1
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Saha S, Mandal SK, Kanaujia SP. Distinct characteristics of putative archaeal 5-methylcytosine RNA methyltransferases unveil their substrate specificities and evolutionary ancestries. J Biomol Struct Dyn 2024:1-18. [PMID: 38450736 DOI: 10.1080/07391102.2024.2325670] [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: 11/30/2023] [Accepted: 02/25/2024] [Indexed: 03/08/2024]
Abstract
5-Methylcytosine methyltransferases (m5C MTases) are known to be involved in the modification of RNA. Although these enzymes have been relatively well characterized in bacteria and eukarya, a complete understanding of the archaeal counterparts is lacking. In this study, the identification and characterization of archaeal RNA m5C MTases were performed. As a case study, a hyperthermophilic archaeon, Pyrococcus horikoshii OT3, which possesses five putative RNA m5C MTases, was chosen. Among the five putative RNA m5C MTases, two proteins (PH0851 and PH1991) have been characterized as homologs of a bacterial rRNA MTase (RsmB) and eukaryal tRNA MTase (NSUN6), respectively. The in-depth characterization of the remaining three putative RNA m5C MTases (PH1078, PH1374, and PH1537) in this study suggests the presence of the signature architecture and catalytic residues plausibly involved in the binding of their cognate RNA substrates. Additionally, the results also suggest the existence of two RsmB-like proteins (PH0851 and PH1078) belonging to the same subfamily IV of m5C RNA MTase. However, the proteins PH1374 and PH1537 belong to the same subfamily V but bind to different substrates, rRNA and tRNA, respectively. The findings further indicate that archaeal RNA m5C MTases link those from bacteria and eukarya.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Sayan Saha
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, India
| | - Suraj Kumar Mandal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, India
| | - Shankar Prasad Kanaujia
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, India
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2
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Kuznetsova SA, Petrukov KS, Pletnev FI, Sergiev PV, Dontsova OA. RNA (C5-cytosine) Methyltransferases. BIOCHEMISTRY (MOSCOW) 2019; 84:851-869. [PMID: 31522668 DOI: 10.1134/s0006297919080029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The review summarizes the data on pro- and eukaryotic RNA (C5-cytosine) methyltransferases. The structure, intracellular location, RNA targets, and catalytic mechanisms of these enzymes, as well as the functional role of methylated cytosine residues in RNA are presented. The functions of RNA (C5-cytosine) methyltransferases unassociated with their methylation activity are discussed. Special attention is given to the similarities and differences in the structures and mechanisms of action of RNA and DNA methyltransferases. The data on the association of mutations in the RNA (C5-cytosine) methyltransferases genes and human diseases are presented.
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Affiliation(s)
- S A Kuznetsova
- Lomonosov Moscow State University, Institute of Functional Genomics, Moscow, 119234, Russia.
| | - K S Petrukov
- Lomonosov Moscow State University, Faculty of Chemistry, Moscow, 119991, Russia
| | - F I Pletnev
- Lomonosov Moscow State University, Faculty of Chemistry, Moscow, 119991, Russia.,Skolkovo Institute of Science and Technology, Skolkovo, 121205, Moscow Region, Russia.,Institute of Bioorganic Chemistry, Moscow, 117997, Russia
| | - P V Sergiev
- Lomonosov Moscow State University, Institute of Functional Genomics, Moscow, 119234, Russia.,Lomonosov Moscow State University, Faculty of Chemistry, Moscow, 119991, Russia.,Skolkovo Institute of Science and Technology, Skolkovo, 121205, Moscow Region, Russia.,Petrov National Medical Research Center of Oncology, St. Petersburg, 197758, Russia
| | - O A Dontsova
- Lomonosov Moscow State University, Faculty of Chemistry, Moscow, 119991, Russia.,Skolkovo Institute of Science and Technology, Skolkovo, 121205, Moscow Region, Russia.,Institute of Bioorganic Chemistry, Moscow, 117997, Russia
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3
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Liu RJ, Long T, Li J, Li H, Wang ED. Structural basis for substrate binding and catalytic mechanism of a human RNA:m5C methyltransferase NSun6. Nucleic Acids Res 2017; 45:6684-6697. [PMID: 28531330 PMCID: PMC5499824 DOI: 10.1093/nar/gkx473] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 05/12/2017] [Indexed: 12/20/2022] Open
Abstract
5-methylcytosine (m5C) modifications of RNA are ubiquitous in nature and play important roles in many biological processes such as protein translational regulation, RNA processing and stress response. Aberrant expressions of RNA:m5C methyltransferases are closely associated with various human diseases including cancers. However, no structural information for RNA-bound RNA:m5C methyltransferase was available until now, hindering elucidation of the catalytic mechanism behind RNA:m5C methylation. Here, we have solved the structures of NSun6, a human tRNA:m5C methyltransferase, in the apo form and in complex with a full-length tRNA substrate. These structures show a non-canonical conformation of the bound tRNA, rendering the base moiety of the target cytosine accessible to the enzyme for methylation. Further biochemical assays reveal the critical, but distinct, roles of two conserved cysteine residues for the RNA:m5C methylation. Collectively, for the first time, we have solved the complex structure of a RNA:m5C methyltransferase and addressed the catalytic mechanism of the RNA:m5C methyltransferase family, which may allow for structure-based drug design toward RNA:m5C methyltransferase–related diseases.
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Affiliation(s)
- Ru-Juan Liu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, P. R. China
| | - Tao Long
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, P. R. China.,University of Chinese Academy of Sciences, Beijing 100039, P. R. China
| | - Jing Li
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, P. R. China.,University of Chinese Academy of Sciences, Beijing 100039, P. R. China
| | - Hao Li
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, P. R. China.,University of Chinese Academy of Sciences, Beijing 100039, P. R. China
| | - En-Duo Wang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, P. R. China.,University of Chinese Academy of Sciences, Beijing 100039, P. R. China.,School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai 201210, P. R. China
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4
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Ashapkin VV, Kutueva LI, Vanyushin BF. Dnmt2 is the most evolutionary conserved and enigmatic cytosine DNA methyltransferase in eukaryotes. RUSS J GENET+ 2016. [DOI: 10.1134/s1022795416030029] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Moon HJ, Redman KL. Trm4 and Nsun2 RNA:m5C Methyltransferases Form Metabolite-Dependent, Covalent Adducts with Previously Methylated RNA. Biochemistry 2014; 53:7132-44. [DOI: 10.1021/bi500882b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Haley J. Moon
- Indiana University School of Medicine-Fort Wayne, 2101 Coliseum Boulevard East, Fort Wayne, Indiana 46805, United States
| | - Kent L. Redman
- Indiana University School of Medicine-Fort Wayne, 2101 Coliseum Boulevard East, Fort Wayne, Indiana 46805, United States
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6
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Spenkuch F, Hinze G, Kellner S, Kreutz C, Micura R, Basché T, Helm M. Dye label interference with RNA modification reveals 5-fluorouridine as non-covalent inhibitor. Nucleic Acids Res 2014; 42:12735-45. [PMID: 25300485 PMCID: PMC4227767 DOI: 10.1093/nar/gku908] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The interest in RNA modification enzymes surges due to their involvement in epigenetic phenomena. Here we present a particularly informative approach to investigate the interaction of dye-labeled RNA with modification enzymes. We investigated pseudouridine (Ψ) synthase TruB interacting with an alleged suicide substrate RNA containing 5-fluorouridine (5FU). A longstanding dogma, stipulating formation of a stable covalent complex was challenged by discrepancies between the time scale of complex formation and enzymatic turnover. Instead of classic mutagenesis, we used differentially positioned fluorescent labels to modulate substrate properties in a range of enzymatic conversion between 6% and 99%. Despite this variegation, formation of SDS-stable complexes occurred instantaneously for all 5FU-substrates. Protein binding was investigated by advanced fluorescence spectroscopy allowing unprecedented simultaneous detection of change in fluorescence lifetime, anisotropy decay, as well as emission and excitation maxima. Determination of Kd values showed that introduction of 5FU into the RNA substrate increased protein affinity by 14× at most. Finally, competition experiments demonstrated reversibility of complex formation for 5FU-RNA. Our results lead us to conclude that the hitherto postulated long-term covalent interaction of TruB with 5FU tRNA is based on the interpretation of artifacts. This is likely true for the entire class of pseudouridine synthases.
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Affiliation(s)
- Felix Spenkuch
- Institute of Pharmacy and Biochemistry, University of Mainz, Staudingerweg 5, D-55128 Mainz, Germany
| | - Gerald Hinze
- Institute of Physical Chemistry, University of Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany
| | - Stefanie Kellner
- Institute of Pharmacy and Biochemistry, University of Mainz, Staudingerweg 5, D-55128 Mainz, Germany
| | - Christoph Kreutz
- Institute of Organic Chemistry, Center for Molecular Biosciences (CMBI), University of Innsbruck, Innrain 52A, A-60230 Innsbruck, Austria
| | - Ronald Micura
- Institute of Organic Chemistry, Center for Chemistry and Biomedicine - CCB, University of Innsbruck, Innrain 80/82, A-60230 Innsbruck, Austria
| | - Thomas Basché
- Institute of Physical Chemistry, University of Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany
| | - Mark Helm
- Institute of Pharmacy and Biochemistry, University of Mainz, Staudingerweg 5, D-55128 Mainz, Germany
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7
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Liu J, Jia G. Methylation modifications in eukaryotic messenger RNA. J Genet Genomics 2013; 41:21-33. [PMID: 24480744 DOI: 10.1016/j.jgg.2013.10.002] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 10/09/2013] [Accepted: 10/20/2013] [Indexed: 10/26/2022]
Abstract
RNA methylation modifications have been found for decades of years, which occur at different RNA types of numerous species, and their distribution is species-specific. However, people rarely know their biological functions. There are several identified methylation modifications in eukaryotic messenger RNA (mRNA), such as N(7)-methylguanosine (m(7)G) at the cap, N(6)-methyl-2'-O-methyladenosine (m(6)Am), 2'-O-methylation (Nm) within the cap and the internal positions, and internal N(6)-methyladenosine (m(6)A) and 5-methylcytosine (m(5)C). Among them, m(7)G cap was studied more clearly and found to have vital roles in several important mRNA processes like mRNA translation, stability and nuclear export. m(6)A as the most abundant modification in mRNA was found in the 1970s and has been proposed to function in mRNA splicing, translation, stability, transport and so on. m(6)A has been discovered as the first RNA reversible modification which is demethylated directly by human fat mass and obesity associated protein (FTO) and its homolog protein, alkylation repair homolog 5 (ALKBH5). FTO has a special demethylation mechanism that demethylases m(6)A to A through two over-oxidative intermediate states: N(6)-hydroxymethyladenosine (hm(6)A) and N(6)-formyladenosine (f(6)A). The two newly discovered m(6)A demethylases, FTO and ALKBH5, significantly control energy homeostasis and spermatogenesis, respectively, indicating that the dynamic and reversible m(6)A, analogous to DNA and histone modifications, plays broad roles in biological kingdoms and brings us an emerging field "RNA Epigenetics". 5-methylcytosine (5mC) as an epigenetic mark in DNA has been studied widely, but m(5)C in mRNA is seldom explored. The bisulfide sequencing showed m(5)C is another abundant modification in mRNA, suggesting that it might be another RNA epigenetic mark. This review focuses on the main methylation modifications in mRNA to describe their formation, distribution, function and demethylation from the current knowledge and to provide future perspectives on functional studies.
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Affiliation(s)
- Jun Liu
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Guifang Jia
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
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8
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Sharma S, Yang J, Watzinger P, Kötter P, Entian KD. Yeast Nop2 and Rcm1 methylate C2870 and C2278 of the 25S rRNA, respectively. Nucleic Acids Res 2013; 41:9062-76. [PMID: 23913415 PMCID: PMC3799443 DOI: 10.1093/nar/gkt679] [Citation(s) in RCA: 145] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Yeast 25S rRNA was reported to contain a single cytosine methylation (m5C). In the present study using a combination of RP-HPLC, mung bean nuclease assay and rRNA mutagenesis, we discovered that instead of one, yeast contains two m5C residues at position 2278 and 2870. Furthermore, we identified and characterized two putative methyltransferases, Rcm1 and Nop2 to be responsible for these two cytosine methylations, respectively. Both proteins are highly conserved, which correlates with the presence of two m5C residues at identical positions in higher eukaryotes, including humans. The human homolog of yeast Nop2, p120 has been discovered to be upregulated in various cancer tissues, whereas the human homolog of Rcm1, NSUN5 is completely deleted in the William's-Beuren Syndrome. The substrates and function of both human homologs remained unknown. In the present study, we also provide insights into the significance of these two m5C residues. The loss of m5C2278 results in anisomycin hypersensitivity, whereas the loss of m5C2870 affects ribosome synthesis and processing. Establishing the locations and enzymes in yeast will not only help identifying the function of their homologs in higher organisms, but will also enable understanding the role of these modifications in ribosome function and architecture.
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Affiliation(s)
- Sunny Sharma
- Department of Molecular Genetics & Cellular Microbiology, Institute of Molecular Biosciences, Goethe University, Max-von-Laue Str. 9, 60438 Frankfurt/M, Germany
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9
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Sibbritt T, Patel HR, Preiss T. Mapping and significance of the mRNA methylome. WILEY INTERDISCIPLINARY REVIEWS-RNA 2013; 4:397-422. [PMID: 23681756 DOI: 10.1002/wrna.1166] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 03/20/2013] [Accepted: 03/22/2013] [Indexed: 12/25/2022]
Abstract
Internal methylation of eukaryotic mRNAs in the form of N6-methyladenosine (m(6)A) and 5-methylcytidine (m(5)C) has long been known to exist, but progress in understanding its role was hampered by difficulties in identifying individual sites. This was recently overcome by high-throughput sequencing-based methods that mapped thousands of sites for both modifications throughout mammalian transcriptomes, with most sites found in mRNAs. The topology of m(6)A in mouse and human revealed both conserved and variable sites as well as plasticity in response to extracellular cues. Within mRNAs, m(5)C and m(6)A sites were relatively depleted in coding sequences and enriched in untranslated regions, suggesting functional interactions with post-transcriptional gene control. Finer distribution analyses and preexisting literature point toward roles in the regulation of mRNA splicing, translation, or decay, through an interplay with RNA-binding proteins and microRNAs. The methyltransferase (MTase) METTL3 'writes' m(6)A marks on mRNA, whereas the demethylase FTO can 'erase' them. The RNA:m(5)C MTases NSUN2 and TRDMT1 have roles in tRNA methylation but they also act on mRNA. Proper functioning of these enzymes is important in development and there are clear links to human disease. For instance, a common variant of FTO is a risk allele for obesity carried by 1 billion people worldwide and mutations cause a lethal syndrome with growth retardation and brain deficits. NSUN2 is linked to cancer and stem cell biology and mutations cause intellectual disability. In this review, we summarize the advances, open questions, and intriguing possibilities in this emerging field that might be called RNA modomics or epitranscriptomics.
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Affiliation(s)
- Tennille Sibbritt
- Genome Biology Department, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
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10
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Auxilien S, Guérineau V, Szweykowska-Kulińska Z, Golinelli-Pimpaneau B. The human tRNA m (5) C methyltransferase Misu is multisite-specific. RNA Biol 2012; 9:1331-8. [PMID: 22995836 DOI: 10.4161/rna.22180] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The human tRNA m ( 5) C methyltransferase Misu is a novel downstream target of the proto-oncogene Myc that participates in controlling cell division and proliferation. Misu catalyzes the transfer of a methyl group from S-adenosyl-L-methionine to carbon 5 of cytosines in tRNAs. It was previously shown to catalyze in vitro the intron-dependent formation of m ( 5) C at the first position of the anticodon (position 34) within the human pre-tRNA (Leu) (CAA). In addition, it was recently reported that C48 and C49 are methylated in vivo by Misu. We report here the expression of hMisu in Escherichia coli and its purification to homogeneity. We show that this enzyme methylates position 48 in tRNA (Leu) (CAA) with or without intron and positions 48, 49 and 50 in tRNA (Gly2) (GCC) in vitro. Therefore, hMisu is the enzyme responsible for the methylation of at least four cytosines in human tRNAs. By comparison, the orthologous yeast enzyme Trm4 catalyzes the methylation of carbon 5 of cytosine at positions 34, 40, 48 or 49 depending on the tRNAs.
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Affiliation(s)
- Sylvie Auxilien
- Laboratoire d'Enzymologie et Biochimie Structurales, Centre de Recherche de Gif, CNRS, Gif-sur-Yvette, France.
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11
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Hamdane D, Argentini M, Cornu D, Myllykallio H, Skouloubris S, Hui-Bon-Hoa G, Golinelli-Pimpaneau B. Insights into folate/FAD-dependent tRNA methyltransferase mechanism: role of two highly conserved cysteines in catalysis. J Biol Chem 2011; 286:36268-80. [PMID: 21846722 DOI: 10.1074/jbc.m111.256966] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The flavoprotein TrmFO methylates specifically the C5 carbon of the highly conserved uridine 54 in tRNAs. Contrary to most methyltransferases, the 1-carbon unit transferred by TrmFO derives from 5,10-methylenetetrahydrofolate and not from S-adenosyl-L-methionine. The enzyme also employs the FAD hydroquinone as a reducing agent of the C5 methylene U54-tRNA intermediate in vitro. By analogy with the catalytic mechanism of thymidylate synthase ThyA, a conserved cysteine located near the FAD isoalloxazine ring was proposed to act as a nucleophile during catalysis. Here, we mutated this residue (Cys-53 in Bacillus subtilis TrmFO) to alanine and investigated its functional role. Biophysical characterization of this variant demonstrated the major structural role of Cys-53 in maintaining both the integrity and plasticity of the flavin binding site. Unexpectedly, gel mobility shift assays showed that, like the wild-type enzyme, the inactive C53A variant was capable of forming a covalent complex with a 5-fluorouridine-containing mini-RNA. This result confirms the existence of a covalent intermediate during catalysis but rules out a nucleophilic role for Cys-53. To identify the actual nucleophile, two other strictly conserved cysteines (Cys-192 and Cys-226) that are relatively far from the active site were replaced with alanine, and a double mutant C53A/C226A was generated. Interestingly, only mutations that target Cys-226 impeded TrmFO from forming a covalent complex and methylating tRNA. Altogether, we propose a revised mechanism for the m(5)U54 modification catalyzed by TrmFO, where Cys-226 attacks the C6 atom of the uridine, and Cys-53 plays the role of the general base abstracting the C5 proton.
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Affiliation(s)
- Djemel Hamdane
- Laboratoire d'Enzymologie et Biochimie Structurales, Centre de Recherche de Gif, CNRS, 1 Avenue de la Terrasse, 91198 Gif-sur-Yvette, France.
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12
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Guelorget A, Golinelli-Pimpaneau B. Mechanism-Based Strategies for Trapping and Crystallizing Complexes of RNA-Modifying Enzymes. Structure 2011; 19:282-91. [DOI: 10.1016/j.str.2011.01.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 12/22/2010] [Accepted: 01/11/2011] [Indexed: 11/26/2022]
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13
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Galimand M, Schmitt E, Panvert M, Desmolaize B, Douthwaite S, Mechulam Y, Courvalin P. Intrinsic resistance to aminoglycosides in Enterococcus faecium is conferred by the 16S rRNA m5C1404-specific methyltransferase EfmM. RNA (NEW YORK, N.Y.) 2011; 17:251-262. [PMID: 21159796 PMCID: PMC3022275 DOI: 10.1261/rna.2233511] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Accepted: 11/04/2010] [Indexed: 05/29/2023]
Abstract
Aminoglycosides are ribosome-targeting antibiotics and a major drug group of choice in the treatment of serious enterococcal infections. Here we show that aminoglycoside resistance in Enterococcus faecium strain CIP 54-32 is conferred by the chromosomal gene efmM, encoding the E. faecium methyltransferase, as well as by the previously characterized aac(6')-Ii that encodes a 6'-N-aminoglycoside acetyltransferase. Inactivation of efmM in E. faecium increases susceptibility to the aminoglycosides kanamycin and tobramycin, and, conversely, expression of a recombinant version of efmM in Escherichia coli confers resistance to these drugs. The EfmM protein shows significant sequence similarity to E. coli RsmF (previously called YebU), which is a 5-methylcytidine (m⁵C) methyltransferase modifying 16S rRNA nucleotide C1407. The target for EfmM is shown by mass spectrometry to be a neighboring 16S rRNA nucleotide at C1404. EfmM uses the methyl group donor S-adenosyl-L-methionine to catalyze formation of m⁵C1404 on the 30S ribosomal subunit, whereas naked 16S rRNA and the 70S ribosome are not substrates. Addition of the 5-methyl to C1404 sterically hinders aminoglycoside binding. Crystallographic structure determination of EfmM at 2.28 Å resolution reveals an N-terminal domain connected to a central methyltransferase domain that is linked by a flexible lysine-rich region to two C-terminal subdomains. Mutagenesis of the methyltransferase domain established that two cysteines at specific tertiary locations are required for catalysis. The tertiary structure of EfmM is highly similar to that of RsmF, consistent with m⁵C formation at adjacent sites on the 30S subunit, while distinctive structural features account for the enzymes' respective specificities for nucleotides C1404 and C1407.
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Affiliation(s)
- Marc Galimand
- Unité des Agents Antibactériens, Institut Pasteur, F-75724 Paris Cedex 15, France.
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14
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Kuratani M, Hirano M, Goto-Ito S, Itoh Y, Hikida Y, Nishimoto M, Sekine SI, Bessho Y, Ito T, Grosjean H, Yokoyama S. Crystal structure of Methanocaldococcus jannaschii Trm4 complexed with sinefungin. J Mol Biol 2010; 401:323-33. [PMID: 20600111 DOI: 10.1016/j.jmb.2010.06.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 06/17/2010] [Accepted: 06/19/2010] [Indexed: 12/19/2022]
Abstract
tRNA:m(5)C methyltransferase Trm4 generates the modified nucleotide 5-methylcytidine in archaeal and eukaryotic tRNA molecules, using S-adenosyl-l-methionine (AdoMet) as methyl donor. Most archaea and eukaryotes possess several Trm4 homologs, including those related to diseases, while the archaeon Methanocaldococcus jannaschii has only one gene encoding a Trm4 homolog, MJ0026. The recombinant MJ0026 protein catalyzed AdoMet-dependent methyltransferase activity on tRNA in vitro and was shown to be the M. jannaschii Trm4. We determined the crystal structures of the substrate-free M. jannaschii Trm4 and its complex with sinefungin at 1.27 A and 2.3 A resolutions, respectively. This AdoMet analog is bound in a negatively charged pocket near helix alpha8. This helix can adopt two different conformations, thereby controlling the entry of AdoMet into the active site. Adjacent to the sinefungin-bound pocket, highly conserved residues form a large, positively charged surface, which seems to be suitable for tRNA binding. The structure explains the roles of several conserved residues that were reportedly involved in the enzymatic activity or stability of Trm4p from the yeast Saccharomyces cerevisiae. We also discuss previous genetic and biochemical data on human NSUN2/hTrm4/Misu and archaeal PAB1947 methyltransferase, based on the structure of M. jannaschii Trm4.
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Affiliation(s)
- Mitsuo Kuratani
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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15
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Motorin Y, Lyko F, Helm M. 5-methylcytosine in RNA: detection, enzymatic formation and biological functions. Nucleic Acids Res 2009; 38:1415-30. [PMID: 20007150 PMCID: PMC2836557 DOI: 10.1093/nar/gkp1117] [Citation(s) in RCA: 240] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The nucleobase modification 5-methylcytosine (m5C) is widespread both in DNA and different cellular RNAs. The functions and enzymatic mechanisms of DNA m5C-methylation were extensively studied during the last decades. However, the location, the mechanism of formation and the cellular function(s) of the same modified nucleobase in RNA still remain to be elucidated. The recent development of a bisulfite sequencing approach for efficient m5C localization in various RNA molecules puts ribo-m5C in a highly privileged position as one of the few RNA modifications whose detection is amenable to PCR-based amplification and sequencing methods. Additional progress in the field also includes the characterization of several specific RNA methyltransferase enzymes in various organisms, and the discovery of a new and unexpected link between DNA and RNA m5C-methylation. Numerous putative RNA:m5C-MTases have now been identified and are awaiting characterization, including the identification of their RNA substrates and their related cellular functions. In order to bring these recent exciting developments into perspective, this review provides an ordered overview of the detection methods for RNA methylation, of the biochemistry, enzymology and molecular biology of the corresponding modification enzymes, and discusses perspectives for the emerging biological functions of these enzymes.
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Affiliation(s)
- Yuri Motorin
- Laboratoire ARN-RNP Maturation-Structure-Fonction, Enzymologie Moléculaire et Structurale (AREMS), UMR 7214 CNRS-UHP Faculté des Sciences et Techniques, Université Henri Poincaré, Nancy 1, Bld des Aiguillettes, BP 70239, 54506 Vandoeuvre-les-Nancy, France
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Jurkowski TP, Meusburger M, Phalke S, Helm M, Nellen W, Reuter G, Jeltsch A. Human DNMT2 methylates tRNA(Asp) molecules using a DNA methyltransferase-like catalytic mechanism. RNA (NEW YORK, N.Y.) 2008; 14:1663-70. [PMID: 18567810 PMCID: PMC2491481 DOI: 10.1261/rna.970408] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Accepted: 04/17/2008] [Indexed: 05/21/2023]
Abstract
Although their amino acid sequences and structure closely resemble DNA methyltransferases, Dnmt2 proteins were recently shown by Goll and colleagues to function as RNA methyltransferases transferring a methyl group to the C5 position of C38 in tRNA(Asp). We observe that human DNMT2 methylates tRNA isolated from Dnmt2 knock-out Drosophila melanogaster and Dictyostelium discoideum. RNA extracted from wild type D. melanogaster was methylated to a lower degree, but in the case of Dictyostelium, there was no difference in the methylation of RNA isolated from wild-type and Dnmt2 knock-out strains. Methylation of in vitro transcribed tRNA(Asp) confirms it to be a target of DNMT2. Using site directed mutagenesis, we show here that the enzyme has a DNA methyltransferase-like mechanism, because similar residues from motifs IV, VI, and VIII are involved in catalysis as identified in DNA methyltransferases. In addition, exchange of C292, which is located in a CFT motif conserved among Dnmt2 proteins, strongly reduced the catalytic activity of DNMT2. Dnmt2 represents the first example of an RNA methyltransferase using a DNA methyltransferase type of mechanism.
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Affiliation(s)
- Tomasz P Jurkowski
- Biochemistry Laboratory, School of Engineering and Science, Jacobs University Bremen, 28759 Bremen, Germany
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Walbott H, Leulliot N, Grosjean H, Golinelli-Pimpaneau B. The crystal structure of Pyrococcus abyssi tRNA (uracil-54, C5)-methyltransferase provides insights into its tRNA specificity. Nucleic Acids Res 2008; 36:4929-40. [PMID: 18653523 PMCID: PMC2528175 DOI: 10.1093/nar/gkn437] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The 5-methyluridine is invariably found at position 54 in the TΨC loop of tRNAs of most organisms. In Pyrococcus abyssi, its formation is catalyzed by the S-adenosyl-l-methionine-dependent tRNA (uracil-54, C5)-methyltransferase (PabTrmU54), an enzyme that emerged through an ancient horizontal transfer of an RNA (uracil, C5)-methyltransferase-like gene from bacteria to archaea. The crystal structure of PabTrmU54 in complex with S-adenosyl-l-homocysteine at 1.9 Å resolution shows the protein organized into three domains like Escherichia coli RumA, which catalyzes the same reaction at position 1939 of 23S rRNA. A positively charged groove at the interface between the three domains probably locates part of the tRNA-binding site of PabTrmU54. We show that a mini-tRNA lacking both the D and anticodon stem-loops is recognized by PabTrmU54. These results were used to model yeast tRNAAsp in the PabTrmU54 structure to get further insights into the different RNA specificities of RumA and PabTrmU54. Interestingly, the presence of two flexible loops in the central domain, unique to PabTrmU54, may explain the different substrate selectivities of both enzymes. We also predict that a large TΨC loop conformational change has to occur for the flipping of the target uridine into the PabTrmU54 active site during catalysis.
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Affiliation(s)
- Hélène Walbott
- Enzymology and Structural Biochemistry Laboratory, CNRS, 1 avenue de la Terrasse, 91198 Gif-sur-Yvette, France
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18
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Current awareness on yeast. Yeast 2008. [DOI: 10.1002/yea.1456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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