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Lu W, Terasaka N, Sakaguchi Y, Suzuki T, Suzuki T, Suga H. An anticodon-sensing T-boxzyme generates the elongator nonproteinogenic aminoacyl-tRNA in situ of a custom-made translation system for incorporation. Nucleic Acids Res 2024; 52:3938-3949. [PMID: 38477328 DOI: 10.1093/nar/gkae151] [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: 11/21/2023] [Revised: 01/24/2024] [Accepted: 02/17/2024] [Indexed: 03/14/2024] Open
Abstract
In the hypothetical RNA world, ribozymes could have acted as modern aminoacyl-tRNA synthetases (ARSs) to charge tRNAs, thus giving rise to the peptide synthesis along with the evolution of a primitive translation apparatus. We previously reported a T-boxzyme, Tx2.1, which selectively charges initiator tRNA with N-biotinyl-phenylalanine (BioPhe) in situ in a Flexible In-vitro Translation (FIT) system to produce BioPhe-initiating peptides. Here, we performed in vitro selection of elongation-capable T-boxzymes (elT-boxzymes), using para-azido-l-phenylalanine (PheAZ) as an acyl-donor. We implemented a new strategy to enrich elT-boxzyme-tRNA conjugates that self-aminoacylated on the 3'-terminus selectively. One of them, elT32, can charge PheAZ onto tRNA in trans in response to its cognate anticodon. Further evolution of elT32 resulted in elT49, with enhanced aminoacylation activity. We have demonstrated the translation of a PheAZ-containing peptide in an elT-boxzyme-integrated FIT system, revealing that elT-boxzymes are able to generate the PheAZ-tRNA in response to the cognate anticodon in situ of a custom-made translation system. This study, together with Tx2.1, illustrates a scenario where a series of ribozymes could have overseen aminoacylation and co-evolved with a primitive RNA-based translation system.
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Affiliation(s)
- Wei Lu
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Naohiro Terasaka
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
| | - Yuriko Sakaguchi
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takeo Suzuki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Department of Medical Biochemistry, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0125, Japan
| | - Tsutomu Suzuki
- Department of Chemistry and Biotechnology, Graduate School of Engineering, 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
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José MV, Bobadilla JR, Zamudio GS, de Farías ST. Symmetrical distributions of aminoacyl-tRNA synthetases during the evolution of the genetic code. Theory Biosci 2023; 142:211-219. [PMID: 37402895 PMCID: PMC10423125 DOI: 10.1007/s12064-023-00394-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 06/10/2023] [Indexed: 07/06/2023]
Abstract
In this work, we formulate the following question: How the distribution of aminoacyl-tRNA synthetases (aaRSs) went from an ancestral bidirectional gene (mirror symmetry) to the symmetrical distribution of aaRSs in a six-dimensional hypercube of the Standard Genetic Code (SGC)? We assume a primeval RNY code, two Extended Genetic RNA codes type 1 and 2, and the SGC. We outline the types of symmetries of the distribution of aaRSs in each code. The symmetry groups of aaRSs in each code are described, until the symmetries of the SGC display a mirror symmetry. Considering both Extended RNA codes the 20 aaRSs were already present before the Last Universal Ancestor. These findings reveal intricacies in the diversification of aaRSs accompanied by the evolution of the genetic code.
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Affiliation(s)
- Marco V José
- Theoretical Biology Group, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, CP 04510, Mexico City, Mexico.
| | - Juan R Bobadilla
- Theoretical Biology Group, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, CP 04510, Mexico City, Mexico
| | - Gabriel S Zamudio
- Theoretical Biology Group, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, CP 04510, Mexico City, Mexico
| | - Sávio Torres de Farías
- Laboratório de Genética Evolutiva Paulo Leminsk, Departamento de Biologia Molecular, Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil
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3
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Krochmal D, Shao Y, Li NS, DasGupta S, Shelke SA, Koirala D, Piccirilli JA. Structural basis for substrate binding and catalysis by a self-alkylating ribozyme. Nat Chem Biol 2022; 18:376-384. [PMID: 35058645 DOI: 10.1038/s41589-021-00950-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 11/23/2021] [Indexed: 12/26/2022]
Abstract
Ribozymes that react with small-molecule probes have important applications in transcriptomics and chemical biology, such as RNA labeling and imaging. Understanding the structural basis for these RNA-modifying reactions will enable the development of better tools for studying RNA. Nevertheless, high-resolution structures and underlying catalytic mechanisms for members of this ribozyme class remain elusive. Here, we focus on a self-alkylating ribozyme that catalyzes nitrogen-carbon bond formation between a specific guanine and a 2,3-disubstituted epoxide substrate and report the crystal structures of a self-alkylating ribozyme, including both alkylated and apo forms, at 1.71-Å and 2.49-Å resolution, respectively. The ribozyme assumes an elongated hairpin-like architecture preorganized to accommodate the epoxide substrate in a hook-shaped conformation. Observed reactivity of substrate analogs together with an inverse, log-linear pH dependence of the reaction rate suggests a requirement for epoxide protonation, possibly assisted by the ether oxygens within the substrate.
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Affiliation(s)
- Daniel Krochmal
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Yaming Shao
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Nan-Sheng Li
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Saurja DasGupta
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Sandip A Shelke
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
| | - Deepak Koirala
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD, USA.
| | - Joseph A Piccirilli
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA.
- Department of Chemistry, The University of Chicago, Chicago, IL, USA.
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4
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Furukawa R, Yokobori SI, Sato R, Kumagawa T, Nakagawa M, Katoh K, Yamagishi A. Amino Acid Specificity of Ancestral Aminoacyl-tRNA Synthetase Prior to the Last Universal Common Ancestor Commonote commonote. J Mol Evol 2022; 90:73-94. [PMID: 35084522 PMCID: PMC8821087 DOI: 10.1007/s00239-021-10043-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 12/16/2021] [Indexed: 11/24/2022]
Abstract
Extant organisms commonly use 20 amino acids in protein synthesis. In the translation system, aminoacyl-tRNA synthetase (ARS) selectively binds an amino acid and transfers it to the cognate tRNA. It is postulated that the amino acid repertoire of ARS expanded during the development of the translation system. In this study we generated composite phylogenetic trees for seven ARSs (SerRS, ProRS, ThrRS, GlyRS-1, HisRS, AspRS, and LysRS) which are thought to have diverged by gene duplication followed by mutation, before the evolution of the last universal common ancestor. The composite phylogenetic tree shows that the AspRS/LysRS branch diverged from the other five ARSs at the deepest node, with the GlyRS/HisRS branch and the other three ARSs (ThrRS, ProRS and SerRS) diverging at the second deepest node. ThrRS diverged next, and finally ProRS and SerRS diverged from each other. Based on the phylogenetic tree, sequences of the ancestral ARSs prior to the evolution of the last universal common ancestor were predicted. The amino acid specificity of each ancestral ARS was then postulated by comparison with amino acid recognition sites of ARSs of extant organisms. Our predictions demonstrate that ancestral ARSs had substantial specificity and that the number of amino acid types amino-acylated by proteinaceous ARSs was limited before the appearance of a fuller range of proteinaceous ARS species. From an assumption that 10 amino acid species are required for folding and function, proteinaceous ARS possibly evolved in a translation system composed of preexisting ribozyme ARSs, before the evolution of the last universal common ancestor.
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Affiliation(s)
- Ryutaro Furukawa
- Department of Applied Life Sciences, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, Japan.,Faculty of Human Science, Waseda University, 2-579-15 Mikajima, Tokorozawa, Saitama, 359-1192, Japan
| | - Shin-Ichi Yokobori
- Department of Applied Life Sciences, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, Japan
| | - Riku Sato
- Department of Applied Life Sciences, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, Japan
| | - Taimu Kumagawa
- Department of Applied Life Sciences, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, Japan
| | - Mizuho Nakagawa
- Department of Applied Life Sciences, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, Japan
| | - Kazutaka Katoh
- Department of Genome Informatics, Genome Information Research Center, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Akihiko Yamagishi
- Department of Applied Life Sciences, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, Japan.
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Afrose SP, Mahato C, Sharma P, Roy L, Das D. Nonequilibrium Catalytic Supramolecular Assemblies of Melamine- and Imidazole-Based Dynamic Building Blocks. J Am Chem Soc 2022; 144:673-678. [PMID: 34990140 DOI: 10.1021/jacs.1c11457] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The development of synthetic nonequilibrium systems has gathered increasing attention due to their potential to illustrate the dynamic, complex, and emergent traits of biological systems. Simple building blocks capable of interacting via dynamic covalent chemistry and physical assembly in a reaction network under nonequilibrium conditions can contribute to our understanding of complex systems of life and its origin. Herein, we have demonstrated the nonequilibrium generation of catalytic supramolecular assemblies from simple heterocycle melamine driven by a thermodynamically activated ester. Utilizing a reversible covalent linkage, an imidazole moiety was recruited by the assemblies to access a catalytic transient state that dissipated energy via accelerated hydrolysis of the activated ester. The nonequilibrium assemblies were further capable of temporally binding to a hydrophobic guest to modulate its photophysical properties. Notably, the presence of an exogenous aromatic base augmented the lifetime of the catalytic microphases, reflecting their higher kinetic stability.
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Affiliation(s)
- Syed Pavel Afrose
- Department of Chemical Sciences and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, India
| | - Chiranjit Mahato
- Department of Chemical Sciences and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, India
| | - Pooja Sharma
- Department of Chemical Sciences and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, India
| | - Lisa Roy
- Institute of Chemical Technology Mumbai-IOC Odisha Campus Bhubaneswar, IIT Kharagpur Extension Centre, Bhubaneswar 751013, India
| | - Dibyendu Das
- Department of Chemical Sciences and Centre for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, India
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6
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Knappenberger AJ, Reiss CW, Strobel SA. Structures of two aptamers with differing ligand specificity reveal ruggedness in the functional landscape of RNA. eLife 2018; 7:36381. [PMID: 29877798 PMCID: PMC6031431 DOI: 10.7554/elife.36381] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Accepted: 06/05/2018] [Indexed: 01/07/2023] Open
Abstract
Two classes of riboswitches related to the ykkC guanidine-I riboswitch bind phosphoribosyl pyrophosphate (PRPP) and guanosine tetraphosphate (ppGpp). Here we report the co-crystal structure of the PRPP aptamer and its ligand. We also report the structure of the G96A point mutant that prefers ppGpp over PRPP with a dramatic 40,000-fold switch in specificity. The ends of the aptamer form a helix that is not present in the guanidine aptamer and is involved in the expression platform. In the mutant, the base of ppGpp replaces G96 in three-dimensional space. This disrupts the S-turn, which is a primary structural feature of the ykkC RNA motif. These dramatic differences in ligand specificity are achieved with minimal mutations. ykkC aptamers are therefore a prime example of an RNA fold with a rugged fitness landscape. The ease with which the ykkC aptamer acquires new specificity represents a striking case of evolvability in RNA.
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Affiliation(s)
- Andrew John Knappenberger
- Department of Molecular Biophysics and BiochemistryYale UniversityNew HavenUnited States,Chemical Biology InstituteYale UniversityWest HavenUnited States
| | - Caroline Wetherington Reiss
- Department of Molecular Biophysics and BiochemistryYale UniversityNew HavenUnited States,Chemical Biology InstituteYale UniversityWest HavenUnited States
| | - Scott A Strobel
- Department of Molecular Biophysics and BiochemistryYale UniversityNew HavenUnited States,Chemical Biology InstituteYale UniversityWest HavenUnited States
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7
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Lau MWL, Ferré-D'Amaré AR. Many Activities, One Structure: Functional Plasticity of Ribozyme Folds. Molecules 2016; 21:molecules21111570. [PMID: 27869745 PMCID: PMC6273943 DOI: 10.3390/molecules21111570] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/12/2016] [Accepted: 11/14/2016] [Indexed: 01/01/2023] Open
Abstract
Catalytic RNAs, or ribozymes, are involved in a number of essential biological processes, such as replication of RNA genomes and mobile genetic elements, RNA splicing, translation, and RNA degradation. The function of ribozymes requires the formation of active sites decorated with RNA functional groups within defined three-dimensional (3D) structures. The genotype (sequence) of RNAs ultimately determines what 3D structures they adopt (as a function of their environmental conditions). These 3D structures, in turn, give rise to biochemical activity, which can further elaborate them by catalytic rearrangements or association with other molecules. The fitness landscape of a non-periodic linear polymer, such as RNA, relates its primary structure to a phenotype. Two major challenges in the analysis of ribozymes is to map all possible genotypes to their corresponding catalytic activity (that is, to determine their fitness landscape experimentally), and to understand whether their genotypes and three-dimensional structures can support multiple different catalytic functions. Recently, the combined results of experiments that employ in vitro evolution methods, high-throughput sequencing and crystallographic structure determination have hinted at answers to these two questions: while the fitness landscape of ribozymes is rugged, meaning that their catalytic activity cannot be optimized by a smooth trajectory in sequence space, once an RNA achieves a stable three-dimensional fold, it can be endowed with distinctly different biochemical activities through small changes in genotype. This functional plasticity of highly structured RNAs may be particularly advantageous for the adaptation of organisms to drastic changes in selective pressure, or for the development of new biotechnological tools.
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Affiliation(s)
- Matthew W L Lau
- National Heart, Lung and Blood Institute, 50 South Drive, MSC 8012, Bethesda, MD 20892-8012, USA.
| | - Adrian R Ferré-D'Amaré
- National Heart, Lung and Blood Institute, 50 South Drive, MSC 8012, Bethesda, MD 20892-8012, USA.
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8
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Lau MWL, Ferré-D'Amaré AR. In vitro evolution of coenzyme-independent variants from the glmS ribozyme structural scaffold. Methods 2016; 106:76-81. [PMID: 27130889 PMCID: PMC4981508 DOI: 10.1016/j.ymeth.2016.04.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/18/2016] [Accepted: 04/25/2016] [Indexed: 12/26/2022] Open
Abstract
Uniquely among known natural ribozymes that cleave RNA sequence-specifically, the glmS ribozyme-riboswitch employs a small molecule, glucosamine-6-phosphate (GlcN6P) as a catalytic cofactor. In vitro selection was employed to search for coenzyme-independent variants of this ribozyme. In addition to shedding light on the catalytic mechanism of the ribozyme, such variants could resemble the evolutionary ancestors of the modern, GlcN6P-regulated ribozyme-riboswitch. A mutant pool was constructed such that the secondary structure elements, which define the triply-pseudoknotted global fold of the ribozyme, was preserved. A stringent selection scheme that relies on thiol-mercury affinity chromatography for separating active and inactive sequences ultimately yielded a triple mutant with a cleavage rate exceeding 3min(-1) that only requires divalent cations for activity. Mutational analysis demonstrated that a point reversion of the variant toward the wild-type sequence was sufficient to partially restore GlcN6P-dependence, suggesting that coenzyme dependence can be readily be acquired by RNAs that adopt the glmS ribozyme fold. The methods employed to perform this selection experiment are described in detail in this review.
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Affiliation(s)
- Matthew W L Lau
- National Heart, Lung and Blood Institute, 50 South Drive, MSC 8012, Bethesda, MD 20892-8012, USA
| | - Adrian R Ferré-D'Amaré
- National Heart, Lung and Blood Institute, 50 South Drive, MSC 8012, Bethesda, MD 20892-8012, USA.
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9
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Brandsen BM, Hesser AR, Castner MA, Chandra M, Silverman SK. DNA-catalyzed hydrolysis of esters and aromatic amides. J Am Chem Soc 2013; 135:16014-7. [PMID: 24127695 DOI: 10.1021/ja4077233] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
We previously reported that DNA catalysts (deoxyribozymes) can hydrolyze DNA phosphodiester linkages, but DNA-catalyzed amide bond hydrolysis has been elusive. Here we used in vitro selection to identify DNA catalysts that hydrolyze ester linkages as well as DNA catalysts that hydrolyze aromatic amides, for which the leaving group is an aniline moiety. The aromatic amide-hydrolyzing deoxyribozymes were examined using linear free energy relationship analysis. The hydrolysis reaction is unaffected by substituents on the aromatic ring (ρ ≈ 0), suggesting general acid-catalyzed elimination as the likely rate-determining step of the addition-elimination hydrolysis mechanism. These findings establish that DNA has the catalytic ability to achieve hydrolysis of esters and aromatic amides as carbonyl-based substrates, and they suggest a mechanism-based approach to achieve DNA-catalyzed aliphatic amide hydrolysis.
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Affiliation(s)
- Benjamin M Brandsen
- Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States
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10
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Suga H, Hayashi G, Terasaka N. The RNA origin of transfer RNA aminoacylation and beyond. Philos Trans R Soc Lond B Biol Sci 2012; 366:2959-64. [PMID: 21930588 DOI: 10.1098/rstb.2011.0137] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Aminoacylation of tRNA is an essential event in the translation system. Although in the modern system protein enzymes play the sole role in tRNA aminoacylation, in the primitive translation system RNA molecules could have catalysed aminoacylation onto tRNA or tRNA-like molecules. Even though such RNA enzymes so far are not identified from known organisms, in vitro selection has generated such RNA catalysts from a pool of random RNA sequences. Among them, a set of RNA sequences, referred to as flexizymes (Fxs), discovered in our laboratory are able to charge amino acids onto tRNAs. Significantly, Fxs allow us to charge a wide variety of amino acids, including those that are non-proteinogenic, onto tRNAs bearing any desired anticodons, and thus enable us to reprogramme the genetic code at our will. This article summarizes the evolutionary history of Fxs and also the most recent advances in manipulating a translation system by integration with Fxs.
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Affiliation(s)
- Hiroaki Suga
- Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-0033 Tokyo, Japan.
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12
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Ma W. The scenario on the origin of translation in the RNA world: in principle of replication parsimony. Biol Direct 2010; 5:65. [PMID: 21110883 PMCID: PMC3002371 DOI: 10.1186/1745-6150-5-65] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 11/27/2010] [Indexed: 01/06/2023] Open
Abstract
Background It is now believed that in the origin of life, proteins should have been "invented" in an RNA world. However, due to the complexity of a possible RNA-based proto-translation system, this evolving process seems quite complicated and the associated scenario remains very blurry. Considering that RNA can bind amino acids with specificity, it has been reasonably supposed that initial peptides might have been synthesized on "RNA templates" containing multiple amino acid binding sites. This "Direct RNA Template (DRT)" mechanism is attractive because it should be the simplest mechanism for RNA to synthesize peptides, thus very likely to have been adopted initially in the RNA world. Then, how this mechanism could develop into a proto-translation system mechanism is an interesting problem. Presentation of the hypothesis Here an explanation to this problem is shown considering the principle of "replication parsimony" --- genetic information tends to be utilized in a parsimonious way under selection pressure, due to its replication cost (e.g., in the RNA world, nucleotides and ribozymes for RNA replication). Because a DRT would be quite long even for a short peptide, its replication cost would be great. Thus the diversity and the length of functional peptides synthesized by the DRT mechanism would be seriously limited. Adaptors (proto-tRNAs) would arise to allow a DRT's complementary strand (called "C-DRT" here) to direct the synthesis of the same peptide synthesized by the DRT itself. Because the C-DRT is a necessary part in the DRT's replication, fewer turns of the DRT's replication would be needed to synthesize definite copies of the functional peptide, thus saving the replication cost. Acting through adaptors, C-DRTs could transform into much shorter templates (called "proto-mRNAs" here) and substitute the role of DRTs, thus significantly saving the replication cost. A proto-rRNA corresponding to the small subunit rRNA would then emerge to aid the binding of proto-tRNAs and proto-mRNAs, allowing the reduction of base pairs between them (ultimately resulting in the triplet anticodon/codon pair), thus further saving the replication cost. In this context, the replication cost saved would allow the appearance of more and longer functional peptides and, finally, proteins. The hypothesis could be called "DRT-RP" ("RP" for "replication parsimony"). Testing the hypothesis The scenario described here is open for experimental work at some key scenes, including the compact DRT mechanism, the development of adaptors from aa-aptamers, the synthesis of peptides by proto-tRNAs and proto-mRNAs without the participation of proto-rRNAs, etc. Interestingly, a recent computer simulation study has demonstrated the plausibility of one of the evolving processes driven by replication parsimony in the scenario. Implication of the hypothesis An RNA-based proto-translation system could arise gradually from the DRT mechanism according to the principle of "replication parsimony" --- to save the replication cost of RNA templates for functional peptides. A surprising side deduction along the logic of the hypothesis is that complex, biosynthetic amino acids might have entered the genetic code earlier than simple, prebiotic amino acids, which is opposite to the common sense. Overall, the present discussion clarifies the blurry scenario concerning the origin of translation with a major clue, which shows vividly how life could "manage" to exploit potential chemical resources in nature, eventually in an efficient way over evolution. Reviewers This article was reviewed by Eugene V. Koonin, Juergen Brosius, and Arcady Mushegian.
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Affiliation(s)
- Wentao Ma
- College of Life Sciences, Wuhan University, Wuhan 430072, PR China.
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13
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Rodin AS, Szathmáry E, Rodin SN. One ancestor for two codes viewed from the perspective of two complementary modes of tRNA aminoacylation. Biol Direct 2009; 4:4. [PMID: 19173731 PMCID: PMC2669802 DOI: 10.1186/1745-6150-4-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2009] [Accepted: 01/27/2009] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND The genetic code is brought into action by 20 aminoacyl-tRNA synthetases. These enzymes are evenly divided into two classes (I and II) that recognize tRNAs from the minor and major groove sides of the acceptor stem, respectively. We have reported recently that: (1) ribozymic precursors of the synthetases seem to have used the same two sterically mirror modes of tRNA recognition, (2) having these two modes might have helped in preventing erroneous aminoacylation of ancestral tRNAs with complementary anticodons, yet (3) the risk of confusion for the presumably earliest pairs of complementarily encoded amino acids had little to do with anticodons. Accordingly, in this communication we focus on the acceptor stem. RESULTS Our main result is the emergence of a palindrome structure for the acceptor stem's common ancestor, reconstructed from the phylogenetic trees of Bacteria, Archaea and Eukarya. In parallel, for pairs of ancestral tRNAs with complementary anticodons, we present updated evidence of concerted complementarity of the second bases in the acceptor stems. These two results suggest that the first pairs of "complementary" amino acids that were engaged in primordial coding, such as Gly and Ala, could have avoided erroneous aminoacylation if and only if the acceptor stems of their adaptors were recognized from the same, major groove, side. The class II protein synthetases then inherited this "primary preference" from isofunctional ribozymes. CONCLUSION Taken together, our results support the hypothesis that the genetic code per se (the one associated with the anticodons) and the operational code of aminoacylation (associated with the acceptor) diverged from a common ancestor that probably began developing before translation. The primordial advantage of linking some amino acids (most likely glycine and alanine) to the ancestral acceptor stem may have been selective retention in a protocell surrounded by a leaky membrane for use in nucleotide and coenzyme synthesis. Such acceptor stems (as cofactors) thus transferred amino acids as groups for biosynthesis. Later, with the advent of an anticodon loop, some amino acids (such as aspartic acid, histidine, arginine) assumed a catalytic role while bound to such extended adaptors, in line with the original coding coenzyme handle (CCH) hypothesis.
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Affiliation(s)
- Andrei S Rodin
- Human Genetics Center, School of Public Health, University of Texas, Houston, TX 77225, USA
| | - Eörs Szathmáry
- Collegium Budapest (Institute for Advanced Study), Szentháromság u. 2, H-1014 Budapest, Hungary
- Parmenides Center for the Study of Thinking, 14a Kardinal Faulhaber Str., D-80333 München, Germany
- Institute of Biology, Eötvös University, 1c Pázmány Péter sétány, H-1117 Budapest, Hungary
| | - Sergei N Rodin
- Collegium Budapest (Institute for Advanced Study), Szentháromság u. 2, H-1014 Budapest, Hungary
- Theoretical Biology, Department of Molecular Biology, Beckman Research Institute of the City of Hope, Duarte, CA 91010, USA
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14
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Davies J, von Ahsen U, Wank H, Schroeder R. Evolution of secondary metabolite production: potential roles for antibiotics as prebiotic effectors of catalytic RNA reactions. CIBA FOUNDATION SYMPOSIUM 2007; 171:24-32; discussion 32-44. [PMID: 1302181 DOI: 10.1002/9780470514344.ch3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
It has been proposed that organic molecules related to known secondary metabolites have existed since the beginning of biochemical evolution and were present in primordial soups. Under primitive earth conditions certain of these molecules may have played roles as effectors in prebiotic reactions, especially those involving catalytic RNA (ribozymes). We demonstrate that a number of antibiotic-related secondary metabolites bind to group I introns and either inhibit splicing reactions or promote the formation of intron oligomers. This is consistent with the functional co-evolution of catalytic RNA and secondary metabolites as antibiotic inhibitors of translation, and supports the notion of an evolutionary relationship between group I introns and ribosomal RNA.
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Affiliation(s)
- J Davies
- Department of Microbiology, University of British Columbia, Vancouver, Canada
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15
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Rodin SN, Rodin AS. Partitioning of aminoacyl-tRNA synthetases in two classes could have been encoded in a strand-symmetric RNA world. DNA Cell Biol 2006; 25:617-26. [PMID: 17132092 DOI: 10.1089/dna.2006.25.617] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The "chicken-or-egg" dilemma dictates that archaic tRNAs be aminoacylated by ribozymic aminoacyl-tRNA synthetases, rAARSs, with protein synthetases (pAARSs) emerging later and, strikingly in two versions. However, the distribution of these two versions among the codons also suggests their involvement in development of the genetic code. Here we propose a solution to this controversy, which relies on a primordial complementarity hypothesis that in a strand-symmetric RNA world both complementary replicas of many genes could encode the first proteins. Accordingly, if one rearranges the code table in a manner that puts complementary codons directly against each other, an almost perfect mirror symmetry in tRNA aminoacylation by the two groups of synthetases is revealed. Specifically, the pairs of complementary anticodons from the same pAARS class tend to contain RR and YY dinucleotides at first and second versus third and second positions, whereas in pairs of pAARSs from the different classes these positions are occupied by YR and RY, including CG, GC, UA, and AU palindromes. The latter are indistinguishable in complementary anticodons, thus leading to erroneous aminoacylation (note that there is no such problem for RR- and YY-containing complementary anticodons). This can be averted by "spreading out" tRNA recognition by two rAARSs away from the anticodons in the opposite directions, giving two complementary rAARSs. The principle of evolutionary continuity suggests that their protein successors also arose on complementary strands. Our analyses support this hypothesis.
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Affiliation(s)
- Sergei N Rodin
- Theoretical Biology Department, Beckman Research Institute of the City of Hope, Duarte, California 91010-3000, USA.
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16
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17
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Abstract
Catalytic promiscuity, the ability of an enzyme to catalyze alternative reactions, has been suggested to have played an important role in the evolution of new catalytic activities in protein enzymes. Similarly, promiscuous activities may have been advantageous in an earlier RNA world. The Tetrahymena Group I ribozyme naturally catalyzes the site-specific guanosine attack on an anionic phosphate diester and has been shown to also catalyze aminoacyl transfer to water, albeit with a small rate acceleration (<10-fold). This inefficient catalysis could be due to the differences in charge and/or geometry requirements for the two reactions. Herein, we describe a new promiscuous activity of this ribozyme, the site-specific guanosine attack on a neutral phosphonate diester. This alternative substrate lacks the negative charge at the reaction center but, in contrast to the aminoacyl substrate, can undergo nucleophilic attack with the same geometry as the natural substrate. Our results show that the neutral phosphonate reaction is catalyzed about 1 x 106-fold, substantially better than the acyl transfer but far below the normal anionic substrate. We conclude that both charge and geometry are important factors for catalysis of the normal reaction and that promiscuous catalytic activities of ribozymes could have been created or enhanced by reorienting and swapping RNA domains.
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Affiliation(s)
- Marcello Forconi
- Department of Biochemistry, B400 Beckman Center, Stanford University, Stanford, California 94305-5307, USA
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18
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Dima RI, Hyeon C, Thirumalai D. Extracting stacking interaction parameters for RNA from the data set of native structures. J Mol Biol 2005; 347:53-69. [PMID: 15733917 DOI: 10.1016/j.jmb.2004.12.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2004] [Revised: 11/01/2004] [Accepted: 12/06/2004] [Indexed: 11/30/2022]
Abstract
A crucial step in the determination of the three-dimensional native structures of RNA is the prediction of their secondary structures, which are stable independent of the tertiary fold. Accurate prediction of the secondary structure requires context-dependent estimates of the interaction parameters. We have exploited the growing database of natively folded RNA structures in the Protein Data Bank (PDB) to obtain stacking interaction parameters using a knowledge-based approach. Remarkably, the calculated values of the resulting statistical potentials (SPs) are in excellent agreement with the parameters determined using measurements in small oligonucleotides. We validate the SPs by predicting 74% of the base-pairs in a dataset of structures using the ViennaRNA package. Interestingly, this number is similar to that obtained using the measured thermodynamic parameters. We also tested the efficacy of the SP in predicting secondary structure by using gapless threading, which we advocate as an alternative method for rapidly predicting RNA structures. For RNA molecules with less than 700 nucleotides, about 70% of the native base-pairs are correctly predicted. As a further validation of the SPs we calculated Z-scores, which measure the relative stability of the native state with respect to a manifold of higher free energy states. The computed Z-scores agree with estimates made using calorimetric measurements for a few RNA molecules. Structural analysis was used to rationalize the success and failures of SP and experimentally determined parameters. First, from the near perfect linear relationship between the number of native base-pairs and sequence length, we show that nearly 46% of nucleotides are not in stacks. Second, by analyzing the suboptimal structures that are generated in gapless threading we show that the SPs and experimentally determined parameters are most successful in predicting stacks that end in hairpins. These results show that further improvement in secondary structure prediction requires reliable estimates of interaction parameters for loops, bulges, and stacks that do not end in hairpins.
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Affiliation(s)
- Ruxandra I Dima
- Biophysics Program, Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA
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19
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Abstract
The chemical modification of nucleic acids is a ubiquitous phenomenon. Aminoacylation of tRNAs by aminoacyl-tRNA synthetases (ARSs) is a reaction essentially devoted to protein synthesis but it is used also as an emergency mechanism to recycle stalled ribosomes, and it is required for genome replication in some RNA viruses. In several aminoacyl-tRNA synthetases a correction mechanism known as editing is present to prevent aminoacylation errors. Genome data reveal a growing number of open reading frames encoding ARS-like proteins. This strongly suggests the existence of a widespread and nonconventional machinery for aminoacylation and editing. Here we review the different biological functions of aminoacylation and editing; also we propose an evolutionary scenario for the origin of these two reactions, and hypothesize an extant role for RNA charging and editing outside the genetic code.
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Affiliation(s)
- Renaud Geslain
- Catalan Institute for Research and Advanced Studies (ICREA) and Barcelona Institute for Biomedical Research, Barcelona Science Park, C/Samitier 1-5, Barcelona 08015, Catalonia, Spain
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20
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Schlatterer JC, Stuhlmann F, Jäschke A. Stereoselective synthesis using immobilized Diels-Alderase ribozymes. Chembiochem 2004; 4:1089-92. [PMID: 14523927 DOI: 10.1002/cbic.200300676] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Development of artificial ribozymes by in vitro selection has so far, mostly been addressed from the viewpoint of fundamental research. However, such ribozymes also have high potential as selective catalysts in practical syntheses. Immobilization of an active and selective ribozyme is an important step towards this end. A 49-nucleotide RNA molecule that was previously found to stereoselectively catalyze Diels-Alder reactions between various anthracene dienes and maleimide dienophiles was quantitatively immobilized on an agarose matrix by periodate oxidation of the 3'-terminal ribose and coupling to a hydrazide moiety. Typical loadings were 45 pmol microL(-1) gel. The specific activity was comparable to that of soluble ribozyme, and high enantioselectivities were obtained in catalyzed cycloadditions. The catalytic matrix was found to be stable and could be regenerated about 40 times with only minimal reduction of catalytic activity. Like the soluble ribozyme, the immobilized catalyst stereoselectively converts various diene and dienophile substrates. By using either natural D-RNA or enantiomeric L-RNA, both product enantiomers were made synthetically accessible with similar selectivities.
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Affiliation(s)
- Jörg C Schlatterer
- Institut für Pharmazie und Molekulare Biotechnologie, Abteilung Chemie, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
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21
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Klemme D, Löchelt M, Riedel R, Schiele-Trauth U, Schwienhorst A, Lindemann BF, Schatanek G, Schmiedebausen H, Kröger M. mini-chiuz. CHEM UNSERER ZEIT 2004. [DOI: 10.1002/ciuz.19920260402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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22
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May JP, Ting R, Lermer L, Thomas JM, Roupioz Y, Perrin DM. Covalent Schiff base catalysis and turnover by a DNAzyme: a M2+ -independent AP-endonuclease mimic. J Am Chem Soc 2004; 126:4145-56. [PMID: 15053604 DOI: 10.1021/ja037625s] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A DNAzyme, synthetically modified with both primary amines and imidazoles, is found to act as a M2+ -independent AP lyase-endonuclease. In the course of the cleavage reaction, this DNAzyme forms a covalent Schiff base intermediate with an abasic site on a complementary oligodeoxyribonucleotide. This intermediate, which is inferred from NaCNBH3 trapping as well as cyanide inhibition, does not evidently accumulate because the second step, dehydrophosphorylative elimination, is fast compared to Schiff base formation. The 5'-product that remains linked to the catalyst hydrolyzes slowly to regenerate free catalyst. The use of duly modified DNAzymes to perform Schiff base catalysis demonstrates the value of modified nucleotides for enhancing the catalytic repertoire of nucleic acids. This work suggests that DNAzymes will be capable of catalyzing aldol condensation reactions.
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Affiliation(s)
- Jonathan P May
- Department of Chemistry, The University of British Columbia, Vancouver, B.C., V6T-1Z1 Canada
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23
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Abstract
The idea that the ancestors of modern cells were RNA cells (ribocytes) can be investigated by asking whether all essential cellular functions might be performed by RNAs. This requires isolating suitable molecules by selection-amplification when the predicted molecules are presently extinct. In fact, RNAs with many properties required during a period in which RNA was the major macromolecular agent in cells (an RNA world) have been selected in modern experiments. There is, accordingly, reason to inquire how such a ribocyte might appear, based on the properties of the RNAs that composed it. Combining the intrinsic qualities of RNA with the fundamental characteristics of selection from randomized sequence pools, one predicts ribocytes with a cell cycle measured (roughly) in weeks. Such cells likely had a rapidly varying genome, composed of many small genetic and catalytic elements made of tens of ribonucleotides. There are substantial arguments that, at the mid-RNA era, a subset of these nucleotides are reproducibly available and resemble the modern four. Such cells are predicted to evolve rapidly. Instead of modifying preexisting genes, ribocytes frequently draw new functions from an internal pool containing zeptomoles (<1 attomole) of predominantly inactive random sequences.
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Affiliation(s)
- Michael Yarus
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347, USA.
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24
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Ganoza MC, Kiel MC, Aoki H. Evolutionary conservation of reactions in translation. Microbiol Mol Biol Rev 2002; 66:460-85, table of contents. [PMID: 12209000 PMCID: PMC120792 DOI: 10.1128/mmbr.66.3.460-485.2002] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Current X-ray diffraction and cryoelectron microscopic data of ribosomes of eubacteria have shed considerable light on the molecular mechanisms of translation. Structural studies of the protein factors that activate ribosomes also point to many common features in the primary sequence and tertiary structure of these proteins. The reconstitution of the complex apparatus of translation has also revealed new information important to the mechanisms. Surprisingly, the latter approach has uncovered a number of proteins whose sequence and/or structure and function are conserved in all cells, indicating that the mechanisms are indeed conserved. The possible mechanisms of a new initiation factor and two elongation factors are discussed in this context.
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Affiliation(s)
- M Clelia Ganoza
- C. H. Best Institute, Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada M5G 1L6.
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25
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Abstract
The origin of translation has stimulated much discussion since the basic processes involved were deciphered during the 1960s and 1970s. One strand of thought suggested that the process originated from RNA replication in the RNA world (Weiner & Maizels, 1987, 1994). In this paper I seek to extend this model. The mRNA originates as a replication intermediate of minus-strand ribozyme replication and thus contains all the genetic information contained in both the ribozyme portion and the putative tRNA-like portion of the RNA molecule. Qualitatively, this is similar to the model for the origin of chromosomes (Szathmary & Maynard-Smith, 1993, Maynard-Smith & Szathmary, 1993). This model explicitly describes the evolution of early chromosomes and the role replication played in generating the modern mRNA. Moreover, by pursuing this model, the START and STOP codons were derived and their original function with regard to the primitive 23S ribosomal RNA is suggested. Co-evolution of the genetic code (Wong, 1975) is also contained within the model. Lastly, I address some of the benefits and costs that the process may have for the organism in the context of autotrophy in the RNA world.
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Affiliation(s)
- David S Stevenson
- Department of Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK.
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26
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MESH Headings
- Amino Acids/metabolism
- Amino Acyl-tRNA Synthetases/genetics
- Amino Acyl-tRNA Synthetases/isolation & purification
- Base Sequence
- Cloning, Molecular/methods
- Directed Molecular Evolution/methods
- Models, Biological
- Models, Chemical
- Models, Molecular
- Molecular Sequence Data
- Protein Engineering/methods
- RNA, Catalytic/genetics
- RNA, Catalytic/isolation & purification
- RNA, Catalytic/metabolism
- RNA, Transfer/genetics
- RNA, Transfer/isolation & purification
- RNA, Transfer/metabolism
- Sensitivity and Specificity
- Substrate Specificity
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27
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Vortler S, Pütz J, Giegé R. Manipulation of tRNA properties by structure-based and combinatorial in vitro approaches. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2002; 70:291-334. [PMID: 11642365 DOI: 10.1016/s0079-6603(01)70020-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The wide knowledge accumulated over the years on the structure and function of transfer RNAs (tRNAs) has allowed molecular biologists to decipher the rules underlying the function and the architecture of these molecules. These rules will be discussed and the implications for manipulating tRNA properties by structure-based and combinatorial in vitro approaches reviewed. Since most of the signals conferring function to tRNAs are located on the two distal extremities of their three-dimensional L shape, this implies that the structure of the RNA domain connecting these two extremities can be of different architecture and/or can be modified without disturbing individual functions. This concept is first supported by the existence in nature of RNAs of peculiar structures having tRNA properties, as well as by engineering experiments on natural tRNAs. The concept is further illustrated by examples of RNAs designed by combinatorial methods. The different procedures used to select RNAs or tRNA-mimics interacting with aminoacyl-tRNA synthetases or with elongation factors and to select tRNA-mimics aminoacylated by synthetases are presented, as well as the functional and structural characteristics of the selected molecules. Production and characteristics of aptameric RNAs fulfilling aminoacyl-tRNA synthetase functions and of RNAs selected to have affinities for amino acids are also described. Finally, properties of RNAs obtained by either the structure-based or the combinatorial methods are discussed in the light of the origin and evolution of the translation machinery, but also with a view to obtain new inhibitors targeting specific steps in translation.
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Affiliation(s)
- S Vortler
- Département Mécanismes et Macromolécules de la Synthèse, Protéique et Cristallogenèse, UPR 9002, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, France
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28
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Ribas de Pouplana L, Schimmel P. Aminoacyl-tRNA synthetases: potential markers of genetic code development. Trends Biochem Sci 2001; 26:591-6. [PMID: 11590011 DOI: 10.1016/s0968-0004(01)01932-6] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Aminoacylation of tRNAs, catalyzed by 20 aminoacyl-tRNA synthetases, is responsible for establishing the genetic code. The enzymes are divided into two classes on the basis of the architectures of their active sites. Members of the two classes also differ in that they bind opposite sides of the tRNA acceptor stem. Importantly, specific pairs of synthetases--one from each class--can be docked simultaneously onto the acceptor stem. This article relates these specific pairings to the organization of the table of codons that defines the universal genetic code.
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Affiliation(s)
- L Ribas de Pouplana
- Skaggs Institute for Chemical Biology and Depts of Molecular Biology and Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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29
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Gillet R, Felden B. Transfer RNA(Ala) recognizes transfer-messenger RNA with specificity; a functional complex prior to entering the ribosome? EMBO J 2001; 20:2966-76. [PMID: 11387229 PMCID: PMC125487 DOI: 10.1093/emboj/20.11.2966] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
tmRNA (SsrA or 10Sa RNA) functions as both a transfer RNA and a messenger RNA, rescues stalled ribosomes and clears the cell of incomplete polypeptides. We report that native Escherichia coli tmRNA interacts specifically with native or synthetic E.coli tRNA alanine (tRNA(Ala)) in vitro, alanine being the first codon of the tmRNA internal open reading frame. Aminoacylatable RNA microhelices also bind tmRNA. Complex formation was monitored by gel retardation assays combined with structural probes. Nucleotides from the acceptor stem of tRNA(Ala) are essential for complex formation with tmRNA. tRNA(Ala) isoacceptors recognize tmRNA with different affinities, with an important contribution from tRNA(Ala) post-transcriptional modifications. The most abundant tRNA(Ala) isoacceptor in vivo binds tmRNA with the highest affinity. A complex between tRNA(Ala) and tmRNA might involve up to 140 tmRNA molecules out of 500 present per E.coli cell. Our data suggest that tmRNA interacts with the tRNA that decodes the resume codon prior to entering the ribosome. Biological implications of promoting specific complexes between tmRNA and aminoacylatable RNAs are discussed, with emphasis on primitive versions of the translation apparatus.
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MESH Headings
- Base Sequence
- Binding Sites
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Kinetics
- Molecular Sequence Data
- Nucleic Acid Conformation
- RNA, Bacterial/chemistry
- RNA, Bacterial/metabolism
- RNA, Messenger/chemistry
- RNA, Messenger/metabolism
- RNA, Transfer, Ala/chemistry
- RNA, Transfer, Ala/metabolism
- RNA, Transfer, Asp/metabolism
- RNA, Transfer, Gln/metabolism
- Ribosomes/metabolism
- Substrate Specificity
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Affiliation(s)
| | - Brice Felden
- Laboratoire de Biochimie Pharmaceutique, Faculté de Pharmacie, Université de Rennes I, UPRES Jeune Equipe 2311, IFR 97, 2 avenue du Pr Léon Bernard, 35043 Rennes, France
Corresponding author e-mail:
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30
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Abstract
A set of catalysts for aminoacyl-tRNA synthesis is an essential component for translation. The RNA world hypothesis postulates that RNA catalysts could have played this role. Here we show an in vitro evolved precursor tRNA consisting of two domains, a catalytic 5'-leader sequence and an aminoacyl-acceptor tRNA. The 5'-leader sequence domain selectively self-charges phenylalanine on the 3'-terminus of the tRNA domain. This cis-acting ribozyme is susceptible to RNase P RNA, generating the corresponding 5'-leader segment and the mature tRNA. Moreover, the 5'-leader segment is able to aminoacylate the mature tRNA in trans. Mutational studies have revealed that C(74) and C(75) at the tRNA aminoacyl-acceptor end form base pairs with G71 and G70 of the trans-acting ribozyme. Such Watson-Crick base pairing with tRNA has been observed in RNase P RNA and 23S rRNA, suggesting that all three ribozymes use a similar mechanism for the recognition of the aminoacyl-acceptor end. Our demonstrations indicate that catalytic precursor tRNAs could have provided the foundations for the genetic coding system in the proto-translation system.
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Affiliation(s)
- Hirohide Saito
- Department of Chemistry, State University of New York at Buffalo, Buffalo, NY 14260-3000, USA and Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan Corresponding author e-mail:
| | - Dimitrios Kourouklis
- Department of Chemistry, State University of New York at Buffalo, Buffalo, NY 14260-3000, USA and Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan Corresponding author e-mail:
| | - Hiroaki Suga
- Department of Chemistry, State University of New York at Buffalo, Buffalo, NY 14260-3000, USA and Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan Corresponding author e-mail:
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31
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Affiliation(s)
- D M Lilley
- CRC Nucleic Acid Structure Research Group, Department of Biochemistry, University of Dundee, Dundee DD1 4HN, UK.
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32
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Abstract
In vitro selection allows rare functional RNA or DNA molecules to be isolated from pools of over 10(15) different sequences. This approach has been used to identify RNA and DNA ligands for numerous small molecules, and recent three-dimensional structure solutions have revealed the basis for ligand recognition in several cases. By selecting high-affinity and -specificity nucleic acid ligands for proteins, promising new therapeutic and diagnostic reagents have been identified. Selection experiments have also been carried out to identify ribozymes that catalyze a variety of chemical transformations, including RNA cleavage, ligation, and synthesis, as well as alkylation and acyl-transfer reactions and N-glycosidic and peptide bond formation. The existence of such RNA enzymes supports the notion that ribozymes could have directed a primitive metabolism before the evolution of protein synthesis. New in vitro protein selection techniques should allow for a direct comparison of the frequency of ligand binding and catalytic structures in pools of random sequence polynucleotides versus polypeptides.
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Affiliation(s)
- D S Wilson
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston 02114-2696, USA.
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33
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34
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35
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36
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Abstract
Comparative path lengths in amino acid biosynthesis and other molecular indicators of the timing of codon assignment were examined to reconstruct the main stages of code evolution. The codon tree obtained was rooted in the 4 N-fixing amino acids (Asp, Glu, Asn, Gln) and 16 triplets of the NAN set. This small, locally phased (commaless) code evidently arose from ambiguous translation on a poly(A) collector strand, in a surface reaction network. Copolymerisation of these amino acids yields polyanionic peptide chains, which could anchor uncharged amide residues to a positively charged mineral surface. From RNA virus structure and replication in vitro, the first genes seemed to be RNA segments spliced into tRNA. Expansion of the code reduced the risk of mutation to an unreadable codon. This step was conditional on initiation at the 5'-codon of a translated sequence. Incorporation of increasingly hydrophobic amino acids accompanied expansion. As codons of the NUN set were assigned most slowly, they received the most nonpolar amino acids. The origin of ferredoxin and Gln synthetase was traced to mid-expansion phase. Surface metabolism ceased by the end of code expansion, as cells bounded by a proteo-phospholipid membrane, with a protoATPase, had emerged. Incorporation of positively charged and aromatic amino acids followed. They entered the post-expansion code by codon capture. Synthesis of efficient enzymes with acid-base catalysis was then possible. Both types of aminoacyl-tRNA synthetases were attributed to this stage. tRNA sequence diversity and error rates in RNA replication indicate the code evolved within 20 million yr in the preIsuan era. These findings on the genetic code provide empirical evidence, from a contemporaneous source, that a surface reaction network, centred on C-fixing autocatalytic cycles, rapidly led to cellular life on Earth.
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Affiliation(s)
- B K Davis
- Research Foundation of Southern California Inc., La Jolla 92037, USA
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37
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Abstract
RNA 77, derived by selection amplification, accelerates its own conversion to Phe-RNA (relative to randomized RNA) more than 6 x 10(7)-fold, by using amino acid adenylates as substrate. A modified assay system allows measurement of slow rates of aa-RNA formation, which for disfavored amino acid substrates can be more than 10(4)-fold slower than phenylalanine. Thus unlike previously characterized self-aminoacylators, RNA 77 catalysis is highly amino acid selective. Remarkably, both rates of aminoacyl transfer and amino acid specificities are greater for RNA 77 than measured for protein PheRS. These data experimentally support the possible existence of an ancestral amino acid-specific translation system relying entirely on RNA catalysis. RNA 77 itself embodies a possible transitional evolutionary state, in which side-chain-specific aa-RNA formation and anticodon-codon pairing were invested in the same molecule.
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Affiliation(s)
- M Illangasekare
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
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38
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39
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Schimmel P, Ribas de Pouplana L. Genetic code origins: experiments confirm phylogenetic predictions and may explain a puzzle. Proc Natl Acad Sci U S A 1999; 96:327-8. [PMID: 9892630 PMCID: PMC33543 DOI: 10.1073/pnas.96.2.327] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- P Schimmel
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, Beckman Center, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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40
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Landweber LF, Pokrovskaya ID. Emergence of a dual-catalytic RNA with metal-specific cleavage and ligase activities: the spandrels of RNA evolution. Proc Natl Acad Sci U S A 1999; 96:173-8. [PMID: 9874791 PMCID: PMC15112 DOI: 10.1073/pnas.96.1.173] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/1998] [Accepted: 10/26/1998] [Indexed: 11/18/2022] Open
Abstract
In vitro selection, or directed molecular evolution, allows the isolation and amplification of rare sequences that satisfy a functional-selection criterion. This technique can be used to isolate novel ribozymes (RNA enzymes) from large pools of random sequences. We used in vitro evolution to select a ribozyme that catalyzes a novel template-directed RNA ligation that requires surprisingly few nucleotides for catalytic activity. With the exception of two nucleotides, most of the ribozyme contributes to a template, suggesting that it is a general prebiotic ligase. More surprisingly, the catalytic core built from randomized sequences actually contains a 7-nt manganese-dependent self-cleavage motif originally discovered in the Tetrahymena group I intron. Further experiments revealed that we have selected a dual-catalytic RNA from random sequences: the RNA promotes both cleavage at one site and ligation at another site, suggesting two conformations surrounding at least one divalent metal ion-binding site. Together, these results imply that similar catalytic RNA motifs can arise under fairly simple conditions and that multiple catalytic structures, including bifunctional ligases, can evolve from very small preexisting parts. By breaking apart and joining different RNA strands, such ribozymes could have led to the production of longer and more complex RNA polymers in prebiotic evolution.
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Affiliation(s)
- L F Landweber
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
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Famulok M, Jenne A. Catalysis Based on Nucleic Acid Structures. IMPLEMENTATION AND REDESIGN OF CATALYTIC FUNCTION IN BIOPOLYMERS 1999. [DOI: 10.1007/3-540-48990-8_4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Zhang B, Cech TR. Peptidyl-transferase ribozymes: trans reactions, structural characterization and ribosomal RNA-like features. CHEMISTRY & BIOLOGY 1998; 5:539-53. [PMID: 9818147 DOI: 10.1016/s1074-5521(98)90113-2] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND One of the most significant questions in understanding the origin of life concerns the order of appearance of DNA, RNA and protein during early biological evolution. If an 'RNA world' was a precursor to extant life, RNA must be able not only to catalyze RNA replication but also to direct peptide synthesis. Iterative RNA selection previously identified catalytic RNAs (ribozymes) that form amide bonds between RNA and an amino acid or between two amino acids. RESULTS We characterized peptidyl-transferase reactions catalyzed by two different families of ribozymes that use substrates that mimic A site and P site tRNAs. The family II ribozyme secondary structure was modeled using chemical modification, enzymatic digestion and mutational analysis. Two regions resemble the peptidyl-transferase region of 23S ribosomal RNA in sequence and structural context; these regions are important for peptide-bond formation. A shortened form of this ribozyme was engineered to catalyze intermolecular ('trans') peptide-bond formation, with the two amino-acid substrates binding through an attached AMP or oligonucleotide moiety. CONCLUSIONS An in vitro-selected ribozyme can catalyze the same type of peptide-bond formation as a ribosome; the ribozyme resembles the ribosome because a very specific RNA structure is required for substrate binding and catalysis, and both amino acids are attached to nucleotides. It is intriguing that, although there are many different possible peptidyl-transferase ribozymes, the sequence and secondary structure of one is strikingly similar to the 'helical wheel' portion of 23S rRNA implicated in ribosomal peptidyl-transferase activity.
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Affiliation(s)
- B Zhang
- Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309-0215, USA
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Ribas de Pouplana L, Turner RJ, Steer BA, Schimmel P. Genetic code origins: tRNAs older than their synthetases? Proc Natl Acad Sci U S A 1998; 95:11295-300. [PMID: 9736730 PMCID: PMC21636 DOI: 10.1073/pnas.95.19.11295] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We present a phylogenetic analysis to determine whether a given tRNA molecule was established in evolution before its cognate aminoacyl-tRNA synthetase. The earlier appearance of tRNA versus their metabolically related enzymes is a prediction of the RNA world theory, but the available synthetase and tRNA sequences previously had not allowed a formal comparison of their relative time of appearance. Using data recently obtained from the emerging genome projects, our analysis points to the extant forms of lysyl-tRNA synthetase being preceded in evolution by the establishment of the identity of lysine tRNA.
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Affiliation(s)
- L Ribas de Pouplana
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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Schimmel P, Alexander R. Diverse RNA substrates for aminoacylation: clues to origins? Proc Natl Acad Sci U S A 1998; 95:10351-3. [PMID: 9724705 PMCID: PMC33886 DOI: 10.1073/pnas.95.18.10351] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- P Schimmel
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, Beckman Center, 10560 North Torrey Pines Road, La Jolla, CA 92037, USA
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Abstract
An attractive solution to the problem of the origin of protein synthesis in an evolving 'RNA world' involves catalysis by nucleic acid without assistance from proteins. Indeed, even the modern ribosome has been considered to be fundamentally an RNA machine, and the large ribosomal subunit can carry out peptidyl transfer in the absence of most of its protein subunits. Successive cycles of in vitro selection and amplification have been used to find RNAs that perform many biochemical reactions, including transfer of an RNA-linked amino acid to their own 5'-amino-modified terminus. Here we demonstrate the in vitro selection of ribozymes (196 nucleotides) that perform the same peptidyl transferase reaction as the ribosome: that is, they can join amino acids by a peptide bond. Like ribosome substrates, one amino acid (N-blocked methionine) is esterified to the 3'(2')-O of adenosine, whereas the acceptor amino acid (phenylalanine) has a free amino group. Our best characterized ribozyme recognizes the amino-acid ester substrate by binding its adenosine moiety, and is therefore capable of utilizing Leu- and Phe- as well as Met-derived substrates. Such lack of specificity with respect to the amino acid is a feature necessary for a generalized protein-synthesizing enzyme.
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Affiliation(s)
- B Zhang
- Howard Hughes Medical Institute, Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309-0215, USA
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Abstract
A model for a parallel evolution of the genetic code and protein synthesis is presented. The main tenet of this model is that the genetic code, that is, a correspondence between nucleotide and amino-acid coding units, originated from sequence-specific interaction between abiotically synthesized polynucleotides and polypeptides. A sequence-specific binding between oligonucleotides and oligopeptides is supported by experimental findings. Moreover, it is parsimonious enough to be consistent with the relatively simple chemistry of a primordial environment. Proximity between peptides and RNA increased the rate of formation of ester bonds between them. This lead to the accumulation of sequence-specific polypeptide-polynucleotide pairs, that is, of primordial-loaded tRNA. Condensation of short polypeptides into longer products could be catalyzed by a sequence-specific juxtaposition of loaded tRNA over complementary RNA, originating the core of protein synthesis. The accumulation of useful encoded products, for example, catalysts for tRNA loading (primordial aminoacyl-tRNA synthetases) or stabilizers of tRNA-mRNA interactions (primordial ribosomes), permitted the subsequent evolution of protein synthesis and of the genetic code to their mature form. This occurred via a parallel reduction in length of the interacting polynucleotides and polypeptides. Thus, it maintained the correct reading frame of mRNA from the preceding stages of evolution.
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Affiliation(s)
- S Alberti
- Department of Cell Biology and Oncology, Istituto di Ricerche Farmacologiche Mario Negri, Consorzio Mario Negri Sud, Chieti, Italy
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Abstract
BACKGROUND It is generally accepted that, during evolution, replicating RNA molecules emerged from pools of random polynucleotides. This prebiotic RNA world was followed by an era of RNA-mediated catalysis of amide-bond formation. RNA would thus have provided the machinery responsible for the assembly of peptides and the beginning of the protein world of today. Naturally occurring ribozymes, which catalyze the cleavage or ligation of oligonucleotide phosphodiester bonds, support the idea that RNA could self-replicate. But was RNA constrained to this path and were RNA-acylated carriers required before RNA could catalyze the formation of amide bonds? RESULTS We have isolated RNA catalysts that are capable of mediating amide-bond synthesis without the need for specifically designed templates to align the substrates, and we have kinetically characterized these catalysts. The rate enhancement observed for these RNA amide synthases exceeds the noncatalyzed amidation rate by a factor of approximately 10(4). In addition, Cu2+ ions caused a change in the affinity of RNA for the substrate rather than being directly involved in amide-bond formation. CONCLUSIONS The discovery of these new amide synthases shows how functionally modified nucleic acids can facilitate covalent-bond formation without templating. Previously unforeseen RNA-evolution pathways can, therefore, be considered; for example, to guide amide-bond formation, en route to the protein world, it appears that substrate-binding pockets were formed that are analogous to those of protein enzymes.
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Affiliation(s)
- T W Wiegand
- NeXstar Pharmaceuticals Incorporated, Boulder, CO 80301, USA
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Huang F, Yarus M. Versatile 5' phosphoryl coupling of small and large molecules to an RNA. Proc Natl Acad Sci U S A 1997; 94:8965-9. [PMID: 9256418 PMCID: PMC22987 DOI: 10.1073/pnas.94.17.8965] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A Ca2+-requiring catalytic RNA is shown to create 5' phosphate-phosphate linkages with all nucleotides and coenzymes including CoA, nicotinamide adenine dinucleotide phosphate, thiamine phosphate, thiamine pyrophosphate, and flavin mononucleotide. In addition to these small molecules, macromolecules such as RNAs with 5'-diphosphates, and nonnucleotide molecules like Nepsilon-phosphate arginine and 6-phosphate gluconic acid also react. That is, the self-capping RNA isolate 6 is an apparently universal 5' phosphate-linker, reacting with any nucleophile containing an unblocked phosphate. These RNA reactions demonstrate a unique RNA catalytic capability and imply versatile and specific posttranscriptional RNA modification by RNA catalysis.
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Affiliation(s)
- F Huang
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
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Abstract
Ribozymes are RNA molecules capable of catalyzing chemical reactions. Natural ribozymes generally accelerate the rate of cleavage and ligation of specific phosphodiester bonds. In vitro selection of RNA is now being used as a powerful technique to isolate novel and variant ribozymes that carry out catalysis at phosphodiester and carbon bonds. The range of reactions catalyzed by in vitro selected ribozymes is now well beyond the scope of known natural ribozymes.
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Affiliation(s)
- T Pan
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA.
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