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Zegarra V, Mais CN, Freitag J, Bange G. The mysterious diadenosine tetraphosphate (AP4A). MICROLIFE 2023; 4:uqad016. [PMID: 37223742 PMCID: PMC10148737 DOI: 10.1093/femsml/uqad016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 03/15/2023] [Accepted: 04/21/2023] [Indexed: 05/25/2023]
Abstract
Dinucleoside polyphosphates, a class of nucleotides found amongst all the Trees of Life, have been gathering a lot of attention in the past decades due to their putative role as cellular alarmones. In particular, diadenosine tetraphosphate (AP4A) has been widely studied in bacteria facing various environmental challenges and has been proposed to be important for ensuring cellular survivability through harsh conditions. Here, we discuss the current understanding of AP4A synthesis and degradation, protein targets, their molecular structure where possible, and insights into the molecular mechanisms of AP4A action and its physiological consequences. Lastly, we will briefly touch on what is known with regards to AP4A beyond the bacterial kingdom, given its increasing appearance in the eukaryotic world. Altogether, the notion that AP4A is a conserved second messenger in organisms ranging from bacteria to humans and is able to signal and modulate cellular stress regulation seems promising.
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Affiliation(s)
- Victor Zegarra
- Department of Chemistry and Center for Synthetic Microbiology, Philipps University Marburg, Marburg 35043, Germany
| | - Christopher-Nils Mais
- Department of Chemistry and Center for Synthetic Microbiology, Philipps University Marburg, Marburg 35043, Germany
| | - Johannes Freitag
- Department of Biology, Philipps University Marburg, Marburg 35043, Germany
| | - Gert Bange
- Corresponding author. Karl-von-Frisch Strasse 14, 35043 Marburg, Germany. E-mail:
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2
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Pinatel E, Calcagnile M, Talà A, Damiano F, Siculella L, Peano C, De Benedetto GE, Pennetta A, De Bellis G, Alifano P. Interplay between non-coding RNA transcription, stringent phenotype and antibiotic production in Streptomyces. J Biotechnol 2022:S0168-1656(22)00029-3. [PMID: 35182607 DOI: 10.1016/j.jbiotec.2022.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 02/12/2022] [Indexed: 11/26/2022]
Abstract
While in recent years the key role of non-coding RNAs (ncRNAs) in regulation of gene expression has become increasingly evident, their interaction with the global regulatory circuits is still obscure. Here we analyzed the structure and organization of the transcriptome of Streptomyces ambofaciens, the producer of spiramycin. We identified ncRNAs including 45 small-RNAs (sRNAs) and 119 antisense-RNAs (asRNAs I) that appear transcribed from dedicated promoters. Some sRNAs and asRNAs are unprecedented in Streptomyces, and were predicted to target mRNAs encoding proteins involved in transcription, translation, ribosomal structure and biogenesis, and regulation of morphological and biochemical differentiation. We then compared ncRNA expression in three strains: i.) the wild type strain; ii.) an isogenic pirA-defective mutant with central carbon metabolism imbalance, "relaxed" phenotype, and repression of antibiotic production; iii.) a pirA-derivative strain harboring a "stringent" RNA polymerase that suppresses pirA-associated phenotypes. Data indicated that expression of most ncRNAs was correlated to the stringent/relaxed phenotype suggesting novel effector mechanisms of the stringent response.
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Affiliation(s)
- Eva Pinatel
- Institute of Biomedical Technologies, National Research Council, Segrate, Milan, Italy
| | - Matteo Calcagnile
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Monteroni, 73100 Lecce, Italy
| | - Adelfia Talà
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Monteroni, 73100 Lecce, Italy
| | - Fabrizio Damiano
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Monteroni, 73100 Lecce, Italy
| | - Luisa Siculella
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Monteroni, 73100 Lecce, Italy
| | - Clelia Peano
- Genomic Unit, IRCCS Humanitas Clinical and Research Center, Rozzano, Milan, Italy; Institute of Genetic and Biomedical Research, UoS of Milan, National Research Council, Rozzano, Milan, Italy
| | | | - Antonio Pennetta
- Department of Cultural Heritage, University of Salento, Via Monteroni, 73100 Lecce, Italy
| | - Gianluca De Bellis
- Institute of Biomedical Technologies, National Research Council, Segrate, Milan, Italy
| | - Pietro Alifano
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Monteroni, 73100 Lecce, Italy.
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3
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Interplay between Non-Coding RNA Transcription, Stringent/Relaxed Phenotype and Antibiotic Production in Streptomyces ambofaciens. Antibiotics (Basel) 2021; 10:antibiotics10080947. [PMID: 34438997 PMCID: PMC8388888 DOI: 10.3390/antibiotics10080947] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 07/28/2021] [Accepted: 08/02/2021] [Indexed: 11/25/2022] Open
Abstract
While in recent years the key role of non-coding RNAs (ncRNAs) in the regulation of gene expression has become increasingly evident, their interaction with the global regulatory circuits is still obscure. Here we analyzed the structure and organization of the transcriptome of Streptomyces ambofaciens, the producer of spiramycin. We identified ncRNAs including 45 small-RNAs (sRNAs) and 119 antisense-RNAs (asRNAs I) that appear transcribed from dedicated promoters. Some sRNAs and asRNAs are unprecedented in Streptomyces and were predicted to target mRNAs encoding proteins involved in transcription, translation, ribosomal structure and biogenesis, and regulation of morphological and biochemical differentiation. We then compared ncRNA expression in three strains: (i) the wild-type strain; (ii) an isogenic pirA-defective mutant with central carbon metabolism imbalance, “relaxed” phenotype, and repression of antibiotic production; and (iii) a pirA-derivative strain harboring a “stringent” RNA polymerase that suppresses pirA-associated phenotypes. Data indicated that the expression of most ncRNAs was correlated to the stringent/relaxed phenotype suggesting novel effector mechanisms of the stringent response.
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4
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Blaschke U, Skiebe E, Wilharm G. Novel Genes Required for Surface-Associated Motility in Acinetobacter baumannii. Curr Microbiol 2021; 78:1509-1528. [PMID: 33666749 PMCID: PMC7997844 DOI: 10.1007/s00284-021-02407-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 02/10/2021] [Indexed: 01/28/2023]
Abstract
Acinetobacter baumannii is an opportunistic and increasingly multi-drug resistant human pathogen rated as a critical priority one pathogen for the development of new antibiotics by the WHO in 2017. Despite the lack of flagella, A. baumannii can move along wet surfaces in two different ways: via twitching motility and surface-associated motility. While twitching motility is known to depend on type IV pili, the mechanism of surface-associated motility is poorly understood. In this study, we established a library of 30 A. baumannii ATCC® 17978™ mutants that displayed deficiency in surface-associated motility. By making use of natural competence, we also introduced these mutations into strain 29D2 to differentiate strain-specific versus species-specific effects of mutations. Mutated genes were associated with purine/pyrimidine/folate biosynthesis (e.g. purH, purF, purM, purE), alarmone/stress metabolism (e.g. Ap4A hydrolase), RNA modification/regulation (e.g. methionyl-tRNA synthetase), outer membrane proteins (e.g. ompA), and genes involved in natural competence (comEC). All tested mutants originally identified as motility-deficient in strain ATCC® 17978™ also displayed a motility-deficient phenotype in 29D2. By contrast, further comparative characterization of the mutant sets of both strains regarding pellicle biofilm formation, antibiotic resistance, and virulence in the Galleria mellonella infection model revealed numerous strain-specific mutant phenotypes. Our studies highlight the need for comparative analyses to characterize gene functions in A. baumannii and for further studies on the mechanisms underlying surface-associated motility.
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Affiliation(s)
- Ulrike Blaschke
- Robert Koch Institute, Project group P2, Burgstr. 37, 38855, Wernigerode, Germany.
| | - Evelyn Skiebe
- Robert Koch Institute, Project group P2, Burgstr. 37, 38855, Wernigerode, Germany
| | - Gottfried Wilharm
- Robert Koch Institute, Project group P2, Burgstr. 37, 38855, Wernigerode, Germany.
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5
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Ferguson F, McLennan AG, Urbaniak MD, Jones NJ, Copeland NA. Re-evaluation of Diadenosine Tetraphosphate (Ap 4A) From a Stress Metabolite to Bona Fide Secondary Messenger. Front Mol Biosci 2020; 7:606807. [PMID: 33282915 PMCID: PMC7705103 DOI: 10.3389/fmolb.2020.606807] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 10/19/2020] [Indexed: 01/14/2023] Open
Abstract
Cellular homeostasis requires adaption to environmental stress. In response to various environmental and genotoxic stresses, all cells produce dinucleoside polyphosphates (NpnNs), the best studied of which is diadenosine tetraphosphate (Ap4A). Despite intensive investigation, the precise biological roles of these molecules have remained elusive. However, recent studies have elucidated distinct and specific signaling mechanisms for these nucleotides in prokaryotes and eukaryotes. This review summarizes these key discoveries and describes the mechanisms of Ap4A and Ap4N synthesis, the mediators of the cellular responses to increased intracellular levels of these molecules and the hydrolytic mechanisms required to maintain low levels in the absence of stress. The intracellular responses to dinucleotide accumulation are evaluated in the context of the "friend" and "foe" scenarios. The "friend (or alarmone) hypothesis" suggests that ApnN act as bona fide secondary messengers mediating responses to stress. In contrast, the "foe" hypothesis proposes that ApnN and other NpnN are produced by non-canonical enzymatic synthesis as a result of physiological and environmental stress in critically damaged cells but do not actively regulate mitigating signaling pathways. In addition, we will discuss potential target proteins, and critically assess new evidence supporting roles for ApnN in the regulation of gene expression, immune responses, DNA replication and DNA repair. The recent advances in the field have generated great interest as they have for the first time revealed some of the molecular mechanisms that mediate cellular responses to ApnN. Finally, areas for future research are discussed with possible but unproven roles for intracellular ApnN to encourage further research into the signaling networks that are regulated by these nucleotides.
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Affiliation(s)
- Freya Ferguson
- Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, United Kingdom.,Materials Science Institute, Lancaster University, Lancaster, United Kingdom
| | - Alexander G McLennan
- Department of Molecular Physiology and Cell Signalling, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Michael D Urbaniak
- Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, United Kingdom
| | - Nigel J Jones
- Department of Molecular Physiology and Cell Signalling, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Nikki A Copeland
- Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, United Kingdom.,Materials Science Institute, Lancaster University, Lancaster, United Kingdom
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6
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Wakasugi K, Yokosawa T. Non-canonical functions of human cytoplasmic tyrosyl-, tryptophanyl- and other aminoacyl-tRNA synthetases. Enzymes 2020; 48:207-242. [PMID: 33837705 DOI: 10.1016/bs.enz.2020.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Aminoacyl-tRNA synthetases catalyze the aminoacylation of their cognate tRNAs. Here we review the accumulated knowledge of non-canonical functions of human cytoplasmic aminoacyl-tRNA synthetases, especially tyrosyl- (TyrRS) and tryptophanyl-tRNA synthetase (TrpRS). Human TyrRS and TrpRS have an extra domain. Two distinct cytokines, i.e., the core catalytic "mini TyrRS" and the extra C-domain, are generated from human TyrRS by proteolytic cleavage. Moreover, the core catalytic domains of human TyrRS and TrpRS function as angiogenic and angiostatic factors, respectively, whereas the full-length forms are inactive for this function. It is also known that many synthetases change their localization in response to a specific signal and subsequently exhibit alternative functions. Furthermore, some synthetases function as sensors for amino acids by changing their protein interactions in an amino acid-dependent manner. Further studies will be necessary to elucidate regulatory mechanisms of non-canonical functions of aminoacyl-tRNA synthetases in particular, by analyzing the effect of their post-translational modifications.
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Affiliation(s)
- Keisuke Wakasugi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan; Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
| | - Takumi Yokosawa
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
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7
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Np 4A alarmones function in bacteria as precursors to RNA caps. Proc Natl Acad Sci U S A 2020; 117:3560-3567. [PMID: 32019889 DOI: 10.1073/pnas.1914229117] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Stresses that increase the cellular concentration of dinucleoside tetraphosphates (Np4Ns) have recently been shown to impact RNA degradation by inducing nucleoside tetraphosphate (Np4) capping of bacterial transcripts. However, neither the mechanism by which such caps are acquired nor the function of Np4Ns in bacteria is known. Here we report that promoter sequence changes upstream of the site of transcription initiation similarly affect both the efficiency with which Escherichia coli RNA polymerase incorporates dinucleoside polyphosphates at the 5' end of nascent transcripts in vitro and the percentage of transcripts that are Np4-capped in E. coli, clear evidence for Np4 cap acquisition by Np4N incorporation during transcription initiation in bacterial cells. E. coli RNA polymerase initiates transcription more efficiently with Np4As than with ATP, particularly when the coding strand nucleotide that immediately precedes the initiation site is a purine. Together, these findings indicate that Np4Ns function in bacteria as precursors to Np4 caps and that RNA polymerase has evolved a predilection for synthesizing capped RNA whenever such precursors are abundant.
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8
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Pietrowska-Borek M, Wojdyła-Mamoń A, Dobrogojski J, Młynarska-Cieślak A, Baranowski MR, Dąbrowski JM, Kowalska J, Jemielity J, Borek S, Pedreño MA, Guranowski A. Purine and pyrimidine dinucleoside polyphosphates differentially affect the phenylpropanoid pathway in Vitis vinifera L. cv. Monastrell suspension cultured cells. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 147:125-132. [PMID: 31855818 DOI: 10.1016/j.plaphy.2019.12.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/25/2019] [Accepted: 12/12/2019] [Indexed: 06/10/2023]
Abstract
It is known that the concentration of dinucleoside polyphosphates (NpnN's) in cells increases under stress and that adverse environmental factors induce biosynthesis of phenylpropanoids, which protect the plant against stress. Previously, we showed that purine NpnN's such as Ap3A and Ap4A induce both the activity of enzymes of the phenylpropanoid pathway and the expression of relevant genes in Arabidopsis seedlings. Moreover, we showed that Ap3A induced stilbene biosynthesis in Vitis vinifera cv. Monastrell suspension cultured cells. Data presented in this paper show that pyrimidine-containing NpnN's also modify the biosynthesis of stilbenes, affecting the transcript level of genes encoding key enzymes of the phenylpropanoid pathway and of these, Up4U caused the most effective accumulation of trans-resveratrol in the culture media. Similar effect was caused by Ap3A and Gp3G. Other pyrimidine NpnN's, such as Cp3C, Cp4C, and Ap4C, strongly inhibited the biosynthesis of stilbenes, but markedly (6- to 8-fold) induced the expression of the cinnamoyl-CoA reductase gene that controls lignin biosynthesis. Purine counterparts also clearly induced biosynthesis of trans-resveratrol and trans-piceid, but only slightly induced the expression of genes involved in lignin biosynthesis. In cells, Up3U caused a greater accumulation of trans-resveratrol and trans-piceid than did Up4U. Each of the NpnN's studied induced expression of the gene encoding the resveratrol transporter VvABCG44, which operates within the Vitis vinifera cell membrane. AMP, GMP, UMP, and CMP, potential products of NpnN degradation, did not affect the accumulation of stilbenes. The results obtained strongly support that NpnN's play a role as signaling molecules in plants.
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Affiliation(s)
- Małgorzata Pietrowska-Borek
- Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, Dojazd 11, 60-632, Poznań, Poland.
| | - Anna Wojdyła-Mamoń
- Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, Dojazd 11, 60-632, Poznań, Poland
| | - Jędrzej Dobrogojski
- Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, Dojazd 11, 60-632, Poznań, Poland
| | - Agnieszka Młynarska-Cieślak
- Division of Biophysics Institute of Experimental Physics, Faculty of Physics University of Warsaw, Żwirki i Wigury 93, 02-089, Warsaw, Poland
| | - Marek R Baranowski
- Division of Biophysics Institute of Experimental Physics, Faculty of Physics University of Warsaw, Żwirki i Wigury 93, 02-089, Warsaw, Poland
| | - Jakub M Dąbrowski
- Division of Biophysics Institute of Experimental Physics, Faculty of Physics University of Warsaw, Żwirki i Wigury 93, 02-089, Warsaw, Poland
| | - Joanna Kowalska
- Division of Biophysics Institute of Experimental Physics, Faculty of Physics University of Warsaw, Żwirki i Wigury 93, 02-089, Warsaw, Poland
| | - Jacek Jemielity
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland
| | - Sławomir Borek
- Department of Plant Physiology, Adam Mickiewicz University Poznań, Uniwersytetu Poznańskiego 6, 61-614, Poznań, Poland
| | - Maria Angeles Pedreño
- Department of Plant Biology, Faculty of Biology, University of Murcia, Campus de Espinardo, 30100, Murcia, Spain
| | - Andrzej Guranowski
- Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, Dojazd 11, 60-632, Poznań, Poland
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9
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Formation of the Alarmones Diadenosine Triphosphate and Tetraphosphate by Ubiquitin- and Ubiquitin-like-Activating Enzymes. Cell Chem Biol 2019; 26:1535-1543.e5. [PMID: 31492597 DOI: 10.1016/j.chembiol.2019.08.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 07/19/2019] [Accepted: 08/08/2019] [Indexed: 01/14/2023]
Abstract
Diadenosine polyphosphates (ApnAs) such as diadenosine tri- and tetraphosphates are formed in prokaryotic as well as eukaryotic cells. Since upon stress intracellular ApnA concentrations increase, it was postulated that ApnAs are alarmones triggering stress-adaptive processes. The major synthesis pathway of ApnAs is assumed to be a side reaction of amino acid activation. How this process is linked to stress adaptation remains enigmatic. The first step of one of the most prominent eukaryotic post-translational modification systems-the conjugation of ubiquitin (Ub) and ubiquitin-like proteins (Ubl) to target proteins-involves the formation of an adenylate as intermediate. Like ApnA formation, Ub and Ubl conjugation is significantly enhanced during stress conditions. Here, we demonstrate that diadenosine tri- and tetraphosphates are indeed synthesized during activation of Ub and Ubls. This links one of the most prevalent eukaryotic protein-modification systems to ApnA formation for the first time.
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10
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Luciano DJ, Levenson-Palmer R, Belasco JG. Stresses that Raise Np 4A Levels Induce Protective Nucleoside Tetraphosphate Capping of Bacterial RNA. Mol Cell 2019; 75:957-966.e8. [PMID: 31178354 DOI: 10.1016/j.molcel.2019.05.031] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 05/17/2019] [Accepted: 05/23/2019] [Indexed: 12/21/2022]
Abstract
Present in all realms of life, dinucleoside tetraphosphates (Np4Ns) are generally considered signaling molecules. However, only a single pathway for Np4N signaling has been delineated in eukaryotes, and no receptor that mediates the influence of Np4Ns has ever been identified in bacteria. Here we show that, under disulfide stress conditions that elevate cellular Np4N concentrations, diverse Escherichia coli mRNAs and sRNAs acquire a cognate Np4 cap. Purified E. coli RNA polymerase and lysyl-tRNA synthetase are both capable of adding such 5' caps. Cap removal by either of two pyrophosphatases, ApaH or RppH, triggers rapid RNA degradation in E. coli. ApaH, the predominant decapping enzyme, functions as both a sensor and an effector of disulfide stress, which inactivates it. These findings suggest that the physiological changes attributed to elevated Np4N concentrations in bacteria may result from widespread Np4 capping, leading to altered RNA stability and consequent changes in gene expression.
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Affiliation(s)
- Daniel J Luciano
- Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA; Department of Microbiology, New York University School of Medicine, 430 E. 29th Street, New York, NY 10016, USA
| | - Rose Levenson-Palmer
- Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA; Department of Microbiology, New York University School of Medicine, 430 E. 29th Street, New York, NY 10016, USA
| | - Joel G Belasco
- Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA; Department of Microbiology, New York University School of Medicine, 430 E. 29th Street, New York, NY 10016, USA.
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11
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Mukkayyan N, Sharan D, Ajitkumar P. A Symmetric Molecule Produced by Mycobacteria Generates Cell-Length Asymmetry during Cell-Division and Thereby Cell-Length Heterogeneity. ACS Chem Biol 2018; 13:1447-1454. [PMID: 29757604 DOI: 10.1021/acschembio.8b00080] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Diadenosine polyphosphates, Ap(2-7)A, which contain two adenosines in a 5',5' linkage through phosphodiester bonds involving 2-7 phosphates, regulate diverse cellular functions in all organisms, from bacteria to humans, under normal and stress conditions. We had earlier reported consistent occurrence of asymmetric constriction during division (ACD) in 20-30% of dividing mycobacterial cells in culture, irrespective of different growth media, implying exogenous action of some factor of mycobacterial origin. Consistent with this premise, concentrated culture supernatant (CCS), but not the equivalent volume-wise concentrated unused medium, dramatically enhanced the ACD proportion to 70-90%. Mass spectrometry and biochemical analyses of the bioactive fraction from CCS revealed the ACD-effecting factor to be Ap6A. Synthetic Ap6A showed a mass spectrometry profile, biochemical characteristics, and bioactivity identical to native Ap6A in the CCS. Thus, the present work reveals a novel role for Ap6A in generating cell-length asymmetry during mycobacterial cell-division and thereby cell-length heterogeneity in the population.
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Affiliation(s)
- Nagaraja Mukkayyan
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, Karnataka, India
| | - Deepti Sharan
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, Karnataka, India
| | - Parthasarathi Ajitkumar
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, Karnataka, India
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12
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Götz KH, Hacker SM, Mayer D, Dürig JN, Stenger S, Marx A. Inhibitors of the Diadenosine Tetraphosphate Phosphorylase Rv2613c of Mycobacterium tuberculosis. ACS Chem Biol 2017; 12:2682-2689. [PMID: 28892605 DOI: 10.1021/acschembio.7b00653] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The intracellular concentration of diadenosine tetraphospate (Ap4A) increases upon exposure to stress conditions. Despite being discovered over 50 years ago, the cellular functions of Ap4A are still enigmatic. If and how the varied Ap4A is a signal and involved in the signaling pathways leading to an appropriate cellular response remain to be discovered. Because the turnover of Ap4A by Ap4A cleaving enzymes is rapid, small molecule inhibitors for these enzymes would provide tools for the more detailed study of the role of Ap4A. Here, we describe the development of a high-throughput screening assay based on a fluorogenic Ap4A substrate for the identification and optimization of small molecule inhibitors for Ap4A cleaving enzymes. As proof-of-concept we screened a library of over 42 000 compounds toward their inhibitory activity against the Ap4A phosphorylase (Rv2613c) of Mycobacterium tuberculosis (Mtb). A sulfanylacrylonitril derivative with an IC50 of 260 ± 50 nM in vitro was identified. Multiple derivatives were synthesized to further optimize their properties with respect to their in vitro IC50 values and their cytotoxicity against human cells (HeLa). In addition, we selected two hits to study their antimycobacterial activity against virulent Mtb to show that they might be candidates for further development of antimycobacterial agents against multidrug-resistant Mtb.
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Affiliation(s)
- Kathrin H. Götz
- Department
of Chemistry, Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstrasse 10, D-78464 Konstanz, Germany
| | - Stephan M. Hacker
- Department
of Chemistry, Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstrasse 10, D-78464 Konstanz, Germany
| | - Daniel Mayer
- Institute
for Medical Microbiology and Hygiene, University Hospital of Ulm, Albert-Einstein-Allee
11, D-89081 Ulm, Germany
| | - Jan-Niklas Dürig
- Department
of Chemistry, Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstrasse 10, D-78464 Konstanz, Germany
| | - Steffen Stenger
- Institute
for Medical Microbiology and Hygiene, University Hospital of Ulm, Albert-Einstein-Allee
11, D-89081 Ulm, Germany
| | - Andreas Marx
- Department
of Chemistry, Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstrasse 10, D-78464 Konstanz, Germany
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13
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Kimura Y, Tanaka C, Sasaki K, Sasaki M. High concentrations of intracellular Ap4A and/or Ap5A in developing Myxococcus xanthus cells inhibit sporulation. MICROBIOLOGY-SGM 2017; 163:86-93. [PMID: 27902428 DOI: 10.1099/mic.0.000403] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Diadenosine polyphosphates (ApnA) are thought to act as signalling molecules regulating stress responses and biofilm formation in prokaryotes. However, ApnA function in Myxococcus xanthus remains unknown. Here, we investigated the role of ApnA in M. xanthus, using the wild-type and ApnA hydrolase (apaH) mutant strains exposed to various stress conditions. In both wild-type and apaH mutant cells cultured on starvation medium (CF agar), the levels of intracellular diadenosine tetraphosphate (Ap4A) and pentaphosphate (Ap5A) increased several fold during the first 16 h of development and decreased gradually thereafter. The levels of Ap4A and Ap5A in the apaH mutant were about 5- and 11-fold higher than those in the wild-type strain at 16 h, respectively. ApnA hydrolase activity of the wild-type strain increased 1.5-fold during the first 8 h of development, and it then gradually decreased. The apaH mutant formed spores 1-2 days after the wild-type strain did, and the yield of viable spores was 5.5 % of that in the wild-type strain 5 days after inoculation onto CF agar. These results suggest the possibility that high intracellular levels of Ap4A and/or Ap5A may inhibit M. xanthus sporulation at the early stage of development and that the bacteria reduce intracellular Ap4A and Ap5A accumulation through ApnA hydrolase activity.
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Affiliation(s)
- Yoshio Kimura
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa 761-0795, Japan
| | - Chihiro Tanaka
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa 761-0795, Japan
| | - Katsuho Sasaki
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa 761-0795, Japan
| | - Masashi Sasaki
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa 761-0795, Japan
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14
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Kwon O, Kwak D, Ha SH, Jeon H, Park M, Chang Y, Suh PG, Ryu SH. Nudix-type motif 2 contributes to cancer proliferation through the regulation of Rag GTPase-mediated mammalian target of rapamycin complex 1 localization. Cell Signal 2017; 32:24-35. [PMID: 28089905 DOI: 10.1016/j.cellsig.2017.01.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 12/19/2016] [Accepted: 01/06/2017] [Indexed: 01/14/2023]
Abstract
Lysosomal localization of mammalian target of rapamycin complex 1 (mTORC1) is a critical step for activation of the molecule. Rag GTPases are essential for this translocation. Here, we demonstrate that Nudix-type motif 2 (NUDT2) is a novel positive regulator of mTORC1 activation. Activation of mTORC1 is impaired in NUDT2-silenced cells. Mechanistically, NUDT2 binds to Rag GTPase and controls mTORC1 translocation to the lysosomal membrane. Furthermore, NUDT2-dependent mTORC1 regulation is critical for proliferation of breast cancer cells, as NUDT2-silenced cells arrest in G0/G1 phases. Taken together, these results show that NUDT2 is a novel complex formation enhancing factor regulating mTORC1-Rag GTPase signaling that is crucial for cell growth control.
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Affiliation(s)
- Ohman Kwon
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea
| | - Dongoh Kwak
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea
| | - Sang Hoon Ha
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea
| | - Hyeona Jeon
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea
| | - Mangeun Park
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea
| | - Yeonho Chang
- Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea
| | - Pann-Ghill Suh
- School of Nano-Biotechnology and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Republic of Korea
| | - Sung Ho Ryu
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea; Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea.
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15
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Opoku-Temeng C, Zhou J, Zheng Y, Su J, Sintim HO. Cyclic dinucleotide (c-di-GMP, c-di-AMP, and cGAMP) signalings have come of age to be inhibited by small molecules. Chem Commun (Camb) 2016; 52:9327-42. [PMID: 27339003 DOI: 10.1039/c6cc03439j] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bacteria utilize nucleotide-based second messengers to regulate a myriad of physiological processes. Cyclic dinucleotides have emerged as central regulators of bacterial physiology, controlling processes ranging from cell wall homeostasis to virulence production, and so far over thousands of manuscripts have provided biological insights into c-di-NMP signaling. The development of small molecule inhibitors of c-di-NMP signaling has significantly lagged behind. Recent developments in assays that allow for high-throughput screening of inhibitors suggest that the time is right for a concerted effort to identify inhibitors of these fascinating second messengers. Herein, we review c-di-NMP signaling and small molecules that have been developed to inhibit cyclic dinucleotide-related enzymes.
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Affiliation(s)
- Clement Opoku-Temeng
- Department of Chemistry, Center for Drug Discovery, Purdue University, West Lafayette, IN 47907, USA.
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16
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Abstract
Aminoacyl-tRNA synthetases (aaRSs) are modular enzymes globally conserved in the three kingdoms of life. All catalyze the same two-step reaction, i.e., the attachment of a proteinogenic amino acid on their cognate tRNAs, thereby mediating the correct expression of the genetic code. In addition, some aaRSs acquired other functions beyond this key role in translation. Genomics and X-ray crystallography have revealed great structural diversity in aaRSs (e.g., in oligomery and modularity, in ranking into two distinct groups each subdivided in 3 subgroups, by additional domains appended on the catalytic modules). AaRSs show huge structural plasticity related to function and limited idiosyncrasies that are kingdom or even species specific (e.g., the presence in many Bacteria of non discriminating aaRSs compensating for the absence of one or two specific aaRSs, notably AsnRS and/or GlnRS). Diversity, as well, occurs in the mechanisms of aaRS gene regulation that are not conserved in evolution, notably between distant groups such as Gram-positive and Gram-negative Bacteria. The review focuses on bacterial aaRSs (and their paralogs) and covers their structure, function, regulation, and evolution. Structure/function relationships are emphasized, notably the enzymology of tRNA aminoacylation and the editing mechanisms for correction of activation and charging errors. The huge amount of genomic and structural data that accumulated in last two decades is reviewed, showing how the field moved from essentially reductionist biology towards more global and integrated approaches. Likewise, the alternative functions of aaRSs and those of aaRS paralogs (e.g., during cell wall biogenesis and other metabolic processes in or outside protein synthesis) are reviewed. Since aaRS phylogenies present promiscuous bacterial, archaeal, and eukaryal features, similarities and differences in the properties of aaRSs from the three kingdoms of life are pinpointed throughout the review and distinctive characteristics of bacterium-like synthetases from organelles are outlined.
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Affiliation(s)
- Richard Giegé
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 67084 Strasbourg, France
| | - Mathias Springer
- Université Paris Diderot, Sorbonne Cité, UPR9073 CNRS, IBPC, 75005 Paris, France
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17
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Structural and functional attributes of malaria parasite diadenosine tetraphosphate hydrolase. Sci Rep 2016; 6:19981. [PMID: 26829485 PMCID: PMC4734340 DOI: 10.1038/srep19981] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 12/15/2015] [Indexed: 11/09/2022] Open
Abstract
Malaria symptoms are driven by periodic multiplication cycles of Plasmodium parasites in human red blood corpuscles (RBCs). Malaria infection still accounts for ~600,000 annual deaths, and hence discovery of both new drug targets and drugs remains vital. In the present study, we have investigated the malaria parasite enzyme diadenosine tetraphosphate (Ap4A) hydrolase that regulates levels of signalling molecules like Ap4A by hydrolyzing them to ATP and AMP. We have tracked the spatial distribution of parasitic Ap4A hydrolase in infected RBCs, and reveal its unusual localization on the infected RBC membrane in subpopulation of infected cells. Interestingly, enzyme activity assays reveal an interaction between Ap4A hydrolase and the parasite growth inhibitor suramin. We also present a high resolution crystal structure of Ap4A hydrolase in apo- and sulphate- bound state, where the sulphate resides in the enzyme active site by mimicking the phosphate of substrates like Ap4A. The unexpected infected erythrocyte localization of the parasitic Ap4A hydrolase hints at a possible role of this enzyme in purinerigic signaling. In addition, atomic structure of Ap4A hydrolase provides insights for selective drug targeting.
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18
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Enzymatic characterization of a class II lysyl-tRNA synthetase, LysS, from Myxococcus xanthus. Arch Biochem Biophys 2015; 579:33-9. [PMID: 26048731 DOI: 10.1016/j.abb.2015.05.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 05/27/2015] [Accepted: 05/28/2015] [Indexed: 11/21/2022]
Abstract
Lysyl-tRNA synthetases efficiently produce diadenosine tetraphosphate (Ap4A) from lysyl-AMP with ATP in the absence of tRNA. We characterized recombinant class II lysyl-tRNA synthetase (LysS) from Myxococcus xanthus and found that it is monomeric and requires Mn(2+) for the synthesis of Ap4A. Surprisingly, Zn(2+) inhibited enzyme activity in the presence of Mn(2+). When incubated with ATP, Mn(2+), lysine, and inorganic pyrophosphatase, LysS first produced Ap4A and ADP, then converted Ap4A to diadenosine triphosphate (Ap3A), and finally converted Ap3A to ADP, the end product of the reaction. Recombinant LysS retained Ap4A synthase activity without lysine addition. Additionally, when incubated with Ap4A (minus pyrophosphatase), LysS converted Ap4A mainly ATP and AMP, or ADP in the presence or absence of lysine, respectively. These results demonstrate that M. xanthus LysS has different enzymatic properties from class II lysyl-tRNA synthetases previously reported.
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19
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Aminoacyl-tRNA synthetase complexes in evolution. Int J Mol Sci 2015; 16:6571-94. [PMID: 25807264 PMCID: PMC4394549 DOI: 10.3390/ijms16036571] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 02/17/2015] [Accepted: 03/11/2015] [Indexed: 11/23/2022] Open
Abstract
Aminoacyl-tRNA synthetases are essential enzymes for interpreting the genetic code. They are responsible for the proper pairing of codons on mRNA with amino acids. In addition to this canonical, translational function, they are also involved in the control of many cellular pathways essential for the maintenance of cellular homeostasis. Association of several of these enzymes within supramolecular assemblies is a key feature of organization of the translation apparatus in eukaryotes. It could be a means to control their oscillation between translational functions, when associated within a multi-aminoacyl-tRNA synthetase complex (MARS), and nontranslational functions, after dissociation from the MARS and association with other partners. In this review, we summarize the composition of the different MARS described from archaea to mammals, the mode of assembly of these complexes, and their roles in maintenance of cellular homeostasis.
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20
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Kaur G, Subramanian S. The insertion domain 1 of class IIA dimeric glycyl-tRNA synthetase is a rubredoxin-like zinc ribbon. J Struct Biol 2015; 190:38-46. [PMID: 25721219 DOI: 10.1016/j.jsb.2015.02.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 02/11/2015] [Accepted: 02/12/2015] [Indexed: 01/20/2023]
Abstract
The insertion domain 1 (ID1) of class IIA dimeric glycyl-tRNA synthetase (α2GRS) is an appended domain in the core catalytic region of the enzyme. ID1 has been shown to play a role in tRNA aminoacylation, mediating interaction with the acceptor arm of tRNA and diadenosine tetraphosphate (Ap4A) synthesis. Mutations in α2GRS, including those in the ID1 region, have been implicated in distal hereditary motor neuropathy-V (dHMN-V) and Charcot-Marie-Tooth (CMT) disease. Through sequence and structure based evolutionary analysis, we show that ID1 of α2GRS is a rubredoxin-like zinc ribbon domain. The zinc-chelating cysteines of ID1 are well conserved in all archaeal versions of the enzyme and also in several eukaryotes, which most likely have acquired them via horizontal gene transfer from bacteria; but in all other eukaryotes, the zinc-chelating residues are not preserved. ID1 from bacteria display a selective preservation of zinc-binding residues, ranging from complete conservation to complete loss. The ID1 from different organisms harbor variable-sized non-conserved insertions between the two zinc-binding half-sites of the zinc ribbon. Three of the previously identified CMT-associated mutations in α2GRS, viz., human D146N, mouse C157R and human S211F, are located in the zinc ribbon region of ID1. Interestingly, human Asp146 which is implicated in the synthesis of Ap4A, a molecule known to act during neuronal transmission, has also been reported to be mutated in dHMN-V, suggesting a possible link between hereditary motor neuropathy and Ap4A synthesis.
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Affiliation(s)
- Gurmeet Kaur
- CSIR-Institute of Microbial Technology, Sector 39A, Chandigarh, India
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21
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Sasaki M, Takegawa K, Kimura Y. Enzymatic characteristics of an ApaH-like phosphatase, PrpA, and a diadenosine tetraphosphate hydrolase, ApaH, from Myxococcus xanthus. FEBS Lett 2014; 588:3395-402. [PMID: 25107648 DOI: 10.1016/j.febslet.2014.07.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 07/08/2014] [Accepted: 07/24/2014] [Indexed: 10/24/2022]
Abstract
We characterized the activities of the Myxococcus xanthus ApaH-like phosphatases PrpA and ApaH, which share homologies with both phosphoprotein phosphatases and diadenosine tetraphosphate (Ap4A) hydrolases. PrpA exhibited a phosphatase activity towards p-nitrophenyl phosphate (pNPP), tyrosine phosphopeptide and tyrosine-phosphorylated protein, and a weak hydrolase activity towards ApnA and ATP. In the presence of Mn(2+), PrpA hydrolyzed Ap4A into AMP and ATP, whereas in the presence of Co(2+) PrpA hydrolyzed Ap4A into two molecules of ADP. ApaH exhibited high phosphatase activity towards pNPP, and hydrolase activity towards ApnA and ATP. Mn(2+) was required for ApaH-mediated pNPP dephosphorylation and ATP hydrolysis, whereas Co(2+) was required for ApnA hydrolysis. Thus, PrpA and ApaH may function mainly as a tyrosine protein phosphatase and an ApnA hydrolase, respectively.
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Affiliation(s)
- Masashi Sasaki
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa, Japan
| | - Kaoru Takegawa
- Department of Bioscience and Biotechnology, Kyusyu University, Hakozaki, Higashi-ku, Fukuoka, Japan
| | - Yoshio Kimura
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa, Japan.
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22
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Shon HK, Cho YL, Lim CS, Choi JS, Chung SJ, Lee TG. ToF-SIMS analysis of diadenosine triphosphate and didadenosine tetraphosphate using bismuth and argon cluster ion beams. SURF INTERFACE ANAL 2014. [DOI: 10.1002/sia.5514] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Hyun Kyong Shon
- Center for Nano-Bio Convergence; Korea Research Institute of Standards and Science; Daejeon 305-340 Republic of Korea
| | - Young-Lai Cho
- Center for Nano-Bio Convergence; Korea Research Institute of Standards and Science; Daejeon 305-340 Republic of Korea
- Department of Chemistry; Dongguk University; Seoul 100-715 Republic of Korea
| | - Choung Su Lim
- Center for Nano-Bio Convergence; Korea Research Institute of Standards and Science; Daejeon 305-340 Republic of Korea
- Department of Biochemistry; Chungnam National University; Daejeon 305-764 Republic of Korea
| | - Joon Sig Choi
- Department of Biochemistry; Chungnam National University; Daejeon 305-764 Republic of Korea
| | - Sang J. Chung
- Department of Chemistry; Dongguk University; Seoul 100-715 Republic of Korea
| | - Tae Geol Lee
- Center for Nano-Bio Convergence; Korea Research Institute of Standards and Science; Daejeon 305-340 Republic of Korea
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23
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Structures of yeast Apa2 reveal catalytic insights into a canonical AP₄A phosphorylase of the histidine triad superfamily. J Mol Biol 2013; 425:2687-98. [PMID: 23628156 DOI: 10.1016/j.jmb.2013.04.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 04/17/2013] [Accepted: 04/19/2013] [Indexed: 11/23/2022]
Abstract
The homeostasis of intracellular diadenosine 5',5″'-P(1),P(4)-tetraphosphate (Ap4A) in the yeast Saccharomyces cerevisiae is maintained by two 60% sequence-identical paralogs of Ap4A phosphorylases (Apa1 and Apa2). Enzymatic assays show that, compared to Apa1, Apa2 has a relatively higher phosphorylase activity towards Ap3A (5',5″'-P(1),P(3)-tetraphosphate), Ap4A, and Ap5A (5',5″'-P(1),P(5)-tetraphosphate), and Ap4A is the favorable substrate for both enzymes. To decipher the catalytic insights, we determined the crystal structures of Apa2 in the apo-, AMP-, and Ap4A-complexed forms at 2.30, 2.80, and 2.70Å resolution, respectively. Apa2 is an α/β protein with a core domain of a twisted eight-stranded antiparallel β-sheet flanked by several α-helices, similar to the galactose-1-phosphate uridylyltransferase (GalT) members of the histidine triad (HIT) superfamily. However, a unique auxiliary domain enables an individual Apa2 monomer to possess an intact substrate-binding cleft, which is distinct from previously reported dimeric GalT proteins. This cleft is perfectly complementary to the favorable substrate Ap4A, the AMP and ATP moieties of which are perpendicular to each other, leaving the α-phosphate group exposed at the sharp turn against the catalytic residue His161. Structural comparisons combined with site-directed mutagenesis and activity assays enable us to define the key residues for catalysis. Furthermore, multiple-sequence alignment reveals that Apa2 and homologs represent canonical Ap4A phosphorylases, which could be grouped as a unique branch in the GalT family.
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24
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Ge H, Chen X, Yang W, Niu L, Teng M. Crystal structure of wild-type and mutant human Ap4A hydrolase. Biochem Biophys Res Commun 2013; 432:16-21. [PMID: 23384440 PMCID: PMC7092880 DOI: 10.1016/j.bbrc.2013.01.095] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 01/27/2013] [Indexed: 11/04/2022]
Abstract
Ap4A hydrolase (asymmetrical diadenosine tetraphosphate hydrolase, EC 3.6.1.17), an enzyme involved in a number of biological processes, is characterized as cleaving the polyphosphate chain at the fourth phosphate from the bound adenosine moiety. This paper presents the crystal structure of wild-type and E58A mutant human Ap4A hydrolase. Similar to the canonical Nudix fold, human Ap4A hydrolase shows the common αβα-sandwich architecture. Interestingly, two sulfate ions and one diphosphate coordinated with some conserved residues were observed in the active cleft, which affords a better understanding of a possible mode of substrate binding.
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Affiliation(s)
- Honghua Ge
- Institute of Health Sciences and Modern Experiment Technology Center, Anhui University, Hefei 230601, People's Republic of China.
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25
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NTP-mediated nucleotide excision activity of hepatitis C virus RNA-dependent RNA polymerase. Proc Natl Acad Sci U S A 2013; 110:E348-57. [PMID: 23307808 DOI: 10.1073/pnas.1214924110] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Hepatitis C virus (HCV) RNA-dependent RNA polymerase replicates the viral genomic RNA and is a primary drug target for antiviral therapy. Previously, we described the purification of an active and stable polymerase-primer-template elongation complex. Here, we show that, unexpectedly, the polymerase elongation complex can use NTPs to excise the terminal nucleotide in nascent RNA. Mismatched ATP, UTP, or CTP could mediate excision of 3'-terminal CMP to generate the dinucleoside tetraphosphate products Ap(4)C, Up(4)C, and Cp(4)C, respectively. Pre-steady-state kinetic studies showed that the efficiency of NTP-mediated excision was highest with ATP. A chain-terminating inhibitor, 3'deoxy-CMP, could also be excised through this mechanism, suggesting important implications for nucleoside drug potency and resistance. The nucleotide excision reaction catalyzed by recombinant hepatitis C virus polymerase was 100-fold more efficient than the corresponding reaction observed with HIV reverse transcriptase.
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26
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Amino-acyl tRNA synthetases generate dinucleotide polyphosphates as second messengers: functional implications. Top Curr Chem (Cham) 2013; 344:189-206. [PMID: 23536246 DOI: 10.1007/128_2013_426] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In this chapter we describe aminoacyl-tRNA synthetase (aaRS) production of dinucleotide polyphosphate in response to stimuli, their interaction with various signaling pathways, and the role of diadenosine tetraphosphate and diadenosine triphosphate as second messengers. The primary role of aaRS is to mediate aminoacylation of cognate tRNAs, thereby providing a central role for the decoding of genetic code during protein translation. However, recent studies suggest that during evolution, "moonlighting" or non-canonical roles were acquired through incorporation of additional domains, leading to regulation by aaRSs of a spectrum of important biological processes, including cell cycle control, tissue differentiation, cellular chemotaxis, and inflammation. In addition to aminoacylation of tRNA, most aaRSs can also produce dinucleotide polyphosphates in a variety of physiological conditions. The dinucleotide polyphosphates produced by aaRS are biologically active both extra- and intra-cellularly, and seem to function as important signaling molecules. Recent findings established the role of dinucleotide polyphosphates as second messengers.
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27
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Chen X, Boonyalai N, Lau C, Thipayang S, Xu Y, Wright M, Miller AD. Multiple catalytic activities of Escherichia coli lysyl-tRNA synthetase (LysU) are dissected by site-directed mutagenesis. FEBS J 2012; 280:102-14. [PMID: 23121660 DOI: 10.1111/febs.12053] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 10/24/2012] [Accepted: 10/29/2012] [Indexed: 11/28/2022]
Abstract
The heat-inducible lysyl-tRNA synthetase from Escherichia coli (LysU; EC6/1/1/6.html) converts ATP to diadenosine tri- and tetraphosphates (Ap(3)A/Ap(4)A) in the presence of L-lysine/Mg(2+)/Zn(2+). To understand LysU in more detail, 26 mutants were prepared: six of E264, four of R269 and sixteen mutants by alanine-scanning of the inner shell/motif 2 loop. In the presence of glycerol and absence of exogenously added Zn(2+)/L-lysine, we unexpectedly found that E264K catalysed the production of glycerol-3-phosphate, powered by ATP turnover to ADP. E264Q and E264N are also capable of this activity, but all three show little formation of Ap(4)A/Ap(3)A under normal conditions (additional Zn(2+)/L-lysine/Mg(2+)). By contrast, wild-type LysU has a weaker glycerol kinase-like capability in the absence of Zn(2+) and is dominated by Ap(4)A/Ap(3)A synthesis in its presence. Kinetic and isothermal titration calorimetry results suggest that E264 is a crucial residue for Zn(2+) promotion of Ap(4)A/Ap(3)A synthesis. This is consistent with the hypothesis that E264 provides an anchor point for a Zn(2+) ion complexed to the active site, with simultaneous coordination to the enzyme bound lysyl-adenylate intermediate and secondary substrate ATP/ADP. The glycerol kinase-like activity is uncovered on disruption of this specific coordination.
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Affiliation(s)
- Xiaolong Chen
- Zhejiang California International NanoSystems Institute, Zhejiang University, Hangzhou, China
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28
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Abstract
Aminoacyl-tRNAsynthetases (aaRSs) are modular enzymesglobally conserved in the three kingdoms of life. All catalyze the same two-step reaction, i.e., the attachment of a proteinogenic amino acid on their cognate tRNAs, thereby mediating the correct expression of the genetic code. In addition, some aaRSs acquired other functions beyond this key role in translation.Genomics and X-ray crystallography have revealed great structural diversity in aaRSs (e.g.,in oligomery and modularity, in ranking into two distinct groups each subdivided in 3 subgroups, by additional domains appended on the catalytic modules). AaRSs show hugestructural plasticity related to function andlimited idiosyncrasies that are kingdom or even speciesspecific (e.g.,the presence in many Bacteria of non discriminating aaRSs compensating for the absence of one or two specific aaRSs, notably AsnRS and/or GlnRS).Diversity, as well, occurs in the mechanisms of aaRS gene regulation that are not conserved in evolution, notably betweendistant groups such as Gram-positive and Gram-negative Bacteria.Thereview focuses on bacterial aaRSs (and their paralogs) and covers their structure, function, regulation,and evolution. Structure/function relationships are emphasized, notably the enzymology of tRNA aminoacylation and the editing mechanisms for correction of activation and charging errors. The huge amount of genomic and structural data that accumulatedin last two decades is reviewed,showing how thefield moved from essentially reductionist biologytowards more global and integrated approaches. Likewise, the alternative functions of aaRSs and those of aaRSparalogs (e.g., during cellwall biogenesis and other metabolic processes in or outside protein synthesis) are reviewed. Since aaRS phylogenies present promiscuous bacterial, archaeal, and eukaryal features, similarities and differences in the properties of aaRSs from the three kingdoms of life are pinpointedthroughout the reviewand distinctive characteristics of bacterium-like synthetases from organelles are outlined.
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29
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Smirnova EV, Lakunina VA, Tarassov I, Krasheninnikov IA, Kamenski PA. Noncanonical functions of aminoacyl-tRNA synthetases. BIOCHEMISTRY (MOSCOW) 2012; 77:15-25. [PMID: 22339629 DOI: 10.1134/s0006297912010026] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Aminoacyl-tRNA synthetases, together with their main function of covalent binding of an amino acid to a corresponding tRNA, also perform many other functions. They take part in regulation of gene transcription, apoptosis, translation, and RNA splicing. Some of them function as cytokines or catalyze different reactions in living cells. Noncanonical functions can be mediated by additional domains of these proteins. On the other hand, some of the noncanonical functions are directly associated with the active center of the aminoacylation reaction. In this review we summarize recent data on the noncanonical functions of aminoacyl-tRNA synthetases and on the mechanisms of their action.
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Affiliation(s)
- E V Smirnova
- Department of Molecular Biology, Lomonosov Moscow State University, Moscow, Russia
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30
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Strazzullo M, Corteggio A, Altamura G, Francioso R, Roperto F, D'Esposito M, Borzacchiello G. Molecular and epigenetic analysis of the fragile histidine triad tumour suppressor gene in equine sarcoids. BMC Vet Res 2012; 8:30. [PMID: 22424615 PMCID: PMC3361464 DOI: 10.1186/1746-6148-8-30] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 03/16/2012] [Indexed: 01/14/2023] Open
Abstract
Background Sarcoids are peculiar equine benign tumours. Their onset is associated with Bovine Papillomavirus type -1 or -2 (BPV-1/2) infection. Little is known about the molecular interplay between viral infection and neoplastic transformation. The data regarding papillomavirus infections in human species show the inactivation of a number of tumour suppressor genes as basic mechanism of transformation. In this study the putative role of the tumour suppressor gene Fragile Histidine Triad (FHIT) in sarcoid tumour was investigated in different experimental models. The expression of the oncosuppressor protein was assessed in normal and sarcoid cells and tissue. Results Nine paraffin embedded sarcoids and sarcoid derived cell lines were analysed for the expression of FHIT protein by immunohistochemistry, immunofluorescence techniques and western blotting. These analyses revealed the absence of signal in seven out of nine sarcoids. The two sarcoid derived cell lines too showed a reduced signal of the protein. To investigate the causes of the altered protein expression, the samples were analysed for the DNA methylation profile of the CpG island associated with the FHIT promoter. The analysis of the 32 CpGs encompassing the region of interest showed no significative differential methylation profile between pathological tissues and cell lines and their normal counterparts. Conclusion This study represent a further evidence of the role of a tumour suppressor gene in equine sarcoids and approaches the epigenetic regulation in this well known equine neoplasm. The data obtained in sarcoid tissues and sarcoid derived cell lines suggest that also in horse, as in humans, there is a possible involvement of the tumour suppressor FHIT gene in BPV induced tumours. DNA methylation seems not to be involved in the gene expression alteration. Further studies are needed to understand the basic molecular mechanisms involved in reduced FHIT expression.
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Affiliation(s)
- Maria Strazzullo
- Department of Pathology and Animal Health, University of Naples Federico II, Via Veterinaria, Naples, Italy
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Andreev DE, Hirnet J, Terenin IM, Dmitriev SE, Niepmann M, Shatsky IN. Glycyl-tRNA synthetase specifically binds to the poliovirus IRES to activate translation initiation. Nucleic Acids Res 2012; 40:5602-14. [PMID: 22373920 PMCID: PMC3384309 DOI: 10.1093/nar/gks182] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Adaptation to the host cell environment to efficiently take-over the host cell's machinery is crucial in particular for small RNA viruses like picornaviruses that come with only small RNA genomes and replicate exclusively in the cytosol. Their Internal Ribosome Entry Site (IRES) elements are specific RNA structures that facilitate the 5′ end-independent internal initiation of translation both under normal conditions and when the cap-dependent host protein synthesis is shut-down in infected cells. A longstanding issue is which host factors play a major role in this internal initiation. Here, we show that the functionally most important domain V of the poliovirus IRES uses tRNAGly anticodon stem–loop mimicry to recruit glycyl-tRNA synthetase (GARS) to the apical part of domain V, adjacent to the binding site of the key initiation factor eIF4G. The binding of GARS promotes the accommodation of the initiation region of the IRES in the mRNA binding site of the ribosome, thereby greatly enhancing the activity of the IRES at the step of the 48S initiation complex formation. Moonlighting functions of GARS that may be additionally needed for other events of the virus–host cell interaction are discussed.
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Affiliation(s)
- Dmitri E Andreev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Building 40, Moscow 119991, Russian Federation
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The phylogenomic roots of modern biochemistry: origins of proteins, cofactors and protein biosynthesis. J Mol Evol 2012; 74:1-34. [PMID: 22210458 DOI: 10.1007/s00239-011-9480-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Accepted: 12/12/2011] [Indexed: 12/20/2022]
Abstract
The complexity of modern biochemistry developed gradually on early Earth as new molecules and structures populated the emerging cellular systems. Here, we generate a historical account of the gradual discovery of primordial proteins, cofactors, and molecular functions using phylogenomic information in the sequence of 420 genomes. We focus on structural and functional annotations of the 54 most ancient protein domains. We show how primordial functions are linked to folded structures and how their interaction with cofactors expanded the functional repertoire. We also reveal protocell membranes played a crucial role in early protein evolution and show translation started with RNA and thioester cofactor-mediated aminoacylation. Our findings allow elaboration of an evolutionary model of early biochemistry that is firmly grounded in phylogenomic information and biochemical, biophysical, and structural knowledge. The model describes how primordial α-helical bundles stabilized membranes, how these were decorated by layered arrangements of β-sheets and α-helices, and how these arrangements became globular. Ancient forms of aminoacyl-tRNA synthetase (aaRS) catalytic domains and ancient non-ribosomal protein synthetase (NRPS) modules gave rise to primordial protein synthesis and the ability to generate a code for specificity in their active sites. These structures diversified producing cofactor-binding molecular switches and barrel structures. Accretion of domains and molecules gave rise to modern aaRSs, NRPS, and ribosomal ensembles, first organized around novel emerging cofactors (tRNA and carrier proteins) and then more complex cofactor structures (rRNA). The model explains how the generation of protein structures acted as scaffold for nucleic acids and resulted in crystallization of modern translation.
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Luo Y, Liu Y, Sun D, Ojcius DM, Zhao J, Lin X, Wu D, Zhang R, Chen M, Li L, Yan J. InvA protein is a Nudix hydrolase required for infection by pathogenic Leptospira in cell lines and animals. J Biol Chem 2011; 286:36852-63. [PMID: 21862592 PMCID: PMC3196074 DOI: 10.1074/jbc.m111.219931] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2011] [Revised: 08/01/2011] [Indexed: 12/11/2022] Open
Abstract
Leptospirosis caused by pathogenic species of the genus Leptospira is a re-emerging zoonotic disease, which affects a wide variety of host species and is transmitted by contaminated water. The genomes of several pathogenic Leptospira species contain a gene named invA, which contains a Nudix domain. However, the function of this gene has never been characterized. Here, we demonstrated that the invA gene was highly conserved in protein sequence and present in all tested pathogenic Leptospira species. The recombinant InvA protein of pathogenic L. interrogans strain Lai hydrolyzed several specific dinucleoside oligophosphate substrates, reflecting the enzymatic activity of Nudix in Leptospira species. Pathogenic leptospires did not express this protein in media but temporarily expressed it at early stages (within 60 min) of infection of macrophages and nephric epithelial cells. Comparing with the wild type, the invA-deficient mutant displayed much lower infectivity and a significantly reduced survival rate in macrophages and nephric epithelial cells. Moreover, the invA-deficient leptospires presented an attenuated virulence in hamsters, caused mild histopathological damage, and were transmitted in lower numbers in the urine, compared with the wild-type strain. The invA revertant, made by complementing the invA-deficient mutant with the invA gene, reacquired virulence similar to the wild type in vitro and in vivo. The LD(50) in hamsters was 1000-fold higher for the invA-deficient mutant than for the invA revertant and wild type. These results demonstrate that the InvA protein is a Nudix hydrolase, and the invA gene is essential for virulence in pathogenic Leptospira species.
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Affiliation(s)
- Yihui Luo
- From the Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of Medical College, Hangzhou, Zhejiang 310003, China
- the Department of Medical Microbiology and Parasitology, College of Medicine, and
| | - Yan Liu
- the National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Dexter Sun
- the New York Presbyterian Hospital and Hospital for Special Surgery, Weill Medical College, Cornell University SinoUnited Health, New York, New York 10021, and
| | - David M. Ojcius
- the Health Sciences Research Institute and School of Natural Sciences, University of California, Merced, California 95343
| | - Jinfang Zhao
- From the Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of Medical College, Hangzhou, Zhejiang 310003, China
- the Department of Medical Microbiology and Parasitology, College of Medicine, and
| | - Xuai Lin
- From the Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of Medical College, Hangzhou, Zhejiang 310003, China
- the Department of Medical Microbiology and Parasitology, College of Medicine, and
| | - Dong Wu
- the National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Rongguang Zhang
- the National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Ming Chen
- the Department of Bioinformatics, College of Life Science, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Lanjuan Li
- From the Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of Medical College, Hangzhou, Zhejiang 310003, China
| | - Jie Yan
- From the Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of Medical College, Hangzhou, Zhejiang 310003, China
- the Department of Medical Microbiology and Parasitology, College of Medicine, and
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Fraga H, Fontes R. Enzymatic synthesis of mono and dinucleoside polyphosphates. Biochim Biophys Acta Gen Subj 2011; 1810:1195-204. [PMID: 21978831 DOI: 10.1016/j.bbagen.2011.09.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 09/09/2011] [Accepted: 09/19/2011] [Indexed: 01/08/2023]
Abstract
BACKGROUND Mono and dinucleoside polyphosphates (p(n)Ns and Np(n)Ns) exist in living organisms and induce diverse biological effects through interaction with intracellular and cytoplasmic membrane proteins. The source of these compounds is associated with secondary activities of a diverse group of enzymes. SCOPE OF REVIEW Here we discuss the mechanisms that can promote their synthesis at a molecular level. Although all the enzymes described in this review are able to catalyse the in vitro synthesis of Np(n)Ns (and/or p(n)N), it is not clear which ones are responsible for their in vivo accumulation. MAJOR CONCLUSIONS Despite the large amount of knowledge already available, important questions remain to be answered and a more complete understanding of p(n)Ns and Np(n)Ns synthesis mechanisms is required. With the possible exception of (GTP:GTP guanylyltransferase of Artemia), all enzymes able to catalyse the synthesis of p(n)Ns and Np(n)Ns are unspecific and the factors that can promote their synthesis relative to the canonical enzyme activities are unclear. GENERAL SIGNIFICANCE The fact that p(n)Ns and Np(n)Ns syntheses are promiscuous activities of housekeeping enzymes does not reduce its physiological or pathological importance. Here we resume the current knowledge regarding their enzymatic synthesis and point the open questions on the field.
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Affiliation(s)
- Hugo Fraga
- Department of Biochemistry, Universitat Autonoma de Barcelona, Spain
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Stachelska-Wierzchowska A, Wieczorek ZJ. Hydrolysis of 5',5'-tri- or tetraphosphate-mRNA 5'-cap analogs promoted by Cu2+ or Zn2+ metal ions. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2011; 30:135-48. [PMID: 21360411 DOI: 10.1080/15257770.2010.551722] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Kinetics of the hydrolysis of a P(1)-(7-methylguanosinyl-5') P(3)-(guanosinyl-5') triphosphate (m(7)GpppG), P(1)-(7-methylguanosinyl-5') P(4)- (guanosinyl-5') tetraphosphate (m(7)GppppG), diadenosine-5',5'''-P(1),P(3)-triphosphate (ApppA), and diadenosine-5',5'''-P(1),P(4)-tetraphosphate (AppppA) promoted by Cu(2+) or Zn(2+) has been investigated. Time-dependent products distributions at various metal ion concentrations have been determined by CZE and HPLC-RP. The results show that in acidic conditions, in the presence of metal ion, the predominant hydrolytic reaction is the cleavage of 5',5'-oligophosphate bridge. The 5',5'-oligophosphate bridge of the dinucleotides studied is hydrolyzed by Cu(2+) more efficiently than by Zn(2+). At the catalyst concentration of 2 mM the cleavage of the 5',5'-triphosphate bridge of m(7)GpppG was ∼3.6 times faster, and that of the tetraphosphate bridge of m(7)GppppG ∼2.3-fold faster in the presence of Cu(2+) compared to the Zn(2+) ion, applied as catalysts. Dependence of the rates of hydrolysis on the catalyst concentration was in some instances not linear, interpreted as evidence for participation of more than one metal ion in the transition complex.
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Krakowiak A, Pęcherzewska R, Kaczmarek R, Tomaszewska A, Nawrot B, Stec WJ. Evaluation of influence of Ap4A analogues on Fhit-positive HEK293T cells; cytotoxicity and ability to induce apoptosis. Bioorg Med Chem 2011; 19:5053-60. [PMID: 21757356 DOI: 10.1016/j.bmc.2011.06.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 06/02/2011] [Accepted: 06/08/2011] [Indexed: 01/06/2023]
Abstract
Fragile histidine triad (Fhit) protein encoded by tumour suppressor FHIT gene is a proapoptotic protein with diadenosine polyphosphate (Ap(n)A, n=2-6) hydrolase activity. It has been hypothesised that formation of Fhit-substrate complex results in an apoptosis initiation signal while subsequent hydrolysis of Ap(n)A terminates this action. A series of Ap(n)A analogues have been identified in vitro as strong Fhit ligands [Varnum, J. M.; Baraniak, J.; Kaczmarek, R.; Stec, W. J.; Brenner, C. BMC Chem. Biol.2001, 1, 3]. We assumed that in Fhit-positive cells these compounds might preferentially bind to Fhit and inhibit its hydrolytic activity what would prolong the lifetime of apoptosis initiation signalling complex. Therefore, several Fhit inhibitors were tested for their cytotoxicity and ability to induce apoptosis in Fhit-positive HEK293T cells. These experiments have shown that Ap(4)A analogue, containing a glycerol residue instead of the central pyrophosphate and two terminal phosphorothioates [A(PS)-CH(2)CH(OH)CH(2)-(PS)A (1)], is the most cytotoxic among test compounds (IC(50)=17.5±4.2 μM) and triggers caspase-dependent cell apoptosis. The Fhit-negative HEK293T cells (in which Fhit was silenced by RNAi) were not sensitive to compound 1. These results indicate that the Ap(4)A analogue 1 induces Fhit-dependent apoptosis and therefore, it can be considered as a drug candidate for anticancer therapy in Fhit-positive cancer cells and in Fhit-negative cancer cells, in which re-expression of Fhit was accomplished by gene therapy.
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Affiliation(s)
- Agnieszka Krakowiak
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Department of Bioorganic Chemistry, Sienkiewicza 112, 90-363 Lodz, Poland.
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Isabella VM, Clark VL. Deep sequencing-based analysis of the anaerobic stimulon in Neisseria gonorrhoeae. BMC Genomics 2011; 12:51. [PMID: 21251255 PMCID: PMC3032703 DOI: 10.1186/1471-2164-12-51] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Accepted: 01/20/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Maintenance of an anaerobic denitrification system in the obligate human pathogen, Neisseria gonorrhoeae, suggests that an anaerobic lifestyle may be important during the course of infection. Furthermore, mounting evidence suggests that reduction of host-produced nitric oxide has several immunomodulary effects on the host. However, at this point there have been no studies analyzing the complete gonococcal transcriptome response to anaerobiosis. Here we performed deep sequencing to compare the gonococcal transcriptomes of aerobically and anaerobically grown cells. Using the information derived from this sequencing, we discuss the implications of the robust transcriptional response to anaerobic growth. RESULTS We determined that 198 chromosomal genes were differentially expressed (~10% of the genome) in response to anaerobic conditions. We also observed a large induction of genes encoded within the cryptic plasmid, pJD1. Validation of RNA-seq data using translational-lacZ fusions or RT-PCR demonstrated the RNA-seq results to be very reproducible. Surprisingly, many genes of prophage origin were induced anaerobically, as well as several transcriptional regulators previously unknown to be involved in anaerobic growth. We also confirmed expression and regulation of a small RNA, likely a functional equivalent of fnrS in the Enterobacteriaceae family. We also determined that many genes found to be responsive to anaerobiosis have also been shown to be responsive to iron and/or oxidative stress. CONCLUSIONS Gonococci will be subject to many forms of environmental stress, including oxygen-limitation, during the course of infection. Here we determined that the anaerobic stimulon in gonococci was larger than previous studies would suggest. Many new targets for future research have been uncovered, and the results derived from this study may have helped to elucidate factors or mechanisms of virulence that may have otherwise been overlooked.
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Affiliation(s)
- Vincent M Isabella
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Box 672, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Virginia L Clark
- Department of Microbiology and Immunology, School of Medicine and Dentistry, University of Rochester, Box 672, 601 Elmwood Avenue, Rochester, NY 14642, USA
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Arczewska KD, Baumeier C, Kassahun H, Sengupta T, Bjørås M, Kuśmierek JT, Nilsen H. Caenorhabditis elegans NDX-4 is a MutT-type enzyme that contributes to genomic stability. DNA Repair (Amst) 2010; 10:176-87. [PMID: 21111690 DOI: 10.1016/j.dnarep.2010.10.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 10/04/2010] [Accepted: 10/22/2010] [Indexed: 12/11/2022]
Abstract
MutT enzymes prevent DNA damage by hydrolysis of 8-oxodGTP, an oxidized substrate for DNA synthesis and antimutagenic, anticarcinogenic, and antineurodegenerative functions of MutT enzymes are well established. MutT has been found in almost all kingdoms of life, including many bacterial species, yeasts, plants and mammals. However, a Caenorhabditis elegans MutT homologue was not previously identified. Here, we demonstrate that NDX-4 exhibits both hallmarks of a MutT-type enzyme with an ability to hydrolyze 8-oxodGTP and suppress the Escherichia coli mutT mutator phenotype. Moreover, we show that NDX-4 contributes to genomic stability in vivo in C. elegans. Phenotypic analyses of an ndx-4 mutant reveal that loss of NDX-4 leads to upregulation of key stress responsive genes that likely compensate for the in vivo role of NDX-4 in protection against deleterious consequences of oxidative stress. This discovery will enable us to use this extremely robust genetic model for further research into the contribution of oxidative DNA damage to phenotypes associated with oxidative stress.
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Francischetti IMB, Calvo E, Andersen JF, Pham VM, Favreau AJ, Barbian KD, Romero A, Valenzuela JG, Ribeiro JMC. Insight into the Sialome of the Bed Bug, Cimex lectularius. J Proteome Res 2010; 9:3820-31. [PMID: 20441151 DOI: 10.1021/pr1000169] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The evolution of insects to a blood diet leads to the development of a saliva that antagonizes their hosts' hemostasis and inflammation. Hemostasis and inflammation are redundant processes, and thus a complex salivary potion composed of dozens or near 100 different polypeptides is commonly found by transcriptome or proteome analysis of these organisms. Several insect orders or families evolved independently to hematophagy, creating unique salivary potions in the form of novel pharmacological use of endogenous substances and in the form of unique proteins not matching other known proteins, these probably arriving by fast evolution of salivary proteins as they evade their hosts' immune response. In this work we present a preliminary description of the sialome (from the Greek Sialo = saliva) of the common bed bug Cimex lectularius, the first such work from a member of the Cimicidae family. This manuscript is a guide for the supplemental database files http://exon.niaid.nih.gov/transcriptome/C_lectularius/S1/Cimex-S1.zip and http://exon.niaid.nih.gov/transcriptome/C_lectularius/S2/Cimex-S2.xls.
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Affiliation(s)
- Ivo M B Francischetti
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, Rockville, Maryland 20852, USA
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Butterfield DA, Hardas SS, Lange MLB. Oxidatively modified glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and Alzheimer's disease: many pathways to neurodegeneration. J Alzheimers Dis 2010; 20:369-93. [PMID: 20164570 DOI: 10.3233/jad-2010-1375] [Citation(s) in RCA: 189] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Recently, the oxidoreductase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), has become a subject of interest as more and more studies reveal a surfeit of diverse GAPDH functions, extending beyond traditional aerobic metabolism of glucose. As a result of multiple isoforms and cellular locales, GAPDH is able to come in contact with a variety of small molecules, proteins, membranes, etc., that play important roles in normal and pathologic cell function. Specifically, GAPDH has been shown to interact with neurodegenerative disease-associated proteins, including the amyloid-beta protein precursor (AbetaPP). Studies from our laboratory have shown significant inhibition of GAPDH dehydrogenase activity in Alzheimer's disease (AD) brain due to oxidative modification. Although oxidative stress and damage is a common phenomenon in the AD brain, it would seem that inhibition of glycolytic enzyme activity is merely one avenue in which AD pathology affects neuronal cell development and survival, as oxidative modification can also impart a toxic gain-of-function to many proteins, including GAPDH. In this review, we examine the many functions of GAPDH with respect to AD brain; in particular, the apparent role(s) of GAPDH in AD-related apoptotic cell death is emphasized.
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Affiliation(s)
- D Allan Butterfield
- Department of Chemistry, University of Kentucky, Center of Membrane Sciences, Lexington, KY40506-0055, USA.
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Park SG, Park HS, Jeong IK, Cho YM, Lee HK, Kang YS, Kim S, Park KS. Autoantibodies against aminoacyl-tRNA synthetase: novel diagnostic marker for type 1 diabetes mellitus. Biomarkers 2010; 15:358-66. [PMID: 20429837 DOI: 10.3109/13547501003777823] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES To investigate whether or not antiaminoacyl-tRNA synthetase (aaRS) autoantibodies could be detected in patients with type 1 diabetes mellitus (DM) and be used as a diagnostic marker for type 1 DM, autoantibodies against aaRSs were measured in the plasma of normal subjects, patients with type 1 DM and patients with type 2 DM. METHODS An enzyme-linked immunosorbent assay was performed to detect anti-aaRS autoantibodies in the plasma of normal subjects, and patients with type 1 DM, and patients with type 2 DM. RESULTS From the 65 (normal), 58 (type 1 DM) and 57 (type 2 DM) subjects, anti-aaRS autoantibodies were found in 37.9% of patients with type 1 DM compared with 1.54% of the non-diabetic controls, and 5.26% of the patients with type 2 DM (p <0.0001). In addition, anti-aaRS autoantibodies were identified in 30% of patients with type 1 DM without classical type 1 DM autoantibodies. CONCLUSION Anti-aaRS autoantibodies were identified in 37.9% of patients with type 1 DM. The results of this study demonstrate for the first time that autoantibodies against aaRSs are specifically associated with type 1 DM.
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Affiliation(s)
- Sang Gyu Park
- Laboratory for Tracing of Gene Function, Department of Biomedical Science, CHA University, Yeoksam-dong, Kangnam-gu, Seoul, Korea.
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Saldivar JC, Shibata H, Huebner K. Pathology and biology associated with the fragile FHIT gene and gene product. J Cell Biochem 2010; 109:858-65. [PMID: 20082323 DOI: 10.1002/jcb.22481] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
More than 12 years and >800 scientific publications after the discovery of the first gene at a chromosome fragile site, the FHIT gene at FRA3B, there are still questions to pursue concerning the selective advantage conferred to cells by loss of expression of FHIT, the most frequent target of allele deletion in precancerous lesions and cancers. These questions are considered in light of recent investigations of genetic and epigenetic alterations to the locus and in a retrospective consideration of biological roles of the Fhit protein discovered through functional studies.
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Affiliation(s)
- Joshua C Saldivar
- Integrated Biomedical Science Graduate Program, Ohio State University Medical Center, Columbus, Ohio, USA
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Di-adenosine tetraphosphate (Ap4A) metabolism impacts biofilm formation by Pseudomonas fluorescens via modulation of c-di-GMP-dependent pathways. J Bacteriol 2010; 192:3011-23. [PMID: 20154123 DOI: 10.1128/jb.01571-09] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dinucleoside tetraphosphates are common constituents of the cell and are thought to play diverse biological roles in organisms ranging from bacteria to humans. In this study we characterized two independent mechanisms by which di-adenosine tetraphosphate (Ap4A) metabolism impacts biofilm formation by Pseudomonas fluorescens. Null mutations in apaH, the gene encoding nucleoside tetraphosphate hydrolase, resulted in a marked increase in the cellular level of Ap4A. Concomitant with this increase, Pho regulon activation in low-inorganic-phosphate (P(i)) conditions was severely compromised. As a consequence, an apaH mutant was not sensitive to Pho regulon-dependent inhibition of biofilm formation. In addition, we characterized a Pho-independent role for Ap4A metabolism in regulation of biofilm formation. In P(i)-replete conditions Ap4A metabolism was found to impact expression and localization of LapA, the major adhesin regulating surface commitment by P. fluorescens. Increases in the level of c-di-GMP in the apaH mutant provided a likely explanation for increased localization of LapA to the outer membrane in response to elevated Ap4A concentrations. Increased levels of c-di-GMP in the apaH mutant were associated with increases in the level of GTP, suggesting that elevated levels of Ap4A may promote de novo purine biosynthesis. In support of this suggestion, supplementation with adenine could partially suppress the biofilm and c-di-GMP phenotypes of the apaH mutant. We hypothesize that changes in the substrate (GTP) concentration mediated by altered flux through nucleotide biosynthetic pathways may be a significant point of regulation for c-di-GMP biosynthesis and regulation of biofilm formation.
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Vasilenko N, Moshynskyy I, Zakhartchouk A. SARS coronavirus protein 7a interacts with human Ap4A-hydrolase. Virol J 2010; 7:31. [PMID: 20144233 PMCID: PMC2831879 DOI: 10.1186/1743-422x-7-31] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Accepted: 02/09/2010] [Indexed: 12/12/2022] Open
Abstract
The SARS coronavirus (SARS-CoV) open reading frame 7a (ORF 7a) encodes a 122 amino acid accessory protein. It has no significant sequence homology with any other known proteins. The 7a protein is present in the virus particle and has been shown to interact with several host proteins; thereby implicating it as being involved in several pathogenic processes including apoptosis, inhibition of cellular protein synthesis, and activation of p38 mitogen activated protein kinase. In this study we present data demonstrating that the SARS-CoV 7a protein interacts with human Ap4A-hydrolase (asymmetrical diadenosine tetraphosphate hydrolase, EC 3.6.1.17). Ap4A-hydrolase is responsible for metabolizing the "allarmone" nucleotide Ap4A and therefore likely involved in regulation of cell proliferation, DNA replication, RNA processing, apoptosis and DNA repair. The interaction between 7a and Ap4A-hydrolase was identified using yeast two-hybrid screening. The interaction was confirmed by co-immunoprecipitation from cultured human cells transiently expressing V5-His tagged 7a and HA tagged Ap4A-hydrolase. Human tissue culture cells transiently expressing 7a and Ap4A-hydrolase tagged with EGFP and Ds-Red2 respectively show these proteins co-localize in the cytoplasm.
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Affiliation(s)
- Natalia Vasilenko
- Vaccine and Infectious Disease Organization (VIDO), University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK S7N5E3, Canada
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Jeyakanthan J, Kanaujia SP, Nishida Y, Nakagawa N, Praveen S, Shinkai A, Kuramitsu S, Yokoyama S, Sekar K. Free and ATP-bound structures of Ap4A hydrolase from Aquifex aeolicus V5. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2010; 66:116-24. [PMID: 20124691 DOI: 10.1107/s0907444909047064] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Accepted: 11/07/2009] [Indexed: 11/10/2022]
Abstract
Asymmetric diadenosine tetraphosphate (Ap(4)A) hydrolases degrade the metabolite Ap(4)A back into ATP and AMP. The three-dimensional crystal structure of Ap(4)A hydrolase (16 kDa) from Aquifex aeolicus has been determined in free and ATP-bound forms at 1.8 and 1.95 A resolution, respectively. The overall three-dimensional crystal structure of the enzyme shows an alphabetaalpha-sandwich architecture with a characteristic loop adjacent to the catalytic site of the protein molecule. The ATP molecule is bound in the primary active site and the adenine moiety of the nucleotide binds in a ring-stacking arrangement equivalent to that observed in the X-ray structure of Ap(4)A hydrolase from Caenorhabditis elegans. Binding of ATP in the active site induces local conformational changes which may have important implications in the mechanism of substrate recognition in this class of enzymes. Furthermore, two invariant water molecules have been identified and their possible structural and/or functional roles are discussed. In addition, modelling of the substrate molecule at the primary active site of the enzyme suggests a possible path for entry and/or exit of the substrate and/or product molecule.
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Affiliation(s)
- Jeyaraman Jeyakanthan
- Life Science Group, National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan
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Wakasugi K. Species-specific differences in the regulation of the aminoacylation activity of mammalian tryptophanyl-tRNA synthetases. FEBS Lett 2010; 584:229-32. [PMID: 19941862 DOI: 10.1016/j.febslet.2009.11.073] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Accepted: 11/19/2009] [Indexed: 11/30/2022]
Abstract
Tryptophanyl-tRNA synthetases (TrpRSs) catalyze the aminoacylation of tRNA(Trp). Previously, I demonstrated that Zn(2+)-depleted human TrpRS is enzymatically inactive and that binding of Zn(2+) or heme to human TrpRS stimulates its aminoacylation activity. In the present study, bovine and mouse TrpRSs were found to be constitutively active regardless of the presence of Zn(2+) or ferriprotoporphyrin IX chloride. Mutagenesis experiments demonstrated that the human H130R mutant is constitutively active and that the bovine R135H, E438A double mutant binds with Zn(2+) or heme to enhance its aminoacylation activity as does human wild-type TrpRS. These results provide the first evidence of species-specific regulation of TrpRS activity.
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Affiliation(s)
- Keisuke Wakasugi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan.
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Hassan MI, Naiyer A, Ahmad F. Fragile histidine triad protein: structure, function, and its association with tumorogenesis. J Cancer Res Clin Oncol 2009; 136:333-50. [PMID: 20033706 DOI: 10.1007/s00432-009-0751-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Accepted: 12/09/2009] [Indexed: 01/31/2023]
Abstract
BACKGROUND The human fragile histidine triad (FHIT) gene is a putative tumor suppressor gene, which is located at chromosome region 3p14.2. It was suggested that the loss of heterozygosity (LOH), homozygous deletions, and abnormal expression of the FHIT gene were involved in several types of human malignancies. MATERIALS AND METHODS To determine the role of FHIT in various cancers, we have performed structural and functional analysis of FHIT in detail. RESULTS AND DISCUSSION The protein FHIT catalyzes the Mg(2+) dependent hydrolysis of P1-5 cent-O-adenosine-P3-5 cent-O-adenosine triphosphate, Ap3A, to AMP, and ADP. The reaction is thought to follow a two-step mechanism. Histidine triad proteins, named for a motif related to the sequence H-cent-H-cent-H-cent-cent- (cent, a hydrophobic amino acid), belong to superfamily of nucleotide hydrolases and transferases. This enzyme acts on the R-phosphate of ribonucleotides, and contain a approximately 30-kDa domain that is typically a homodimer of approximately 15 kDa polypeptides with catalytic site. CONCLUSION Here we have gathered information is known about biological activities of FHIT, the structural and biochemical bases for their functions. Our approach may provide a comparative framework for further investigation of FHIT.
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Affiliation(s)
- Md Imtaiyaz Hassan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025, India
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Guo RT, Chong YE, Guo M, Yang XL. Crystal structures and biochemical analyses suggest a unique mechanism and role for human glycyl-tRNA synthetase in Ap4A homeostasis. J Biol Chem 2009; 284:28968-76. [PMID: 19710017 PMCID: PMC2781443 DOI: 10.1074/jbc.m109.030692] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Aminoacyl-tRNA synthetases catalyze the attachment of amino acids to their cognate tRNAs for protein synthesis. However, the aminoacylation reaction can be diverted to produce diadenosine tetraphosphate (Ap4A), a universal pleiotropic signaling molecule needed for cell regulation pathways. The only known mechanism for Ap4A production by a tRNA synthetase is through the aminoacylation reaction intermediate aminoacyl-AMP, thus making Ap4A synthesis amino acid-dependent. Here, we demonstrate a new mechanism for Ap4A synthesis. Crystal structures and biochemical analyses show that human glycyl-tRNA synthetase (GlyRS) produces Ap4A by direct condensation of two ATPs, independent of glycine concentration. Interestingly, whereas the first ATP-binding pocket is conserved for all class II tRNA synthetases, the second ATP pocket is formed by an insertion domain that is unique to GlyRS, suggesting that GlyRS is the only tRNA synthetase catalyzing direct Ap4A synthesis. A special role for GlyRS in Ap4A homeostasis is proposed.
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Affiliation(s)
- Rey-Ting Guo
- From the Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Yeeting E. Chong
- From the Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Min Guo
- From the Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Xiang-Lei Yang
- From the Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, To whom correspondence should be addressed: Scripps Research Inst., BCC110, North Torrey Pines Rd., La Jolla, CA 92037. Tel.: 858-784-8976; Fax: 858-784-7250; E-mail:
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Enlightened protein: Fhit tumor suppressor protein structure and function and its role in the toxicity of protoporphyrin IX-mediated photodynamic reaction. Toxicol Appl Pharmacol 2009; 241:246-52. [PMID: 19716840 DOI: 10.1016/j.taap.2009.08.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 08/18/2009] [Accepted: 08/20/2009] [Indexed: 12/12/2022]
Abstract
The Fhit tumor suppressor protein possesses Ap(3)A (diadenosine triphosphate - ApppA) hydrolytic activity in vitro and its gene is found inactive in many pre-malignant states due to gene inactivation. For several years Fhit has been a widely investigated protein as its cellular function still remains largely unsolved. Fhit was shown to act as a molecular 'switch' of cell death via cascade operating on the influence of ATR-Chk1 pathway but also through the mitochondrial apoptotic pathway. Notably, Fhit was reported by our group to enhance the overall eradication effect of porphyrin-mediated photodynamic treatment (PDT). In this review the up-to-date findings on Fhit protein as a tumor suppressor and its role in PDT are presented.
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