here, we report the structure of the intact H. influenzae VapXD complex, revealing an unusual 2:1 TA molecular stoichiometry where a Cas2-like homodimer of VapD binds a single VapX antitoxin. VapX consists of an oligonucleotide/oligosaccharide-binding domain that docks into an asymmetrical cavity on the toxin dimer. Structures of isolated VapD further reveal how a symmetrical toxin homodimer adapts to interacting with an asymmetrical antitoxin and suggest how a primordial TA system evolved to become part of CRISPR-Cas immunity systems.
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Jurėnas D, Van Melderen L. The Variety in the Common Theme of Translation Inhibition by Type II Toxin-Antitoxin Systems. Front Genet 2020; 11:262. [PMID: 32362907 PMCID: PMC7180214 DOI: 10.3389/fgene.2020.00262] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 03/05/2020] [Indexed: 12/12/2022] Open
Abstract
Type II Toxin-antitoxin (TA) modules are bacterial operons that encode a toxic protein and its antidote, which form a self-regulating genetic system. Antitoxins put a halter on toxins in many ways that distinguish different types of TA modules. In type II TA modules, toxin and antitoxin are proteins that form a complex which physically sequesters the toxin, thereby preventing its toxic activity. Type II toxins inhibit various cellular processes, however, the translation process appears to be their favorite target and nearly every step of this complex process is inhibited by type II toxins. The structural features, enzymatic activities and target specificities of the different toxin families are discussed. Finally, this review emphasizes that the structural folds presented by these toxins are not restricted to type II TA toxins or to one particular cellular target, and discusses why so many of them evolved to target translation as well as the recent developments regarding the role(s) of these systems in bacterial physiology and evolution.
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Affiliation(s)
- Dukas Jurėnas
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie de la Méditerranée, CNRS, Aix-Marseille Université, Marseille, France
| | - Laurence Van Melderen
- Cellular and Molecular Microbiology, Faculté des Sciences, Université libre de Bruxelles, Gosselies, Belgium
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15
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Morales-Espinosa R, Delgado G, Serrano LR, Castillo E, Santiago CA, Hernández-Castro R, Gonzalez-Pedraza A, Mendez JL, Mundo-Gallardo LF, Manzo-Merino J, Ayala S, Cravioto A. High expression of Helicobacter pylori VapD in both the intracellular environment and biopsies from gastric patients with severity. PLoS One 2020; 15:e0230220. [PMID: 32163505 PMCID: PMC7067408 DOI: 10.1371/journal.pone.0230220] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 02/24/2020] [Indexed: 12/15/2022] Open
Abstract
Helicobacter pylori is a Gram-negative bacterium that causes chronic atrophic gastritis and peptic ulcers and it has been associated with the development of gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT). One of the more remarkable characteristics of H. pylori is its ability to survive in the hostile environment of the stomach. H. pylori regulates the expression of specific sets of genes allowing it to survive high acidity levels and nutrient scarcity. In the present study, we determined the expression of virulence associated protein D (VapD) of H. pylori inside adenocarcinoma gastric (AGS) cells and in gastric biopsies. Using qRT-PCR, VapD expression was quantified in intracellular H. pylori-AGS cell cultures at different time points and in gastric mucosa biopsies from patients suffering from chronic atrophic gastritis, follicular gastritis, peptic ulcers, gastritis precancerous intestinal metaplasia and adenocarcinoma. Our results show that vapD of H. pylori presented high transcription levels inside AGS cells, which increased up to two-fold above basal values across all assays over time. Inside AGS cells, H. pylori acquired a coccoid form that is metabolically active in expressing VapD as a protection mechanism, thereby maintaining its permanence in a viable non-cultivable state. VapD of H. pylori was expressed in all gastric biopsies, however, higher expression levels (p = 0.029) were observed in gastric antrum biopsies from patients with follicular gastritis. The highest VapD expression levels were found in both antrum and corpus gastric biopsies from older patients (>57 years old). We observed that VapD in H. pylori is a protein that is only produced in response to interactions with eukaryotic cells. Our results suggest that VapD contributes to the persistence of H. pylori inside the gastric epithelial cells, protecting the microorganism from the intracellular environment, reducing its growth rate, enabling long-term infection and treatment resistance.
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Affiliation(s)
- Rosario Morales-Espinosa
- Facultad de Medicina, Departamento de Microbiología y Parasitología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Gabriela Delgado
- Facultad de Medicina, Departamento de Microbiología y Parasitología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Luis-Roberto Serrano
- Facultad de Medicina, Departamento de Microbiología y Parasitología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Elizabeth Castillo
- Facultad de Medicina, Departamento de Microbiología y Parasitología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Carlos A. Santiago
- Facultad de Medicina, Departamento de Microbiología y Parasitología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | | | - Alberto Gonzalez-Pedraza
- Facultad de Medicina, Departamento de Microbiología y Parasitología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Jose L. Mendez
- Facultad de Medicina, Departamento de Microbiología y Parasitología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | | | | | - Sergio Ayala
- Cátedras CONACyT-Instituto Nacional de Cancerología, Mexico City, Mexico
| | - Alejandro Cravioto
- Facultad de Medicina, Departamento de Microbiología y Parasitología, Universidad Nacional Autónoma de México, Mexico City, Mexico
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16
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García-Zea JA, de la Herrán R, Robles Rodríguez F, Navajas-Pérez R, Ruiz Rejón C. Detection and variability analyses of CRISPR-like loci in the H. pylori genome. PeerJ 2019; 7:e6221. [PMID: 30648020 PMCID: PMC6330956 DOI: 10.7717/peerj.6221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 12/05/2018] [Indexed: 12/16/2022] Open
Abstract
Helicobacter pylori is a human pathogenic bacterium with a high genomic plasticity. Although the functional CRISPR-Cas system has not been found in its genome, CRISPR-like loci have been recently identified. In this work, 53 genomes from different geographical areas are analyzed for the search and analysis of variability of this type of structure. We confirm the presence of a locus that was previously described in the VlpC gene in al lgenomes, and we characterize new CRISPR-like loci in other genomic locations. By studying the variability and gene location of these loci, the evolution and the possible roles of these sequences are discussed. Additionally, the usefulness of this type of sequences as a phylogenetic marker has been demonstrated, associating the different strains by geographical area.
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Affiliation(s)
| | - Roberto de la Herrán
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | | | - Rafael Navajas-Pérez
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Carmelo Ruiz Rejón
- Departamento de Genética, Facultad de Ciencias, Universidad de Granada, Granada, Spain
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17
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Roachford O, Nelson KE, Mohapatra BR. Virulence and molecular adaptation of human urogenital mycoplasmas: a review. BIOTECHNOL BIOTEC EQ 2019. [DOI: 10.1080/13102818.2019.1607556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Affiliation(s)
- Orville Roachford
- Department of Biological and Chemical Sciences, The University of the West Indies, Cave Hill Campus, Bridgetown, Barbados
| | | | - Bidyut Ranjan Mohapatra
- Department of Biological and Chemical Sciences, The University of the West Indies, Cave Hill Campus, Bridgetown, Barbados
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18
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Faure G, Makarova KS, Koonin EV. CRISPR-Cas: Complex Functional Networks and Multiple Roles beyond Adaptive Immunity. J Mol Biol 2018; 431:3-20. [PMID: 30193985 DOI: 10.1016/j.jmb.2018.08.030] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 08/28/2018] [Accepted: 08/29/2018] [Indexed: 01/26/2023]
Abstract
CRISPR-Cas is a prokaryotic adaptive immune system that functions by incorporating fragments of foreign DNA into CRISPR arrays. The arrays containing spacers derived from foreign DNA are transcribed, and the transcripts are processed to generate spacer-containing mature CRISPR-RNAs that are employed as guides to specifically recognize and cleave the DNA or RNA of the cognate parasitic genetic elements. The CRISPR-Cas systems show remarkable complexity and diversity of molecular organization and appear to be involved in various cellular functions that are distinct from, even if connected to, adaptive immunity. In this review, we discuss some of such functional links of CRISPR-Cas systems including their effect on horizontal gene transfer that can be either inhibitory or stimulatory, connections between CRISPR-Cas and DNA repair systems as well as programmed cell death and signal transduction mechanisms, and potential role of CRISPR-Cas in transposon integration and plasmid maintenance. The interplay between the primary function of CRISPR-Cas as an adaptive immunity mechanism and these other roles defines the richness of the biological effects of these systems and affects their spread among bacteria and archaea.
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Affiliation(s)
- Guilhem Faure
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Kira S Makarova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA.
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19
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Abstract
Neisseria gonorrhoeae, the causative agent of the sexually transmitted disease gonorrhoeae, possesses several mobile genetic elements (MGEs). The MGEs such as transposable elements mediate intrachromosomal rearrangements, while plasmids and the gonococcal genetic island are involved in interchromosomal gene transfer. Additionally, gonococcal MGEs serve as hotspots for recombination and integration of other genetic elements such as bacteriophages, contribute to gene regulation or spread genes through gonococcal populations by horizontal gene transfer. In this review, we summarise the literature on the structure and biology of MGEs and discuss how these genetic elements may play a role in the pathogenesis and spread of antimicrobial resistance in N. gonorrhoeae. Although an abundance of information about gonococcal MGEs exists (mainly from whole genome sequencing and bioinformatic analysis), there are still many open questions on how MGEs influence the biology of N. gonorrhoeae.
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Affiliation(s)
- Ana Cehovin
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Steven B Lewis
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
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20
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Gauthier J, Vincent AT, Charette SJ, Derome N. Strong Genomic and Phenotypic Heterogeneity in the Aeromonas sobria Species Complex. Front Microbiol 2017; 8:2434. [PMID: 29276504 PMCID: PMC5727048 DOI: 10.3389/fmicb.2017.02434] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 11/23/2017] [Indexed: 12/18/2022] Open
Abstract
Aeromonas sobria is a mesophilic motile aeromonad currently depicted as an opportunistic pathogen, despite increasing evidence of mutualistic interactions in salmonid fish. However, the determinants of its host-microbe associations, either mutualistic or pathogenic, remain less understood than for other aeromonad species. On one side, there is an over-representation of pathogenic interactions in the A. sobria literature, of which only three articles to date report mutualistic interactions; on the other side, genomic characterization of this species is still fairly incomplete as only two draft genomes were published prior to the present work. Consequently, no study specifically investigated the biodiversity of A. sobria. In fact, the investigation of A. sobria as a species complex may have been clouded by: (i) confusion with A. veronii biovar sobria because of their similar biochemical profiles, and (ii) the intrinsic low resolution of previous studies based on 16S rRNA gene sequences and multilocus sequence typing. So far, the only high-resolution, phylogenomic studies of the genus Aeromonas included one A. sobria strain (CECT 4245 / Popoff 208), making it impossible to robustly conclude on the phylogenetic intra-species diversity and the positioning among other Aeromonas species. To further understand the biodiversity and the spectrum of host-microbe interactions in A. sobria as well as its potential genomic diversity, we assessed the genomic and phenotypic heterogeneity among five A. sobria strains: two clinical isolates recovered from infected fish (JF2635 and CECT 4245), one from an infected amphibian (08005) and two recently isolated brook charr probionts (TM12 and TM18) which inhibit in vitro growth of A. salmonicida subsp. salmonicida (a salmonid fish pathogen). A phylogenomic assessment including 2,154 softcore genes corresponding to 946,687 variable sites from 33 Aeromonas genomes confirms the status of A. sobria as a distinct species divided in two subclades, with 100% bootstrap support. The phylogenomic split of A. sobria in two subclades is corroborated by a deep dichotomy between all five A. sobria strains in terms of inhibitory effect against A. salmonicida subsp. salmonicida, gene contents and codon usage. Finally, the antagonistic effect of A. sobria strains TM12 and TM18 suggests novel control methods against A. salmonicida subsp. salmonicida.
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Affiliation(s)
- Jeff Gauthier
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes, Université Laval, Quebec City, QC, Canada
| | - Antony T Vincent
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec City, QC, Canada.,Département de Biochimie, de Microbiologie et de Bio-informatique, Institut de Biologie Intégrative et des Systèmes, Université Laval, Quebec City, QC, Canada
| | - Steve J Charette
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Quebec City, QC, Canada.,Département de Biochimie, de Microbiologie et de Bio-informatique, Institut de Biologie Intégrative et des Systèmes, Université Laval, Quebec City, QC, Canada
| | - Nicolas Derome
- Département de Biologie, Institut de Biologie Intégrative et des Systèmes, Université Laval, Quebec City, QC, Canada
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21
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Bangpanwimon K, Sottisuporn J, Mittraparp-Arthorn P, Ueaphatthanaphanich W, Rattanasupar A, Pourcel C, Vuddhakul V. CRISPR-like sequences in Helicobacter pylori and application in genotyping. Gut Pathog 2017; 9:65. [PMID: 29177012 PMCID: PMC5693588 DOI: 10.1186/s13099-017-0215-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 11/06/2017] [Indexed: 02/07/2023] Open
Abstract
Background Many bacteria and archaea possess a defense system called clustered regularly interspaced short palindromic repeats (CRISPR) associated proteins (CRISPR-Cas system) against invaders such as phages or plasmids. This system has not been demonstrated in Helicobacter pylori. The numbers of spacer in CRISPR array differ among bacterial strains and can be used as a genetic marker for bacterial typing. Results A total of 36 H. pylori isolates were collected from patients in three hospitals located in the central (PBH) and southern (SKH) regions of Thailand. It is of interest that CRISPR-like sequences of this bacterium were detected in vlpC encoded for VacA-like protein C. Virulence genes were investigated and the most pathogenic genotype (cagA vacA s1m1) was detected in 17 out of 29 (58.6%) isolates from PBH and 5 out of 7 (71.4%) from SKH. vapD gene was identified in each one isolate from PBH and SKH. CRISPR-like sequences and virulence genes of 20 isolates of H. pylori obtained in this study were analyzed and CRISPR-virulence typing was constructed and compared to profiles obtained by the random amplification of polymorphic DNA (RAPD) technique. The discriminatory power (DI) of CRISPR-virulence typing was not different from RAPD typing. Conclusion CRISPR-virulence typing in H. pylori is easy and reliable for epidemiology and can be used for inter-laboratory interpretation. Electronic supplementary material The online version of this article (10.1186/s13099-017-0215-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Khotchawan Bangpanwimon
- Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Thailand
| | - Jaksin Sottisuporn
- NKC Institute of Gastroenterology and Hepatology, Songklanagarind Hospital, Faculty of Medicine, Prince of Songkla University, Hat Yai, Thailand
| | | | | | - Attapon Rattanasupar
- KC Center of Gastroenterology and Hepatology, Hat Yai Hospital, Hat Yai, Thailand
| | - Christine Pourcel
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Varaporn Vuddhakul
- Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai, Thailand
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22
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Ka D, Hong S, Jeong U, Jeong M, Suh N, Suh JY, Bae E. Structural and dynamic insights into the role of conformational switching in the nuclease activity of the Xanthomonas albilineans Cas2 in CRISPR-mediated adaptive immunity. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2017; 4:054701. [PMID: 28612041 PMCID: PMC5438308 DOI: 10.1063/1.4984052] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 05/11/2017] [Indexed: 06/07/2023]
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPRs) and CRISPR-associated (Cas) proteins constitute a microbial, adaptive immune system countering invading nucleic acids. Cas2 is a universal Cas protein found in all types of CRISPR-Cas systems, and its role is implicated in new spacer acquisition into CRISPR loci. In subtype I-C CRISPR-Cas systems, Cas2 proteins are metal-dependent double-stranded DNA (dsDNA) nucleases, and a pH-dependent conformational transition has been proposed as a prerequisite for catalytic action. Here, we report the crystal structure of Xanthomonas albilineans Cas2 (XaCas2) and provide experimental evidence of a pH-dependent conformational change during functional activation. XaCas2 crystallized at an acidic pH represented a catalytically inactive conformational state in which two Asp8 residues were too far apart to coordinate a single catalytic metal ion. Consistently, XaCas2 exhibited dsDNA nuclease activity only under neutral and basic conditions. Despite the overall structural similarity of the two protomers, significant conformational heterogeneity was evident in the putative hinge regions, suggesting that XaCas2 engages in hinge-bending conformational switching. The presence of a Trp residue in the hinge region enabled the investigation of hinge dynamics by fluorescence spectroscopy. The pH dependence of the fluorescence intensity overlapped precisely with that of nuclease activity. Mutational analyses further suggested that conformational activation proceeded via a rigid-body hinge-bending motion as both D8E and hinge mutations significantly reduced nuclease activity. Together, our results reveal strong correlations between the conformational states, catalytic activity, and hinge dynamics of XaCas2, and provide structural and dynamic insights into the conformational activation of the nuclease function of Cas2.
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Affiliation(s)
- Donghyun Ka
- Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, South Korea
| | - Suji Hong
- Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, South Korea
| | - Ugeene Jeong
- Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, South Korea
| | - Migyeong Jeong
- Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, South Korea
| | - Nayoung Suh
- Department of Pharmaceutical Engineering, Soon Chun Hyang University, Asan 31538, South Korea
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23
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Henrich B, Kretzmer F, Deenen R, Köhrer K. Validation of a novel Mho microarray for a comprehensive characterisation of the Mycoplasma hominis action in HeLa cell infection. PLoS One 2017; 12:e0181383. [PMID: 28753664 PMCID: PMC5533444 DOI: 10.1371/journal.pone.0181383] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 06/29/2017] [Indexed: 12/30/2022] Open
Abstract
Mycoplasma hominis is the second smallest facultative pathogen of the human urogenital tract. With less than 600 protein-encoding genes, it represents an ideal model organism for the study of host-pathogen interactions. For a comprehensive characterisation of the M. hominis action in infection a customized Mho microarray, which was based on two genome sequences (PG21 and LBD-4), was designed to analyze the dynamics of the mycoplasma transcriptome during infection and validated for M. hominis strain FBG. RNA preparation was evaluated and adapted to ensure the highest recovery of mycoplasmal mRNAs from in vitro HeLa cell infection assays. Following cRNA hybridization, the read-out strategy of the hybridization results was optimized and confirmed by RT-PCR. A statistically robust infection assay with M. hominis strain FBG enabled the identification of differentially regulated key effector molecules such as critical cytoadhesins (4 h post infection (pI)), invasins (48 h pI) and proteins associated with establishing chronic infection of the host (336 h pI). Of the 294 differentially regulated genes (>2-fold) 128 (43.5%) encoded hypothetical proteins, including lipoproteins that seem to play a central role as virulence factors at each stage of infection: P75 as a novel cytoadhesin candidate, which is also differentially upregulated in chronic infection; the MHO_2100 protein, a postulated invasin and the MHO_730-protein, a novel ecto-nuclease and domain of an ABC transporter, the function of which in chronic infection has still to be elucidated. Implementation of the M. hominis microarray strategy led to a comprehensive identification of to date unknown candidates for virulence factors at relevant stages of host cell infection.
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Affiliation(s)
- Birgit Henrich
- Institute of Medical Microbiology and Hospital Hygiene, Medical Faculty of Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany
- * E-mail:
| | - Freya Kretzmer
- Institute of Medical Microbiology and Hospital Hygiene, Medical Faculty of Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany
- Biological and Medical Research Centre (BMFZ), Medical Faculty of the Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany
| | - René Deenen
- Biological and Medical Research Centre (BMFZ), Medical Faculty of the Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany
| | - Karl Köhrer
- Biological and Medical Research Centre (BMFZ), Medical Faculty of the Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany
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24
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Krupovic M, Béguin P, Koonin EV. Casposons: mobile genetic elements that gave rise to the CRISPR-Cas adaptation machinery. Curr Opin Microbiol 2017; 38:36-43. [PMID: 28472712 DOI: 10.1016/j.mib.2017.04.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 04/04/2017] [Accepted: 04/12/2017] [Indexed: 01/26/2023]
Abstract
A casposon, a member of a distinct superfamily of archaeal and bacterial self-synthesizing transposons that employ a recombinase (casposase) homologous to the Cas1 endonuclease, appears to have given rise to the adaptation module of CRISPR-Cas systems as well as the CRISPR repeats themselves. Comparison of the mechanistic features of the reactions catalyzed by the casposase and the Cas1-Cas2 heterohexamer, the CRISPR integrase, reveals close similarity but also important differences that explain the requirement of Cas2 for integration of short DNA fragments, the CRISPR spacers.
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Affiliation(s)
- Mart Krupovic
- Unité Biologie Moléculaire du Gène chez les Extrêmophiles, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France.
| | - Pierre Béguin
- Unité Biologie Moléculaire du Gène chez les Extrêmophiles, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20894, USA
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25
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Lifestyle and Horizontal Gene Transfer-Mediated Evolution of Mucispirillum schaedleri, a Core Member of the Murine Gut Microbiota. mSystems 2017; 2:mSystems00171-16. [PMID: 28168224 PMCID: PMC5285517 DOI: 10.1128/msystems.00171-16] [Citation(s) in RCA: 137] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 01/04/2017] [Indexed: 01/01/2023] Open
Abstract
Shifts in gut microbiota composition have been associated with intestinal inflammation, but it remains unclear whether inflammation-associated bacteria are commensal or detrimental to their host. Here, we studied the lifestyle of the gut bacterium Mucispirillum schaedleri, which is associated with inflammation in widely used mouse models. We found that M. schaedleri has specialized systems to handle oxidative stress during inflammation. Additionally, it expresses secretion systems and effector proteins and can modify the mucosal gene expression of its host. This suggests that M. schaedleri undergoes intimate interactions with its host and may play a role in inflammation. The insights presented here aid our understanding of how commensal gut bacteria may be involved in altering susceptibility to disease. Mucispirillum schaedleri is an abundant inhabitant of the intestinal mucus layer of rodents and other animals and has been suggested to be a pathobiont, a commensal that plays a role in disease. In order to gain insights into its lifestyle, we analyzed the genome and transcriptome of M. schaedleri ASF 457 and performed physiological experiments to test traits predicted by its genome. Although described as a mucus inhabitant, M. schaedleri has limited capacity for degrading host-derived mucosal glycans and other complex polysaccharides. Additionally, M. schaedleri reduces nitrate and expresses systems for scavenging oxygen and reactive oxygen species in vivo, which may account for its localization close to the mucosal tissue and expansion during inflammation. Also of note, M. schaedleri harbors a type VI secretion system and putative effector proteins and can modify gene expression in mucosal tissue, suggesting intimate interactions with its host and a possible role in inflammation. The M. schaedleri genome has been shaped by extensive horizontal gene transfer, primarily from intestinal Epsilon- and Deltaproteobacteria, indicating that horizontal gene transfer has played a key role in defining its niche in the gut ecosystem. IMPORTANCE Shifts in gut microbiota composition have been associated with intestinal inflammation, but it remains unclear whether inflammation-associated bacteria are commensal or detrimental to their host. Here, we studied the lifestyle of the gut bacterium Mucispirillum schaedleri, which is associated with inflammation in widely used mouse models. We found that M. schaedleri has specialized systems to handle oxidative stress during inflammation. Additionally, it expresses secretion systems and effector proteins and can modify the mucosal gene expression of its host. This suggests that M. schaedleri undergoes intimate interactions with its host and may play a role in inflammation. The insights presented here aid our understanding of how commensal gut bacteria may be involved in altering susceptibility to disease.
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26
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Cárdenas-Mondragón MG, Ares MA, Panunzi LG, Pacheco S, Camorlinga-Ponce M, Girón JA, Torres J, De la Cruz MA. Transcriptional Profiling of Type II Toxin-Antitoxin Genes of Helicobacter pylori under Different Environmental Conditions: Identification of HP0967-HP0968 System. Front Microbiol 2016; 7:1872. [PMID: 27920769 PMCID: PMC5118875 DOI: 10.3389/fmicb.2016.01872] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 11/07/2016] [Indexed: 12/24/2022] Open
Abstract
Helicobacter pylori is a Gram-negative bacterium that colonizes the human gastric mucosa and is responsible for causing peptic ulcers and gastric carcinoma. The expression of virulence factors allows the persistence of H. pylori in the stomach, which results in a chronic, sometimes uncontrolled inflammatory response. Type II toxin-antitoxin (TA) systems have emerged as important virulence factors in many pathogenic bacteria. Three type II TA systems have previously been identified in the genome of H. pylori 26695: HP0315-HP0316, HP0892-HP0893, and HP0894-HP0895. Here we characterized a heretofore undescribed type II TA system in H. pylori, HP0967-HP0968, which is encoded by the bicistronic operon hp0968-hp0967 and belongs to the Vap family. The predicted HP0967 protein is a toxin with ribonuclease activity whereas HP0968 is an antitoxin that binds to its own regulatory region. We found that all type II TA systems were expressed in H. pylori during early stationary growth phase, and differentially expressed in the presence of urea, nickel, and iron, although, the hp0968-hp0967 pair was the most affected under these environmental conditions. Transcription of hp0968-hp0967 was strongly induced in a mature H. pylori biofilm and when the bacteria interacted with AGS epithelial cells. Kanamycin and chloramphenicol considerably boosted transcription levels of all the four type II TA systems. The hp0968-hp0967 TA system was the most frequent among 317 H. pylori strains isolated from all over the world. This study is the first report on the transcription of type II TA genes in H. pylori under different environmental conditions. Our data show that the HP0967 and HP0968 proteins constitute a bona fide type II TA system in H. pylori, whose expression is regulated by environmental cues, which are relevant in the context of infection of the human gastric mucosa.
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Affiliation(s)
- María G Cárdenas-Mondragón
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatria, Centro Médico Nacional Siglo XXI, IMSS Mexico City, Mexico
| | - Miguel A Ares
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatria, Centro Médico Nacional Siglo XXI, IMSS Mexico City, Mexico
| | - Leonardo G Panunzi
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université UM2, Inserm, U1104, CNRS UMR7280 Marseille, France
| | - Sabino Pacheco
- Departamento de Microbiología Molecular, Instituto de Biotecnología UNAM Cuernavaca, Mexico
| | - Margarita Camorlinga-Ponce
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatria, Centro Médico Nacional Siglo XXI, IMSS Mexico City, Mexico
| | - Jorge A Girón
- Centro de Detección Biomolecular, Benemérita Universidad Autónoma de Puebla Puebla, Mexico
| | - Javier Torres
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatria, Centro Médico Nacional Siglo XXI, IMSS Mexico City, Mexico
| | - Miguel A De la Cruz
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatria, Centro Médico Nacional Siglo XXI, IMSS Mexico City, Mexico
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27
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Westra ER, Dowling AJ, Broniewski JM, van Houte S. Evolution and Ecology of CRISPR. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2016. [DOI: 10.1146/annurev-ecolsys-121415-032428] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Edze R. Westra
- Environment and Sustainability Institute and Centre for Ecology and Conservation, Biosciences, University of Exeter, Tremough Campus, Penryn TR10 9FE, United Kingdom;
| | - Andrea J. Dowling
- Environment and Sustainability Institute and Centre for Ecology and Conservation, Biosciences, University of Exeter, Tremough Campus, Penryn TR10 9FE, United Kingdom;
| | - Jenny M. Broniewski
- Environment and Sustainability Institute and Centre for Ecology and Conservation, Biosciences, University of Exeter, Tremough Campus, Penryn TR10 9FE, United Kingdom;
| | - Stineke van Houte
- Environment and Sustainability Institute and Centre for Ecology and Conservation, Biosciences, University of Exeter, Tremough Campus, Penryn TR10 9FE, United Kingdom;
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28
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Mendes JS, Santiago ADS, Toledo MAS, Rosselli-Murai LK, Favaro MTP, Santos CA, Horta MAC, Crucello A, Beloti LL, Romero F, Tasic L, de Souza AA, de Souza AP. VapD in Xylella fastidiosa Is a Thermostable Protein with Ribonuclease Activity. PLoS One 2015; 10:e0145765. [PMID: 26694028 PMCID: PMC4687846 DOI: 10.1371/journal.pone.0145765] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Accepted: 12/08/2015] [Indexed: 01/15/2023] Open
Abstract
Xylella fastidiosa strain 9a5c is a gram-negative phytopathogen that is the causal agent of citrus variegated chlorosis (CVC), a disease that is responsible for economic losses in Brazilian agriculture. The most well-known mechanism of pathogenicity for this bacterial pathogen is xylem vessel occlusion, which results from bacterial movement and the formation of biofilms. The molecular mechanisms underlying the virulence caused by biofilm formation are unknown. Here, we provide evidence showing that virulence-associated protein D in X. fastidiosa (Xf-VapD) is a thermostable protein with ribonuclease activity. Moreover, protein expression analyses in two X. fastidiosa strains, including virulent (Xf9a5c) and nonpathogenic (XfJ1a12) strains, showed that Xf-VapD was expressed during all phases of development in both strains and that increased expression was observed in Xf9a5c during biofilm growth. This study is an important step toward characterizing and improving our understanding of the biological significance of Xf-VapD and its potential functions in the CVC pathosystem.
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Affiliation(s)
- Juliano S. Mendes
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil, CEP 13083-875
| | - André da S. Santiago
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil, CEP 13083-875
| | - Marcelo A. S. Toledo
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil, CEP 13083-875
| | - Luciana K. Rosselli-Murai
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil, CEP 13083-875
| | - Marianna T. P. Favaro
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil, CEP 13083-875
| | - Clelton A. Santos
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil, CEP 13083-875
| | - Maria Augusta C. Horta
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil, CEP 13083-875
| | - Aline Crucello
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil, CEP 13083-875
| | - Lilian L. Beloti
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil, CEP 13083-875
| | - Fabian Romero
- Departamento de Química Orgânica, Instituto de Química, Universidade Estadual de Campinas, Campinas, SP, Brazil, CEP 13083-970
| | - Ljubica Tasic
- Departamento de Química Orgânica, Instituto de Química, Universidade Estadual de Campinas, Campinas, SP, Brazil, CEP 13083-970
| | | | - Anete P. de Souza
- Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil, CEP 13083-875
- Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, SP, Brazil, CEP 13083-862
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An updated evolutionary classification of CRISPR-Cas systems. NATURE REVIEWS. MICROBIOLOGY 2015. [PMID: 26411297 DOI: 10.1038/nrmicro3569.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The evolution of CRISPR-cas loci, which encode adaptive immune systems in archaea and bacteria, involves rapid changes, in particular numerous rearrangements of the locus architecture and horizontal transfer of complete loci or individual modules. These dynamics complicate straightforward phylogenetic classification, but here we present an approach combining the analysis of signature protein families and features of the architecture of cas loci that unambiguously partitions most CRISPR-cas loci into distinct classes, types and subtypes. The new classification retains the overall structure of the previous version but is expanded to now encompass two classes, five types and 16 subtypes. The relative stability of the classification suggests that the most prevalent variants of CRISPR-Cas systems are already known. However, the existence of rare, currently unclassifiable variants implies that additional types and subtypes remain to be characterized.
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Makarova KS, Wolf YI, Alkhnbashi OS, Costa F, Shah SA, Saunders SJ, Barrangou R, Brouns SJJ, Charpentier E, Haft DH, Horvath P, Moineau S, Mojica FJM, Terns RM, Terns MP, White MF, Yakunin AF, Garrett RA, van der Oost J, Backofen R, Koonin EV. An updated evolutionary classification of CRISPR-Cas systems. Nat Rev Microbiol 2015; 13:722-36. [PMID: 26411297 DOI: 10.1038/nrmicro3569] [Citation(s) in RCA: 1576] [Impact Index Per Article: 175.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The evolution of CRISPR-cas loci, which encode adaptive immune systems in archaea and bacteria, involves rapid changes, in particular numerous rearrangements of the locus architecture and horizontal transfer of complete loci or individual modules. These dynamics complicate straightforward phylogenetic classification, but here we present an approach combining the analysis of signature protein families and features of the architecture of cas loci that unambiguously partitions most CRISPR-cas loci into distinct classes, types and subtypes. The new classification retains the overall structure of the previous version but is expanded to now encompass two classes, five types and 16 subtypes. The relative stability of the classification suggests that the most prevalent variants of CRISPR-Cas systems are already known. However, the existence of rare, currently unclassifiable variants implies that additional types and subtypes remain to be characterized.
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Affiliation(s)
- Kira S Makarova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
| | - Omer S Alkhnbashi
- Bioinformatics group, Department of Computer Science, University of Freiberg, Georges-Kohler-Allee 106, 79110 Freiberg, Germany
| | - Fabrizio Costa
- Bioinformatics group, Department of Computer Science, University of Freiberg, Georges-Kohler-Allee 106, 79110 Freiberg, Germany
| | - Shiraz A Shah
- Archaea Centre, Department of Biology, Copenhagen University, Ole Maaløes Vej 5, DK2200 Copenhagen N, Denmark
| | - Sita J Saunders
- Bioinformatics group, Department of Computer Science, University of Freiberg, Georges-Kohler-Allee 106, 79110 Freiberg, Germany
| | - Rodolphe Barrangou
- Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, North Carolina 27606, USA
| | - Stan J J Brouns
- Laboratory of Microbiology, Wageningen University, Dreijenplein 10, 6703HB Wageningen, Netherlands
| | - Emmanuelle Charpentier
- Department of Regulation in Infection Biology, Helmholtz Centre for Infection Research, D-38124 Braunschweig, Germany
| | - Daniel H Haft
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
| | - Philippe Horvath
- DuPont Nutrition and Health, BP10, Dangé-Saint-Romain 86220, France
| | - Sylvain Moineau
- Département de Biochimie, de Microbiologie et de Bio-informatique, Faculté des Sciences et de Génie, Groupe de Recherche en Écologie Buccale, Félix d'Hérelle Reference Center for Bacterial Viruses, Faculté de médecine dentaire, Université Laval, Québec City, Québec, Canada
| | - Francisco J M Mojica
- Departamento de Fisiología, Genética y Microbiología. Universidad de Alicante. 03080-Alicante, Spain
| | - Rebecca M Terns
- Biochemistry and Molecular Biology, Genetics and Microbiology, University of Georgia, Davison Life Sciences Complex, Green Street, Athens, Georgia 30602, USA
| | - Michael P Terns
- Biochemistry and Molecular Biology, Genetics and Microbiology, University of Georgia, Davison Life Sciences Complex, Green Street, Athens, Georgia 30602, USA
| | - Malcolm F White
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews, KY16 9TZ, UK
| | - Alexander F Yakunin
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, M5S 3E5, Canada
| | - Roger A Garrett
- Archaea Centre, Department of Biology, Copenhagen University, Ole Maaløes Vej 5, DK2200 Copenhagen N, Denmark
| | - John van der Oost
- Laboratory of Microbiology, Wageningen University, Dreijenplein 10, 6703HB Wageningen, Netherlands
| | - Rolf Backofen
- Bioinformatics group, Department of Computer Science, University of Freiberg, Georges-Kohler-Allee 106, 79110 Freiberg, Germany.,BIOSS Centre for Biological Signaling Studies, Cluster of Excellence, University of Freiburg, Germany
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
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31
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Lee KY, Lee KY, Kim JH, Lee IG, Lee SH, Sim DW, Won HS, Lee BJ. Structure-based functional identification of Helicobacter pylori HP0268 as a nuclease with both DNA nicking and RNase activities. Nucleic Acids Res 2015; 43:5194-207. [PMID: 25916841 PMCID: PMC4446426 DOI: 10.1093/nar/gkv348] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 04/03/2015] [Indexed: 12/18/2022] Open
Abstract
HP0268 is a conserved, uncharacterized protein from Helicobacter pylori. Here, we determined the solution structure of HP0268 using three-dimensional nuclear magnetic resonance (NMR) spectroscopy, revealing that this protein is structurally most similar to a small MutS-related (SMR) domain that exhibits nicking endonuclease activity. We also demonstrated for the first time that HP0268 is a nicking endonuclease and a purine-specific ribonuclease through gel electrophoresis and fluorescence spectroscopy. The nuclease activities for DNA and RNA were maximally increased by Mn2+ and Mg2+ ions, respectively, and decreased by Cu2+ ions. Using NMR chemical shift perturbations, the metal and nucleotide binding sites of HP0268 were determined to be spatially divided but close to each other. The lysine residues (Lys7, Lys11 and Lys43) are clustered and form the nucleotide binding site. Moreover, site-directed mutagenesis was used to define the catalytic active site of HP0268, revealing that this site contains two acidic residues, Asp50 and Glu54, in the metal binding site. The nucleotide binding and active sites are not conserved in the structural homologues of HP0268. This study will contribute to improving our understanding of the structure and functionality of a wide spectrum of nucleases.
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Affiliation(s)
- Ki-Young Lee
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Korea
| | - Kyu-Yeon Lee
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Korea
| | - Ji-Hun Kim
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Korea
| | - In-Gyun Lee
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Korea
| | - Sung-Hee Lee
- Department of Biotechnology, College of Biomedical and Health Science, Konkuk University, Chungju, Chungbuk 380-701, Korea
| | - Dae-Won Sim
- Department of Biotechnology, College of Biomedical and Health Science, Konkuk University, Chungju, Chungbuk 380-701, Korea
| | - Hyung-Sik Won
- Department of Biotechnology, College of Biomedical and Health Science, Konkuk University, Chungju, Chungbuk 380-701, Korea
| | - Bong-Jin Lee
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Korea
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32
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Chan WT, Balsa D, Espinosa M. One cannot rule them all: Are bacterial toxins-antitoxins druggable? FEMS Microbiol Rev 2015; 39:522-40. [PMID: 25796610 PMCID: PMC4487406 DOI: 10.1093/femsre/fuv002] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/02/2015] [Indexed: 01/31/2023] Open
Abstract
Type II (proteic) toxin–antitoxin (TA) operons are widely spread in bacteria and archaea. They are organized as operons in which, usually, the antitoxin gene precedes the cognate toxin gene. The antitoxin generally acts as a transcriptional self-repressor, whereas the toxin acts as a co-repressor, both proteins constituting a harmless complex. When bacteria encounter a stressful environment, TAs are triggered. The antitoxin protein is unstable and will be degraded by host proteases, releasing the free toxin to halt essential processes. The result is a cessation of cell growth or even death. Because of their ubiquity and the essential processes targeted, TAs have been proposed as good candidates for development of novel antimicrobials. We discuss here the possible druggability of TAs as antivirals and antibacterials, with focus on the potentials and the challenges that their use may find in the ‘real’ world. We present strategies to develop TAs as antibacterials in view of novel technologies, such as the use of very small molecules (fragments) as inhibitors of protein–protein interactions. Appropriate fragments could disrupt the T:A interfaces leading to the release of the targeted TA pair. Possible ways of delivery and formulation of Tas are also discussed. We consider various approaches to develop the toxins of the type II family as possible candidates to drug discovery; druggability of toxins-antitoxins could be possible as antivirals. As antibacterials, they might be considered as druggable but delivery and formulation may not be simple so far.
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Affiliation(s)
- Wai Ting Chan
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, 9, 28006-Madrid, Spain
| | - Dolors Balsa
- Immunology & Vaccines, Laboratorios LETI, Gran Via de les Corts Catalanes 184. 08034-Barcelona, Spain
| | - Manuel Espinosa
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, 9, 28006-Madrid, Spain
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33
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Bumgardner EA, Kittichotirat W, Bumgarner RE, Lawrence PK. Comparative genomic analysis of seven Mycoplasma hyosynoviae strains. Microbiologyopen 2015; 4:343-359. [PMID: 25693846 PMCID: PMC4398514 DOI: 10.1002/mbo3.242] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/12/2015] [Accepted: 01/26/2015] [Indexed: 12/16/2022] Open
Abstract
Infection with Mycoplasma hyosynoviae can result in debilitating arthritis in pigs, particularly those aged 10 weeks or older. Strategies for controlling this pathogen are becoming increasingly important due to the rise in the number of cases of arthritis that have been attributed to infection in recent years. In order to begin to develop interventions to prevent arthritis caused by M. hyosynoviae, more information regarding the specific proteins and potential virulence factors that its genome encodes was needed. However, the genome of this emerging swine pathogen had not been sequenced previously. In this report, we present a comparative analysis of the genomes of seven strains of M. hyosynoviae isolated from different locations in North America during the years 2010 to 2013. We identified several putative virulence factors that may contribute to the ability of this pathogen to adhere to host cells. Additionally, we discovered several prophage genes present within the genomes of three strains that show significant similarity to MAV1, a phage isolated from the related species, M. arthritidis. We also identified CRISPR-Cas and type III restriction and modification systems present in two strains that may contribute to their ability to defend against phage infection.
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Affiliation(s)
| | - Weerayuth Kittichotirat
- Systems Biology and Bioinformatics Research Group, Pilot Plant, Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkhuntien, Bangkok, Thailand
| | - Roger E Bumgarner
- Department of Microbiology, University of Washington, Seattle, Washington
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34
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Nam KH, DeLisa MP, Ke A. Characterizing Metal-Dependent Nucleases of CRISPR-Cas Prokaryotic Adaptive Immunity Systems. Methods Mol Biol 2015; 1311:265-276. [PMID: 25981479 DOI: 10.1007/978-1-4939-2687-9_17] [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] [Indexed: 06/04/2023]
Abstract
CRISPRs (clustered regularly interspaced short palindromic repeats), together with the nearby CRISPR-associated (cas) operon, constitute a prokaryotic RNA-based adaptive immune system against exogenous genetic elements. Here, we describe nuclease assays that are useful for characterizing the substrate-specific function of CRISPR-associated protein Cas2. We also provide methods for characterizing the stoichiometry and affinity between Cas2 and divalent metal ions using isothermal titration calorimetry (ITC).
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Affiliation(s)
- Ki H Nam
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14853, USA
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35
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Nuclease activity of Legionella pneumophila Cas2 promotes intracellular infection of amoebal host cells. Infect Immun 2014; 83:1008-18. [PMID: 25547789 DOI: 10.1128/iai.03102-14] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Legionella pneumophila, the primary agent of Legionnaires' disease, flourishes in both natural and man-made environments by growing in a wide variety of aquatic amoebae. Recently, we determined that the Cas2 protein of L. pneumophila promotes intracellular infection of Acanthamoeba castellanii and Hartmannella vermiformis, the two amoebae most commonly linked to cases of disease. The Cas2 family of proteins is best known for its role in the bacterial and archeal clustered regularly interspaced short palindromic repeat (CRISPR)-CRISPR-associated protein (Cas) system that constitutes a form of adaptive immunity against phage and plasmid. However, the infection event mediated by L. pneumophila Cas2 appeared to be distinct from this function, because cas2 mutants exhibited infectivity defects in the absence of added phage or plasmid and since mutants lacking the CRISPR array or any one of the other cas genes were not impaired in infection ability. We now report that the Cas2 protein of L. pneumophila has both RNase and DNase activities, with the RNase activity being more pronounced. By characterizing a catalytically deficient version of Cas2, we determined that nuclease activity is critical for promoting infection of amoebae. Also, introduction of Cas2, but not its catalytic mutant form, into a strain of L. pneumophila that naturally lacks a CRISPR-Cas locus caused that strain to be 40- to 80-fold more infective for amoebae, unequivocally demonstrating that Cas2 facilitates the infection process independently of any other component encoded within the CRISPR-Cas locus. Finally, a cas2 mutant was impaired for infection of Willaertia magna but not Naegleria lovaniensis, suggesting that Cas2 promotes infection of most but not all amoebal hosts.
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36
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Koonin EV, Krupovic M. Evolution of adaptive immunity from transposable elements combined with innate immune systems. Nat Rev Genet 2014; 16:184-92. [PMID: 25488578 DOI: 10.1038/nrg3859] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Adaptive immune systems in prokaryotes and animals give rise to long-term memory through modification of specific genomic loci, such as by insertion of foreign (viral or plasmid) DNA fragments into clustered regularly interspaced short palindromic repeat (CRISPR) loci in prokaryotes and by V(D)J recombination of immunoglobulin genes in vertebrates. Strikingly, recombinases derived from unrelated mobile genetic elements have essential roles in both prokaryotic and vertebrate adaptive immune systems. Mobile elements, which are ubiquitous in cellular life forms, provide the only known, naturally evolved tools for genome engineering that are successfully adopted by both innate immune systems and genome-editing technologies. In this Opinion article, we present a general scenario for the origin of adaptive immunity from mobile elements and innate immune systems.
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Affiliation(s)
- Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, Maryland 20894, USA
| | - Mart Krupovic
- Institut Pasteur, Unité Biologie Moléculaire du Gène chez les Extrêmophiles, 25 rue du Docteur Roux, 75015 Paris, France
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37
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Abstract
The discovery of CRISPR-Cas (clustered, regularly interspaced short palindromic repeats-CRISPR-associated proteins) adaptive immune systems in prokaryotes has been one of the most exciting advances in microbiology in the past decade. Their role in host protection against mobile genetic elements is now well established, but there is mounting evidence that these systems modulate other processes, such as the genetic regulation of group behaviour and virulence, DNA repair and genome evolution. In this Progress article, we discuss recent studies that have provided insights into these unconventional CRISPR-Cas functions and consider their potential evolutionary implications. Understanding the role of CRISPR-Cas in these processes will improve our understanding of the evolution and maintenance of CRISPR-Cas systems in prokaryotic genomes.
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Abstract
CRISPR (cluster of regularly interspaced palindromic repeats) is a prokaryotic adaptive defence system, providing immunity against mobile genetic elements such as viruses. Genomically encoded crRNA (CRISPR RNA) is used by Cas (CRISPR-associated) proteins to target and subsequently degrade nucleic acids of invading entities in a sequence-dependent manner. The process is known as ‘interference’. In the present review we cover recent progress on the structural biology of the CRISPR/Cas system, focusing on the Cas proteins and complexes that catalyse crRNA biogenesis and interference. Structural studies have helped in the elucidation of key mechanisms, including the recognition and cleavage of crRNA by the Cas6 and Cas5 proteins, where remarkable diversity at the level of both substrate recognition and catalysis has become apparent. The RNA-binding RAMP (repeat-associated mysterious protein) domain is present in the Cas5, Cas6, Cas7 and Cmr3 protein families and RAMP-like domains are found in Cas2 and Cas10. Structural analysis has also revealed an evolutionary link between the small subunits of the type I and type III-B interference complexes. Future studies of the interference complexes and their constituent components will transform our understanding of the system.
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39
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Koonin EV, Makarova KS. CRISPR-Cas: evolution of an RNA-based adaptive immunity system in prokaryotes. RNA Biol 2013; 10:679-86. [PMID: 23439366 DOI: 10.4161/rna.24022] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The CRISPR-Cas (clustered regularly interspaced short palindromic repeats, CRISPR-associated genes) is an adaptive immunity system in bacteria and archaea that functions via a distinct self-non-self recognition mechanism that is partially analogous to the mechanism of eukaryotic RNA interference (RNAi). The CRISPR-Cas system incorporates fragments of virus or plasmid DNA into the CRISPR repeat cassettes and employs the processed transcripts of these spacers as guide RNAs to cleave the cognate foreign DNA or RNA. The Cas proteins, however, are not homologous to the proteins involved in RNAi and comprise numerous, highly diverged families. The majority of the Cas proteins contain diverse variants of the RNA recognition motif (RRM), a widespread RNA-binding domain. Despite the fast evolution that is typical of the cas genes, the presence of diverse versions of the RRM in most Cas proteins provides for a simple scenario for the evolution of the three distinct types of CRISPR-cas systems. In addition to several proteins that are directly implicated in the immune response, the cas genes encode a variety of proteins that are homologous to prokaryotic toxins that typically possess nuclease activity. The predicted toxins associated with CRISPR-Cas systems include the essential Cas2 protein, proteins of COG1517 that, in addition to a ligand-binding domain and a helix-turn-helix domain, typically contain different nuclease domains and several other predicted nucleases. The tight association of the CRISPR-Cas immunity systems with predicted toxins that, upon activation, would induce dormancy or cell death suggests that adaptive immunity and dormancy/suicide response are functionally coupled. Such coupling could manifest in the persistence state being induced and potentially providing conditions for more effective action of the immune system or in cell death being triggered when immunity fails.
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Affiliation(s)
- Eugene V Koonin
- National Center for Biotechnology Information, NLM, National Institutes of Health, Bethesda, MD, USA.
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40
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A new type V toxin-antitoxin system where mRNA for toxin GhoT is cleaved by antitoxin GhoS. Nat Chem Biol 2013; 8:855-61. [PMID: 22941047 PMCID: PMC3514572 DOI: 10.1038/nchembio.1062] [Citation(s) in RCA: 223] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 07/31/2012] [Indexed: 12/04/2022]
Abstract
Among bacterial toxin/antitoxin (TA) systems, to date no antitoxin has been identified that functions by cleaving toxin mRNA. Here we demonstrate YjdO (renamed GhoT) is a membrane lytic peptide that causes ghost cell formation (lysed cells with damaged membranes) and increases persistence (persister cells are tolerant to antibiotics without undergoing genetic change). GhoT is part of a novel TA system with YjdK (renamed GhoS) since in vitro RNA degradation studies, qRT-PCR, and whole-transcriptome studies revealed GhoS masks GhoT toxicity by cleaving specifically ghoT mRNA. Alanine substitutions showed arginine 28 is important for GhoS activity, and RNA sequencing indicated the GhoS cleavage site is rich in uridine and adenosine. The NMR structure of GhoS indicates it is related to the CAS2 CRISPR RNase, and GhoS is a monomer. Hence, GhoT/GhoS is the first type V TA system where a protein antitoxin inhibits the toxin by cleaving specifically its mRNA.
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41
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Ren D, Walker AN, Daines DA. Toxin-antitoxin loci vapBC-1 and vapXD contribute to survival and virulence in nontypeable Haemophilus influenzae. BMC Microbiol 2012; 12:263. [PMID: 23157645 PMCID: PMC3560280 DOI: 10.1186/1471-2180-12-263] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 11/14/2012] [Indexed: 12/21/2022] Open
Abstract
Background Nontypeable Haemophilus influenzae (NTHi) is a significant human pathogen responsible for respiratory tract infections and the most common cause of recurrent otitis media. Type II toxin-antitoxin (TA) systems are genetic elements that code for a stable protein toxin and a labile antitoxin that are thought to be involved in metabolic regulation of bacteria by enabling a switch to a dormant state under stress conditions. The contribution to infection persistence of the NTHi TA loci vapBC-1 and vapXD was examined in this study. Results Deletions in vapBC-1, vapXD and vapBC-1 vapXD significantly decreased the survival of NTHi co-cultured with primary human respiratory tissue at the air-liquid interface and in the chinchilla model of otitis media. The TA deletions did not affect the growth dynamics of the mutants in rich media, their ultra-structural morphology, or display appreciable synergy during NTHi infections. The toxin and antitoxin proteins of both pairs heterodimerized in vivo. Consistent with our previous findings regarding the VapC-1 toxin, the NTHi VapD toxin also displayed ribonuclease activity. Conclusions We conclude that the vapBC-1 and vapXD TA loci enhance NTHi survival and virulence during infection in vitro and in vivo using a mechanism of mRNA cleavage, and that these conserved TA pairs represent new targets for the prophylaxis and therapy of otitis media and other NTHi-caused mucosal diseases.
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Affiliation(s)
- Dabin Ren
- Division of Basic Medical Sciences, Mercer University School of Medicine, Macon, GA, USA
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42
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Makarova KS, Anantharaman V, Aravind L, Koonin EV. Live virus-free or die: coupling of antivirus immunity and programmed suicide or dormancy in prokaryotes. Biol Direct 2012; 7:40. [PMID: 23151069 PMCID: PMC3506569 DOI: 10.1186/1745-6150-7-40] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 11/06/2012] [Indexed: 01/21/2023] Open
Abstract
Background The virus-host arms race is a major theater for evolutionary innovation. Archaea and bacteria have evolved diverse, elaborate antivirus defense systems that function on two general principles: i) immune systems that discriminate self DNA from nonself DNA and specifically destroy the foreign, in particular viral, genomes, whereas the host genome is protected, or ii) programmed cell suicide or dormancy induced by infection. Presentation of the hypothesis Almost all genomic loci encoding immunity systems such as CRISPR-Cas, restriction-modification and DNA phosphorothioation also encompass suicide genes, in particular those encoding known and predicted toxin nucleases, which do not appear to be directly involved in immunity. In contrast, the immunity systems do not appear to encode antitoxins found in typical toxin-antitoxin systems. This raises the possibility that components of the immunity system themselves act as reversible inhibitors of the associated toxin proteins or domains as has been demonstrated for the Escherichia coli anticodon nuclease PrrC that interacts with the PrrI restriction-modification system. We hypothesize that coupling of diverse immunity and suicide/dormancy systems in prokaryotes evolved under selective pressure to provide robustness to the antivirus response. We further propose that the involvement of suicide/dormancy systems in the coupled antivirus response could take two distinct forms: 1) induction of a dormancy-like state in the infected cell to ‘buy time’ for activation of adaptive immunity; 2) suicide or dormancy as the final recourse to prevent viral spread triggered by the failure of immunity. Testing the hypothesis This hypothesis entails many experimentally testable predictions. Specifically, we predict that Cas2 protein present in all cas operons is a mRNA-cleaving nuclease (interferase) that might be activated at an early stage of virus infection to enable incorporation of virus-specific spacers into the CRISPR locus or to trigger cell suicide when the immune function of CRISPR-Cas systems fails. Similarly, toxin-like activity is predicted for components of numerous other defense loci. Implications of the hypothesis The hypothesis implies that antivirus response in prokaryotes involves key decision-making steps at which the cell chooses the path to follow by sensing the course of virus infection. Reviewers This article was reviewed by Arcady Mushegian, Etienne Joly and Nick Grishin. For complete reviews, go to the Reviewers’ reports section.
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Affiliation(s)
- Kira S Makarova
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD 20894, USA
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Structural analysis of hypothetical proteins from Helicobacter pylori: an approach to estimate functions of unknown or hypothetical proteins. Int J Mol Sci 2012; 13:7109-7137. [PMID: 22837682 PMCID: PMC3397514 DOI: 10.3390/ijms13067109] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 05/29/2012] [Accepted: 06/01/2012] [Indexed: 12/12/2022] Open
Abstract
Helicobacter pylori (H. pylori) have a unique ability to survive in extreme acidic environments and to colonize the gastric mucosa. It can cause diverse gastric diseases such as peptic ulcers, chronic gastritis, mucosa-associated lymphoid tissue (MALT) lymphoma, gastric cancer, etc. Based on genomic research of H. pylori, over 1600 genes have been functionally identified so far. However, H. pylori possess some genes that are uncharacterized since: (i) the gene sequences are quite new; (ii) the function of genes have not been characterized in any other bacterial systems; and (iii) sometimes, the protein that is classified into a known protein based on the sequence homology shows some functional ambiguity, which raises questions about the function of the protein produced in H. pylori. Thus, there are still a lot of genes to be biologically or biochemically characterized to understand the whole picture of gene functions in the bacteria. In this regard, knowledge on the 3D structure of a protein, especially unknown or hypothetical protein, is frequently useful to elucidate the structure-function relationship of the uncharacterized gene product. That is, a structural comparison with known proteins provides valuable information to help predict the cellular functions of hypothetical proteins. Here, we show the 3D structures of some hypothetical proteins determined by NMR spectroscopy and X-ray crystallography as a part of the structural genomics of H. pylori. In addition, we show some successful approaches of elucidating the function of unknown proteins based on their structural information.
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