1
|
Espadas G, Llovera L, Ollivier A, Tuorto F, Novoa EM, Sabidó E. Spectral libraries from nucleobases and deoxyribonucleosides facilitate the identification of ribonucleosides by nano-flow liquid chromatography-tandem mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2024; 38:e9759. [PMID: 38680121 DOI: 10.1002/rcm.9759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 03/05/2024] [Accepted: 03/31/2024] [Indexed: 05/01/2024]
Abstract
RATIONALE The study addresses the challenge of identifying RNA post-transcriptional modifications when commercial standards are not available to generate reference spectral libraries. It proposes employing homologous nucleobases and deoxyribonucleosides as alternative reference spectral libraries to aid in identifying modified ribonucleosides and distinguishing them from their positional isomers when the standards are unavailable. METHODS Complete sets of ribonucleoside, deoxyribonucleoside and nucleobase standards were analyzed using high-performance nano-flow liquid chromatography coupled to an Orbitrap Eclipse Tribrid mass spectrometer. Spectral libraries were constructed from homologous nucleobases and deoxyribonucleosides using targeted MS2 and neutral-loss-triggered MS3 methods, and collision energies were optimized. The feasibility of using these libraries for identifying modified ribonucleosides and their positional isomers was assessed through comparison of spectral fragmentation patterns. RESULTS Our analysis reveals that both MS2 and neutral-loss-triggered MS3 methods yielded rich spectra with similar fragmentation patterns across ribonucleosides, deoxyribonucleosides and nucleobases. Moreover, we demonstrate that spectra from nucleobases and deoxyribonucleosides, generated at optimized collision energies, exhibited sufficient similarity to those of modified ribonucleosides to enable their use as reference spectra for accurate identification of positional isomers within ribonucleoside families. CONCLUSIONS The study demonstrates the efficacy of utilizing homologous nucleobases and deoxyribonucleosides as interchangeable reference spectral libraries for identifying modified ribonucleosides and their positional isomers. This approach offers a valuable solution for overcoming limitations posed by the unavailability of commercial standards, enhancing the analysis of RNA post-transcriptional modifications via mass spectrometry.
Collapse
Affiliation(s)
- Guadalupe Espadas
- Center for Genomics Regulation, The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Universitat Pompeu Fabra, Barcelona, Spain
| | - Laia Llovera
- Center for Genomics Regulation, The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Alexane Ollivier
- Center for Genomics Regulation, The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Francesca Tuorto
- Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Eva Maria Novoa
- Center for Genomics Regulation, The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Universitat Pompeu Fabra, Barcelona, Spain
| | - Eduard Sabidó
- Center for Genomics Regulation, The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Universitat Pompeu Fabra, Barcelona, Spain
| |
Collapse
|
2
|
Boswinkle K, McKinney J, Allen KD. Highlighting the Unique Roles of Radical S-Adenosylmethionine Enzymes in Methanogenic Archaea. J Bacteriol 2022; 204:e0019722. [PMID: 35880875 PMCID: PMC9380564 DOI: 10.1128/jb.00197-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Radical S-adenosylmethionine (SAM) enzymes catalyze an impressive variety of difficult biochemical reactions in various pathways across all domains of life. These metalloenzymes employ a reduced [4Fe-4S] cluster and SAM to generate a highly reactive 5'-deoxyadenosyl radical that is capable of initiating catalysis on otherwise unreactive substrates. Interestingly, the genomes of methanogenic archaea encode many unique radical SAM enzymes with underexplored or completely unknown functions. These organisms are responsible for the yearly production of nearly 1 billion tons of methane, a potent greenhouse gas as well as a valuable energy source. Thus, understanding the details of methanogenic metabolism and elucidating the functions of essential enzymes in these organisms can provide insights into strategies to decrease greenhouse gas emissions as well as inform advances in bioenergy production processes. This minireview provides an overview of the current state of the field regarding the functions of radical SAM enzymes in methanogens and discusses gaps in knowledge that should be addressed.
Collapse
Affiliation(s)
- Kaleb Boswinkle
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - Justin McKinney
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - Kylie D. Allen
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| |
Collapse
|
3
|
Wang JT, Zhou JB, Mao XL, Zhou L, Chen M, Zhang W, Wang ED, Zhou XL. OUP accepted manuscript. Nucleic Acids Res 2022; 50:2223-2239. [PMID: 35104889 PMCID: PMC8887486 DOI: 10.1093/nar/gkac056] [Citation(s) in RCA: 12] [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: 12/16/2021] [Revised: 01/16/2022] [Accepted: 01/25/2022] [Indexed: 11/14/2022] Open
Abstract
N6-Threonylcarbamoyladenosine (t6A) is a universal and pivotal tRNA modification. KEOPS in eukaryotes participates in its biogenesis, whose mutations are connected with Galloway-Mowat syndrome. However, the tRNA substrate selection mechanism by KEOPS and t6A modification function in mammalian cells remain unclear. Here, we confirmed that all ANN-decoding human cytoplasmic tRNAs harbor a t6A moiety. Using t6A modification systems from various eukaryotes, we proposed the possible coevolution of position 33 of initiator tRNAMet and modification enzymes. The role of the universal CCA end in t6A biogenesis varied among species. However, all KEOPSs critically depended on C32 and two base pairs in the D-stem. Knockdown of the catalytic subunit OSGEP in HEK293T cells had no effect on the steady-state abundance of cytoplasmic tRNAs but selectively inhibited tRNAIle aminoacylation. Combined with in vitro aminoacylation assays, we revealed that t6A functions as a tRNAIle isoacceptor-specific positive determinant for human cytoplasmic isoleucyl-tRNA synthetase (IARS1). t6A deficiency had divergent effects on decoding efficiency at ANN codons and promoted +1 frameshifting. Altogether, our results shed light on the tRNA recognition mechanism, revealing both commonality and diversity in substrate recognition by eukaryotic KEOPSs, and elucidated the critical role of t6A in tRNAIle aminoacylation and codon decoding in human cells.
Collapse
Affiliation(s)
| | | | - Xue-Ling Mao
- 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, University of Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
| | - Li Zhou
- School of Life Sciences, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, Gansu
| | - Meirong Chen
- School of Pharmacy, China Pharmaceutical University, 639 Longmian Avenue, Nanjing 211198, Jiangsu
| | - Wenhua Zhang
- School of Life Sciences, Lanzhou University, 222 South Tianshui Road, Lanzhou 730000, Gansu
| | - En-Duo Wang
- Correspondence may also be addressed to En-Duo Wang. Tel: +86 21 5492 1241; Fax: +86 21 5492 1011;
| | - Xiao-Long Zhou
- To whom correspondence should be addressed. Tel: +86 21 5492 1247 Fax: +86 21 5492 1011;
| |
Collapse
|
4
|
Kopina BJ, Missoury S, Collinet B, Fulton MG, Cirio C, van Tilbeurgh H, Lauhon CT. Structure of a reaction intermediate mimic in t6A biosynthesis bound in the active site of the TsaBD heterodimer from Escherichia coli. Nucleic Acids Res 2021; 49:2141-2160. [PMID: 33524148 PMCID: PMC7913687 DOI: 10.1093/nar/gkab026] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 12/21/2020] [Accepted: 01/15/2021] [Indexed: 11/14/2022] Open
Abstract
The tRNA modification N6-threonylcarbamoyladenosine (t6A) is universally conserved in all organisms. In bacteria, the biosynthesis of t6A requires four proteins (TsaBCDE) that catalyze the formation of t6A via the unstable intermediate l-threonylcarbamoyl-adenylate (TC-AMP). While the formation and stability of this intermediate has been studied in detail, the mechanism of its transfer to A37 in tRNA is poorly understood. To investigate this step, the structure of the TsaBD heterodimer from Escherichia coli has been solved bound to a stable phosphonate isosteric mimic of TC-AMP. The phosphonate inhibits t6A synthesis in vitro with an IC50 value of 1.3 μM in the presence of millimolar ATP and L-threonine. The inhibitor binds to TsaBD by coordination to the active site Zn atom via an oxygen atom from both the phosphonate and the carboxylate moieties. The bound conformation of the inhibitor suggests that the catalysis exploits a putative oxyanion hole created by a conserved active site loop of TsaD and that the metal essentially serves as a binding scaffold for the intermediate. The phosphonate bound crystal structure should be useful for the rational design of potent, drug-like small molecule inhibitors as mechanistic probes or potentially novel antibiotics.
Collapse
Affiliation(s)
- Brett J Kopina
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin, Madison, WI 53705, USA
| | - Sophia Missoury
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Bruno Collinet
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.,Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne-Université, UMR7590 CNRS, MNHN, Paris, France
| | - Mark G Fulton
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin, Madison, WI 53705, USA
| | - Charles Cirio
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Herman van Tilbeurgh
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Charles T Lauhon
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin, Madison, WI 53705, USA
| |
Collapse
|
5
|
Nainytė M, Müller F, Ganazzoli G, Chan CY, Crisp A, Globisch D, Carell T. Amino Acid Modified RNA Bases as Building Blocks of an Early Earth RNA-Peptide World. Chemistry 2020; 26:14856-14860. [PMID: 32573861 PMCID: PMC7756884 DOI: 10.1002/chem.202002929] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Indexed: 12/14/2022]
Abstract
Fossils of extinct species allow us to reconstruct the process of Darwinian evolution that led to the species diversity we see on Earth today. The origin of the first functional molecules able to undergo molecular evolution and thus eventually able to create life, are largely unknown. The most prominent idea in the field posits that biology was preceded by an era of molecular evolution, in which RNA molecules encoded information and catalysed their own replication. This RNA world concept stands against other hypotheses, that argue for example that life may have begun with catalytic peptides and primitive metabolic cycles. The question whether RNA or peptides were first is addressed by the RNA‐peptide world concept, which postulates a parallel existence of both molecular species. A plausible experimental model of how such an RNA‐peptide world may have looked like, however, is absent. Here we report the synthesis and physicochemical evaluation of amino acid containing adenosine bases, which are closely related to molecules that are found today in the anticodon stem‐loop of tRNAs from all three kingdoms of life. We show that these adenosines lose their base pairing properties, which allow them to equip RNA with amino acids independent of the sequence context. As such we may consider them to be living molecular fossils of an extinct molecular RNA‐peptide world.
Collapse
Affiliation(s)
- Milda Nainytė
- Department of Chemistry, LMU München, Butenandtstr. 5-13, 81377, München, Germany
| | - Felix Müller
- Department of Chemistry, LMU München, Butenandtstr. 5-13, 81377, München, Germany
| | - Giacomo Ganazzoli
- Department of Chemistry, LMU München, Butenandtstr. 5-13, 81377, München, Germany
| | - Chun-Yin Chan
- Department of Chemistry, LMU München, Butenandtstr. 5-13, 81377, München, Germany
| | - Antony Crisp
- Department of Chemistry, LMU München, Butenandtstr. 5-13, 81377, München, Germany
| | - Daniel Globisch
- Department of Medicinal Chemistry, Uppsala University, Husargatan 3, 75123, Uppsala, Sweden
| | - Thomas Carell
- Department of Chemistry, LMU München, Butenandtstr. 5-13, 81377, München, Germany
| |
Collapse
|
6
|
Swinehart W, Deutsch C, Sarachan KL, Luthra A, Bacusmo JM, de Crécy-Lagard V, Swairjo MA, Agris PF, Iwata-Reuyl D. Specificity in the biosynthesis of the universal tRNA nucleoside N6-threonylcarbamoyl adenosine (t 6A)-TsaD is the gatekeeper. RNA (NEW YORK, N.Y.) 2020; 26:1094-1103. [PMID: 32385138 PMCID: PMC7430679 DOI: 10.1261/rna.075747.120] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 05/03/2020] [Indexed: 06/11/2023]
Abstract
N6-threonylcarbamoyl adenosine (t6A) is a nucleoside modification found in all kingdoms of life at position 37 of tRNAs decoding ANN codons, which functions in part to restrict translation initiation to AUG and suppress frameshifting at tandem ANN codons. In Bacteria the proteins TsaB, TsaC (or C2), TsaD, and TsaE, comprise the biosynthetic apparatus responsible for t6A formation. TsaC(C2) and TsaD harbor the relevant active sites, with TsaC(C2) catalyzing the formation of the intermediate threonylcarbamoyladenosine monophosphate (TC-AMP) from ATP, threonine, and CO2, and TsaD catalyzing the transfer of the threonylcarbamoyl moiety from TC-AMP to A37 of substrate tRNAs. Several related modified nucleosides, including hydroxynorvalylcarbamoyl adenosine (hn6A), have been identified in select organisms, but nothing is known about their biosynthesis. To better understand the mechanism and structural constraints on t6A formation, and to determine if related modified nucleosides are formed via parallel biosynthetic pathways or the t6A pathway, we carried out biochemical and biophysical investigations of the t6A systems from E. coli and T. maritima to address these questions. Using kinetic assays of TsaC(C2), tRNA modification assays, and NMR, our data demonstrate that TsaC(C2) exhibit relaxed substrate specificity, producing a variety of TC-AMP analogs that can differ in both the identity of the amino acid and nucleotide component, whereas TsaD displays more stringent specificity, but efficiently produces hn6A in E. coli and T. maritima tRNA. Thus, in organisms that contain modifications such as hn6A in their tRNA, we conclude that their origin is due to formation via the t6A pathway.
Collapse
Affiliation(s)
- William Swinehart
- Department of Chemistry, Portland State University, Portland, Oregon 97201, USA
| | - Christopher Deutsch
- Department of Chemistry, Portland State University, Portland, Oregon 97201, USA
| | - Kathryn L Sarachan
- The RNA Institute, State University of New York, Albany, New York 12222, USA
| | - Amit Luthra
- Department of Chemistry and Biochemistry, and The Viral Information Institute, San Diego State University, San Diego, California 92182, USA
| | - Jo Marie Bacusmo
- Department of Microbiology and Cell Science, University of Florida, Gainsville, Florida 32611, USA
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, University of Florida, Gainsville, Florida 32611, USA
| | - Manal A Swairjo
- Department of Chemistry and Biochemistry, and The Viral Information Institute, San Diego State University, San Diego, California 92182, USA
| | - Paul F Agris
- The RNA Institute, State University of New York, Albany, New York 12222, USA
| | - Dirk Iwata-Reuyl
- Department of Chemistry, Portland State University, Portland, Oregon 97201, USA
| |
Collapse
|
7
|
McCown PJ, Ruszkowska A, Kunkler CN, Breger K, Hulewicz JP, Wang MC, Springer NA, Brown JA. Naturally occurring modified ribonucleosides. WILEY INTERDISCIPLINARY REVIEWS. RNA 2020; 11:e1595. [PMID: 32301288 PMCID: PMC7694415 DOI: 10.1002/wrna.1595] [Citation(s) in RCA: 107] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 03/09/2020] [Accepted: 03/11/2020] [Indexed: 12/18/2022]
Abstract
The chemical identity of RNA molecules beyond the four standard ribonucleosides has fascinated scientists since pseudouridine was characterized as the "fifth" ribonucleotide in 1951. Since then, the ever-increasing number and complexity of modified ribonucleosides have been found in viruses and throughout all three domains of life. Such modifications can be as simple as methylations, hydroxylations, or thiolations, complex as ring closures, glycosylations, acylations, or aminoacylations, or unusual as the incorporation of selenium. While initially found in transfer and ribosomal RNAs, modifications also exist in messenger RNAs and noncoding RNAs. Modifications have profound cellular outcomes at various levels, such as altering RNA structure or being essential for cell survival or organism viability. The aberrant presence or absence of RNA modifications can lead to human disease, ranging from cancer to various metabolic and developmental illnesses such as Hoyeraal-Hreidarsson syndrome, Bowen-Conradi syndrome, or Williams-Beuren syndrome. In this review article, we summarize the characterization of all 143 currently known modified ribonucleosides by describing their taxonomic distributions, the enzymes that generate the modifications, and any implications in cellular processes, RNA structure, and disease. We also highlight areas of active research, such as specific RNAs that contain a particular type of modification as well as methodologies used to identify novel RNA modifications. This article is categorized under: RNA Processing > RNA Editing and Modification.
Collapse
Affiliation(s)
- Phillip J. McCown
- Department of Chemistry and BiochemistryUniversity of Notre DameNotre DameIndianaUSA
| | - Agnieszka Ruszkowska
- Department of Chemistry and BiochemistryUniversity of Notre DameNotre DameIndianaUSA
- Present address:
Institute of Bioorganic ChemistryPolish Academy of SciencesPoznanPoland
| | - Charlotte N. Kunkler
- Department of Chemistry and BiochemistryUniversity of Notre DameNotre DameIndianaUSA
| | - Kurtis Breger
- Department of Chemistry and BiochemistryUniversity of Notre DameNotre DameIndianaUSA
| | - Jacob P. Hulewicz
- Department of Chemistry and BiochemistryUniversity of Notre DameNotre DameIndianaUSA
| | - Matthew C. Wang
- Department of Chemistry and BiochemistryUniversity of Notre DameNotre DameIndianaUSA
| | - Noah A. Springer
- Department of Chemistry and BiochemistryUniversity of Notre DameNotre DameIndianaUSA
| | - Jessica A. Brown
- Department of Chemistry and BiochemistryUniversity of Notre DameNotre DameIndianaUSA
| |
Collapse
|
8
|
tRNA Modification Profiles and Codon-Decoding Strategies in Methanocaldococcus jannaschii. J Bacteriol 2019; 201:JB.00690-18. [PMID: 30745370 DOI: 10.1128/jb.00690-18] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 01/31/2019] [Indexed: 12/13/2022] Open
Abstract
tRNAs play a critical role in mRNA decoding, and posttranscriptional modifications within tRNAs drive decoding efficiency and accuracy. The types and positions of tRNA modifications in model bacteria have been extensively studied, and tRNA modifications in a few eukaryotic organisms have also been characterized and localized to particular tRNA sequences. However, far less is known regarding tRNA modifications in archaea. While the identities of modifications have been determined for multiple archaeal organisms, Haloferax volcanii is the only organism for which modifications have been extensively localized to specific tRNA sequences. To improve our understanding of archaeal tRNA modification patterns and codon-decoding strategies, we have used liquid chromatography and tandem mass spectrometry to characterize and then map posttranscriptional modifications on 34 of the 35 unique tRNA sequences of Methanocaldococcus jannaschii A new posttranscriptionally modified nucleoside, 5-cyanomethyl-2-thiouridine (cnm5s2U), was discovered and localized to position 34. Moreover, data consistent with wyosine pathway modifications were obtained beyond the canonical tRNAPhe as is typical for eukaryotes. The high-quality mapping of tRNA anticodon loops enriches our understanding of archaeal tRNA modification profiles and decoding strategies.IMPORTANCE While many posttranscriptional modifications in M. jannaschii tRNAs are also found in bacteria and eukaryotes, several that are unique to archaea were identified. By RNA modification mapping, the modification profiles of M. jannaschii tRNA anticodon loops were characterized, allowing a comparative analysis with H. volcanii modification profiles as well as a general comparison with bacterial and eukaryotic decoding strategies. This general comparison reveals that M. jannaschii, like H. volcanii, follows codon-decoding strategies similar to those used by bacteria, although position 37 appears to be modified to a greater extent than seen in H. volcanii.
Collapse
|
9
|
Hori H, Kawamura T, Awai T, Ochi A, Yamagami R, Tomikawa C, Hirata A. Transfer RNA Modification Enzymes from Thermophiles and Their Modified Nucleosides in tRNA. Microorganisms 2018; 6:E110. [PMID: 30347855 PMCID: PMC6313347 DOI: 10.3390/microorganisms6040110] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 10/17/2018] [Accepted: 10/17/2018] [Indexed: 12/11/2022] Open
Abstract
To date, numerous modified nucleosides in tRNA as well as tRNA modification enzymes have been identified not only in thermophiles but also in mesophiles. Because most modified nucleosides in tRNA from thermophiles are common to those in tRNA from mesophiles, they are considered to work essentially in steps of protein synthesis at high temperatures. At high temperatures, the structure of unmodified tRNA will be disrupted. Therefore, thermophiles must possess strategies to stabilize tRNA structures. To this end, several thermophile-specific modified nucleosides in tRNA have been identified. Other factors such as RNA-binding proteins and polyamines contribute to the stability of tRNA at high temperatures. Thermus thermophilus, which is an extreme-thermophilic eubacterium, can adapt its protein synthesis system in response to temperature changes via the network of modified nucleosides in tRNA and tRNA modification enzymes. Notably, tRNA modification enzymes from thermophiles are very stable. Therefore, they have been utilized for biochemical and structural studies. In the future, thermostable tRNA modification enzymes may be useful as biotechnology tools and may be utilized for medical science.
Collapse
Affiliation(s)
- Hiroyuki Hori
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan.
| | - Takuya Kawamura
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan.
| | - Takako Awai
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan.
| | - Anna Ochi
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan.
| | - Ryota Yamagami
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan.
| | - Chie Tomikawa
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan.
| | - Akira Hirata
- Department of Materials Science and Biotechnology, Graduate School of Science and Engineering, Ehime University, Bunkyo 3, Matsuyama, Ehime 790-8577, Japan.
| |
Collapse
|
10
|
Seidu-Larry S, Krieg B, Hirsch M, Helm M, Domingo O. A modified guanosine phosphoramidite for click functionalization of RNA on the sugar edge. Chem Commun (Camb) 2012; 48:11014-6. [DOI: 10.1039/c2cc34015a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
|
11
|
Kuratani M, Kasai T, Akasaka R, Higashijima K, Terada T, Kigawa T, Shinkai A, Bessho Y, Yokoyama S. Crystal structure of Sulfolobus tokodaii Sua5 complexed with L-threonine and AMPPNP. Proteins 2011; 79:2065-75. [PMID: 21538543 DOI: 10.1002/prot.23026] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Revised: 01/31/2011] [Accepted: 02/25/2011] [Indexed: 11/09/2022]
Abstract
The hypermodified nucleoside N(6)-threonylcarbamoyladenosine resides at position 37 of tRNA molecules bearing U at position 36 and maintains translational fidelity in the three kingdoms of life. The N(6)-threonylcarbamoyl moiety is composed of L-threonine and bicarbonate, and its synthesis was genetically shown to require YrdC/Sua5. YrdC/Sua5 binds to tRNA and ATP. In this study, we analyzed the L-threonine-binding mode of Sua5 from the archaeon Sulfolobus tokodaii. Isothermal titration calorimetry measurements revealed that S. tokodaii Sua5 binds L-threonine more strongly than L-serine and glycine. The Kd values of Sua5 for L-threonine and L-serine are 9.3 μM and 2.6 mM, respectively. We determined the crystal structure of S. tokodaii Sua5, complexed with AMPPNP and L-threonine, at 1.8 Å resolution. The L-threonine is bound next to AMPPNP in the same pocket of the N-terminal domain. Thr118 and two water molecules form hydrogen bonds with AMPPNP in a unique manner for adenine-specific recognition. The carboxyl group and the side-chain hydroxyl and methyl groups of L-threonine are buried deep in the pocket, whereas the amino group faces AMPPNP. The L-threonine is located in a suitable position to react together with ATP for the synthesis of N(6)-threonylcarbamoyladenosine.
Collapse
Affiliation(s)
- Mitsuo Kuratani
- RIKEN Systems and Structural Biology Center, Yokohama 230-0045, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Arragain S, Handelman SK, Forouhar F, Wei FY, Tomizawa K, Hunt JF, Douki T, Fontecave M, Mulliez E, Atta M. Identification of eukaryotic and prokaryotic methylthiotransferase for biosynthesis of 2-methylthio-N6-threonylcarbamoyladenosine in tRNA. J Biol Chem 2010; 285:28425-33. [PMID: 20584901 DOI: 10.1074/jbc.m110.106831] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bacterial and eukaryotic transfer RNAs have been shown to contain hypermodified adenosine, 2-methylthio-N(6)-threonylcarbamoyladenosine, at position 37 (A(37)) adjacent to the 3'-end of the anticodon, which is essential for efficient and highly accurate protein translation by the ribosome. Using a combination of bioinformatic sequence analysis and in vivo assay coupled to HPLC/MS technique, we have identified, from distinct sequence signatures, two methylthiotransferase (MTTase) subfamilies, designated as MtaB in bacterial cells and e-MtaB in eukaryotic and archaeal cells. Both subfamilies are responsible for the transformation of N(6)-threonylcarbamoyladenosine into 2-methylthio-N(6)-threonylcarbamoyladenosine. Recently, a variant within the human CDKAL1 gene belonging to the e-MtaB subfamily was shown to predispose for type 2 diabetes. CDKAL1 is thus the first eukaryotic MTTase identified so far. Using purified preparations of Bacillus subtilis MtaB (YqeV), a CDKAL1 bacterial homolog, we demonstrate that YqeV/CDKAL1 enzymes, as the previously studied MTTases MiaB and RimO, contain two [4Fe-4S] clusters. This work lays the foundation for elucidating the function of CDKAL1.
Collapse
Affiliation(s)
- Simon Arragain
- Institut de Recherches en Technologie et Sciences pour le Vivant IRTSV-LCBM, UMR 5249 CEA/CNRS/UJF, Commissariat à l'Energie Atomique-Grenoble, 17 Avenue des Martyrs, 38054 Grenoble Cedex 09, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Anton BP, Russell SP, Vertrees J, Kasif S, Raleigh EA, Limbach PA, Roberts RJ. Functional characterization of the YmcB and YqeV tRNA methylthiotransferases of Bacillus subtilis. Nucleic Acids Res 2010; 38:6195-205. [PMID: 20472640 PMCID: PMC2952846 DOI: 10.1093/nar/gkq364] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Methylthiotransferases (MTTases) are a closely related family of proteins that perform both radical-S-adenosylmethionine (SAM) mediated sulfur insertion and SAM-dependent methylation to modify nucleic acid or protein targets with a methyl thioether group (-SCH(3)). Members of two of the four known subgroups of MTTases have been characterized, typified by MiaB, which modifies N(6)-isopentenyladenosine (i(6)A) to 2-methylthio-N(6)-isopentenyladenosine (ms(2)i(6)A) in tRNA, and RimO, which modifies a specific aspartate residue in ribosomal protein S12. In this work, we have characterized the two MTTases encoded by Bacillus subtilis 168 and find that, consistent with bioinformatic predictions, ymcB is required for ms(2)i(6)A formation (MiaB activity), and yqeV is required for modification of N(6)-threonylcarbamoyladenosine (t(6)A) to 2-methylthio-N(6)-threonylcarbamoyladenosine (ms(2)t(6)A) in tRNA. The enzyme responsible for the latter activity belongs to a third MTTase subgroup, no member of which has previously been characterized. We performed domain-swapping experiments between YmcB and YqeV to narrow down the protein domain(s) responsible for distinguishing i(6)A from t(6)A and found that the C-terminal TRAM domain, putatively involved with RNA binding, is likely not involved with this discrimination. Finally, we performed a computational analysis to identify candidate residues outside the TRAM domain that may be involved with substrate recognition. These residues represent interesting targets for further analysis.
Collapse
|
14
|
Abstract
In order to survive extremes of pH, temperature, salinity and pressure, organisms have been found to develop unique defences against their environment, leading to the biosynthesis of novel molecules ranging from simple osmolytes and lipids to complex secondary metabolites. This review highlights novel molecules isolated from microorganisms that either tolerate or favour extreme growth conditions.
Collapse
Affiliation(s)
- Zoe E Wilson
- Department of Chemistry, University of Auckland, 23 Symonds St, Auckland, 1010, New Zealand
| | | |
Collapse
|
15
|
RimO, a MiaB-like enzyme, methylthiolates the universally conserved Asp88 residue of ribosomal protein S12 in Escherichia coli. Proc Natl Acad Sci U S A 2008; 105:1826-31. [PMID: 18252828 DOI: 10.1073/pnas.0708608105] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ribosomal protein S12 undergoes a unique posttranslational modification, methylthiolation of residue D88, in Escherichia coli and several other bacteria. Using mass spectrometry, we have identified the enzyme responsible for this modification in E. coli, the yliG gene product. This enzyme, which we propose be called RimO, is a radical-S-adenosylmethionine protein that bears strong sequence similarity to MiaB, which methylthiolates tRNA. We show that RimO and MiaB represent two of four subgroups of a larger, ancient family of likely methylthiotransferases, the other two of which are typified by Bacillus subtilis YqeV and Methanococcus jannaschii Mj0867, and we predict that RimO is unique among these subgroups in its modification of protein as opposed to tRNA. Despite this, RimO has not significantly diverged from the other three subgroups at the sequence level even within the C-terminal TRAM domain, which in the methyltransferase RumA is known to bind the RNA substrate and which we presume to be responsible for substrate binding and recognition in all four subgroups of methylthiotransferases. To our knowledge, RimO and MiaB represent the most extreme known case of resemblance between enzymes modifying protein and nucleic acid. The initial results presented here constitute a bioinformatics-driven prediction with preliminary experimental validation that should serve as the starting point for several interesting lines of further inquiry.
Collapse
|
16
|
Zhang X, van der Donk WA. On the substrate specificity of dehydration by lacticin 481 synthetase. J Am Chem Soc 2007; 129:2212-3. [PMID: 17266311 PMCID: PMC2517113 DOI: 10.1021/ja067672v] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dehydroamino acids are valuable building blocks that are a challenge to incorporate synthetically into unprotected peptides. Lantibiotic synthetases possess dehydration activity that converts Ser and Thr residues in their peptide substrates into dehydroalanine and dehydrobutyrine residues, respectively. We show here that lacticin 481 synthetase can convert the Thr analogs (R )-3-EtSer, (R )-3-vinylSer, (R )-3-ethynylSer, and (R )-3-[(E )-propenyl]Ser into the corresponding dehydro amino acids when incorporated into its peptide substrate. This relaxed substrate specificity holds promise for using the enzyme for synthetic purposes and for lantibiotic engineering. On the other hand, (R )-3-PrSer, (R )-3-i PrSer, and allo -Thr are not substrates for the enzyme.
Collapse
Affiliation(s)
- Xingang Zhang
- Roger Adams Laboratory, Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL, 61801
| | - Wilfred A. van der Donk
- Roger Adams Laboratory, Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL, 61801
| |
Collapse
|
17
|
KELLY ROBERTM, PEEPLES TONYAL, HALIO SHERYLB, RINKER KRISTINAD, DUFFAUD GUYD. Extremely Thermophilic Microorganisms. Ann N Y Acad Sci 2006. [DOI: 10.1111/j.1749-6632.1994.tb44393.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
18
|
Louw R, Potgieter HC, Vorster W. Teratogenicity of 3-hydroxynorvaline in chicken and mouse embryos. Amino Acids 2005; 29:207-12. [PMID: 16082502 DOI: 10.1007/s00726-005-0233-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2005] [Accepted: 06/30/2005] [Indexed: 11/26/2022]
Abstract
3-Hydroxynorvaline (HNV; 2-amino-3-hydroxypentanoic acid), a microbial L-threonine analogue, is toxic to mammalian cells and displays antiviral properties. In view of this, we investigated the toxicity and/or potential teratogenicity of HNV in developing chicken and mouse embryos. HNV was administered to chicken embryos (in ovo; dose 75-300 mumole/egg; 48 h post-incubation) and pregnant Hanover NMRI mice (per os; total dose 900-1800 mg/kg body mass; gestation days 7-9). Control animals received sterile saline solutions. Harvested embryos (chicken embryos, 10 days post-incubation; mouse embryos; gestation day 18) were fixed in glutaraldehyde and stereomicroscopically inspected for signs of dysmorphogenesis. Body mass, body and toe length and mortality of chicken embryos, and the body mass and mortality of mouse embryos were recorded. HNV exposure significantly increased the incidence of embryotoxic (growth retardation, toxic mortality) and congenital defects in both chicken and mouse embryos. All the observed effects were dose-dependent. In conclusion, HNV is an embryotoxic and teratogenic compound, which caused significant developmental delay and congenital defects in developing chicken and mouse embryos.
Collapse
Affiliation(s)
- R Louw
- Division of Biochemistry, School for Chemistry and Biochemistry, Faculty of Science, North-West University, Potchefstroom, South Africa.
| | | | | |
Collapse
|
19
|
Kamel AM, Munson B. Collisionally-induced dissociation of purine antiviral agents: mechanisms of ion formation using gas phase hydrogen/deuterium exchange and electrospray ionization tandem mass spectrometry. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2004; 10:239-257. [PMID: 15103102 DOI: 10.1255/ejms.538] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
ESI and CID mass spectra were obtained for two purine nucleoside antiviral agents (acycloguanosine and vidarabine) and one purine nucleotide (vidarabine monophosphate) and the corresponding compounds in which the labile hydrogens were replaced by deuterium gas phase exchange. The number of labile hydrogens, x, was determined from a comparison of ESI spectra obtained with N(2) and with ND(3) as the nebulizer gas. CID mass spectra were obtained for [M+H](+) and [M -H](-) ions and the exchanged analogs, [M(Dx)+D](+) and [M(Dx)-D](-), produced by ESI using a Sciex API-IIIplus mass spectrometer. Compositions of product ions and mechanisms of decomposition were determined by comparison of the CID mass spectra of the undeuterated and deuterated species. Protonated purine antiviral agents dissociate through rearrangement decompositions of base-protonated [M+H](+) ions by cleavage of the glycosidic bonds to give the protonated bases with a sugar moiety as the neutral fragment. Cleavage of the same bonds with charge retention on the sugar moiety gives low abundance ions, due to the low proton affinity of the sugar moiety compared to that of purine base. CID of protonated purine bases [B+H](+) occurs through two major pathways: (1) elimination of NH(3) (ND(3)) and (2) loss of NH(2)CN (ND(2)CN). Minor pathways include elimination of HNCO (DNCO), loss of CO, and loss of HCN (DCN). Deprotonated acycloguanosine and vidarabine exhibit the deprotonated base [B-H](-) as a major fragment from glycosidic bond cleavage and charge delocalization on the base. Deprotonated vidarabine monophosphate, however, shows predominantly phosphate related product ions. CID of deprotonated guanine shows two principal pathways: (1) elimination of NH(3) (ND(3)) and (2) loss of NH(2)CN (ND(2)CN). Minor pathways include elimination of HNCO (DNCO), loss of CO, and loss of HCN (DCN). The dissociation reactions of deprotonated adenine, however, proceed by elimination of HCN and (2) elimination of NCHNH (NCHND). The mass spectra of the antiviral agents studied in this paper may be useful in predicting reaction pathways in other heteroaromatic ring decompositions of nucleosides and nucleotides.
Collapse
Affiliation(s)
- Amin M Kamel
- Department of Pharmacokinetics, Dynamics and Metabolism, Pfizer Global Research and Development, Groton Laboratories, Groton, CT 06340, USA.
| | | |
Collapse
|
20
|
Noon KR, Guymon R, Crain PF, McCloskey JA, Thomm M, Lim J, Cavicchioli R. Influence of temperature on tRNA modification in archaea: Methanococcoides burtonii (optimum growth temperature [Topt], 23 degrees C) and Stetteria hydrogenophila (Topt, 95 degrees C). J Bacteriol 2003; 185:5483-90. [PMID: 12949100 PMCID: PMC193749 DOI: 10.1128/jb.185.18.5483-5490.2003] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2003] [Accepted: 07/03/2003] [Indexed: 11/20/2022] Open
Abstract
We report the first study of tRNA modification in psychrotolerant archaea, specifically in the archaeon Methanococcoides burtonii grown at 4 and 23 degrees C. For comparison, unfractionated tRNA from the archaeal hyperthermophile Stetteria hydrogenophila cultured at 93 degrees C was examined. Analysis of modified nucleosides using liquid chromatography-electrospray ionization mass spectrometry revealed striking differences in levels and identities of tRNA modifications between the two organisms. Although the modification levels in M. burtonii tRNA are the lowest in any organism of which we are aware, it contains more than one residue per tRNA molecule of dihydrouridine, a molecule associated with maintenance of polynucleotide flexibility at low temperatures. No differences in either identities or levels of modifications, including dihydrouridine, as a function of culture temperature were observed, in contrast to selected tRNA modifications previously reported for archaeal hyperthermophiles. By contrast, S. hydrogenophila tRNA was found to contain a remarkable structural diversity of 31 modified nucleosides, including nine methylated guanosines, with eight different nucleoside species methylated at O-2' of ribose, known to be an effective stabilizing motif in RNA. These results show that some aspects of tRNA modification in archaea are strongly associated with environmental temperature and support the thesis that posttranscriptional modification is a universal natural mechanism for control of RNA molecular structure that operates across a wide temperature range in archaea as well as bacteria.
Collapse
Affiliation(s)
- Kathleen R Noon
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | | | | | | | | | | | | |
Collapse
|
21
|
McCloskey JA, Graham DE, Zhou S, Crain PF, Ibba M, Konisky J, Söll D, Olsen GJ. Post-transcriptional modification in archaeal tRNAs: identities and phylogenetic relations of nucleotides from mesophilic and hyperthermophilic Methanococcales. Nucleic Acids Res 2001; 29:4699-706. [PMID: 11713320 PMCID: PMC92529 DOI: 10.1093/nar/29.22.4699] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2001] [Revised: 09/19/2001] [Accepted: 09/19/2001] [Indexed: 11/15/2022] Open
Abstract
Post-transcriptional modifications in archaeal RNA are known to be phylogenetically distinct but relatively little is known of tRNA from the Methanococci, a lineage of methanogenic marine euryarchaea that grow over an unusually broad temperature range. Transfer RNAs from Methanococcus vannielii, Methanococcus maripaludis, the thermophile Methanococcus thermolithotrophicus, and hyperthermophiles Methanococcus jannaschii and Methanococcus igneus were studied to determine whether modification patterns reflect the close phylogenetic relationships inferred from small ribosomal subunit RNA sequences, and to examine modification differences associated with temperature of growth. Twenty-four modified nucleosides were characterized, including the complex tricyclic nucleoside wyosine characteristic of position 37 in tRNA(Phe) and known previously only in eukarya, plus two new wye family members of presently unknown structure. The hypermodified nucleoside 5-methylaminomethyl-2-thiouridine, reported previously only in bacterial tRNA at the first position of the anticodon, was identified by liquid chromatography-electrospray ionization mass spectrometry in four of the five organisms. The ribose-methylated nucleosides, 2'-O-methyladenosine, N(2),2'-O-dimethylguanosine and N(2),N(2),2'-O-trimethylguanosine, were found only in hyperthermophile tRNA, consistent with their proposed roles in thermal stabilization of tRNA.
Collapse
Affiliation(s)
- J A McCloskey
- Departments of Biochemistry and Medicinal Chemistry, University of Utah, Salt Lake City, UT 84112-5820, USA.
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Wang PP, Kotra LP, Chu CK, Bartlett MG. Structure determination of 4-azido-2-pyrimidinone nucleoside analogs using mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 1999; 34:724-732. [PMID: 10407356 DOI: 10.1002/(sici)1096-9888(199907)34:7<724::aid-jms820>3.0.co;2-t] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The nucleoside prodrugs 4-azido-ara-C and 2'-fluoro-2', 3'-dideoxy-4-azido-ara-C and their base-catalyzed reaction products were thoroughly characterized by mass spectrometry. The structures of the base-catalyzed reaction products were determined and confirmed using a combination of high-resolution and tandem mass spectrometry with deuterium exchange. An intra-molecular rearrangement reaction occurred in 4-azido-ara-C at physiological pH leading to the formation of a 2',6-anhydro product. A nucleoside of similar structure, 2'-fluoro-2'3'-dideoxy-4-azido-ara-C was studied to determine if the formation of the 2',6-anhydro ring was due to the presence of the 4-azido group or the arabinose 2'-OH group. The 6-position of 2'-fluoro-2',3'-dideoxy-4-azido-ara-C was found to be unreactive at physiological pH, but could add ammonia under strongly basic conditions (pH 11.0, ammonia solution). Finally, the formation of an intriguing tetrazole ring by the 4-azido moiety was observed.
Collapse
Affiliation(s)
- P P Wang
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602-2352, USA
| | | | | | | |
Collapse
|
23
|
Grosjean H, Constantinesco F, Foiret D, Benachenhou N. A novel enzymatic pathway leading to 1-methylinosine modification in Haloferax volcanii tRNA. Nucleic Acids Res 1995; 23:4312-9. [PMID: 7501451 PMCID: PMC307385 DOI: 10.1093/nar/23.21.4312] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Transfer RNAs of the extreme halophile Haloferax volcanii contain several modified nucleosides, among them 1-methylpseudouridine (m1 psi), pseudouridine (psi), 2'-0-methylcytosine (Cm) and 1-methylinosine (m1l), present in positions 54, 55, 56 and 57 of the psi-loop, respectively. At the same positions in tRNAs from eubacteria and eukaryotes, ribothymidine (T-54), pseudouridine (psi-55), non-modified cytosine (C-56) and non-modified adenosine or guanosine (A-57 or G-57) are found in the so-called T psi-loop. Using as substrate a T7 transcript of Haloferax volcanii tRNA(Ile) devoid of modified nucleosides, the enzymatic activities of several tRNA modification enzymes, including those for m1 psi-54, psi-55, Cm-56 and m1l-57, were detected in cell extracts of H.volcanii. Here, we demonstrate that modification of A-57 into m1l-57 in H.volcanii tRNA(Ile) occurs via a two-step enzymatic process. The first step corresponds to the formation of m1A-57 catalyzed by a S-adenosylmethionine-dependent tRNA methyltransferase, followed by the deamination of the 6-amino group of the adenine moiety by a 1-methyladenosine-57 deaminase. This enzymatic pathway differs from that leading to the formation of m1l-37 in the anticodon loop of eukaryotic tRNA(Ala). In the latter case, inosine-37 formation preceeds the S-adenosylmethionine-dependent methylation of l-37 into m1l-37. Thus, enzymatic strategies for catalyzing the formation of 1-methylinosine in tRNAs differ in organisms from distinct evolutionary kingdoms.
Collapse
Affiliation(s)
- H Grosjean
- Laboratoire d'Enzymologie et de Biochimie Structurales, CNRS, Gif-sur-Yvette, France
| | | | | | | |
Collapse
|
24
|
Abstract
A comprehensive listing is made of posttranscriptionally modified nucleosides from RNA reported in the literature through mid-1994. Included are chemical structures, common names, symbols, Chemical Abstracts registry numbers (for ribonucleoside and corresponding base), Chemical Abstracts Index Name, phylogenetic sources, and initial literature citations for structural characterization or occurrence, and for chemical synthesis. The listing is categorized by type of RNA: tRNA, rRNA, mRNA, snRNA, and other RNAs. A total of 93 different modified nucleosides have been reported in RNA, with the largest number and greatest structural diversity in tRNA, 79; and 28 in rRNA, 12 in mRNA, 11 in snRNA and 3 in other small RNAs.
Collapse
Affiliation(s)
- P A Limbach
- Department of Medicinal Chemistry, University of Utah, Salt Lake City 84112
| | | | | |
Collapse
|
25
|
Décout JL, Maurel MC. N6-substituted adenine derivatives and RNA primitive catalysts. ORIGINS LIFE EVOL B 1993; 23:299-306. [PMID: 7509474 DOI: 10.1007/bf01582080] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In our search for primitive RNA catalysts, we noticed that N6-ribosyl-adenine, a compound easily synthesized under presumed prebiotic conditions, has a free imidazole group. We showed that it is, as a catalyst, a potential analogue of histidine. Furthermore, among the chemical groups involved in protein catalysis, the imidazole ring of histidine has no equivalent in the RNA world. We have synthesized aliphatic amino groups containing polymers with adenine rings linked to macromolecules by their 6-amino group. These polymers exhibit pronounced catalytic activities in the hydrolysis of p-nitrophenylacetate. We discuss here the fact that in primitive catalysis the imidazole group could have been replaced by N6-substituted adenine derivatives.
Collapse
Affiliation(s)
- J L Décout
- L.E.D.S.S.6., Univ. J. Fourier, Grenoble, France
| | | |
Collapse
|