1
|
Katoh T, Suga H. A comprehensive analysis of translational misdecoding pattern and its implication on genetic code evolution. Nucleic Acids Res 2023; 51:10642-10652. [PMID: 37638759 PMCID: PMC10602915 DOI: 10.1093/nar/gkad707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 07/19/2023] [Accepted: 08/19/2023] [Indexed: 08/29/2023] Open
Abstract
The universal genetic code is comprised of 61 sense codons, which are assigned to 20 canonical amino acids. However, the evolutionary basis for the highly conserved mapping between amino acids and their codons remains incompletely understood. A possible selective pressure of evolution would be minimization of deleterious effects caused by misdecoding. Here we comprehensively analyzed the misdecoding pattern of 61 codons against 19 noncognate amino acids where an arbitrary amino acid was omitted, and revealed the following two rules. (i) If the second codon base is U or C, misdecoding is frequently induced by mismatches at the first and/or third base, where any mismatches are widely tolerated; whereas misdecoding with the second-base mismatch is promoted by only U-G or C-A pair formation. (ii) If the second codon base is A or G, misdecoding is promoted by only G-U or U-G pair formation at the first or second position. In addition, evaluation of functional/structural diversities of amino acids revealed that less diverse amino acid sets are assigned at codons that induce more frequent misdecoding, and vice versa, so as to minimize deleterious effects of misdecoding in the modern genetic code.
Collapse
Affiliation(s)
- Takayuki Katoh
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hiroaki Suga
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| |
Collapse
|
2
|
Kimura S, Dedon PC, Waldor MK. Comparative tRNA sequencing and RNA mass spectrometry for surveying tRNA modifications. Nat Chem Biol 2020; 16:964-972. [PMID: 32514182 DOI: 10.1038/s41589-020-0558-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 04/22/2020] [Indexed: 12/12/2022]
Abstract
Chemical modifications of the nucleosides that comprise transfer RNAs are diverse. However, the structure, location and extent of modifications have been systematically charted in very few organisms. Here, we describe an approach in which rapid prediction of modified sites through reverse transcription-derived signatures in high-throughput transfer RNA-sequencing (tRNA-seq) data is coupled with identification of tRNA modifications through RNA mass spectrometry. Comparative tRNA-seq enabled prediction of several Vibrio cholerae modifications that are absent from Escherichia coli and also revealed the effects of various environmental conditions on V. cholerae tRNA modification. Through RNA mass spectrometric analyses, we showed that two of the V. cholerae-specific reverse transcription signatures reflected the presence of a new modification (acetylated acp3U (acacp3U)), while the other results from C-to-Ψ RNA editing, a process not described before. These findings demonstrate the utility of this approach for rapid surveillance of tRNA modification profiles and environmental control of tRNA modification.
Collapse
Affiliation(s)
- Satoshi Kimura
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA, USA. .,Department of Microbiology, Harvard Medical School, Boston, MA, USA. .,Howard Hughes Medical Institute, Boston, MA, USA.
| | - Peter C Dedon
- Department of Biological Engineering, Massachusetts Institution of Technology, Cambridge, MA, USA.,Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore
| | - Matthew K Waldor
- Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA, USA. .,Department of Microbiology, Harvard Medical School, Boston, MA, USA. .,Howard Hughes Medical Institute, Boston, MA, USA.
| |
Collapse
|
3
|
Nilsson EM, Alexander RW. Bacterial wobble modifications of NNA-decoding tRNAs. IUBMB Life 2019; 71:1158-1166. [PMID: 31283100 DOI: 10.1002/iub.2120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 06/21/2019] [Indexed: 01/18/2023]
Abstract
Nucleotides of transfer RNAs (tRNAs) are highly modified, particularly at the anticodon. Bacterial tRNAs that read A-ending codons are especially notable. The U34 nucleotide canonically present in these tRNAs is modified by a wide range of complex chemical constituents. An additional two A-ending codons are not read by U34-containing tRNAs but are accommodated by either inosine or lysidine at the wobble position (I34 or L34). The structural basis for many N34 modifications in both tRNA aminoacylation and ribosome decoding has been elucidated, and evolutionary conservation of modifying enzymes is also becoming clearer. Here we present a brief review of the structure, function, and conservation of wobble modifications in tRNAs that translate A-ending codons. © 2019 IUBMB Life, 2019 © 2019 IUBMB Life, 71(8):1158-1166, 2019.
Collapse
Affiliation(s)
- Emil M Nilsson
- Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina
| | - Rebecca W Alexander
- Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina
| |
Collapse
|
4
|
Kumbhar NM, Gopal JS. Structural significance of hypermodified nucleoside 5-carboxymethylaminomethyluridine (cmnm 5U) from 'wobble' (34th) position of mitochondrial tRNAs: Molecular modeling and Markov state model studies. J Mol Graph Model 2018; 86:66-83. [PMID: 30336453 DOI: 10.1016/j.jmgm.2018.10.004] [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: 03/06/2018] [Revised: 10/02/2018] [Accepted: 10/04/2018] [Indexed: 11/28/2022]
Abstract
A quantum chemical semi-empirical RM1 approach was used to deduce the structural role of hypermodified nucleoside 5-carboxymethylaminomethyluridine 5'-monophosphate (pcmnm5U) from 'wobble' (34th) position of mitochondrial tRNAs. The energetically preferred pcmnm5U(34) adopted a 'skew' conformation for C5-substituted side chain (-CH2-NH2+-CH2-COO-) moiety that orient towards the 5'-ribose-phosphate backbone, which support 'anti' orientation of glycosyl (χ34) torsion angle. Preferred conformation of pcmnm5U(34) was stabilized by O(4) … HC(10), O1P⋯HN(11), O(15) … HN(11), O(15) … HC(10), O4' … HC(6) and O(2) … HC2' hydrogen bonding interactions. The high flexibility of side chain moiety displayed different structural properties for pcmnm5U(34). Three different conformations of pcmnm5U(34) were observed in molecular dynamics simulations and Markov state model studies. The unmodified uracil revealed 'syn' and 'anti' orientations for glycosyl (χ34) torsion angle that substantiate the role of "-CH2-NH2+-CH2-COO-" moiety in maintaining the 'anti' orientation of pcmnm5U(34). The preferred conformation of pcmnm5U(34) helps to recognize Guanosine more proficiently than Adenosine from the third position of codons. The role of pcmnm5U(34) in tRNA biogenesis paves the way to understand its structural significance in usual mitochondrial metabolism and respiration.
Collapse
Affiliation(s)
- Navanath M Kumbhar
- Garware Research Centre, Department of Chemistry, Savitribai Phule Pune University (Formerly University of Pune), Pune, 411007, India.
| | - Janhavi S Gopal
- Institute of Bioinformatics and Biotechnology, Savitribai Phule Pune University (Formerly University of Pune), Pune, 411007, India
| |
Collapse
|
5
|
Sochacka E, Lodyga-Chruscinska E, Pawlak J, Cypryk M, Bartos P, Ebenryter-Olbinska K, Leszczynska G, Nawrot B. C5-substituents of uridines and 2-thiouridines present at the wobble position of tRNA determine the formation of their keto-enol or zwitterionic forms - a factor important for accuracy of reading of guanosine at the 3΄-end of the mRNA codons. Nucleic Acids Res 2017; 45:4825-4836. [PMID: 28088758 PMCID: PMC5416851 DOI: 10.1093/nar/gkw1347] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 12/30/2016] [Indexed: 12/19/2022] Open
Abstract
Modified nucleosides present in the wobble position of the tRNA anticodons regulate protein translation through tuning the reading of mRNA codons. Among 40 of such nucleosides, there are modified uridines containing either a sulfur atom at the C2 position and/or a substituent at the C5 position of the nucleobase ring. It is already evidenced that tRNAs with 2-thiouridines at the wobble position preferentially read NNA codons, while the reading mode of the NNG codons by R5U/R5S2U-containing anticodons is still elusive. For a series of 18 modified uridines and 2-thiouridines, we determined the pKa values and demonstrated that both modifying elements alter the electron density of the uracil ring and modulate the acidity of their N3H proton. In aqueous solutions at physiological pH the 2-thiouridines containing aminoalkyl C5-substituents are ionized in ca. 50%. The results, confirmed also by theoretical calculations, indicate that the preferential binding of the modified units bearing non-ionizable 5-substituents to guanosine in the NNG codons may obey the alternative C-G-like (Watson–Crick) mode, while binding of those bearing aminoalkyl C5-substituents (protonated under physiological conditions) and especially those with a sulfur atom at the C2 position, adopt a zwitterionic form and interact with guanosine via a ‘new wobble’ pattern.
Collapse
Affiliation(s)
- Elzbieta Sochacka
- Institute of Organic Chemistry, Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland
| | - Elzbieta Lodyga-Chruscinska
- Institute of General Food Chemistry, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland
| | - Justyna Pawlak
- Institute of General Food Chemistry, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland
| | - Marek Cypryk
- Department of Bioorganic Chemistry, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland
| | - Paulina Bartos
- Institute of Organic Chemistry, Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland
| | - Katarzyna Ebenryter-Olbinska
- Institute of Organic Chemistry, Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland.,Department of Computer Modeling, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland
| | - Grazyna Leszczynska
- Institute of Organic Chemistry, Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland
| | - Barbara Nawrot
- Department of Computer Modeling, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland
| |
Collapse
|
6
|
Giessing AMB, Kirpekar F. Mass spectrometry in the biology of RNA and its modifications. J Proteomics 2012; 75:3434-49. [PMID: 22348820 DOI: 10.1016/j.jprot.2012.01.032] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 01/20/2012] [Accepted: 01/26/2012] [Indexed: 01/31/2023]
Abstract
Many powerful analytical techniques for investigation of nucleic acids exist in the average modern molecular biology lab. The current review will focus on questions in RNA biology that have been answered by the use of mass spectrometry, which means that new biological information is the purpose and outcome of most of the studies we refer to. The review begins with a brief account of the subject "MS in the biology of RNA" and an overview of the prevalent RNA modifications identified to date. Fundamental considerations about mass spectrometric analysis of RNA are presented with the aim of detailing the analytical possibilities and challenges relating to the unique chemical nature of nucleic acids. The main biological topics covered are RNA modifications and the enzymes that perform the modifications. Modifications of RNA are essential in biology, and it is a field where mass spectrometry clearly adds knowledge of biological importance compared to traditional methods used in nucleic acid research. The biological applications are divided into analyses exclusively performed at the building block (mainly nucleoside) level and investigations involving mass spectrometry at the oligonucleotide level. We conclude the review discussing aspects of RNA identification and quantifications, which are upcoming fields for MS in RNA research. This article is part of a Special Section entitled: Understanding genome regulation and genetic diversity by mass spectrometry.
Collapse
Affiliation(s)
- Anders M B Giessing
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | | |
Collapse
|
7
|
Watanabe K, Yokobori SI. tRNA Modification and Genetic Code Variations in Animal Mitochondria. J Nucleic Acids 2011; 2011:623095. [PMID: 22007289 PMCID: PMC3191813 DOI: 10.4061/2011/623095] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 07/04/2011] [Indexed: 12/03/2022] Open
Abstract
In animal mitochondria, six codons have been known as nonuniversal genetic codes, which vary in the course of animal evolution. They are UGA (termination codon in the universal genetic code changes to Trp codon in all animal mitochondria), AUA (Ile to Met in most metazoan mitochondria), AAA (Lys to Asn in echinoderm and some platyhelminth mitochondria), AGA/AGG (Arg to Ser in most invertebrate, Arg to Gly in tunicate, and Arg to termination in vertebrate mitochondria), and UAA (termination to Tyr in a planaria and a nematode mitochondria, but conclusive evidence is lacking in this case). We have elucidated that the anticodons of tRNAs deciphering these nonuniversal codons (tRNATrp for UGA, tRNAMet for AUA, tRNAAsn for AAA, and tRNASer and tRNAGly for AGA/AGG) are all modified; tRNATrp has 5-carboxymethylaminomethyluridine or 5-taurinomethyluridine, tRNAMet has 5-formylcytidine or 5-taurinomethyluridine, tRNASer has 7-methylguanosine and tRNAGly has 5-taurinomethyluridine in their anticodon wobble position, and tRNAAsn has pseudouridine in the anticodon second position. This review aims to clarify the structural relationship between these nonuniversal codons and the corresponding tRNA anticodons including modified nucleosides and to speculate on the possible mechanisms for explaining the evolutional changes of these nonuniversal codons in the course of animal evolution.
Collapse
Affiliation(s)
- Kimitsuna Watanabe
- Department of Molecular Biology, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
| | | |
Collapse
|
8
|
Kitamura A, Sengoku T, Nishimoto M, Yokoyama S, Bessho Y. Crystal structure of the bifunctional tRNA modification enzyme MnmC from Escherichia coli. Protein Sci 2011; 20:1105-13. [PMID: 21574198 DOI: 10.1002/pro.659] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 04/30/2011] [Accepted: 05/02/2011] [Indexed: 11/10/2022]
Abstract
Post-transcriptional modifications of bases within the transfer RNAs (tRNA) anticodon significantly affect the decoding system. In bacteria and eukaryotes, uridines at the wobble position (U34) of some tRNAs are modified to 5-methyluridine derivatives (xm⁵U). These xm⁵U34-containing tRNAs read codons ending with A or G, whereas tRNAs with the unmodified U34 are able to read all four synonymous codons of a family box. In Escherichia coli (E.coli), the bifunctional enzyme MnmC catalyzes the two consecutive reactions that convert 5-carboxymethylaminomethyl uridine (cmnm⁵U) to 5-methylaminomethyl uridine (mnm⁵U). The C-terminal domain of MnmC (MnmC1) is responsible for the flavin adenine dinucleotide (FAD)-dependent deacetylation of cmnm⁵U to 5-aminomethyl uridine (nm⁵U), whereas the N-terminal domain (MnmC2) catalyzes the subsequent S-adenosyl-L-methionine-dependent methylation of nm⁵U, leading to the final product, mnm⁵U34. Here, we determined the crystal structure of E.coli MnmC containing FAD, at 3.0 Å resolution. The structure of the MnmC1 domain can be classified in the FAD-dependent glutathione reductase 2 structural family, including the glycine oxidase ThiO, whereas the MnmC2 domain adopts the canonical class I methyltransferase fold. A structural comparison with ThiO revealed the residues that may be involved in cmnm⁵U recognition, supporting previous mutational analyses. The catalytic sites of the two reactions are both surrounded by conserved basic residues for possible anticodon binding, and are located far away from each other, on opposite sides of the protein. These results suggest that, although the MnmC1 and MnmC2 domains are physically linked, they could catalyze the two consecutive reactions in a rather independent manner.
Collapse
Affiliation(s)
- Aya Kitamura
- RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | | | | | | | | |
Collapse
|
9
|
Benítez-Páez A, Villarroya M, Douthwaite S, Gabaldón T, Armengod ME. YibK is the 2'-O-methyltransferase TrmL that modifies the wobble nucleotide in Escherichia coli tRNA(Leu) isoacceptors. RNA (NEW YORK, N.Y.) 2010; 16:2131-43. [PMID: 20855540 PMCID: PMC2957053 DOI: 10.1261/rna.2245910] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Accepted: 08/18/2010] [Indexed: 05/25/2023]
Abstract
Transfer RNAs are the most densely modified nucleic acid molecules in living cells. In Escherichia coli, more than 30 nucleoside modifications have been characterized, ranging from methylations and pseudouridylations to more complex additions that require multiple enzymatic steps. Most of the modifying enzymes have been identified, although a few notable exceptions include the 2'-O-methyltransferase(s) that methylate the ribose at the nucleotide 34 wobble position in the two leucyl isoacceptors tRNA(Leu)(CmAA) and tRNA(Leu)(cmnm5UmAA). Here, we have used a comparative genomics approach to uncover candidate E. coli genes for the missing enzyme(s). Transfer RNAs from null mutants for candidate genes were analyzed by mass spectrometry and revealed that inactivation of yibK leads to loss of 2'-O-methylation at position 34 in both tRNA(Leu)(CmAA) and tRNA(Leu)(cmnm5UmAA). Loss of YibK methylation reduces the efficiency of codon-wobble base interaction, as demonstrated in an amber suppressor supP system. Inactivation of yibK had no detectable effect on steady-state growth rate, although a distinct disadvantage was noted in multiple-round, mixed-population growth experiments, suggesting that the ability to recover from the stationary phase was impaired. Methylation is restored in vivo by complementing with a recombinant copy of yibK. Despite being one of the smallest characterized α/β knot proteins, YibK independently catalyzes the methyl transfer from S-adenosyl-L-methionine to the 2'-OH of the wobble nucleotide; YibK recognition of this target requires a pyridine at position 34 and N⁶-(isopentenyl)-2-methylthioadenosine at position 37. YibK is one of the last remaining E. coli tRNA modification enzymes to be identified and is now renamed TrmL.
Collapse
Affiliation(s)
- Alfonso Benítez-Páez
- Laboratorio de Genética Molecular, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | | | | | | | | |
Collapse
|
10
|
Kodama K, Nakayama H, Sakamoto K, Fukuzawa S, Kigawa T, Yabuki T, Kitabatake M, Takio K, Yokoyama S. Site-specific incorporation of 4-Iodo-l-phenylalanine through opal suppression. ACTA ACUST UNITED AC 2010; 148:179-87. [DOI: 10.1093/jb/mvq051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
|
11
|
Takai K. Classification of the possible pairs between the first anticodon and the third codon positions based on a simple model assuming two geometries with which the pairing effectively potentiates the decoding complex. J Theor Biol 2006; 242:564-80. [PMID: 16764891 DOI: 10.1016/j.jtbi.2006.04.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2005] [Revised: 02/11/2006] [Accepted: 04/11/2006] [Indexed: 11/24/2022]
Abstract
Crick's wobble theory states that some specific pairs between the bases at the first position of the anticodon (position 34) and the third position of the codon (position III) are allowed and the others are disallowed during the correct codon recognition. However, later researches have shown that the pairing rule, or the wobble rule, is different from the supposed one. Despite the continuing efforts including computer-aided model building studies and analyses of three-dimensional structures in the crystals of the ribosomes, the structural backgrounds of the wobble rule are still unclear. Here, I classify the possible pairs into 6 classes according to the increases accompanying the formation of the pairs in the potential productivity of the decoding complex on the basis of a simple model that was originally proposed previously and is refined here. In the model, the conformation with the base at position 34 displaced toward the minor groove side from the position for the Watson-Crick pairs is supposed to be equivalent to the conformation with the Watson-Crick pairs. It is also reasoned and supposed that some weak pairs may sometimes be allowed depending on the structural context. It is demonstrated that most of the experimental results reported so far are consistent with the model. I discuss on which experimental facts can be reasoned with the model and which need further explanations. I expect that the model will be a good basis for further understanding of the wobble rule and its structural backgrounds.
Collapse
Affiliation(s)
- Kazuyuki Takai
- Cell-free Science and Technology Research Center, Ehime University, 3, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan.
| |
Collapse
|
12
|
Kothe U, Paleskava A, Konevega AL, Rodnina MV. Single-step purification of specific tRNAs by hydrophobic tagging. Anal Biochem 2006; 356:148-50. [PMID: 16750812 DOI: 10.1016/j.ab.2006.04.038] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2006] [Accepted: 04/19/2006] [Indexed: 11/23/2022]
Affiliation(s)
- Ute Kothe
- Institute of Physical Biochemistry, University of Witten/Herdecke, D-58448 Witten, Germany
| | | | | | | |
Collapse
|
13
|
Sakurai M, Ohtsuki T, Suzuki T, Watanabe K. Unusual usage of wobble modifications in mitochondrial tRNAs of the nematode Ascaris suum. FEBS Lett 2005; 579:2767-72. [PMID: 15907479 DOI: 10.1016/j.febslet.2005.04.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Revised: 04/05/2005] [Accepted: 04/07/2005] [Indexed: 10/25/2022]
Abstract
To understand the decoding property of nematode mitochondrial tRNAs with unusual secondary structures, post-transcriptional modifications at wobble positions of Ascaris suum mitochondrial tRNAs corresponding to two-codon families ending with a purine were analyzed. 5-Carboxymethylaminomethyluridine (cmnm(5)U) was identified at the wobble positions of tRNA(Lys), tRNA(Glu) and tRNA(Gln), while 5-carboxymethylaminomethyl-2-thiouridine (cmnm(5)s(2)U) was present in tRNA(UAA)(Leu)andtRNA(Trp). In most bacterial and mitochondrial tRNAs, the 2-thiouridine derivative is present in tRNAs for Lys, Glu and Gln. These is no report that cmnm(5)s(2)U is used in tRNA(UAA)(Leu)andtRNA(Trp). The unusual usage of wobble modifications might assist decoding of nematode mitochondrial mRNAs.
Collapse
Affiliation(s)
- Masayuki Sakurai
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, Japan
| | | | | | | |
Collapse
|
14
|
Takai K, Yokoyama S. Roles of 5-substituents of tRNA wobble uridines in the recognition of purine-ending codons. Nucleic Acids Res 2003; 31:6383-91. [PMID: 14602896 PMCID: PMC275538 DOI: 10.1093/nar/gkg839] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2003] [Revised: 09/10/2003] [Accepted: 09/20/2003] [Indexed: 11/14/2022] Open
Abstract
Many tRNA molecules that recognize the purine-ending codons but not the pyrimidine-ending codons have a modified uridine at the wobble position, in which a methylene carbon is attached directly to position 5 of the uracil ring. Although several models have been proposed concerning the mechanism by which the 5-substituents regulate codon-reading properties of the tRNAs, none could explain recent results of the experiments utilizing well-characterized modification-deficient strains of Escherichia coli. Here, we first summarize previous studies on the codon-reading properties of tRNA molecules with a U derivative at the wobble position. Then, we propose a hypothetical mechanism of the reading of the G-ending codons by such tRNA molecules that could explain the experimental results. The hypothesis supposes unconventional base pairs between a protonated form of the modified uridines and the G at the third position of the codon stabilized by two direct hydrogen bonds between the bases. The hypothesis also addresses differences between the prokaryotic and eukaryotic decoding systems.
Collapse
Affiliation(s)
- Kazuyuki Takai
- Cell-Free Science and Technology Research Center, Department of Applied Chemistry, Faculty of Engineering, Ehime University, 3, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan.
| | | |
Collapse
|
15
|
Brégeon D, Colot V, Radman M, Taddei F. Translational misreading: a tRNA modification counteracts a +2 ribosomal frameshift. Genes Dev 2001; 15:2295-306. [PMID: 11544186 PMCID: PMC312767 DOI: 10.1101/gad.207701] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Errors during gene expression from DNA to proteins via transcription and translation may be deleterious for the functional maintenance of cells. In this paper, extensive genetic studies of the misreading of a GA repeat introduced into the lacZ gene of Escherichia coli indicate that in this bacteria, errors occur predominantly by a +2 translational frameshift, which is controlled by a tRNA modification involving the MnmE and GidA proteins. This ribosomal frameshift results from the coincidence of three events: (1) decreased codon-anticodon affinity at the P-site, which is caused by tRNA hypomodification in mnmE(-) and gidA(-) strains; (2) a repetitive mRNA sequence predisposing to slippage; and (3) increased translational pausing attributable to the presence of a rare codon at the A-site. Based on genetic analysis, we propose that GidA and MnmE act in the same pathway of tRNA modification, the absence of which is responsible for the +2 translational frameshift. The difference in the impact of the mutant gene on cell growth, however, indicates that GidA has at least one other function.
Collapse
Affiliation(s)
- D Brégeon
- INSERM EPI9916, Faculté de Médecine Necker-Enfants Malades, 75730 Paris Cedex 15, France.
| | | | | | | |
Collapse
|
16
|
Knight RD, Freeland SJ, Landweber LF. Rewiring the keyboard: evolvability of the genetic code. Nat Rev Genet 2001; 2:49-58. [PMID: 11253070 DOI: 10.1038/35047500] [Citation(s) in RCA: 264] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The genetic code evolved in two distinct phases. First, the 'canonical' code emerged before the last universal ancestor; subsequently, this code diverged in numerous nuclear and organelle lineages. Here, we examine the distribution and causes of these secondary deviations from the canonical genetic code. The majority of non-standard codes arise from alterations in the tRNA, with most occurring by post-transcriptional modifications, such as base modification or RNA editing, rather than by substitutions within tRNA anticodons.
Collapse
Affiliation(s)
- R D Knight
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey 08544, USA.
| | | | | |
Collapse
|
17
|
Raychaudhuri S, Niu L, Conrad J, Lane BG, Ofengand J. Functional effect of deletion and mutation of the Escherichia coli ribosomal RNA and tRNA pseudouridine synthase RluA. J Biol Chem 1999; 274:18880-6. [PMID: 10383384 DOI: 10.1074/jbc.274.27.18880] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Escherichia coli gene rluA, coding for the pseudouridine synthase RluA that forms 23 S rRNA pseudouridine 746 and tRNA pseudouridine 32, was deleted in strains MG1655 and BL21/DE3. The rluA deletion mutant failed to form either 23 S RNA pseudouridine 746 or tRNA pseudouridine 32. Replacement of rluA in trans on a rescue plasmid restored both pseudouridines. Therefore, RluA is the sole protein responsible for the in vivo formation of 23 S RNA pseudouridine 746 and tRNA pseudouridine 32. Plasmid rescue of both rluA- strains using an rluA gene carrying asparagine or threonine replacements for the highly conserved aspartate 64 demonstrated that neither mutant could form 23 S RNA pseudouridine 746 or tRNA pseudouridine 32 in vivo, showing that this conserved aspartate is essential for enzyme-catalyzed formation of both pseudouridines. In vitro assays using overexpressed wild-type and mutant synthases confirmed that only the wild-type protein was active despite the overexpression of wild-type and mutant synthases in approximately equal amounts. There was no difference in exponential growth rate between wild-type and MG1655(rluA-) either in rich or minimal medium at 24, 37, or 42 degrees C, but when both strains were grown together, a strong selection against the deletion strain was observed.
Collapse
Affiliation(s)
- S Raychaudhuri
- Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, Miami, Florida 33101, USA
| | | | | | | | | |
Collapse
|