51
|
Slayden RA, Dawson CC, Cummings JE. Toxin-antitoxin systems and regulatory mechanisms in Mycobacterium tuberculosis. Pathog Dis 2018; 76:4969681. [PMID: 29788125 DOI: 10.1093/femspd/fty039] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/01/2018] [Indexed: 11/14/2022] Open
Abstract
There has been a significant reduction in annual tuberculosis incidence since the World Health Organization declared tuberculosis a global health threat. However, treatment of M. tuberculosis infections requires lengthy multidrug therapeutic regimens to achieve a durable cure. The development of new drugs that are active against resistant strains and phenotypically diverse organisms continues to present the greatest challenge in the future. Numerous phylogenomic analyses have revealed that the Mtb genome encodes a significantly expanded repertoire of toxin-antitoxin (TA) loci that makes up the Mtb TA system. A TA loci is a two-gene operon encoding a 'toxin' protein that inhibits bacterial growth and an interacting 'antitoxin' partner that neutralizes the inhibitory activity of the toxin. The presence of multiple chromosomally encoded TA loci in Mtb raises important questions in regard to expansion, regulation and function. Thus, the functional roles of TA loci in Mtb pathogenesis have received considerable attention over the last decade. The cumulative results indicate that they are involved in regulating adaptive responses to stresses associated with the host environment and drug treatment. Here we review the TA families encoded in Mtb, discuss the duplication of TA loci in Mtb, regulatory mechanism of TA loci, and phenotypic heterogeneity and pathogenesis.
Collapse
Affiliation(s)
- Richard A Slayden
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-0922, USA
| | - Clinton C Dawson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-0922, USA
| | - Jason E Cummings
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-0922, USA
| |
Collapse
|
52
|
Wang YJ, Vaidyanathan PP, Rojas-Duran MF, Udeshi ND, Bartoli KM, Carr SA, Gilbert WV. Lso2 is a conserved ribosome-bound protein required for translational recovery in yeast. PLoS Biol 2018; 16:e2005903. [PMID: 30208026 PMCID: PMC6135351 DOI: 10.1371/journal.pbio.2005903] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Accepted: 08/09/2018] [Indexed: 02/05/2023] Open
Abstract
Ribosome-binding proteins function broadly in protein synthesis, gene regulation, and cellular homeostasis, but the complete complement of functional ribosome-bound proteins remains unknown. Using quantitative mass spectrometry, we identified late-annotated short open reading frame 2 (Lso2) as a ribosome-associated protein that is broadly conserved in eukaryotes. Genome-wide crosslinking and immunoprecipitation of Lso2 and its human ortholog coiled-coil domain containing 124 (CCDC124) recovered 25S ribosomal RNA in a region near the A site that overlaps the GTPase activation center. Consistent with this location, Lso2 also crosslinked to most tRNAs. Ribosome profiling of yeast lacking LSO2 (lso2Δ) revealed global translation defects during recovery from stationary phase with translation of most genes reduced more than 4-fold. Ribosomes accumulated at start codons, were depleted from stop codons, and showed codon-specific changes in occupancy in lso2Δ. These defects, and the conservation of the specific ribosome-binding activity of Lso2/CCDC124, indicate broadly important functions in translation and physiology. Translation, or the production of protein from messenger RNA (mRNA), is catalyzed by a universally conserved macromolecular machine known as the ribosome. Ribosome-binding factors are also required for all substeps of translation, from initial recruitment of mRNA to peptide chain elongation to release of the mature polypeptide. However, many ribosome interactors have been identified whose effects on translation and physiology are unknown. Here, we show that the uncharacterized yeast protein late-annotated short open reading frame 2 (Lso2) crosslinks to a region of the ribosome that underlies accurate progression through all substeps of translation, the GTPase activation center. This specific binding activity is conserved in the human ortholog of Lso2, coiled-coil domain containing 124 (CCDC124). Null mutants of lso2 also show severe translation defects during recovery from extended starvation, including failure to initiate on most mRNAs and a general block to peptide chain elongation. We propose that these defects could arise from a function for Lso2 in modulating the activity or integrity of the ribosome GTPase activation center during challenging growth regimes.
Collapse
Affiliation(s)
- Yinuo J. Wang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Microbiology Graduate Program, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | | | - Maria F. Rojas-Duran
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Namrata D. Udeshi
- The Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Kristen M. Bartoli
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Steven A. Carr
- The Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Wendy V. Gilbert
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail:
| |
Collapse
|
53
|
Condon C, Piton J, Braun F. Distribution of the ribosome associated endonuclease Rae1 and the potential role of conserved amino acids in codon recognition. RNA Biol 2018; 15:683-688. [PMID: 29557713 DOI: 10.1080/15476286.2018.1454250] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
We recently identified a novel ribonuclease in Bacillus subtilis called Rae1 that cleaves mRNAs in a translation-dependent manner. Rae1 is a member of the NYN/PIN family of ribonucleases and is highly conserved in the Firmicutes, the Cyanobacteria and the chloroplasts of photosynthetic algae and plants. We have proposed a model in which Rae1 enters the A-site of ribosomes that are paused following translation of certain sequences that are still ill-defined. In the only case identified thus far, Rae1 cleaves between a conserved glutamate and lysine codon during translation of a short peptide called S1025. Certain other codons are also tolerated on either side of the cleavage site, but these are recognized less efficiently. The model of Rae1 docked in the A-site allows us to make predictions about which conserved residues may be important for recognition of mRNA, the tRNA in the adjacent P-site and binding to the 50S ribosome subunit.
Collapse
Affiliation(s)
- Ciarán Condon
- a UMR 8261 (CNRS - Univ. Paris Diderot), Institut de Biologie Physico-Chimique , 13 rue Pierre et Marie Curie, Paris , France
| | | | - Frédérique Braun
- a UMR 8261 (CNRS - Univ. Paris Diderot), Institut de Biologie Physico-Chimique , 13 rue Pierre et Marie Curie, Paris , France
| |
Collapse
|
54
|
Mohanty BK, Kushner SR. Enzymes Involved in Posttranscriptional RNA Metabolism in Gram-Negative Bacteria. Microbiol Spectr 2018; 6:10.1128/microbiolspec.RWR-0011-2017. [PMID: 29676246 PMCID: PMC5912700 DOI: 10.1128/microbiolspec.rwr-0011-2017] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Indexed: 02/08/2023] Open
Abstract
Gene expression in Gram-negative bacteria is regulated at many levels, including transcription initiation, RNA processing, RNA/RNA interactions, mRNA decay, and translational controls involving enzymes that alter translational efficiency. In this review, we discuss the various enzymes that control transcription, translation, and RNA stability through RNA processing and degradation. RNA processing is essential to generate functional RNAs, while degradation helps control the steady-state level of each individual transcript. For example, all the pre-tRNAs are transcribed with extra nucleotides at both their 5' and 3' termini, which are subsequently processed to produce mature tRNAs that can be aminoacylated. Similarly, rRNAs that are transcribed as part of a 30S polycistronic transcript are matured to individual 16S, 23S, and 5S rRNAs. Decay of mRNAs plays a key role in gene regulation through controlling the steady-state level of each transcript, which is essential for maintaining appropriate protein levels. In addition, degradation of both translated and nontranslated RNAs recycles nucleotides to facilitate new RNA synthesis. To carry out all these reactions, Gram-negative bacteria employ a large number of endonucleases, exonucleases, RNA helicases, and poly(A) polymerase, as well as proteins that regulate the catalytic activity of particular RNases. Under certain stress conditions, an additional group of specialized endonucleases facilitate the cell's ability to adapt and survive. Many of the enzymes, such as RNase E, RNase III, polynucleotide phosphorylase, RNase R, and poly(A) polymerase I, participate in multiple RNA processing and decay pathways.
Collapse
Affiliation(s)
| | - Sidney R Kushner
- Department of Genetics
- Department of Microbiology, University of Georgia, Athens, GA 30602
| |
Collapse
|
55
|
Gilcrease EB, Casjens SR. The genome sequence of Escherichia coli tailed phage D6 and the diversity of Enterobacteriales circular plasmid prophages. Virology 2018; 515:203-214. [PMID: 29304472 PMCID: PMC5800970 DOI: 10.1016/j.virol.2017.12.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 12/15/2017] [Accepted: 12/17/2017] [Indexed: 11/29/2022]
Abstract
The temperate Escherichia coli bacteriophage D6 can exist as a circular plasmid prophage, and we report here its 91,159bp complete genome sequence. It is a distant relative of the well-studied phage P1, but it is sufficiently different that it typifies a previously undescribed tailed phage type or cluster. Examination of the database of bacterial genome sequences revealed that phage P1 and D6 prophage plasmids are common in the Enterobacteriales, and in addition, previously described Salmonella phage SSU5 represents a different type of temperate tailed phage with a circular plasmid prophage that is also very common in this host order. This analysis also discovered additional divergent clusters of putative circular plasmid prophages within the two larger P1 and SSU5 groups (superclusters) that inhabit the Enterobacteriales as well as bacteria in several other orders in the Gamma-proteobacteria class. Very few of these sequences are annotated as putative prophages.
Collapse
Affiliation(s)
- Eddie B Gilcrease
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Sherwood R Casjens
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Biology Department, University of Utah, Salt Lake City, UT 84112, USA.
| |
Collapse
|
56
|
Gerdes K. Hypothesis: type I toxin-antitoxin genes enter the persistence field-a feedback mechanism explaining membrane homoeostasis. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2016.0189. [PMID: 27672159 DOI: 10.1098/rstb.2016.0189] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2016] [Indexed: 11/12/2022] Open
Abstract
Bacteria form persisters, cells that are tolerant to multiple antibiotics and other types of environmental stress. Persister formation can be induced either stochastically in single cells of a growing bacterial ensemble, or by environmental stresses, such as nutrient starvation, in a subpopulation of cells. In many cases, the molecular mechanisms underlying persistence are still unknown. However, there is growing evidence that, in enterobacteria, both stochastically and environmentally induced persistence are controlled by the second messenger (p)ppGpp. For example, the 'alarmone' (p)ppGpp activates Lon, which, in turn, activates type II toxin-antitoxin (TA) modules to thereby induce persistence. Recently, it has been shown that a type I TA module, hokB/sokB, also can induce persistence. In this case, the underlying mechanism depends on the universally conserved GTPase Obg and, surprisingly, also (p)ppGpp. In the presence of (p)ppGpp, Obg stimulates hokB transcription and induces persistence. HokB toxin expression is under both negative and positive control: SokB antisense RNA inhibits hokB mRNA translation, while (p)ppGpp and Obg together stimulate hokB transcription. HokB is a small toxic membrane protein that, when produced in modest amounts, leads to membrane depolarization, cell stasis and persistence. By contrast, overexpression of HokB disrupts the membrane potential and kills the cell. These observations raise the question of how expression of HokB is regulated. Here, I propose a homoeostatic control mechanism that couples HokB expression to the membrane-bound RNase E that degrades and inactivates SokB antisense RNA.This article is part of the themed issue 'The new bacteriology'.
Collapse
Affiliation(s)
- Kenn Gerdes
- Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark
| |
Collapse
|
57
|
Hadži S, Garcia-Pino A, Haesaerts S, Jurenas D, Gerdes K, Lah J, Loris R. Ribosome-dependent Vibrio cholerae mRNAse HigB2 is regulated by a β-strand sliding mechanism. Nucleic Acids Res 2017; 45:4972-4983. [PMID: 28334932 PMCID: PMC5416850 DOI: 10.1093/nar/gkx138] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 02/25/2017] [Indexed: 11/12/2022] Open
Abstract
Toxin–antitoxin (TA) modules are small operons involved in bacterial stress response and persistence. higBA operons form a family of TA modules with an inverted gene organization and a toxin belonging to the RelE/ParE superfamily. Here, we present the crystal structures of chromosomally encoded Vibrio cholerae antitoxin (VcHigA2), toxin (VcHigB2) and their complex, which show significant differences in structure and mechanisms of function compared to the higBA module from plasmid Rts1, the defining member of the family. The VcHigB2 is more closely related to Escherichia coli RelE both in terms of overall structure and the organization of its active site. VcHigB2 is neutralized by VcHigA2, a modular protein with an N-terminal intrinsically disordered toxin-neutralizing segment followed by a C-terminal helix-turn-helix dimerization and DNA binding domain. VcHigA2 binds VcHigB2 with picomolar affinity, which is mainly a consequence of entropically favorable de-solvation of a large hydrophobic binding interface and enthalpically favorable folding of the N-terminal domain into an α-helix followed by a β-strand. This interaction displaces helix α3 of VcHigB2 and at the same time induces a one-residue shift in the register of β-strand β3, thereby flipping the catalytically important Arg64 out of the active site.
Collapse
Affiliation(s)
- San Hadži
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, B-1050 Brussel, Belgium.,Molecular Recognition Unit, Center for Structural Biology, Vlaams Instituut voor Biotechnologie, B-1050 Brussel, Belgium.,Department of Physical Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Abel Garcia-Pino
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, B-1050 Brussel, Belgium.,Biologie Structurale et Biophysique, IBMM-DBM, Université Libre de Bruxelles (ULB), B-6041 Gosselies, Belgium
| | - Sarah Haesaerts
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, B-1050 Brussel, Belgium.,Molecular Recognition Unit, Center for Structural Biology, Vlaams Instituut voor Biotechnologie, B-1050 Brussel, Belgium
| | - Dukas Jurenas
- Biologie Structurale et Biophysique, IBMM-DBM, Université Libre de Bruxelles (ULB), B-6041 Gosselies, Belgium
| | - Kenn Gerdes
- Department of Biology, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Jurij Lah
- Department of Physical Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Remy Loris
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, B-1050 Brussel, Belgium.,Molecular Recognition Unit, Center for Structural Biology, Vlaams Instituut voor Biotechnologie, B-1050 Brussel, Belgium
| |
Collapse
|
58
|
Polyvalent Proteins, a Pervasive Theme in the Intergenomic Biological Conflicts of Bacteriophages and Conjugative Elements. J Bacteriol 2017; 199:JB.00245-17. [PMID: 28559295 PMCID: PMC5512222 DOI: 10.1128/jb.00245-17] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 05/17/2017] [Indexed: 12/29/2022] Open
Abstract
Intense biological conflicts between prokaryotic genomes and their genomic parasites have resulted in an arms race in terms of the molecular “weaponry” deployed on both sides. Using a recursive computational approach, we uncovered a remarkable class of multidomain proteins with 2 to 15 domains in the same polypeptide deployed by viruses and plasmids in such conflicts. Domain architectures and genomic contexts indicate that they are part of a widespread conflict strategy involving proteins injected into the host cell along with parasite DNA during the earliest phase of infection. Their unique feature is the combination of domains with highly disparate biochemical activities in the same polypeptide; accordingly, we term them polyvalent proteins. Of the 131 domains in polyvalent proteins, a large fraction are enzymatic domains predicted to modify proteins, target nucleic acids, alter nucleotide signaling/metabolism, and attack peptidoglycan or cytoskeletal components. They further contain nucleic acid-binding domains, virion structural domains, and 40 novel uncharacterized domains. Analysis of their architectural network reveals both pervasive common themes and specialized strategies for conjugative elements and plasmids or (pro)phages. The themes include likely processing of multidomain polypeptides by zincin-like metallopeptidases and mechanisms to counter restriction or CRISPR/Cas systems and jump-start transcription or replication. DNA-binding domains acquired by eukaryotes from such systems have been reused in XPC/RAD4-dependent DNA repair and mitochondrial genome replication in kinetoplastids. Characterization of the novel domains discovered here, such as RNases and peptidases, are likely to aid in the development of new reagents and elucidation of the spread of antibiotic resistance. IMPORTANCE This is the first report of the widespread presence of large proteins, termed polyvalent proteins, predicted to be transmitted by genomic parasites such as conjugative elements, plasmids, and phages during the initial phase of infection along with their DNA. They are typified by the presence of multiple domains with disparate activities combined in the same protein. While some of these domains are predicted to assist the invasive element in replication, transcription, or protection of their DNA, several are likely to target various host defense systems or modify the host to favor the parasite's life cycle. Notably, DNA-binding domains from these systems have been transferred to eukaryotes, where they have been incorporated into DNA repair and mitochondrial genome replication systems.
Collapse
|
59
|
Belasco JG. Death by translation: ribosome-assisted degradation of mRNA by endonuclease toxins. FEBS Lett 2017. [PMID: 28649728 DOI: 10.1002/1873-3468.12715] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Joel G Belasco
- Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, New York, NY, USA.,Department of Microbiology, New York University School of Medicine, NY, USA
| |
Collapse
|
60
|
Choi W, Yamaguchi Y, Lee JW, Jang KM, Inouye M, Kim SG, Yoon MH, Park JH. Translation-dependent mRNA cleavage by YhaV in Escherichia coli. FEBS Lett 2017; 591:1853-1861. [PMID: 28573789 DOI: 10.1002/1873-3468.12705] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/22/2017] [Accepted: 05/22/2017] [Indexed: 11/08/2022]
Abstract
Many bacteria have toxin-antitoxin (TA) systems, where toxin gene expression inhibits their own cell growth. mRNA is one of the well-known targets of the toxins in the type II toxin-antitoxin systems. Here, we examined the ribosome dependency of the endoribonuclease activity of YhaV, one of the toxins in type II TA systems, on mRNA in vitro and in vivo. A polysome profiling assay revealed that YhaV is bound to the 70S ribosomes and 50S ribosomal subunits. Moreover, we found that while YhaV cleaves ompF and lpp mRNAs in a translation-dependent manner, they did not cleave the 5' untranslated region in primer extension experiments. From these results, we conclude that YhaV is a ribosome-dependent toxin that cleaves mRNA in a translation-dependent manner.
Collapse
Affiliation(s)
- Wonho Choi
- Bio-Evaluation Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, South Korea.,Department of Bio-Environmental Chemistry, College of Agriculture and Life Sciences, Chungnam National University, Yuseong-gu, South Korea
| | - Yoshihiro Yamaguchi
- OCU Advanced Research Institute for Natural Science and Technology, Osaka City University, Japan
| | - Jae-Woo Lee
- Bio-Evaluation Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, South Korea.,Department of Food Science and Technology, College of Agriculture and Life Sciences, Chungnam National University, Yuseong-gu, South Korea
| | - Kyung-Min Jang
- Bio-Evaluation Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, South Korea
| | - Masayori Inouye
- Department of Biochemistry, Rutgers-Robert Wood Johnson Medical School and Center for Advanced Biotechnology and Medicine, Piscataway, NJ, USA
| | - Sung-Gun Kim
- Department of Biomedical Sicience, U1 University, Youngdong, South Korea
| | - Min-Ho Yoon
- Department of Bio-Environmental Chemistry, College of Agriculture and Life Sciences, Chungnam National University, Yuseong-gu, South Korea
| | - Jung-Ho Park
- Bio-Evaluation Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, South Korea
| |
Collapse
|
61
|
Huter P, Müller C, Arenz S, Beckert B, Wilson DN. Structural Basis for Ribosome Rescue in Bacteria. Trends Biochem Sci 2017. [PMID: 28629612 DOI: 10.1016/j.tibs.2017.05.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Ribosomes that translate mRNAs lacking stop codons become stalled at the 3' end of the mRNA. Recycling of these stalled ribosomes is essential for cell viability. In bacteria three ribosome rescue systems have been identified so far, with the most ubiquitous and best characterized being the trans-translation system mediated by transfer-messenger RNA (tmRNA) and small protein B (SmpB). The two additional rescue systems present in some bacteria employ alternative rescue factor (Arf) A and release factor (RF) 2 or ArfB. Recent structures have revealed how ArfA mediates ribosome rescue by recruiting the canonical termination factor RF2 to ribosomes stalled on truncated mRNAs. This now provides us with the opportunity to compare and contrast the available structures of all three bacterial ribosome rescue systems.
Collapse
Affiliation(s)
- Paul Huter
- Gene Center, Department of Biochemistry and Center for Integrated Protein Science Munich (CiPSM), Feodor-Lynenstr. 25, 81377 München, Germany
| | - Claudia Müller
- Gene Center, Department of Biochemistry and Center for Integrated Protein Science Munich (CiPSM), Feodor-Lynenstr. 25, 81377 München, Germany
| | - Stefan Arenz
- Gene Center, Department of Biochemistry and Center for Integrated Protein Science Munich (CiPSM), Feodor-Lynenstr. 25, 81377 München, Germany
| | - Bertrand Beckert
- Gene Center, Department of Biochemistry and Center for Integrated Protein Science Munich (CiPSM), Feodor-Lynenstr. 25, 81377 München, Germany; Institute for Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
| | - Daniel N Wilson
- Gene Center, Department of Biochemistry and Center for Integrated Protein Science Munich (CiPSM), Feodor-Lynenstr. 25, 81377 München, Germany; Institute for Biochemistry and Molecular Biology, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany.
| |
Collapse
|
62
|
Senissar M, Manav MC, Brodersen DE. Structural conservation of the PIN domain active site across all domains of life. Protein Sci 2017; 26:1474-1492. [PMID: 28508407 DOI: 10.1002/pro.3193] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 05/08/2017] [Accepted: 05/08/2017] [Indexed: 01/26/2023]
Abstract
The PIN (PilT N-terminus) domain is a compact RNA-binding protein domain present in all domains of life. This 120-residue domain consists of a central and parallel β sheet surrounded by α helices, which together organize 4-5 acidic residues in an active site that binds one or more divalent metal ions and in many cases has endoribonuclease activity. In bacteria and archaea, the PIN domain is primarily associated with toxin-antitoxin loci, consisting of a toxin (the PIN domain nuclease) and an antitoxin that inhibits the function of the toxin under normal growth conditions. During nutritional or antibiotic stress, the antitoxin is proteolytically degraded causing activation of the PIN domain toxin leading to a dramatic reprogramming of cellular metabolism to cope with the new situation. In eukaryotes, PIN domains are commonly found as parts of larger proteins and are involved in a range of processes involving RNA cleavage, including ribosomal RNA biogenesis and nonsense-mediated mRNA decay. In this review, we provide a comprehensive overview of the structural characteristics of the PIN domain and compare PIN domains from all domains of life in terms of structure, active site architecture, and activity.
Collapse
Affiliation(s)
- M Senissar
- Centre for Bacterial Stress Response and Persistence, Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, Aarhus, 8000, Denmark
| | - M C Manav
- Centre for Bacterial Stress Response and Persistence, Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, Aarhus, 8000, Denmark
| | - D E Brodersen
- Centre for Bacterial Stress Response and Persistence, Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, Aarhus, 8000, Denmark
| |
Collapse
|
63
|
Zhang J, Ito H, Hino M, Kimura M. A RelE/ParE superfamily toxin in Vibrio parahaemolyticus has DNA nicking endonuclease activity. Biochem Biophys Res Commun 2017; 489:29-34. [PMID: 28533087 DOI: 10.1016/j.bbrc.2017.05.105] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 05/19/2017] [Indexed: 12/12/2022]
Abstract
Type II toxins in toxin-antitoxin (TA) systems fold into a similar fold and belong to the RelE/ParE superfamily. However, they display two distinct biochemical activities: RelE toxins are mRNA interferases, while ParE toxins are DNA gyrase (Gyr) inhibitors. Previously, we found a TA system, vp1842/vp1843, on the Vibrio parahaemolyticus genome whose toxin Vp1843 belongs to the RelE/ParE toxin superfamily. Vp1843, unlike RelE toxins, has neither protein synthesis inhibitory activity nor ribonuclease activity. In this study, we examined the inhibitory potency of Vp1843 with Escherichia coli Gyr. The result showed that Vp1843, unlike other ParE toxins, had little Gyr inhibitory activity, but rather converted supercoiled DNA to open-circular DNA. Analysis showed further that Vp1843 cleaves a single strand in DNA, and that the antitoxin Vp1842 neutralized the nicking endonuclease activity of Vp1843. Mutations of Lys37 and Pro45 in Vp1843 abolished its nicking activity, suggesting that they play a crucial role in nicking endonuclease activity. To our knowledge, Vp1843 is the first toxin with DNA nicking endonuclease activity among the RelE/ParE toxin superfamily.
Collapse
Affiliation(s)
- Jing Zhang
- Laboratory of Structural Biology, Graduate School of Systems Life Sciences, Hakozaki 6-10-1, Fukuoka 812-8581, Japan
| | - Hironori Ito
- Laboratory of Biochemistry, Department of Bioscience and Biotechnology, Graduate School, Faculty of Agriculture, Kyushu University, Hakozaki 6-10-1, Fukuoka 812-8581, Japan
| | - Madoka Hino
- Department of Health and Nutrition Sciences, Faculty of Health and Social Welfare Science, Nishikyushu University, 4490-9 Ozaki, Kanzaki-machi, Kanzaki-shi, Saga 842-8585, Japan
| | - Makoto Kimura
- Laboratory of Structural Biology, Graduate School of Systems Life Sciences, Hakozaki 6-10-1, Fukuoka 812-8581, Japan; Laboratory of Biochemistry, Department of Bioscience and Biotechnology, Graduate School, Faculty of Agriculture, Kyushu University, Hakozaki 6-10-1, Fukuoka 812-8581, Japan.
| |
Collapse
|
64
|
Gautam LK, Yadav M, Rathore JS. Functional annotation of a novel toxin-antitoxin system Xn-RelT of Xenorhabdus nematophila; a combined in silico and in vitro approach. J Mol Model 2017; 23:189. [PMID: 28508139 DOI: 10.1007/s00894-017-3361-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Accepted: 04/26/2017] [Indexed: 12/19/2022]
Abstract
Toxin-antitoxin (TA) complexes play an important role in stress responses and programmed cell death in bacteria. The RelB-RelE toxin antitoxin system is well studied in Escherichia coli. In this study, we used combined in silico and in vitro approaches to study a novel Xn-RelT toxin from Xenorhabdus nematophila bearing its own antitoxin Xn-RelAT-a RelB homolog of E. coli. The structure for this toxin-antitoxin pair is yet unknown. We generated homology-based models of X. nematophila RelT toxin and antitoxin. The deduced models were further characterized for protein-nucleic acid, protein-protein interactions and gene ontology. A detrimental effect of recombinant Xn-RelT on host E. coli was determined through endogenous toxicity assay. When expressed from a isopropyl β-D-1-thiogalactopyranoside-regulated LacZ promoter, Xn-RelT toxin showed a toxic effect on E. coli cells. These observations imply that the conditional cooperativity governing the Xn-RelT TA operon in X. nematophila plays an important role in stress management and programmed cell death.
Collapse
Affiliation(s)
- Lalit Kumar Gautam
- School of Biotechnology, Gautam Buddha University, Yamuna Expressway, Gautam Buddha Nagar, Greater Noida, Uttar Pradesh, 201312, India.,Department of Biotechnology, Panjab University, Chandigarh, 160014, India
| | - Mohit Yadav
- School of Biotechnology, Gautam Buddha University, Yamuna Expressway, Gautam Buddha Nagar, Greater Noida, Uttar Pradesh, 201312, India
| | - Jitendra Singh Rathore
- School of Biotechnology, Gautam Buddha University, Yamuna Expressway, Gautam Buddha Nagar, Greater Noida, Uttar Pradesh, 201312, India.
| |
Collapse
|
65
|
Abstract
Transcription and translation are two complex mechanisms that are tightly coupled in prokaryotic cells. Even before the completion of transcription, ribosomes attach to the nascent mRNA and initiate protein synthesis. Remarkably, recent publications have indicated an association between translation and decay of certain mRNAs. In this issue of The EMBO Journal, Leroy et al (2017) depicts a fascinating mechanism of mRNA degradation, which involves the ribosome-associated ribonuclease Rae1 in Bacillus subtilis In a translation-dependent manner, Rae1 binds the ribosomal aminoacylation (A)-site and cleaves between specific codons of the targeted mRNA.
Collapse
Affiliation(s)
- David Lalaouna
- Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Eric Massé
- Department of Biochemistry, RNA Group, Université de Sherbrooke, Sherbrooke, QC, Canada
| |
Collapse
|
66
|
Jurėnas D, Chatterjee S, Konijnenberg A, Sobott F, Droogmans L, Garcia-Pino A, Van Melderen L. AtaT blocks translation initiation by N-acetylation of the initiator tRNAfMet. Nat Chem Biol 2017; 13:640-646. [DOI: 10.1038/nchembio.2346] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 01/12/2017] [Indexed: 11/09/2022]
|
67
|
Leroy M, Piton J, Gilet L, Pellegrini O, Proux C, Coppée JY, Figaro S, Condon C. Rae1/YacP, a new endoribonuclease involved in ribosome-dependent mRNA decay in Bacillus subtilis. EMBO J 2017; 36:1167-1181. [PMID: 28363943 DOI: 10.15252/embj.201796540] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 03/02/2017] [Accepted: 03/02/2017] [Indexed: 11/09/2022] Open
Abstract
The PIN domain plays a central role in cellular RNA biology and is involved in processes as diverse as rRNA maturation, mRNA decay and telomerase function. Here, we solve the crystal structure of the Rae1 (YacP) protein of Bacillus subtilis, a founding member of the NYN (Nedd4-BP1/YacP nuclease) subfamily of PIN domain proteins, and identify potential substrates in vivo Unexpectedly, degradation of a characterised target mRNA was completely dependent on both its translation and reading frame. We provide evidence that Rae1 associates with the B. subtilis ribosome and cleaves between specific codons of this mRNA in vivo Critically, we also demonstrate translation-dependent Rae1 cleavage of this substrate in a purified translation assay in vitro Multiple lines of evidence converge to suggest that Rae1 is an A-site endoribonuclease. We present a docking model of Rae1 bound to the B. subtilis ribosomal A-site that is consistent with this hypothesis and show that Rae1 cleaves optimally immediately upstream of a lysine codon (AAA or AAG) in vivo.
Collapse
Affiliation(s)
- Magali Leroy
- UMR 8261 (CNRS - Univ. Paris Diderot, Sorbonne Paris Cité), Institut de Biologie Physico-Chimique, Paris, France
| | - Jérémie Piton
- UMR 8261 (CNRS - Univ. Paris Diderot, Sorbonne Paris Cité), Institut de Biologie Physico-Chimique, Paris, France
| | - Laetitia Gilet
- UMR 8261 (CNRS - Univ. Paris Diderot, Sorbonne Paris Cité), Institut de Biologie Physico-Chimique, Paris, France
| | - Olivier Pellegrini
- UMR 8261 (CNRS - Univ. Paris Diderot, Sorbonne Paris Cité), Institut de Biologie Physico-Chimique, Paris, France
| | - Caroline Proux
- Transcriptome and EpiGenome, Biomics Center for Innovation and Technological Research Institut Pasteur, Paris, France
| | - Jean-Yves Coppée
- Transcriptome and EpiGenome, Biomics Center for Innovation and Technological Research Institut Pasteur, Paris, France
| | - Sabine Figaro
- UMR 8261 (CNRS - Univ. Paris Diderot, Sorbonne Paris Cité), Institut de Biologie Physico-Chimique, Paris, France
| | - Ciarán Condon
- UMR 8261 (CNRS - Univ. Paris Diderot, Sorbonne Paris Cité), Institut de Biologie Physico-Chimique, Paris, France
| |
Collapse
|
68
|
Interaction of Type IV Toxin/Antitoxin Systems in Cryptic Prophages of Escherichia coli K-12. Toxins (Basel) 2017; 9:toxins9030077. [PMID: 28257056 PMCID: PMC5371832 DOI: 10.3390/toxins9030077] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 02/23/2017] [Accepted: 02/24/2017] [Indexed: 01/27/2023] Open
Abstract
Toxin/antitoxin (TA) systems are widespread in prokaryotic chromosomes and in mobile genetic elements including plasmids and prophages. The first characterized Type IV TA system CbtA/CbeA was found in cryptic prophage CP4-44 in Escherichia coli K-12. Two homologous TA loci of CbtA/CbeA also reside in cryptic prophages of E. coli K-12, YkfI/YafW in CP4-6 and YpjF/YfjZ in CP4-57. In this study, we demonstrated that YkfI and YpjF inhibited cell growth and led to the formation of "lemon-shaped" cells. Prolonged overproduction of YkfI led to the formation of "gourd-shaped" cells and immediate cell lysis. YafW and YfjZ can neutralize the toxicity of YkfI or YpjF. Furthermore, we found that YkfI and YpjF interacted with cell division protein FtsZ in E. coli, but ectopic expression in Pseudomonas and Shewanella did not cause the formation of "lemon-shaped" cells. Moreover, deletion of all of the three toxin genes together decreased resistance to oxidative stress and deletion of the antitoxin genes increased early biofilm formation. Collectively, these results demonstrated that the homologous Type IV TA systems in E. coli may target cell division protein FtsZ in E. coli and may have different physiological functions in E. coli.
Collapse
|
69
|
Hwang JY, Buskirk AR. A ribosome profiling study of mRNA cleavage by the endonuclease RelE. Nucleic Acids Res 2016; 45:327-336. [PMID: 27924019 PMCID: PMC5224514 DOI: 10.1093/nar/gkw944] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 10/05/2016] [Accepted: 10/11/2016] [Indexed: 11/12/2022] Open
Abstract
Implicated in persistence and stress response pathways in bacteria, RelE shuts down protein synthesis by cleaving mRNA within the ribosomal A site. Structural and biochemical studies have shown that RelE cuts with some sequence specificity, which we further characterize here, and that it shows no activity outside the context of the ribosome. We obtained a global view of the effect of RelE on translation by ribosome profiling, observing that ribosomes accumulate on the 5′-end of genes through dynamic cycles of mRNA cleavage, ribosome rescue and initiation. Moreover, the addition of purified RelE to cell lysates shows promise as a method for generating ribosome footprints. In bacteria, profiling studies have suffered from relatively low resolution and have yielded no information on reading frame due to problems inherent to MNase digestion, the method used to degrade unprotected regions of mRNA. In contrast, we find that RelE yields precise 3′-ends that for the first time reveal reading frame in bacteria. Given that RelE has been shown to function in all three domains of life, RelE has potential to improve reading frame and shed light on A-site occupancy in ribosome profiling experiments more broadly.
Collapse
Affiliation(s)
- Jae-Yeon Hwang
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Allen R Buskirk
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| |
Collapse
|
70
|
Schureck MA, Repack A, Miles SJ, Marquez J, Dunham CM. Mechanism of endonuclease cleavage by the HigB toxin. Nucleic Acids Res 2016; 44:7944-53. [PMID: 27378776 PMCID: PMC5027501 DOI: 10.1093/nar/gkw598] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 06/17/2016] [Accepted: 06/22/2016] [Indexed: 01/11/2023] Open
Abstract
Bacteria encode multiple type II toxin-antitoxin modules that cleave ribosome-bound mRNAs in response to stress. All ribosome-dependent toxin family members structurally characterized to date adopt similar microbial RNase architectures despite possessing low sequence identities. Therefore, determining which residues are catalytically important in this specialized RNase family has been a challenge in the field. Structural studies of RelE and YoeB toxins bound to the ribosome provided significant insights but biochemical experiments with RelE were required to clearly demonstrate which residues are critical for acid-base catalysis of mRNA cleavage. Here, we solved an X-ray crystal structure of the wild-type, ribosome-dependent toxin HigB bound to the ribosome revealing potential catalytic residues proximal to the mRNA substrate. Using cell-based and biochemical assays, we further determined that HigB residues His54, Asp90, Tyr91 and His92 are critical for activity in vivo, while HigB H54A and Y91A variants have the largest effect on mRNA cleavage in vitro Comparison of X-ray crystal structures of two catalytically inactive HigB variants with 70S-HigB bound structures reveal that HigB active site residues undergo conformational rearrangements likely required for recognition of its mRNA substrate. These data support the emerging concept that ribosome-dependent toxins have diverse modes of mRNA recognition.
Collapse
Affiliation(s)
- Marc A Schureck
- Emory University School of Medicine, Department of Biochemistry, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Adrienne Repack
- Emory University School of Medicine, Department of Biochemistry, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Stacey J Miles
- Emory University School of Medicine, Department of Biochemistry, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Jhomar Marquez
- Emory University School of Medicine, Department of Biochemistry, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Christine M Dunham
- Emory University School of Medicine, Department of Biochemistry, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| |
Collapse
|
71
|
Identification and characterization of chromosomal relBE toxin-antitoxin locus in Streptomyces cattleya DSM46488. Sci Rep 2016; 6:32047. [PMID: 27534445 PMCID: PMC4989188 DOI: 10.1038/srep32047] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 08/01/2016] [Indexed: 01/25/2023] Open
Abstract
The relBE family of Type II toxin-antitoxin (TA) systems have been widely reported in bacteria but none in Streptomyces. With the conserved domain searches for TA pairs in the sequenced Streptomyces genomes, we identified two putative relBE loci, relBE1sca and relBE2sca, on the chromosome of Streptomyces cattleya DSM 46488. Overexpression of the S. cattleya toxin RelE2sca caused severe growth inhibition of E. coli and S. lividans, but RelE1sca had no toxic effect. The toxicity of RelE2sca could be abolished by the co-expression of its cognate RelB2sca antitoxin. Moreover, the RelBE2sca complex, or the antitoxin RelB2sca alone, specifically interacted with the relBE2sca operon and repressed its transcription. The relBE2sca operon transcription was induced under osmotic stress, along with the ClpP proteinase genes. The subsequent in vivo analysis showed that the antitoxin was degraded by ClpP. Interestingly, the E. coli antitoxin RelBeco was able to alleviate the toxicity of S. cattleya RelE2sca while the mutant RelB2sca(N61V&M68L) but not the wild type could alleviate the toxicity of E. coli RelEeco as well. The experimental demonstration of the relBEsca locus might be helpful to investigate the key roles of type II TA systems in Streptomyces physiology and environmental stress responses.
Collapse
|
72
|
Burroughs AM, Aravind L. RNA damage in biological conflicts and the diversity of responding RNA repair systems. Nucleic Acids Res 2016; 44:8525-8555. [PMID: 27536007 PMCID: PMC5062991 DOI: 10.1093/nar/gkw722] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 08/08/2016] [Indexed: 12/16/2022] Open
Abstract
RNA is targeted in biological conflicts by enzymatic toxins or effectors. A vast diversity of systems which repair or ‘heal’ this damage has only recently become apparent. Here, we summarize the known effectors, their modes of action, and RNA targets before surveying the diverse systems which counter this damage from a comparative genomics viewpoint. RNA-repair systems show a modular organization with extensive shuffling and displacement of the constituent domains; however, a general ‘syntax’ is strongly maintained whereby systems typically contain: a RNA ligase (either ATP-grasp or RtcB superfamilies), nucleotidyltransferases, enzymes modifying RNA-termini for ligation (phosphatases and kinases) or protection (methylases), and scaffold or cofactor proteins. We highlight poorly-understood or previously-uncharacterized repair systems and components, e.g. potential scaffolding cofactors (Rot/TROVE and SPFH/Band-7 modules) with their respective cognate non-coding RNAs (YRNAs and a novel tRNA-like molecule) and a novel nucleotidyltransferase associating with diverse ligases. These systems have been extensively disseminated by lateral transfer between distant prokaryotic and microbial eukaryotic lineages consistent with intense inter-organismal conflict. Components have also often been ‘institutionalized’ for non-conflict roles, e.g. in RNA-splicing and in RNAi systems (e.g. in kinetoplastids) which combine a distinct family of RNA-acting prim-pol domains with DICER-like proteins.
Collapse
Affiliation(s)
- A Maxwell Burroughs
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - L Aravind
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| |
Collapse
|
73
|
Schureck MA, Maehigashi T, Miles SJ, Marquez J, Dunham CM. mRNA bound to the 30S subunit is a HigB toxin substrate. RNA (NEW YORK, N.Y.) 2016; 22:1261-70. [PMID: 27307497 PMCID: PMC4931118 DOI: 10.1261/rna.056218.116] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 05/07/2016] [Indexed: 05/22/2023]
Abstract
Activation of bacterial toxins during stress results in cleavage of mRNAs in the context of the ribosome. These toxins are thought to function as global translational inhibitors yet recent studies suggest each may have distinct mRNA specificities that result in selective translation for bacterial survival. Here we demonstrate that mRNA in the context of a bacterial 30S subunit is sufficient for ribosome-dependent toxin HigB endonucleolytic activity, suggesting that HigB interferes with the initiation step of translation. We determined the X-ray crystal structure of HigB bound to the 30S, revealing that two solvent-exposed clusters of HigB basic residues directly interact with 30S 16S rRNA helices 18, 30, and 31. We further show that these HigB residues are essential for ribosome recognition and function. Comparison with other ribosome-dependent toxins RelE and YoeB reveals that each interacts with similar features of the 30S aminoacyl (A) site yet does so through presentation of diverse structural motifs.
Collapse
Affiliation(s)
- Marc A Schureck
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Tatsuya Maehigashi
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Stacey J Miles
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Jhomar Marquez
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Christine M Dunham
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| |
Collapse
|
74
|
Shen Z, Patil RD, Sahin O, Wu Z, Pu XY, Dai L, Plummer PJ, Yaeger MJ, Zhang Q. Identification and functional analysis of two toxin-antitoxin systems in Campylobacter jejuni. Mol Microbiol 2016; 101:909-23. [PMID: 27291507 DOI: 10.1111/mmi.13431] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2016] [Indexed: 01/31/2023]
Abstract
Toxin-antitoxin (TA) systems are widely distributed in bacteria and play an important role in maintaining plasmid stability. The leading foodborne pathogen, Campylobacter jejuni, can carry multiple plasmids associated with antibiotic resistance or virulence. Previously a virulence plasmid named pVir was identified in C. jejuni 81-176 and IA3902, but determining the role of pVir in pathogenesis has been hampered because the plasmid cannot be cured. In this study, we report the identification of two TA systems that are located on the pVir plasmid in 81-176 and IA3902, respectively. The virA (proteic antitoxin)/virT (proteic toxin) pair in IA3902 belongs to a Type II TA system, while the cjrA (RNA antitoxin)/cjpT (proteic toxin) pair in 81-176 belongs to a Type I TA system. Notably, cjrA (antitoxin) represents the first noncoding small RNA demonstrated to play a functional role in Campylobacter physiology to date. By inactivating the TA systems, pVir was readily cured from Campylobacter, indicating their functionality in Campylobacter. Using pVir-cured IA3902, we demonstrated that pVir is not required for abortion induction in the guinea pig model. These findings establish the key role of the TA systems in maintaining plasmid stability and provide a means to evaluate the function of pVir in Campylobacter pathobiology.
Collapse
Affiliation(s)
- Zhangqi Shen
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Rocky D Patil
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Orhan Sahin
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, 50011, USA.,Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Zuowei Wu
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Xiao-Ying Pu
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, 50011, USA.,Microbiology Laboratory, Hangzhou Center for Disease Control and Prevention, Hangzhou, Zhejiang, 310021, China
| | - Lei Dai
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Paul J Plummer
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, 50011, USA.,Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Michael J Yaeger
- Department of Veterinary Pathology, Iowa State University, Ames, IA, 50011, USA
| | - Qijing Zhang
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, 50011, USA.
| |
Collapse
|
75
|
Ero R, Kumar V, Chen Y, Gao YG. Similarity and diversity of translational GTPase factors EF-G, EF4, and BipA: From structure to function. RNA Biol 2016; 13:1258-1273. [PMID: 27325008 PMCID: PMC5207388 DOI: 10.1080/15476286.2016.1201627] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
EF-G, EF4, and BipA are members of the translation factor family of GTPases with a common ribosome binding mode and GTPase activation mechanism. However, topological variations of shared as well as unique domains ensure different roles played by these proteins during translation. Recent X-ray crystallography and cryo-electron microscopy studies have revealed the structural basis for the involvement of EF-G domain IV in securing the movement of tRNAs and mRNA during translocation as well as revealing how the unique C-terminal domains of EF4 and BipA interact with the ribosome and tRNAs contributing to the regulation of translation under certain conditions. EF-G, EF-4, and BipA are intriguing examples of structural variations on a common theme that results in diverse behavior and function. Structural studies of translational GTPase factors have been greatly facilitated by the use of antibiotics, which have revealed their mechanism of action.
Collapse
Affiliation(s)
- Rya Ero
- a School of Biological Sciences , Nanyang Technological University , Singapore
| | - Veerendra Kumar
- a School of Biological Sciences , Nanyang Technological University , Singapore.,b Institute of Molecular and Cell Biology, A*STAR , Singapore
| | - Yun Chen
- a School of Biological Sciences , Nanyang Technological University , Singapore
| | - Yong-Gui Gao
- a School of Biological Sciences , Nanyang Technological University , Singapore.,b Institute of Molecular and Cell Biology, A*STAR , Singapore
| |
Collapse
|
76
|
Wang X, Wood TK. Cryptic prophages as targets for drug development. Drug Resist Updat 2016; 27:30-8. [PMID: 27449596 DOI: 10.1016/j.drup.2016.06.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 05/30/2016] [Accepted: 05/30/2016] [Indexed: 12/20/2022]
Abstract
Bacterial chromosomes may contain up to 20% phage DNA that encodes diverse proteins ranging from those for photosynthesis to those for autoimmunity; hence, phages contribute greatly to the metabolic potential of pathogens. Active prophages carrying genes encoding virulence factors and antibiotic resistance can be excised from the host chromosome to form active phages and are transmissible among different bacterial hosts upon SOS responses. Cryptic prophages are artifacts of mutagenesis in which lysogenic phage are captured in the bacterial chromosome: they may excise but they do not form active phage particles or lyse their captors. Hence, cryptic prophages are relatively permanent reservoirs of genes, many of which benefit pathogens, in ways we are just beginning to discern. Here we explore the role of active prophage- and cryptic prophage-derived proteins in terms of (i) virulence, (ii) antibiotic resistance, and (iii) antibiotic tolerance; antibiotic tolerance occurs as a result of the non-heritable phenotype of dormancy which is a result of activation of toxins of toxin/antitoxin loci that are frequently encoded in cryptic prophages. Therefore, cryptic prophages are promising targets for drug development.
Collapse
Affiliation(s)
- Xiaoxue Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China.
| | - Thomas K Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA 16802-4400, United States; Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802-4400, United States.
| |
Collapse
|
77
|
Coussens NP, Daines DA. Wake me when it's over - Bacterial toxin-antitoxin proteins and induced dormancy. Exp Biol Med (Maywood) 2016; 241:1332-42. [PMID: 27216598 DOI: 10.1177/1535370216651938] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Toxin-antitoxin systems are encoded by bacteria and archaea to enable an immediate response to environmental stresses, including antibiotics and the host immune response. During normal conditions, the antitoxin components prevent toxins from interfering with metabolism and arresting growth; however, toxin activation enables microbes to remain dormant through unfavorable conditions that might continue over millions of years. Intense investigations have revealed a multitude of mechanisms for both regulation and activation of toxin-antitoxin systems, which are abundant in pathogenic microorganisms. This minireview provides an overview of the current knowledge regarding type II toxin-antitoxin systems along with their clinical and environmental implications.
Collapse
Affiliation(s)
- Nathan P Coussens
- Division of Pre-Clinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD 20850, USA
| | - Dayle A Daines
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA
| |
Collapse
|
78
|
Toxin-antitoxin systems in bacterial growth arrest and persistence. Nat Chem Biol 2016; 12:208-14. [DOI: 10.1038/nchembio.2044] [Citation(s) in RCA: 477] [Impact Index Per Article: 59.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 02/09/2016] [Indexed: 02/04/2023]
|
79
|
Sterckx YGJ, Jové T, Shkumatov AV, Garcia-Pino A, Geerts L, De Kerpel M, Lah J, De Greve H, Van Melderen L, Loris R. A unique hetero-hexadecameric architecture displayed by the Escherichia coli O157 PaaA2-ParE2 antitoxin-toxin complex. J Mol Biol 2016; 428:1589-603. [PMID: 26996937 DOI: 10.1016/j.jmb.2016.03.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 03/08/2016] [Accepted: 03/09/2016] [Indexed: 10/24/2022]
Abstract
Many bacterial pathogens modulate their metabolic activity, virulence and pathogenicity through so-called "toxin-antitoxin" (TA) modules. The genome of the human pathogen Escherichia coli O157 contains two three-component TA modules related to the known parDE module. Here, we show that the toxin EcParE2 maps in a branch of the RelE/ParE toxin superfamily that is distinct from the branches that contain verified gyrase and ribosome inhibitors. The structure of EcParE2 closely resembles that of Caulobacter crescentus ParE but shows a distinct pattern of conserved surface residues, in agreement with its apparent inability to interact with GyrA. The antitoxin EcPaaA2 is characterized by two α-helices (H1 and H2) that serve as molecular recognition elements to wrap itself around EcParE2. Both EcPaaA2 H1 and H2 are required to sustain a high-affinity interaction with EcParE2 and for the inhibition of EcParE2-mediated killing in vivo. Furthermore, evidence demonstrates that EcPaaA2 H2, but not H1, determines specificity for EcParE2. The initially formed EcPaaA2-EcParE2 heterodimer then assembles into a hetero-hexadecamer, which is stable in solution and is formed in a highly cooperative manner. Together these findings provide novel data on quaternary structure, TA interactions and activity of a hitherto poorly characterized family of TA modules.
Collapse
Affiliation(s)
- Yann G-J Sterckx
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussel, Belgium; Structural Biology Research Centre, VIB, Pleinlaan 2, B-1050 Brussel, Belgium
| | - Thomas Jové
- Génétique et Physiologie Bactérienne, Faculté des Sciences, Université Libre de Bruxelles (ULB), 12 rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - Alexander V Shkumatov
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussel, Belgium; Structural Biology Research Centre, VIB, Pleinlaan 2, B-1050 Brussel, Belgium
| | - Abel Garcia-Pino
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussel, Belgium; Structural Biology Research Centre, VIB, Pleinlaan 2, B-1050 Brussel, Belgium; Génétique et Physiologie Bactérienne, Faculté des Sciences, Université Libre de Bruxelles (ULB), 12 rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - Lieselotte Geerts
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussel, Belgium
| | - Maia De Kerpel
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussel, Belgium; Structural Biology Research Centre, VIB, Pleinlaan 2, B-1050 Brussel, Belgium
| | - Jurij Lah
- Department of Physical Chemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Henri De Greve
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussel, Belgium; Structural Biology Research Centre, VIB, Pleinlaan 2, B-1050 Brussel, Belgium
| | - Laurence Van Melderen
- Génétique et Physiologie Bactérienne, Faculté des Sciences, Université Libre de Bruxelles (ULB), 12 rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - Remy Loris
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel (VUB), Pleinlaan 2, B-1050 Brussel, Belgium; Structural Biology Research Centre, VIB, Pleinlaan 2, B-1050 Brussel, Belgium.
| |
Collapse
|
80
|
Kirkpatrick CL, Martins D, Redder P, Frandi A, Mignolet J, Chapalay JB, Chambon M, Turcatti G, Viollier PH. Growth control switch by a DNA-damage-inducible toxin-antitoxin system in Caulobacter crescentus. Nat Microbiol 2016; 1:16008. [PMID: 27572440 DOI: 10.1038/nmicrobiol.2016.8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 01/19/2016] [Indexed: 11/09/2022]
Abstract
Bacterial toxin-antitoxin systems (TASs) are thought to respond to various stresses, often inducing growth-arrested (persistent) sub-populations of cells whose housekeeping functions are inhibited. Many such TASs induce this effect through the translation-dependent RNA cleavage (RNase) activity of their toxins, which are held in check by their cognate antitoxins in the absence of stress. However, it is not always clear whether specific mRNA targets of orthologous RNase toxins are responsible for their phenotypic effect, which has made it difficult to accurately place the multitude of TASs within cellular and adaptive regulatory networks. Here, we show that the TAS HigBA of Caulobacter crescentus can promote and inhibit bacterial growth dependent on the dosage of HigB, a toxin regulated by the DNA damage (SOS) repressor LexA in addition to its antitoxin HigA, and the target selectivity of HigB's mRNA cleavage activity. HigB reduced the expression of an efflux pump that is toxic to a polarity control mutant, cripples the growth of cells lacking LexA, and targets the cell cycle circuitry. Thus, TASs can have outcome switching activity in bacterial adaptive (stress) and systemic (cell cycle) networks.
Collapse
Affiliation(s)
- Clare L Kirkpatrick
- Department of Microbiology &Molecular Medicine, Institute of Genetics &Genomics in Geneva (iGE3), Faculty of Medicine/CMU, University of Geneva, Rue Michel-Servet 1, 1211 Genève 4, Switzerland
| | - Daniel Martins
- Department of Microbiology &Molecular Medicine, Institute of Genetics &Genomics in Geneva (iGE3), Faculty of Medicine/CMU, University of Geneva, Rue Michel-Servet 1, 1211 Genève 4, Switzerland
| | - Peter Redder
- Department of Microbiology &Molecular Medicine, Institute of Genetics &Genomics in Geneva (iGE3), Faculty of Medicine/CMU, University of Geneva, Rue Michel-Servet 1, 1211 Genève 4, Switzerland
| | - Antonio Frandi
- Department of Microbiology &Molecular Medicine, Institute of Genetics &Genomics in Geneva (iGE3), Faculty of Medicine/CMU, University of Geneva, Rue Michel-Servet 1, 1211 Genève 4, Switzerland
| | - Johann Mignolet
- Department of Microbiology &Molecular Medicine, Institute of Genetics &Genomics in Geneva (iGE3), Faculty of Medicine/CMU, University of Geneva, Rue Michel-Servet 1, 1211 Genève 4, Switzerland
| | - Julien Bortoli Chapalay
- Biomolecular Screening Facility, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Marc Chambon
- Biomolecular Screening Facility, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Gerardo Turcatti
- Biomolecular Screening Facility, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Patrick H Viollier
- Department of Microbiology &Molecular Medicine, Institute of Genetics &Genomics in Geneva (iGE3), Faculty of Medicine/CMU, University of Geneva, Rue Michel-Servet 1, 1211 Genève 4, Switzerland
| |
Collapse
|
81
|
Dunican BF, Hiller DA, Strobel SA. Transition State Charge Stabilization and Acid-Base Catalysis of mRNA Cleavage by the Endoribonuclease RelE. Biochemistry 2015; 54:7048-57. [PMID: 26535789 DOI: 10.1021/acs.biochem.5b00866] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The bacterial toxin RelE is a ribosome-dependent endoribonuclease. It is part of a type II toxin-antitoxin system that contributes to antibiotic resistance and biofilm formation. During amino acid starvation, RelE cleaves mRNA in the ribosomal A-site, globally inhibiting protein translation. RelE is structurally similar to microbial RNases that employ general acid-base catalysis to facilitate RNA cleavage. The RelE active site is atypical for acid-base catalysis, in that it is enriched with positively charged residues and lacks the prototypical histidine-glutamate catalytic pair, making the mechanism of mRNA cleavage unclear. In this study, we use a single-turnover kinetic analysis to measure the effect of pH and phosphorothioate substitution on the rate constant for cleavage of mRNA by wild-type RelE and seven active-site mutants. Mutation and thio effects indicate a major role for stabilization of increased negative change in the transition state by arginine 61. The wild-type RelE cleavage rate constant is pH-independent, but the reaction catalyzed by many of the mutants is strongly dependent on pH, suggestive of general acid-base catalysis. pH-rate curves indicate that wild-type RelE operates with the pK(a) of at least one catalytic residue significantly downshifted by the local environment. Mutation of any single active-site residue is sufficient to disrupt this microenvironment and revert the shifted pK(a) back above neutrality. pH-rate curves are consistent with K54 functioning as a general base and R81 as a general acid. The capacity of RelE to effect a large pK(a) shift and facilitate a common catalytic mechanism by uncommon means furthers our understanding of other atypical enzymatic active sites.
Collapse
Affiliation(s)
- Brian F Dunican
- Department of Molecular Biophysics and Biochemistry, Yale University , New Haven, Connecticut 06511, United States
| | - David A Hiller
- Department of Molecular Biophysics and Biochemistry, Yale University , New Haven, Connecticut 06511, United States
| | - Scott A Strobel
- Department of Molecular Biophysics and Biochemistry, Yale University , New Haven, Connecticut 06511, United States
| |
Collapse
|
82
|
The Mycobacterium tuberculosis relBE toxin:antitoxin genes are stress-responsive modules that regulate growth through translation inhibition. J Microbiol 2015; 53:783-95. [PMID: 26502963 DOI: 10.1007/s12275-015-5333-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/30/2015] [Accepted: 10/05/2015] [Indexed: 12/11/2022]
Abstract
Toxin-antitoxin (TA) genes are ubiquitous among bacteria and are associated with persistence and dormancy. Following exposure to unfavorable environmental stimuli, several species (Escherichia coli, Staphylococcus aureus, Myxococcus xanthus) employ toxin proteins such as RelE and MazF to downregulate growth or initiate cell death. Mycobacterium tuberculosis possesses three Rel TA modules (Rel Mtb ): RelBE Mtb , RelFG Mtb and RelJK Mtb (Rv1246c-Rv1247c, Rv2865-Rv2866, and Rv3357-Rv3358, respectively), which inhibit mycobacterial growth when the toxin gene (relE, relG, relK) is expressed independently of the antitoxin gene (relB, relF, relJ). In the present study, we examined the in vivo mechanism of the RelE Mtb toxin protein, the impact of RelE Mtb on M. tuberculosis physiology and the environmental conditions that regulate all three rel Mtb modules. RelE Mtb negatively impacts growth and the structural integrity of the mycobacterial envelope, generating cells with aberrant forms that are prone to extensive aggregation. At a time coincident with growth defects, RelE Mtb mediates mRNA degradation in vivo resulting in significant changes to the proteome. We establish that rel Mtb modules are stress responsive, as all three operons are transcriptionally activated following mycobacterial exposure to oxidative stress or nitrogen-limiting growth environments. Here we present evidence that the rel Mtb toxin:antitoxin family is stress-responsive and, through the degradation of mRNA, the RelE Mtb toxin influences the growth, proteome and morphology of mycobacterial cells.
Collapse
|
83
|
Defining the mRNA recognition signature of a bacterial toxin protein. Proc Natl Acad Sci U S A 2015; 112:13862-7. [PMID: 26508639 DOI: 10.1073/pnas.1512959112] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacteria contain multiple type II toxins that selectively degrade mRNAs bound to the ribosome to regulate translation and growth and facilitate survival during the stringent response. Ribosome-dependent toxins recognize a variety of three-nucleotide codons within the aminoacyl (A) site, but how these endonucleases achieve substrate specificity remains poorly understood. Here, we identify the critical features for how the host inhibition of growth B (HigB) toxin recognizes each of the three A-site nucleotides for cleavage. X-ray crystal structures of HigB bound to two different codons on the ribosome illustrate how HigB uses a microbial RNase-like nucleotide recognition loop to recognize either cytosine or adenosine at the second A-site position. Strikingly, a single HigB residue and 16S rRNA residue C1054 form an adenosine-specific pocket at the third A-site nucleotide, in contrast to how tRNAs decode mRNA. Our results demonstrate that the most important determinant for mRNA cleavage by ribosome-dependent toxins is interaction with the third A-site nucleotide.
Collapse
|
84
|
Averina O, Alekseeva M, Shkoporov A, Danilenko V. Functional analysis of the type II toxin–antitoxin systems of the MazEF and RelBE families in Bifidobacterium longum subsp. infantis ATCC 15697. Anaerobe 2015. [DOI: 10.1016/j.anaerobe.2015.07.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
85
|
Maehigashi T, Ruangprasert A, Miles SJ, Dunham CM. Molecular basis of ribosome recognition and mRNA hydrolysis by the E. coli YafQ toxin. Nucleic Acids Res 2015; 43:8002-12. [PMID: 26261214 PMCID: PMC4652777 DOI: 10.1093/nar/gkv791] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 07/22/2015] [Indexed: 01/30/2023] Open
Abstract
Bacterial type II toxin-antitoxin modules are protein–protein complexes whose functions are finely tuned by rapidly changing environmental conditions. E. coli toxin YafQ is suppressed under steady state growth conditions by virtue of its interaction with its cognate antitoxin, DinJ. During stress, DinJ is proteolytically degraded and free YafQ halts translation by degrading ribosome-bound mRNA to slow growth until the stress has passed. Although structures of the ribosome with toxins RelE and YoeB have been solved, it is unclear what residues among ribosome-dependent toxins are essential for mediating both recognition of the ribosome and the mRNA substrate given their low sequence identities. Here we show that YafQ coordinates binding to the 70S ribosome via three surface-exposed patches of basic residues that we propose directly interact with 16S rRNA. We demonstrate that YafQ residues H50, H63, D67 and H87 participate in acid-base catalysis during mRNA hydrolysis and further show that H50 and H63 functionally complement as general bases to initiate the phosphodiester cleavage reaction. Moreover YafQ residue F91 likely plays an important role in mRNA positioning. In summary, our findings demonstrate the plasticity of ribosome-dependent toxin active site residues and further our understanding of which toxin residues are important for function.
Collapse
Affiliation(s)
- Tatsuya Maehigashi
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | | | - Stacey J Miles
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Christine M Dunham
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| |
Collapse
|
86
|
Yao J, Guo Y, Zeng Z, Liu X, Shi F, Wang X. Identification and characterization of a HEPN-MNT family type II toxin-antitoxin in Shewanella oneidensis. Microb Biotechnol 2015; 8:961-73. [PMID: 26112399 PMCID: PMC4621449 DOI: 10.1111/1751-7915.12294] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 04/20/2015] [Accepted: 05/02/2015] [Indexed: 11/30/2022] Open
Abstract
Toxin-antitoxin (TA) systems are prevalent in bacteria and archaea. However, related studies in the ecologically and bioelectrochemically important strain Shewanella oneidensis are limited. Here, we show that SO_3166, a member of the higher eukaryotes and prokaryotes nucleotide-binding (HEPN) superfamily, strongly inhibited cell growth in S. oneidensis and Escherichia coli. SO_3165, a putative minimal nucleotidyltransferase (MNT), neutralized the toxicity of SO_3166. Gene SO_3165 lies upstream of SO_3166, and they are co-transcribed. Moreover, the SO_3165 and SO_3166 proteins interact with each other directly in vivo, and antitoxin SO_3165 bound to the promoter of the TA operon and repressed its activity. Finally, the conserved Rx4-6H domain in HEPN family was identified in SO_3166. Mutating either the R or H abolished SO_3166 toxicity, confirming that Rx4-6H domain is critical for SO_3166 activity. Taken together, these results demonstrate that SO_3166 and SO_3165 in S. oneidensis form a typical type II TA pair. This TA pair plays a critical role in regulating bacterial functions because its disruption led to impaired cell motility in S. oneidensis. Thus, we demonstrated for the first time that HEPN-MNT can function as a TA system, thereby providing important insights into the understanding of the function and regulation of HEPNs and MNTs in prokaryotes.
Collapse
Affiliation(s)
- Jianyun Yao
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yunxue Guo
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Zhenshun Zeng
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaoxiao Liu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Fei Shi
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Xiaoxue Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
| |
Collapse
|
87
|
Response to the Formal Letter of Z. Chrzanowska-Lightowlers and R. N. Lightowlers Regarding Our Article "Ribosome Rescue and Translation Termination at Non-Standard Stop Codons by ICT1 in Mammalian Mitochondria". PLoS Genet 2015; 11:e1005218. [PMID: 26087150 PMCID: PMC4472662 DOI: 10.1371/journal.pgen.1005218] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 04/13/2015] [Indexed: 11/18/2022] Open
|
88
|
Wang P, Selvadurai K, Huang RH. Reconstitution and structure of a bacterial Pnkp1-Rnl-Hen1 RNA repair complex. Nat Commun 2015; 6:6876. [PMID: 25882814 PMCID: PMC4411300 DOI: 10.1038/ncomms7876] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 03/08/2015] [Indexed: 01/12/2023] Open
Abstract
Ribotoxins cleave essential RNAs for cell killing, and RNA repair neutralizes the damage inflicted by ribotoxins for cell survival. Here we report a new bacterial RNA repair complex that performs RNA repair linked to immunity. This new RNA repair complex is a 270-kDa heterohexamer composed of three proteins-Pnkp1, Rnl and Hen1-that are required to repair ribotoxin-cleaved RNA in vitro. The crystal structure of the complex reveals the molecular architecture of the heterohexamer as two rhomboid-shaped ring structures of Pnkp1-Rnl-Hen1 heterotrimer fused at the Pnkp1 dimer interface. The four active sites required for RNA repair are located on the inner rim of each ring. The architecture and the locations of the active sites of the Pnkp1-Rnl-Hen1 heterohexamer suggest an ordered series of repair reactions at the broken RNA ends that confer immunity to recurrent damage.
Collapse
Affiliation(s)
- Pei Wang
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Kiruthika Selvadurai
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Raven H. Huang
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| |
Collapse
|
89
|
Boulouis A, Drapier D, Razafimanantsoa H, Wostrikoff K, Tourasse NJ, Pascal K, Girard-Bascou J, Vallon O, Wollman FA, Choquet Y. Spontaneous dominant mutations in chlamydomonas highlight ongoing evolution by gene diversification. THE PLANT CELL 2015; 27:984-1001. [PMID: 25804537 PMCID: PMC4558696 DOI: 10.1105/tpc.15.00010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 02/10/2015] [Accepted: 03/05/2015] [Indexed: 05/04/2023]
Abstract
We characterized two spontaneous and dominant nuclear mutations in the unicellular alga Chlamydomonas reinhardtii, ncc1 and ncc2 (for nuclear control of chloroplast gene expression), which affect two octotricopeptide repeat (OPR) proteins encoded in a cluster of paralogous genes on chromosome 15. Both mutations cause a single amino acid substitution in one OPR repeat. As a result, the mutated NCC1 and NCC2 proteins now recognize new targets that we identified in the coding sequences of the chloroplast atpA and petA genes, respectively. Interaction of the mutated proteins with these targets leads to transcript degradation; however, in contrast to the ncc1 mutation, the ncc2 mutation requires on-going translation to promote the decay of the petA mRNA. Thus, these mutants reveal a mechanism by which nuclear factors act on chloroplast mRNAs in Chlamydomonas. They illustrate how diversifying selection can allow cells to adapt the nuclear control of organelle gene expression to environmental changes. We discuss these data in the wider context of the evolution of regulation by helical repeat proteins.
Collapse
Affiliation(s)
- Alix Boulouis
- Unité Mixte de Recherche 7141, CNRS/UPMC, Institut de Biologie Physico-Chimique, F-75005 Paris, France
| | - Dominique Drapier
- Unité Mixte de Recherche 7141, CNRS/UPMC, Institut de Biologie Physico-Chimique, F-75005 Paris, France
| | - Hélène Razafimanantsoa
- Unité Mixte de Recherche 7141, CNRS/UPMC, Institut de Biologie Physico-Chimique, F-75005 Paris, France
| | - Katia Wostrikoff
- Unité Mixte de Recherche 7141, CNRS/UPMC, Institut de Biologie Physico-Chimique, F-75005 Paris, France
| | - Nicolas J Tourasse
- Unité Mixte de Recherche 7141, CNRS/UPMC, Institut de Biologie Physico-Chimique, F-75005 Paris, France
| | - Kevin Pascal
- Unité Mixte de Recherche 7141, CNRS/UPMC, Institut de Biologie Physico-Chimique, F-75005 Paris, France
| | - Jacqueline Girard-Bascou
- Unité Mixte de Recherche 7141, CNRS/UPMC, Institut de Biologie Physico-Chimique, F-75005 Paris, France
| | - Olivier Vallon
- Unité Mixte de Recherche 7141, CNRS/UPMC, Institut de Biologie Physico-Chimique, F-75005 Paris, France
| | - Francis-André Wollman
- Unité Mixte de Recherche 7141, CNRS/UPMC, Institut de Biologie Physico-Chimique, F-75005 Paris, France
| | - Yves Choquet
- Unité Mixte de Recherche 7141, CNRS/UPMC, Institut de Biologie Physico-Chimique, F-75005 Paris, France
| |
Collapse
|
90
|
Sterckx YGJ, De Gieter S, Zorzini V, Hadži S, Haesaerts S, Loris R, Garcia-Pino A. An efficient method for the purification of proteins from four distinct toxin–antitoxin modules. Protein Expr Purif 2015; 108:30-40. [DOI: 10.1016/j.pep.2015.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 12/27/2014] [Accepted: 01/04/2015] [Indexed: 11/24/2022]
|
91
|
Brantl S, Jahn N. sRNAs in bacterial type I and type III toxin-antitoxin systems. FEMS Microbiol Rev 2015; 39:413-27. [PMID: 25808661 DOI: 10.1093/femsre/fuv003] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/20/2015] [Indexed: 01/17/2023] Open
Abstract
Toxin-antitoxin (TA) loci consist of two genes: a stable toxin whose overexpression kills the cell or causes growth stasis and an unstable antitoxin that neutralizes the toxin action. Currently, five TA systems are known. Here, we review type I and type III systems in which the antitoxins are regulatory RNAs. Type I antitoxins act by a base-pairing mechanism on toxin mRNAs. By contrast, type III antitoxins are RNA pseudoknots that bind their cognate toxins directly in an RNA-protein interaction. Whereas for a number of plasmid-encoded systems detailed information on structural requirements, kinetics of interaction with their targets and regulatory mechanisms employed by the antitoxin RNAs is available, the investigation of chromosomal systems is still in its infancy. Here, we summarize our current knowledge on that topic. Furthermore, we compare factors and conditions that induce antitoxins or toxins and different mechanisms of toxin action. Finally, we discuss biological roles for chromosome-encoded TA systems.
Collapse
Affiliation(s)
- Sabine Brantl
- AG Bakteriengenetik, Lehrstuhl für Genetik, Friedrich-Schiller-Universität Jena, Philosophenweg 12, D-07743 Jena, Germany
| | - Natalie Jahn
- AG Bakteriengenetik, Lehrstuhl für Genetik, Friedrich-Schiller-Universität Jena, Philosophenweg 12, D-07743 Jena, Germany
| |
Collapse
|
92
|
Susorov D, Mikhailova T, Ivanov A, Sokolova E, Alkalaeva E. Stabilization of eukaryotic ribosomal termination complexes by deacylated tRNA. Nucleic Acids Res 2015; 43:3332-43. [PMID: 25753665 PMCID: PMC4381076 DOI: 10.1093/nar/gkv171] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 02/21/2015] [Indexed: 01/12/2023] Open
Abstract
Stabilization of the ribosomal complexes plays an important role in translational control. Mechanisms of ribosome stabilization have been studied in detail for initiation and elongation of eukaryotic translation, but almost nothing is known about stabilization of eukaryotic termination ribosomal complexes. Here, we present one of the mechanisms of fine-tuning of the translation termination process in eukaryotes. We show that certain deacylated tRNAs, remaining in the E site of the ribosome at the end of the elongation cycle, increase the stability of the termination and posttermination complexes. Moreover, only the part of eRF1 recognizing the stop codon is stabilized in the A site of the ribosome, and the stabilization is not dependent on the hydrolysis of peptidyl-tRNA. The determinants, defining this property of the tRNA, reside in the acceptor stem. It was demonstrated by site-directed mutagenesis of tRNAVal and construction of a mini-helix structure identical to the acceptor stem of tRNA. The mechanism of this stabilization is different from the fixation of the unrotated state of the ribosome by CCA end of tRNA or by cycloheximide in the E site. Our data allow to reveal the possible functions of the isodecoder tRNAs in eukaryotes.
Collapse
Affiliation(s)
- Denis Susorov
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia Faculty of Bioengineering and Bioinformatics, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
| | - Tatiana Mikhailova
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Alexander Ivanov
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia Faculty of Bioengineering and Bioinformatics, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
| | - Elizaveta Sokolova
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia
| | - Elena Alkalaeva
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, 119991 Moscow, Russia
| |
Collapse
|
93
|
Cut to the chase--Regulating translation through RNA cleavage. Biochimie 2015; 114:10-7. [PMID: 25633441 DOI: 10.1016/j.biochi.2015.01.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 01/19/2015] [Indexed: 11/23/2022]
Abstract
Activation of toxin-antitoxin (TA) systems provides an important mechanism for bacteria to adapt to challenging and ever changing environmental conditions. Known TA systems are classified into five families based on the mechanisms of antitoxin inhibition and toxin activity. For type II TA systems, the toxin is inactivated in exponentially growing cells by tightly binding its antitoxin partner protein, which also serves to regulate cellular levels of the complex through transcriptional auto-repression. During cellular stress, however, the antitoxin is degraded thus freeing the toxin, which is then able to regulate central cellular processes, primarily protein translation to adjust cell growth to the new conditions. In this review, we focus on the type II TA pairs that regulate protein translation through cleavage of ribosomal, transfer, or messenger RNA.
Collapse
|
94
|
De Gieter S, Konijnenberg A, Talavera A, Butterer A, Haesaerts S, De Greve H, Sobott F, Loris R, Garcia-Pino A. The intrinsically disordered domain of the antitoxin Phd chaperones the toxin Doc against irreversible inactivation and misfolding. J Biol Chem 2014; 289:34013-23. [PMID: 25326388 PMCID: PMC4256337 DOI: 10.1074/jbc.m114.572396] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 10/16/2014] [Indexed: 11/06/2022] Open
Abstract
The toxin Doc from the phd/doc toxin-antitoxin module targets the cellular translation machinery and is inhibited by its antitoxin partner Phd. Here we show that Phd also functions as a chaperone, keeping Doc in an active, correctly folded conformation. In the absence of Phd, Doc exists in a relatively expanded state that is prone to dimerization through domain swapping with its active site loop acting as hinge region. The domain-swapped dimer is not capable of arresting protein synthesis in vitro, whereas the Doc monomer is. Upon binding to Phd, Doc becomes more compact and is secured in its monomeric state with a neutralized active site.
Collapse
Affiliation(s)
- Steven De Gieter
- From Structural Biology Brussels, Department of Biotechnology (DBIT), Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium, Molecular Recognition Unit (MoRe)
| | - Albert Konijnenberg
- Biomolecular and Analytical Mass Spectrometry group, Department of Chemistry and
| | - Ariel Talavera
- From Structural Biology Brussels, Department of Biotechnology (DBIT), Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium, Molecular Recognition Unit (MoRe)
| | - Annika Butterer
- Biomolecular and Analytical Mass Spectrometry group, Department of Chemistry and
| | - Sarah Haesaerts
- From Structural Biology Brussels, Department of Biotechnology (DBIT), Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium, Molecular Recognition Unit (MoRe)
| | - Henri De Greve
- From Structural Biology Brussels, Department of Biotechnology (DBIT), Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium, Structural Biology Research Center, Vlaams Instituut voor Biotechnologie (VIB), Pleinlaan 2, B-1050 Brussels, Belgium, and
| | - Frank Sobott
- Biomolecular and Analytical Mass Spectrometry group, Department of Chemistry and Center for Proteomics (CFP-CeProMa), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
| | - Remy Loris
- From Structural Biology Brussels, Department of Biotechnology (DBIT), Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium, Molecular Recognition Unit (MoRe)
| | - Abel Garcia-Pino
- From Structural Biology Brussels, Department of Biotechnology (DBIT), Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium, Molecular Recognition Unit (MoRe),
| |
Collapse
|
95
|
Guglielmini J, Van Melderen L. Bacterial toxin-antitoxin systems: Translation inhibitors everywhere. Mob Genet Elements 2014; 1:283-290. [PMID: 22545240 PMCID: PMC3337138 DOI: 10.4161/mge.18477] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Toxin-antitoxin (TA) systems are composed of two elements: a toxic protein and an antitoxin which is either an RNA (type I and III) or a protein (type II). Type II systems are abundant in bacterial genomes in which they move via horizontal gene transfer. They are generally composed of two genes organized in an operon, encoding a toxin and a labile antitoxin. When carried by mobile genetic elements, these small modules contribute to their stability by a phenomenon denoted as addiction. Recently, we developed a bioinformatics procedure that, along with experimental validation, allowed the identification of nine novel toxin super-families. Here, considering that some toxin super-families exhibit dramatic sequence diversity but similar structure, bioinformatics tools were used to predict tertiary structures of novel toxins. Seven of the nine novel super-families did not show any structural homology with known toxins, indicating that combination of sequence similarity and three-dimensional structure prediction allows a consistent classification. Interestingly, the novel super-families are translation inhibitors similar to the majority of known toxins indicating that this activity might have been selected rather than more detrimental traits such as DNA-gyrase inhibitors, which are very toxic for cells.
Collapse
|
96
|
Starosta AL, Lassak J, Jung K, Wilson DN. The bacterial translation stress response. FEMS Microbiol Rev 2014; 38:1172-201. [PMID: 25135187 DOI: 10.1111/1574-6976.12083] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 07/18/2014] [Accepted: 08/07/2014] [Indexed: 11/30/2022] Open
Abstract
Throughout their life, bacteria need to sense and respond to environmental stress. Thus, such stress responses can require dramatic cellular reprogramming, both at the transcriptional as well as the translational level. This review focuses on the protein factors that interact with the bacterial translational apparatus to respond to and cope with different types of environmental stress. For example, the stringent factor RelA interacts with the ribosome to generate ppGpp under nutrient deprivation, whereas a variety of factors have been identified that bind to the ribosome under unfavorable growth conditions to shut-down (RelE, pY, RMF, HPF and EttA) or re-program (MazF, EF4 and BipA) translation. Additional factors have been identified that rescue ribosomes stalled due to stress-induced mRNA truncation (tmRNA, ArfA, ArfB), translation of unfavorable protein sequences (EF-P), heat shock-induced subunit dissociation (Hsp15), or antibiotic inhibition (TetM, FusB). Understanding the mechanism of how the bacterial cell responds to stress will not only provide fundamental insight into translation regulation, but will also be an important step to identifying new targets for the development of novel antimicrobial agents.
Collapse
Affiliation(s)
- Agata L Starosta
- Gene Center, Department for Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany; Center for integrated Protein Science Munich (CiPSM), Ludwig-Maximilians-Universität München, Munich, Germany
| | | | | | | |
Collapse
|
97
|
Sterckx YGJ, Haesaerts S, Van Melderen L, Loris R. Crystallization and preliminary X-ray analysis of two variants of the Escherichia coli O157 ParE2-PaaA2 toxin-antitoxin complex. Acta Crystallogr F Struct Biol Commun 2014; 70:1284-91. [PMID: 25195911 PMCID: PMC4157438 DOI: 10.1107/s2053230x1401749x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 07/30/2014] [Indexed: 11/11/2022] Open
Abstract
The paaR2-paaA2-parE2 operon is a three-component toxin-antitoxin module encoded in the genome of the human pathogen Escherichia coli O157. The toxin (ParE2) and antitoxin (PaaA2) interact to form a nontoxic toxin-antitoxin complex. In this paper, the crystallization and preliminary characterization of two variants of the ParE2-PaaA2 toxin-antitoxin complex are described. Selenomethionine-derivative crystals of the full-length ParE2-PaaA2 toxin-antitoxin complex diffracted to 2.8 Å resolution and belonged to space group P41212 (or P43212), with unit-cell parameters a = b = 90.5, c = 412.3 Å. It was previously reported that the full-length ParE2-PaaA2 toxin-antitoxin complex forms a higher-order oligomer. In contrast, ParE2 and PaaA213-63, a truncated form of PaaA2 in which the first 12 N-terminal residues of the antitoxin have been deleted, form a heterodimer as shown by analytical gel filtration, dynamic light scattering and small-angle X-ray scattering. Crystals of the PaaA213-63-ParE2 complex diffracted to 2.7 Å resolution and belonged to space group P6122 (or P6522), with unit-cell parameters a = b = 91.6, c = 185.6 Å.
Collapse
Affiliation(s)
- Yann G. J. Sterckx
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium
- Structural Biology Research Center, VIB, Pleinlaan 2, B-1050 Brussel, Belgium
| | - Sarah Haesaerts
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium
- Structural Biology Research Center, VIB, Pleinlaan 2, B-1050 Brussel, Belgium
| | - Laurence Van Melderen
- Génétique et Physiologie Bactérienne, IBMM, Université Libre de Bruxelles (ULB), 12 Rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - Remy Loris
- Structural Biology Brussels, Department of Biotechnology, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium
- Structural Biology Research Center, VIB, Pleinlaan 2, B-1050 Brussel, Belgium
| |
Collapse
|
98
|
Xu W, Deng R, Wang L, Li J. Multiresponsive Rolling Circle Amplification for DNA Logic Gates Mediated by Endonuclease. Anal Chem 2014; 86:7813-8. [DOI: 10.1021/ac501726s] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Weidong Xu
- Department
of Chemistry,
Beijing Key Laboratory for Analytical Methods and Instrumentation, Tsinghua University, Beijing 100084, China
| | - Ruijie Deng
- Department
of Chemistry,
Beijing Key Laboratory for Analytical Methods and Instrumentation, Tsinghua University, Beijing 100084, China
| | - Lida Wang
- Department
of Chemistry,
Beijing Key Laboratory for Analytical Methods and Instrumentation, Tsinghua University, Beijing 100084, China
| | - Jinghong Li
- Department
of Chemistry,
Beijing Key Laboratory for Analytical Methods and Instrumentation, Tsinghua University, Beijing 100084, China
| |
Collapse
|
99
|
Liang Y, Gao Z, Wang F, Zhang Y, Dong Y, Liu Q. Structural and functional characterization of Escherichia coli toxin-antitoxin complex DinJ-YafQ. J Biol Chem 2014; 289:21191-202. [PMID: 24923448 DOI: 10.1074/jbc.m114.559773] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Toxin YafQ functions as a ribonuclease in the dinJ-yafQ toxin-antitoxin system of Escherichia coli. Antitoxin DinJ neutralizes YafQ-mediated toxicity by forming a stable protein complex. Here, crystal structures of the (DinJ)2-(YafQ)2 complex and the isolated YafQ toxin have been determined. The structure of the heterotetrameric complex (DinJ)2-(YafQ)2 revealed that the N-terminal region of DinJ folds into a ribbon-helix-helix motif and dimerizes for DNA recognition, and the C-terminal portion of each DinJ exclusively wraps around a YafQ molecule. Upon incorporation into the heterotetrameric complex, a conformational change of YafQ in close proximity to the catalytic site of the typical microbial ribonuclease fold was observed and validated. Mutagenesis experiments revealed that a DinJ mutant restored YafQ RNase activity in a tetramer complex in vitro but not in vivo. An electrophoretic mobility shift assay showed that one of the palindromic sequences present in the upstream intergenic region of DinJ served as a binding sequences for both the DinJ-YafQ complex and the antitoxin DinJ alone. Based on structure-guided and site-directed mutagenesis of DinJ-YafQ, we showed that two pairs of amino acids in DinJ were important for DNA binding; the R8A and K16A substitutions and the S31A and R35A substitutions in DinJ abolished the DNA binding ability of the DinJ-YafQ complex.
Collapse
Affiliation(s)
- Yajing Liang
- From the School of Life Sciences, University of Science and Technology of China, Hefei, Anhui Province 230027, China, the Multidiscipline Research Center, Institute of High Energy Physics of the Chinese Academy of Sciences, 19B Yuequan Road, Beijing 100049, China, and
| | - Zengqiang Gao
- the Multidiscipline Research Center, Institute of High Energy Physics of the Chinese Academy of Sciences, 19B Yuequan Road, Beijing 100049, China, and
| | - Fei Wang
- the Multidiscipline Research Center, Institute of High Energy Physics of the Chinese Academy of Sciences, 19B Yuequan Road, Beijing 100049, China, and
| | - Yangli Zhang
- the Key Laboratory of Molecular Biology on Infectious Disease, Chongqing Medical University, YiXueYuanlu-1, Chongqing 400016, China
| | - Yuhui Dong
- the Multidiscipline Research Center, Institute of High Energy Physics of the Chinese Academy of Sciences, 19B Yuequan Road, Beijing 100049, China, and
| | - Quansheng Liu
- the Multidiscipline Research Center, Institute of High Energy Physics of the Chinese Academy of Sciences, 19B Yuequan Road, Beijing 100049, China, and
| |
Collapse
|
100
|
Zorzini V, Buts L, Sleutel M, Garcia-Pino A, Talavera A, Haesaerts S, De Greve H, Cheung A, van Nuland NAJ, Loris R. Structural and biophysical characterization of Staphylococcus aureus SaMazF shows conservation of functional dynamics. Nucleic Acids Res 2014; 42:6709-25. [PMID: 24748664 PMCID: PMC4041440 DOI: 10.1093/nar/gku266] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 03/18/2014] [Accepted: 03/19/2014] [Indexed: 01/19/2023] Open
Abstract
The Staphylococcus aureus genome contains three toxin-antitoxin modules, including one mazEF module, SamazEF. Using an on-column separation protocol we are able to obtain large amounts of wild-type SaMazF toxin. The protein is well-folded and highly resistant against thermal unfolding but aggregates at elevated temperatures. Crystallographic and nuclear magnetic resonance (NMR) solution studies show a well-defined dimer. Differences in structure and dynamics between the X-ray and NMR structural ensembles are found in three loop regions, two of which undergo motions that are of functional relevance. The same segments also show functionally relevant dynamics in the distantly related CcdB family despite divergence of function. NMR chemical shift mapping and analysis of residue conservation in the MazF family suggests a conserved mode for the inhibition of MazF by MazE.
Collapse
Affiliation(s)
- Valentina Zorzini
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Molecular Recognition Unit, Department of Structural Biology, VIB, Pleinlaan 2, 1050 Brussels, Belgium
| | - Lieven Buts
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Molecular Recognition Unit, Department of Structural Biology, VIB, Pleinlaan 2, 1050 Brussels, Belgium
| | - Mike Sleutel
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Abel Garcia-Pino
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Molecular Recognition Unit, Department of Structural Biology, VIB, Pleinlaan 2, 1050 Brussels, Belgium
| | - Ariel Talavera
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Molecular Recognition Unit, Department of Structural Biology, VIB, Pleinlaan 2, 1050 Brussels, Belgium
| | - Sarah Haesaerts
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Molecular Recognition Unit, Department of Structural Biology, VIB, Pleinlaan 2, 1050 Brussels, Belgium
| | - Henri De Greve
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Molecular Recognition Unit, Department of Structural Biology, VIB, Pleinlaan 2, 1050 Brussels, Belgium
| | - Ambrose Cheung
- Department of Microbiology and Immunology, Dartmouth Medical School, Hanover, NH 03755, USA
| | - Nico A J van Nuland
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Molecular Recognition Unit, Department of Structural Biology, VIB, Pleinlaan 2, 1050 Brussels, Belgium
| | - Remy Loris
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Molecular Recognition Unit, Department of Structural Biology, VIB, Pleinlaan 2, 1050 Brussels, Belgium
| |
Collapse
|