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Rivas M, Fox GE. On the Nature of the Last Common Ancestor: A Story from its Translation Machinery. J Mol Evol 2024; 92:593-604. [PMID: 39259330 DOI: 10.1007/s00239-024-10199-4] [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: 02/26/2024] [Accepted: 08/22/2024] [Indexed: 09/13/2024]
Abstract
The Last Common Ancestor (LCA) is understood as a hypothetical population of organisms from which all extant living creatures are thought to have descended. Its biology and environment have been and continue to be the subject of discussions within the scientific community. Since the first bacterial genomes were obtained, multiple attempts to reconstruct the genetic content of the LCA have been made. In this review, we compare 10 of the most extensive reconstructions of the gene content possessed by the LCA as they relate to aspects of the translation machinery. Although each reconstruction has its own methodological biases and many disagree in the metabolic nature of the LCA all, to some extent, indicate that several components of the translation machinery are among the most conserved genetic elements. The datasets from each reconstruction clearly show that the LCA already had a largely complete translational system with a genetic code already in place and therefore was not a progenote. Among these features several ribosomal proteins, transcription factors like IF2, EF-G, and EF-Tu and both class I and class II aminoacyl tRNA synthetases were found in essentially all reconstructions. Due to the limitations of the various methodologies, some features such as the occurrence of rRNA posttranscriptional modified bases are not fully addressed. However, conserved as it is, non-universal ribosomal features found in various reconstructions indicate that LCA's translation machinery was still evolving, thereby acquiring the domain specific features in the process. Although progenotes from the pre-LCA likely no longer exist recent results obtained by unraveling the early history of the ribosome and other genetic processes can provide insight to the nature of the pre-LCA world.
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Affiliation(s)
- Mario Rivas
- Department of Biology and Biochemistry, University of Houston, Houston, TX, 77204-5001, USA.
| | - George E Fox
- Department of Biology and Biochemistry, University of Houston, Houston, TX, 77204-5001, USA
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Codispoti S, Yamaguchi T, Makarov M, Giacobelli VG, Mašek M, Kolář MH, Sanchez Rocha AC, Fujishima K, Zanchetta G, Hlouchová K. The interplay between peptides and RNA is critical for protoribosome compartmentalization and stability. Nucleic Acids Res 2024:gkae823. [PMID: 39340303 DOI: 10.1093/nar/gkae823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 09/04/2024] [Accepted: 09/10/2024] [Indexed: 09/30/2024] Open
Abstract
The ribosome, owing to its exceptional conservation, harbours a remarkable molecular fossil known as the protoribosome. It surrounds the peptidyl transferase center (PTC), responsible for peptide bond formation. While previous studies have demonstrated the PTC activity in RNA alone, our investigation reveals the intricate roles of the ribosomal protein fragments (rPeptides) within the ribosomal core. This research highlights the significance of rPeptides in stability and coacervation of two distinct protoribosomal evolutionary stages. The 617nt 'big' protoribosome model, which associates with rPeptides specifically, exhibits a structurally defined and rigid nature, further stabilized by the peptides. In contrast, the 136nt 'small' model, previously linked to peptidyltransferase activity, displays greater structural flexibility. While this construct interacts with rPeptides with lower specificity, they induce coacervation of the 'small' protoribosome across a wide concentration range, which is concomitantly dependent on the RNA sequence and structure. Moreover, these conditions protect RNA from degradation. This phenomenon suggests a significant evolutionary advantage in the RNA-protein interaction at the early stages of ribosome evolution. The distinct properties of the two protoribosomal stages suggest that rPeptides initially provided compartmentalization and prevented RNA degradation, preceding the emergence of specific RNA-protein interactions crucial for the ribosomal structural integrity.
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Affiliation(s)
- Simone Codispoti
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università di Milano, Segrate 20054, Italy
| | - Tomoko Yamaguchi
- Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, Prague 12800, Czech Republic
| | - Mikhail Makarov
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, Prague 12800, Czech Republic
| | - Valerio G Giacobelli
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, Prague 12800, Czech Republic
| | - Martin Mašek
- Department of Physical Chemistry, University of Chemistry and Technology, Technicka 5, 16628 Prague, Czech Republic
| | - Michal H Kolář
- Department of Physical Chemistry, University of Chemistry and Technology, Technicka 5, 16628 Prague, Czech Republic
| | | | - Kosuke Fujishima
- Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
- Graduate School of Media and Governance, Keio University, 5322 Endo, Fujisawa 252-0882, Japan
| | - Giuliano Zanchetta
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università di Milano, Segrate 20054, Italy
| | - Klára Hlouchová
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, Prague 12800, Czech Republic
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo n. 2, Prague 16610, Czech Republic
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Prosdocimi F, de Farias ST. Major evolutionary transitions before cells: A journey from molecules to organisms. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2024; 191:11-24. [PMID: 38971326 DOI: 10.1016/j.pbiomolbio.2024.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 05/25/2024] [Accepted: 07/03/2024] [Indexed: 07/08/2024]
Abstract
Basing on logical assumptions and necessary steps of complexification along biological evolution, we propose here an evolutionary path from molecules to cells presenting four ages and three major transitions. At the first age, the basic biomolecules were formed and become abundant. The first transition happened with the event of a chemical symbiosis between nucleic acids and peptides worlds, which marked the emergence of both life and the process of organic encoding. FUCA, the first living process, was composed of self-replicating RNAs linked to amino acids and capable to catalyze their binding. The second transition, from the age of FUCA to the age of progenotes, involved the duplication and recombination of proto-genomes, leading to specialization in protein production and the exploration of protein to metabolite interactions in the prebiotic soup. Enzymes and metabolic pathways were incorporated into biology from protobiotic reactions that occurred without chemical catalysts, step by step. Then, the fourth age brought origin of organisms and lineages, occurring when specific proteins capable to stackle together facilitated the formation of peptidic capsids. LUCA was constituted as a progenote capable to operate the basic metabolic functions of a cell, but still unable to interact with lipid molecules. We present evidence that the evolution of lipid interaction pathways occurred at least twice, with the development of bacterial-like and archaeal-like membranes. Also, data in literature suggest at least two paths for the emergence of DNA biosynthesis, allowing the stabilization of early life strategies in viruses, archaeas and bacterias. Two billion years later, the eukaryotes arouse, and after 1,5 billion years of evolution, they finally learn how to evolve multicellularity via tissue specialization.
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Affiliation(s)
- Francisco Prosdocimi
- Laboratório de Biologia Teórica e de Sistemas, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
| | - Sávio Torres de Farias
- Laboratório de Genética Evolutiva Paulo Leminski, Centro de Ciências Exatas e da Natureza, Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil; Network of Researchers on the Chemical Evolution of Life (NoRCEL), Leeds, LS7 3RB, UK
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Halpern A, Bartsch LR, Ibrahim K, Harrison SA, Ahn M, Christodoulou J, Lane N. Biophysical Interactions Underpin the Emergence of Information in the Genetic Code. Life (Basel) 2023; 13:1129. [PMID: 37240774 PMCID: PMC10221087 DOI: 10.3390/life13051129] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 04/25/2023] [Accepted: 04/30/2023] [Indexed: 05/28/2023] Open
Abstract
The genetic code conceals a 'code within the codons', which hints at biophysical interactions between amino acids and their cognate nucleotides. Yet, research over decades has failed to corroborate systematic biophysical interactions across the code. Using molecular dynamics simulations and NMR, we have analysed interactions between the 20 standard proteinogenic amino acids and 4 RNA mononucleotides in 3 charge states. Our simulations show that 50% of amino acids bind best with their anticodonic middle base in the -1 charge state common to the backbone of RNA, while 95% of amino acids interact most strongly with at least 1 of their codonic or anticodonic bases. Preference for the cognate anticodonic middle base was greater than 99% of randomised assignments. We verify a selection of our results using NMR, and highlight challenges with both techniques for interrogating large numbers of weak interactions. Finally, we extend our simulations to a range of amino acids and dinucleotides, and corroborate similar preferences for cognate nucleotides. Despite some discrepancies between the predicted patterns and those observed in biology, the existence of weak stereochemical interactions means that random RNA sequences could template non-random peptides. This offers a compelling explanation for the emergence of genetic information in biology.
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Affiliation(s)
- Aaron Halpern
- UCL Centre for Life’s Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Lilly R. Bartsch
- UCL Centre for Life’s Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Kaan Ibrahim
- UCL Centre for Life’s Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Stuart A. Harrison
- UCL Centre for Life’s Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Minkoo Ahn
- Department of Structural and Molecular Biology, Institute of Structural and Molecular Biology (ISMB), University College London, London WC1E 6BT, UK
| | - John Christodoulou
- Department of Structural and Molecular Biology, Institute of Structural and Molecular Biology (ISMB), University College London, London WC1E 6BT, UK
| | - Nick Lane
- UCL Centre for Life’s Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
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Prosdocimi F, de Farias ST. Origin of life: Drawing the big picture. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 180-181:28-36. [PMID: 37080436 DOI: 10.1016/j.pbiomolbio.2023.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/15/2023] [Accepted: 04/17/2023] [Indexed: 04/22/2023]
Abstract
Trying to provide a broad overview about the origin of life in Earth, the most significant transitions of life before cells are listed and discussed. The current approach emphasizes the symbiotic relationships that emerged with life. We propose a rational, stepwise scenario for the origin of life that starts with the origin of the first biomolecules and steps forward until the origins of the first cells. Along this path, we aim to provide a brief, though comprehensive theoretical model that will consider the following steps: (i) how nucleotides and other biomolecules could be made prebiotically in specific prebiotic refuges; (ii) how the first molecules of RNAs were formed; (iii) how the proto-peptidyl transferase center was built by the concatenation of proto-tRNAs; (iv) how the ribosome and the genetic code could be structured; (v) how progenotes could live and reproduce as "naked" ribonucleoprotein molecules; (vi) how peptides started to bind molecules in the prebiotic soup allowing biochemical pathways to evolve from those bindings; (vii) how genomes got bigger by the symbiotic relationship of progenotes and lateral transference of genetic material; (viii) how the progenote LUCA has been formed by assembling most biochemical routes; (ix) how the first virion capsids probably emerged and evolved; (x) how phospholipid membranes emerged probably twice by the evolution of lipid-binding proteins; (xi) how DNA synthesis have been formed in parallel in Bacteria and Archaea; and, finally, (xii) how DNA-based cells of Bacteria and Archaeabacteria have been constituted. The picture provided is conjectural and present epistemological gaps. Future research will help to advance into the elucidation of gaps and confirmation/refutation of current statements.
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Affiliation(s)
- Francisco Prosdocimi
- Laboratório de Biologia Teórica e de Sistemas, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
| | - Sávio Torres de Farias
- Laboratório de Genética Evolutiva Paulo Leminski, Centro de Ciências Exatas e da Natureza, Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil; Network of Researchers on the Chemical Evolution of Life (NoRCEL), Leeds, LS7 3RB, UK
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Villarreal L, Witzany G. Self-empowerment of life through RNA networks, cells and viruses. F1000Res 2023; 12:138. [PMID: 36785664 PMCID: PMC9918806 DOI: 10.12688/f1000research.130300.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/20/2023] [Indexed: 01/05/2024] Open
Abstract
Our understanding of the key players in evolution and of the development of all organisms in all domains of life has been aided by current knowledge about RNA stem-loop groups, their proposed interaction motifs in an early RNA world and their regulative roles in all steps and substeps of nearly all cellular processes, such as replication, transcription, translation, repair, immunity and epigenetic marking. Cooperative evolution was enabled by promiscuous interactions between single-stranded regions in the loops of naturally forming stem-loop structures in RNAs. It was also shown that cooperative RNA stem-loops outcompete selfish ones and provide foundational self-constructive groups (ribosome, editosome, spliceosome, etc.). Self-empowerment from abiotic matter to biological behavior does not just occur at the beginning of biological evolution; it is also essential for all levels of socially interacting RNAs, cells and viruses.
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Affiliation(s)
- Luis Villarreal
- Center for Virus Research, University of California, Irvine, California, USA
| | - Guenther Witzany
- Telos - Philosophische Praxis, Buermoos, Salzburg, 5111, Austria
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Abstract
Our understanding of the key players in evolution and of the development of all organisms in all domains of life has been aided by current knowledge about RNA stem-loop groups, their proposed interaction motifs in an early RNA world and their regulative roles in all steps and substeps of nearly all cellular processes, such as replication, transcription, translation, repair, immunity and epigenetic marking. Cooperative evolution was enabled by promiscuous interactions between single-stranded regions in the loops of naturally forming stem-loop structures in RNAs. It was also shown that cooperative RNA stem-loops outcompete selfish ones and provide foundational self-constructive groups (ribosome, editosome, spliceosome, etc.). Self-empowerment from abiotic matter to biological behavior does not just occur at the beginning of biological evolution; it is also essential for all levels of socially interacting RNAs, cells and viruses.
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Affiliation(s)
- Luis Villarreal
- Center for Virus Research, University of California, Irvine, California, USA
| | - Guenther Witzany
- Telos - Philosophische Praxis, Buermoos, Salzburg, 5111, Austria
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8
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Prosdocimi F, de Farias ST. Entering the labyrinth: A hypothesis about the emergence of metabolism from protobiotic routes. Biosystems 2022; 220:104751. [DOI: 10.1016/j.biosystems.2022.104751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/26/2022] [Accepted: 07/31/2022] [Indexed: 11/26/2022]
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Bose T, Fridkin G, Bashan A, Yonath A. Origin of Life: Chiral Short RNA Chains Capable of Non‐Enzymatic Peptide Bond Formation. Isr J Chem 2022. [DOI: 10.1002/ijch.202100054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Tanaya Bose
- Department of Structural Biology Weizmann Institute of Science 76100 Rehovot Israel
| | - Gil Fridkin
- Department of Structural Biology Weizmann Institute of Science 76100 Rehovot Israel
- Department of Organic Chemistry Israel Institute for Biological Research P.O. Box 19 Ness Ziona 7410001 Israel
| | - Anat Bashan
- Department of Structural Biology Weizmann Institute of Science 76100 Rehovot Israel
| | - Ada Yonath
- Department of Structural Biology Weizmann Institute of Science 76100 Rehovot Israel
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Farias STD, Prosdocimi F. RNP-world: The ultimate essence of life is a ribonucleoprotein process. Genet Mol Biol 2022; 45:e20220127. [PMID: 36190700 PMCID: PMC9528728 DOI: 10.1590/1678-4685-gmb-2022-0127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 06/03/2022] [Indexed: 11/22/2022] Open
Abstract
The fundamental essence of life is based on process of interaction between nucleic acids and proteins. In a prebiotic world, amino acids, peptides, ions, and other metabolites acted in protobiotic routes at the same time on which RNAs performed catalysis and self-replication. Nevertheless, it was only when nucleic acids and peptides started to interact together in an organized process that life emerged. First, the ignition was sparked with the formation of a Peptidyl Transferase Center (PTC), possibly by concatenation of proto-tRNAs. This molecule that would become the catalytic site of ribosomes started a process of self-organization that gave origin to a protoorganism named FUCA, a ribonucleic ribosomal-like apparatus capable to polymerize amino acids. In that sense, we review hypotheses about the origin and early evolution of the genetic code. Next, populations of open biological systems named progenotes were capable of accumulating and exchanging genetic material, producing the first genomes. Progenotes then evolved in two paths: some presented their own ribosomes and others used available ribosomes in the medium to translate their encoded information. At some point, two different types of organisms emerged from populations of progenotes: the ribosome-encoding organisms (cells) and the capsid-encoding organisms (viruses).
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Affiliation(s)
- Sávio Torres de Farias
- Universidade Federal da Paraíba, Brazil; Network of Researchers on the Chemical Evolution of Life, UK
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11
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Kovalenko SP. On the Origin of Genetically Coded Protein Synthesis. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2021. [DOI: 10.1134/s1068162021060121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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de Farias ST, Rêgo TG, José MV. Origin of the 16S Ribosomal Molecule from Ancestor tRNAs. J Mol Evol 2021; 89:249-256. [PMID: 33760964 DOI: 10.1007/s00239-021-10002-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/06/2021] [Indexed: 12/15/2022]
Abstract
We tested the hypothesis that concatemers of ancestral tRNAs gave rise to the 16S ribosomal RNA. We built an ancestral sequence of proto-tRNAs that showed a significant identity of 51.69% and a percentage of structural identity of 0.941 with the 3' upper domain of 16S ribosomal molecule. We also propose a hypothesis in which the small ribosomal subunit emerged by proto-tRNA fusion and worked as a point to bind RNAs in an open structure configuration. In this context, the two ribosomal subunits initially worked independently, and that the subunit junction, with consequent primitive ribosome formation, was mediated by interactions with tRNA molecules during the primordial genetic code formation.
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Affiliation(s)
- Savio Torres de Farias
- Laboratório de Genética Evolutiva Paulo Leminsk, Departamento de Biologia Molecular, Universidade Federal da Paraíba, João Pessoa, 58051-900, Brazil. .,Network of Researchers on the Chemical Evolution of Life (NoRCEL), Leeds, LS7 3RB, UK.
| | - Thais Gaudêncio Rêgo
- Departamento de Informática, Universidade Federal da Paraíba, João Pessoa, 58051-900, Brazil
| | - Marco V José
- Theoretical Biology Group, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, C.P. 04510, Mexico, D.F., Mexico
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Abstract
We tested the hypothesis that concatemers of ancestral tRNAs gave rise to the 16S ribosomal RNA. We built an ancestral sequence of proto-tRNAs that showed a significant identity of 51.69% and a percentage of structural identity of 0.941 with the 16S ribosomal molecule. We also propose a hypothesis for the emergence of translation.
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Bowman JC, Petrov AS, Frenkel-Pinter M, Penev PI, Williams LD. Root of the Tree: The Significance, Evolution, and Origins of the Ribosome. Chem Rev 2020; 120:4848-4878. [PMID: 32374986 DOI: 10.1021/acs.chemrev.9b00742] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The ribosome is an ancient molecular fossil that provides a telescope to the origins of life. Made from RNA and protein, the ribosome translates mRNA to coded protein in all living systems. Universality, economy, centrality and antiquity are ingrained in translation. The translation machinery dominates the set of genes that are shared as orthologues across the tree of life. The lineage of the translation system defines the universal tree of life. The function of a ribosome is to build ribosomes; to accomplish this task, ribosomes make ribosomal proteins, polymerases, enzymes, and signaling proteins. Every coded protein ever produced by life on Earth has passed through the exit tunnel, which is the birth canal of biology. During the root phase of the tree of life, before the last common ancestor of life (LUCA), exit tunnel evolution is dominant and unremitting. Protein folding coevolved with evolution of the exit tunnel. The ribosome shows that protein folding initiated with intrinsic disorder, supported through a short, primitive exit tunnel. Folding progressed to thermodynamically stable β-structures and then to kinetically trapped α-structures. The latter were enabled by a long, mature exit tunnel that partially offset the general thermodynamic tendency of all polypeptides to form β-sheets. RNA chaperoned the evolution of protein folding from the very beginning. The universal common core of the ribosome, with a mass of nearly 2 million Daltons, was finalized by LUCA. The ribosome entered stasis after LUCA and remained in that state for billions of years. Bacterial ribosomes never left stasis. Archaeal ribosomes have remained near stasis, except for the superphylum Asgard, which has accreted rRNA post LUCA. Eukaryotic ribosomes in some lineages appear to be logarithmically accreting rRNA over the last billion years. Ribosomal expansion in Asgard and Eukarya has been incremental and iterative, without substantial remodeling of pre-existing basal structures. The ribosome preserves information on its history.
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Affiliation(s)
- Jessica C Bowman
- Center for the Origins of Life, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Anton S Petrov
- Center for the Origins of Life, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Moran Frenkel-Pinter
- Center for the Origins of Life, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Petar I Penev
- Center for the Origins of Life, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Loren Dean Williams
- Center for the Origins of Life, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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de Farias ST, José MV. Transfer RNA: The molecular demiurge in the origin of biological systems. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 153:28-34. [PMID: 32105652 DOI: 10.1016/j.pbiomolbio.2020.02.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 02/03/2020] [Accepted: 02/11/2020] [Indexed: 01/24/2023]
Abstract
Herein, we review recent works on the role that the tRNA molecule played in the early origins of biological systems. tRNAs gave origin to the first genes (mRNA), the peptidyl transferase center (PTC), the 16S ribosomal molecule, proto-tRNAs were at the core of a proto-translation system, and the anticodon and operational codes appeared in tRNAs molecules. Metabolic pathways emerged from evolutionary pressures of the decoding systems. The transitions from the RNA world to the ribonucleoprotein world to modern biological systems were driven by two kinds of tRNAs transitions, to wit, tRNAs leading to both mRNA and rRNA.
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Affiliation(s)
- Sávio Torres de Farias
- Laboratório de Genética Evolutiva Paulo Leminsk, Departamento de Biologia Molecular, Universidade Federal da Paraíba, João Pessoa, Brazil.
| | - Marco V José
- Theoretical Biology Group, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México CDMX, C.P. 04510, Mexico.
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de Farias ST, Jheeta S, Prosdocimi F. Viruses as a survival strategy in the armory of life. HISTORY AND PHILOSOPHY OF THE LIFE SCIENCES 2019; 41:45. [PMID: 31612293 DOI: 10.1007/s40656-019-0287-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 10/08/2019] [Indexed: 06/10/2023]
Abstract
Viruses have generally been thought of as infectious agents. New data on mimivirus, however, suggests a reinterpretation of this thought. Earth's biosphere seems to contain many more viruses than previously thought and they are relevant in the maintenance of ecosystems and biodiversity. Viruses are not considered to be alive because they are not free-living entities and do not have cellular units. Current hypotheses indicate that some viruses may have been the result of genomic reduction of cellular life forms. However, new studies relating to the origins of biological systems suggest that viruses could also have originated during the transition from First to the Last Universal Common Ancestor (from FUCA to LUCA). Within this setting, life has been established as chemical informational system and could be interpreted as a macrocode of multiple layers. The first entity to acquire these features was the First Universal Common Ancestor (FUCA) that evolved to an intermediate ancestral that could be named T-LUCA (Transitional-LUCA) and be equated to Woese's concept of progenotes. T-LUCA may have remained as undifferentiated subsystems with viruses-like structures. The net result is that both cellular life forms and viruses shared protein synthesis apparatuses. In short, virus is a strategy of life reached by two paths: T-LUCAs like entities and the reduction of cellular life forms.
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Affiliation(s)
- Sávio Torres de Farias
- Laboratório de Genética Evolutiva Paulo Leminsk, Departamento de Biologia Molecular, Universidade Federal da Paraíba, João Pessoa, Paraíba, Brazil.
- Departamento de Filosofia, Programa de Pós-Graduação em Filosofia, Universidade Federal de Santa Catarina, Florianopólis, Santa Catarina, Brazil.
| | - Sohan Jheeta
- Network of Researchers on the Chemical Evolution of Life, Leeds, UK
| | - Francisco Prosdocimi
- Laboratório de Biologia Teórica e de Sistemas, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
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Abstract
We tested the hypothesis that concatemers of ancestral tRNAs gave rise to the 16S ribosomal RNA. We built an ancestral sequence of proto-tRNAs that showed a significant identity of 51.69% and a percentage of structural identity of 0.941 with the 16S ribosomal molecule. We also propose a hypothesis for the emergence of translation.
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Demongeot J, Norris V. Emergence of a "Cyclosome" in a Primitive Network Capable of Building "Infinite" Proteins. Life (Basel) 2019; 9:E51. [PMID: 31216720 PMCID: PMC6617141 DOI: 10.3390/life9020051] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/08/2019] [Accepted: 06/13/2019] [Indexed: 01/02/2023] Open
Abstract
We argue for the existence of an RNA sequence, called the AL (for ALpha) sequence, which may have played a role at the origin of life; this role entailed the AL sequence helping generate the first peptide assemblies via a primitive network. These peptide assemblies included "infinite" proteins. The AL sequence was constructed on an economy principle as the smallest RNA ring having one representative of each codon's synonymy class and capable of adopting a non-functional but nevertheless evolutionarily stable hairpin form that resisted denaturation due to environmental changes in pH, hydration, temperature, etc. Long subsequences from the AL ring resemble sequences from tRNAs and 5S rRNAs of numerous species like the proteobacterium, Rhodobacter sphaeroides. Pentameric subsequences from the AL are present more frequently than expected in current genomes, in particular, in genes encoding some of the proteins associated with ribosomes like tRNA synthetases. Such relics may help explain the existence of universal sequences like exon/intron frontier regions, Shine-Dalgarno sequence (present in bacterial and archaeal mRNAs), CRISPR and mitochondrial loop sequences.
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Affiliation(s)
- Jacques Demongeot
- Faculty of Medicine, Université Grenoble Alpes, AGEIS EA 7407 Tools for e-Gnosis Medical, 38700 La Tronche, France.
| | - Vic Norris
- Laboratory of Microbiology Signals and Microenvironment, Université de Rouen, 76821 Mont-Saint-Aignan CEDEX, France.
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Bernier CR, Petrov AS, Kovacs NA, Penev PI, Williams LD. Translation: The Universal Structural Core of Life. Mol Biol Evol 2019; 35:2065-2076. [PMID: 29788252 PMCID: PMC6063299 DOI: 10.1093/molbev/msy101] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The Universal Gene Set of Life (UGSL) is common to genomes of all extant organisms. The UGSL is small, consisting of <100 genes, and is dominated by genes encoding the translation system. Here we extend the search for biological universality to three dimensions. We characterize and quantitate the universality of structure of macromolecules that are common to all of life. We determine that around 90% of prokaryotic ribosomal RNA (rRNA) forms a common core, which is the structural and functional foundation of rRNAs of all cytoplasmic ribosomes. We have established a database, which we call the Sparse and Efficient Representation of the Extant Biology (the SEREB database). This database contains complete and cross-validated rRNA sequences of species chosen, as far as possible, to sparsely and efficiently sample all known phyla. Atomic-resolution structures of ribosomes provide data for structural comparison and validation of sequence-based models. We developed a similarity statistic called pairing adjusted sequence entropy, which characterizes paired nucleotides by their adherence to covariation and unpaired nucleotides by conventional conservation of identity. For canonically paired nucleotides the unit of structure is the nucleotide pair. For unpaired nucleotides, the unit of structure is the nucleotide. By quantitatively defining the common core of rRNA, we systematize the conservation and divergence of the translational system across the tree of life, and can begin to understand the unique evolutionary pressures that cause its universality. We explore the relationship between ribosomal size and diversity, geological time, and organismal complexity.
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Affiliation(s)
- Chad R Bernier
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332
| | - Anton S Petrov
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332
| | - Nicholas A Kovacs
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332
| | - Petar I Penev
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332
| | - Loren Dean Williams
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332
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Sleep NH. Geological and Geochemical Constraints on the Origin and Evolution of Life. ASTROBIOLOGY 2018; 18:1199-1219. [PMID: 30124324 DOI: 10.1089/ast.2017.1778] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The traditional tree of life from molecular biology with last universal common ancestor (LUCA) branching into bacteria and archaea (though fuzzy) is likely formally valid enough to be a basis for discussion of geological processes on the early Earth. Biologists infer likely properties of nodal organisms within the tree and, hence, the environment they inhabited. Geologists both vet tenuous trees and putative origin of life scenarios for geological and ecological reasonability and conversely infer geological information from trees. The latter approach is valuable as geologists have only weakly constrained the time when the Earth became habitable and the later time when life actually existed to the long interval between ∼4.5 and ∼3.85 Ga where no intact surface rocks are known. With regard to vetting, origin and early evolution hypotheses from molecular biology have recently centered on serpentinite settings in marine and alternatively land settings that are exposed to ultraviolet sunlight. The existence of these niches on the Hadean Earth is virtually certain. With regard to inferring geological environment from genomics, nodes on the tree of life can arise from true bottlenecks implied by the marine serpentinite origin scenario and by asteroid impact. Innovation of a very useful trait through a threshold allows the successful organism to quickly become very abundant and later root a large clade. The origin of life itself, that is, the initial Darwinian ancestor, the bacterial and archaeal roots as free-living cellular organisms that independently escaped hydrothermal chimneys above marine serpentinite or alternatively from shallow pore-water environments on land, the Selabacteria root with anoxygenic photosynthesis, and the Terrabacteria root colonizing land are attractive examples that predate the geological record. Conversely, geological reasoning presents likely events for appraisal by biologists. Asteroid impacts may have produced bottlenecks by decimating life. Thermophile roots of bacteria and archaea as well as a thermophile LUCA are attractive.
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Affiliation(s)
- Norman H Sleep
- Department of Geophysics, Stanford University , Stanford, California
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21
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Saladino R, Šponer JE, Šponer J, Di Mauro E. Rewarming the Primordial Soup: Revisitations and Rediscoveries in Prebiotic Chemistry. Chembiochem 2018; 19:22-25. [PMID: 29164768 PMCID: PMC5768021 DOI: 10.1002/cbic.201700534] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Indexed: 01/11/2023]
Abstract
A short history of Campbell's primordial soup: In this essay we try to disclose some of the historical connections between the studies that have contributed to our current understanding of the emergence of catalytic RNA molecules and their components from an inanimate matter.
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Affiliation(s)
- Raffaele Saladino
- Dipartimento di Scienze Ecologiche e BiologicheUniversità della TusciaVia San Camillo De Lellis01100ViterboItaly
| | - Judit E. Šponer
- Institute of Biophysics of the Czech Academy of SciencesKrálovopolská 13561265BrnoCzech Republic
| | - Jiří Šponer
- Institute of Biophysics of the Czech Academy of SciencesKrálovopolská 13561265BrnoCzech Republic
| | - Ernesto Di Mauro
- Dipartimento di Scienze Ecologiche e BiologicheUniversità della TusciaVia San Camillo De Lellis01100ViterboItaly
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22
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Abstract
Multiple models have been advanced for the evolution of cloverleaf tRNA. Here, the conserved archaeal tRNA core (75-nt) is posited to have evolved from ligation of three proto-tRNA minihelices (31-nt) and two-symmetrical 9-nt deletions within joined acceptor stems (93 – 18 = 75-nt). The primary evidence for this conclusion is that the 5-nt stem 7-nt anticodon loop and the 5-nt stem 7-nt T loop are structurally homologous and related by coding sequence. We posit that the D loop was generated from a third minihelix (31-nt) in which the stem and loop became rearranged after 9-nt acceptor stem deletions and cloverleaf folding. The most 3´-5-nt segment of the D loop and the 5-nt V loop are apparent remnants of the joined acceptor stems (14 – 9 = 5-nt). Before refolding in the tRNA cloverleaf, we posit that the 3′-5-nt segment of the D loop and the 5-nt V loop were paired, and, in the tRNA cloverleaf, frequent pairing of positions 29 (D loop) and 47 (V loop) remains (numbered on a 75-nt tRNA cloverleaf core). Amazingly, after >3.5 billion years of evolutionary pressure on the tRNA cloverleaf structure, a model can be constructed that convincingly describes the genesis of 75/75-nt conserved archaeal tRNA core positions. Judging from the tRNA structure, cloverleaf tRNA appears to represent at least a second-generation scheme (and possibly a third-generation scheme) that replaced a robust 31-nt minihelix protein-coding system, evidence for which is preserved in the cloverleaf structure. Understanding tRNA evolution provides insights into ribosome and rRNA evolution.
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Affiliation(s)
| | | | | | - Zachary F Burton
- c Department of Biochemistry and Molecular Biology , Michigan State University , E. Lansing , MI , USA
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Yonath A. Quantum mechanic glimpse into peptide bond formation within the ribosome shed light on origin of life. Struct Chem 2017. [DOI: 10.1007/s11224-017-0980-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Peptidyl Transferase Center and the Emergence of the Translation System. Life (Basel) 2017; 7:life7020021. [PMID: 28441334 PMCID: PMC5492143 DOI: 10.3390/life7020021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 04/05/2017] [Accepted: 04/17/2017] [Indexed: 11/16/2022] Open
Abstract
In this work, the three-dimensional (3D) structure of the ancestral Peptidyl Transferase Center (PTC) built by concatamers of ancestral sequences of tRNAs was reconstructed, and its possible interactions with tRNAs molecules were analyzed. The 3D structure of the ancestral PTC was also compared with the current PTC of T. thermophilus. Docking experiments between the ancestral PTC and tRNAs suggest that in the origin of the translation system, the PTC functioned as an adhesion center for tRNA molecules. The approximation of tRNAs charged with amino acids to the PTC permitted peptide synthesis without the need of a genetic code.
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Abstract
In this paper, we revisit several issues relevant to origin-of-life research and propose a Phosphate Transfer Catalyst hypothesis that furthers our understanding of some of the key events in prebiotic chemical evolution. In the Phosphate Transfer Catalyst hypothesis, we assume the existence of hypothetical metallopeptides with phosphate transfer activity that use abundant polyphosphates as both substrates and energy sources. Nonspecific catalysis by this phosphate transfer catalyst would provide a variety of different products such as phosphoryl amino acids, nucleosides, polyphosphate nucleotides, nucleic acids, and aminoacylated nucleic acids. Moreover, being an autocatalytic set and metabolic driver at the same time, it could possibly replicate itself and produce a collective system of two polymerases; a nucleic acid able to catalyze peptide bond formation and a peptide able to polymerize nucleic acids. The genetic code starts at first as a system that reduces the energy barrier by bringing substrates (2'/3' aminoacyl-nucleotides) together, an ancestral form of the catalysis performed by modern ribosomes. Key Words: Origin of life-Prebiotic chemistry-Catalysis-Nucleic acids. Astrobiology 17, 277-285.
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Could a Proto-Ribosome Emerge Spontaneously in the Prebiotic World? Molecules 2016; 21:molecules21121701. [PMID: 27941673 PMCID: PMC6274258 DOI: 10.3390/molecules21121701] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 11/21/2016] [Accepted: 11/24/2016] [Indexed: 11/17/2022] Open
Abstract
An indispensable prerequisite for establishing a scenario of life emerging by natural processes is the requirement that the first simple proto-molecules could have had a realistic probability of self-assembly from random molecular polymers in the prebiotic world. The vestige of the proto-ribosome, which is believed to be still embedded in the contemporary ribosome, is used to assess the feasibility of such spontaneous emergence. Three concentric structural elements of different magnitudes, having a dimeric nature derived from the symmetrical region of the ribosomal large subunit, were suggested to constitute the vestige of the proto-ribosome. It is assumed to have materialized spontaneously in the prebiotic world, catalyzing non-coded peptide bond formation and simple elongation. Probabilistic and energetic considerations are applied in order to evaluate the suitability of the three contenders for being the initial proto-ribosome. The analysis points to the simplest proto-ribosome, comprised of a dimer of tRNA-like molecules presently embedded in the core of the symmetrical region, as the only one having a realistic statistical likelihood of spontaneous emergence from random RNA chains. Hence it offers a feasible starting point for a continuous evolutionary path from the prebiotic matter, through natural processes, into the intricate modern translation system.
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Macé K, Gillet R. Origins of tmRNA: the missing link in the birth of protein synthesis? Nucleic Acids Res 2016; 44:8041-51. [PMID: 27484476 PMCID: PMC5041485 DOI: 10.1093/nar/gkw693] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 07/22/2016] [Accepted: 07/26/2016] [Indexed: 12/20/2022] Open
Abstract
The RNA world hypothesis refers to the early period on earth in which RNA was central in assuring both genetic continuity and catalysis. The end of this era coincided with the development of the genetic code and protein synthesis, symbolized by the apparition of the first non-random messenger RNA (mRNA). Modern transfer-messenger RNA (tmRNA) is a unique hybrid molecule which has the properties of both mRNA and transfer RNA (tRNA). It acts as a key molecule during trans-translation, a major quality control pathway of modern bacterial protein synthesis. tmRNA shares many common characteristics with ancestral RNA. Here, we present a model in which proto-tmRNAs were the first molecules on earth to support non-random protein synthesis, explaining the emergence of early genetic code. In this way, proto-tmRNA could be the missing link between the first mRNA and tRNA molecules and modern ribosome-mediated protein synthesis.
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Affiliation(s)
- Kevin Macé
- Université de Rennes 1, CNRS UMR 6290 IGDR, Translation and Folding Team, 35042 Rennes cedex, France
| | - Reynald Gillet
- Université de Rennes 1, CNRS UMR 6290 IGDR, Translation and Folding Team, 35042 Rennes cedex, France Institut Universitaire de France
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28
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Seligmann H, Raoult D. Unifying view of stem–loop hairpin RNA as origin of current and ancient parasitic and non-parasitic RNAs, including in giant viruses. Curr Opin Microbiol 2016; 31:1-8. [DOI: 10.1016/j.mib.2015.11.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 11/19/2015] [Accepted: 11/25/2015] [Indexed: 12/20/2022]
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tRNA Core Hypothesis for the Transition from the RNA World to the Ribonucleoprotein World. Life (Basel) 2016; 6:life6020015. [PMID: 27023615 PMCID: PMC4931452 DOI: 10.3390/life6020015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 02/29/2016] [Accepted: 03/18/2016] [Indexed: 01/10/2023] Open
Abstract
Herein we present the tRNA core hypothesis, which emphasizes the central role of tRNAs molecules in the origin and evolution of fundamental biological processes. tRNAs gave origin to the first genes (mRNA) and the peptidyl transferase center (rRNA), proto-tRNAs were at the core of a proto-translation system, and the anticodon and operational codes then arose in tRNAs molecules. Metabolic pathways emerged from evolutionary pressures of the decoding systems. The transitions from the RNA world to the ribonucleoprotein world to modern biological systems were driven by three kinds of tRNAs transitions, to wit, tRNAs leading to both mRNA and rRNA.
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30
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Dibrova DV, Galperin MY, Koonin EV, Mulkidjanian AY. Ancient Systems of Sodium/Potassium Homeostasis as Predecessors of Membrane Bioenergetics. BIOCHEMISTRY (MOSCOW) 2016; 80:495-516. [PMID: 26071768 DOI: 10.1134/s0006297915050016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Cell cytoplasm of archaea, bacteria, and eukaryotes contains substantially more potassium than sodium, and potassium cations are specifically required for many key cellular processes, including protein synthesis. This distinct ionic composition and requirements have been attributed to the emergence of the first cells in potassium-rich habitats. Different, albeit complementary, scenarios have been proposed for the primordial potassium-rich environments based on experimental data and theoretical considerations. Specifically, building on the observation that potassium prevails over sodium in the vapor of inland geothermal systems, we have argued that the first cells could emerge in the pools and puddles at the periphery of primordial anoxic geothermal fields, where the elementary composition of the condensed vapor would resemble the internal milieu of modern cells. Marine and freshwater environments generally contain more sodium than potassium. Therefore, to invade such environments, while maintaining excess of potassium over sodium in the cytoplasm, primordial cells needed means to extrude sodium ions. The foray into new, sodium-rich habitats was the likely driving force behind the evolution of diverse redox-, light-, chemically-, or osmotically-dependent sodium export pumps and the increase of membrane tightness. Here we present a scenario that details how the interplay between several, initially independent sodium pumps might have triggered the evolution of sodium-dependent membrane bioenergetics, followed by the separate emergence of the proton-dependent bioenergetics in archaea and bacteria. We also discuss the development of systems that utilize the sodium/potassium gradient across the cell membranes.
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Affiliation(s)
- D V Dibrova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia
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31
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Maurel MC. From neontsto filiontsand their progenies... BIO WEB OF CONFERENCES 2015. [DOI: 10.1051/bioconf/20150400014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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32
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de Farias ST, do Rêgo TG, José MV. Evolution of transfer RNA and the origin of the translation system. Front Genet 2014; 5:303. [PMID: 25221573 PMCID: PMC4147829 DOI: 10.3389/fgene.2014.00303] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 08/12/2014] [Indexed: 11/21/2022] Open
Affiliation(s)
- Savio T de Farias
- Laboratório de Genética Evolutiva Paulo Leminsk, Departamento de Biologia Molecular, Universidade Federal da Paraíba João Pessoa, Brazil
| | - Thaís G do Rêgo
- Departamento de Informática, Universidade Federal da Paraíba João Pessoa, Brazil
| | - Marco V José
- Theoretical Biology Group, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México México, México
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33
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Egel R. Origins and emergent evolution of life: the colloid microsphere hypothesis revisited. ORIGINS LIFE EVOL B 2014; 44:87-110. [PMID: 25208738 DOI: 10.1007/s11084-014-9363-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 08/14/2014] [Indexed: 11/28/2022]
Abstract
Self-replicating molecules, in particular RNA, have long been assumed as key to origins of life on Earth. This notion, however, is not very secure since the reduction of life's complexity to self-replication alone relies on thermodynamically untenable assumptions. Alternative, earlier hypotheses about peptide-dominated colloid self-assembly should be revived. Such macromolecular conglomerates presumably existed in a dynamic equilibrium between confluent growth in sessile films and microspheres detached in turbulent suspension. The first organic syntheses may have been driven by mineral-assisted photoactivation at terrestrial geothermal fields, allowing photo-dependent heterotrophic origins of life. Inherently endowed with rudimentary catalyst activities, mineral-associated organic microstructures can have evolved adaptively toward cooperative 'protolife' communities, in which 'protoplasmic continuity' was maintained throughout a graded series of 'proto-biofilms', 'protoorganisms' and 'protocells' toward modern life. The proneness of organic microspheres to merge back into the bulk of sessile films by spontaneous fusion can have made large populations promiscuous from the beginning, which was important for the speed of collective evolution early on. In this protein-centered scenario, the emergent coevolution of uncoded peptides, metabolic cofactors and oligoribonucleotides was primarily optimized for system-supporting catalytic capabilities arising from nonribosomal peptide synthesis and nonreplicative ribonucleotide polymerization, which in turn incorporated other reactive micromolecular organics as vitamins and cofactors into composite macromolecular colloid films and microspheres. Template-dependent replication and gene-encoded protein synthesis emerged as secondary means for further optimization of overall efficieny later on. Eventually, Darwinian speciation of cell-like lineages commenced after minimal gene sets had been bundled in transmissible genomes from multigenomic protoorganisms.
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Affiliation(s)
- Richard Egel
- Department of Biology, University of Copenhagen Biocenter, Ole Maaløes Vej 5, DK-2200, Copenhagen, Denmark,
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34
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Farias ST, Rêgo TG, José MV. Origin and evolution of the Peptidyl Transferase Center from proto-tRNAs. FEBS Open Bio 2014; 4:175-8. [PMID: 24649398 PMCID: PMC3953717 DOI: 10.1016/j.fob.2014.01.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 01/29/2014] [Indexed: 11/29/2022] Open
Abstract
We tested the proposal that the Peptidyl Transferase Center (PTC) originated from proto-tRNAs. Proto-tRNA ancestors were reconstructed. Their sequences were compared to the sequences of the PTC from several organisms. We conclude that fusions of proto-tRNAs may have given rise to the PTC.
We tested the hypothesis of Tamura (2011) [3] that molecules of tRNA gave origin to ribosomes, particularly to the Peptidyl Transferase Center (PTC) of the 23S ribosomal RNA. We reconstructed the ancestral sequences from all types of tRNA and compared them in their sequences with the current PTC of 23S ribosomal RNA from different organisms. We built an ancestral sequence of proto-tRNAs that showed a remarkable overall identity of 50.53% with the catalytic site of PTC. We conclude that the Peptidyl Transferase Center was indeed originated by the fusion of ancestral sequences of proto-tRNA.
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Affiliation(s)
- Sávio T Farias
- Universidade Federal da Paraîba, Campus I, Departamento de Biologia Molecular, Laboratório de Genética Evolutiva Paulo Leminsk, João Pessoa, Paraíba, Brazil
| | - Thais G Rêgo
- Universidade Federal da Paraíba, Campus I, Departamento de Informática, João Pessoa, Paraíba, Brazil
| | - Marco V José
- Theoretical Biology Group, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, CP 04510, DF, Mexico ; Centro Internacional de Ciencias, Cuernavaca, Morelos, Mexico
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35
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Zimmerman E, Bashan A, Yonath A. Antibiotics at the Ribosomal Exit Tunnel-Selected Structural Aspects. Antibiotics (Basel) 2013. [DOI: 10.1002/9783527659685.ch22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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36
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Rivas M, Tran Q, Fox GE. Nanometer scale pores similar in size to the entrance of the ribosomal exit cavity are a common feature of large RNAs. RNA (NEW YORK, N.Y.) 2013; 19:1349-1354. [PMID: 23940386 PMCID: PMC3854525 DOI: 10.1261/rna.038828.113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 06/19/2013] [Indexed: 06/02/2023]
Abstract
The highly conserved peptidyl transferase center (PTC) of the ribosome contains an RNA pore that serves as the entrance to the exit tunnel. Analysis of available ribosome crystal structures has revealed the presence of multiple additional well-defined pores of comparable size in the ribosomal (rRNA) RNAs. These typically have dimensions of 1-2 nm, with a total area of ∼100 Å(2) or more, and most are associated with one or more ribosomal proteins. The PTC example and the other rRNA pores result from the packing of helices. However, in the non-PTC cases the nitrogenous bases do not protrude into the pore, thereby limiting the potential for hydrogen bonding within the pore. Instead, it is the RNA backbone that largely defines the pore likely resulting in a negatively charged environment. In many but not all cases, ribosomal proteins are associated with the pores to a greater or lesser extent. With the exception of the PTC case, the large subunit pores are not found in what are thought to be the evolutionarily oldest regions of the 23S rRNA. The unusual nature of the PTC pore may reflect a history of being created by hybridization between two or more RNAs early in evolution rather than simple folding of a single RNA. An initial survey of nonribosomal RNA crystal structures revealed additional pores, thereby showing that they are likely a general feature of RNA tertiary structure.
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Affiliation(s)
- Mario Rivas
- Laboratorio de Origen de la Vida, Departamento de Biología Evolutiva, Facultad de Ciencias, Universidad Nacional Autónoma de México, Coyoacán, C.P. 0451, Mexico
| | - Quyen Tran
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204-5001, USA
| | - George E. Fox
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204-5001, USA
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37
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Abstract
Experimental evidence suggests the existence of an RNA molecular prebiotic entity, called by us the "protoribosome," which may have evolved in the RNA world before evolution of the genetic code and proteins. This vestige of the RNA world, which possesses all of the capabilities required for peptide bond formation, seems to be still functioning in the heart of all of the contemporary ribosome. Within the modern ribosome this remnant includes the peptidyl transferase center. Its highly conserved nucleotide sequence is suggestive of its robustness under diverse environmental conditions, and hence on its prebiotic origin. Its twofold pseudosymmetry suggests that this entity could have been a dimer of self-folding RNA units that formed a pocket within which two activated amino acids might be accommodated, similar to the binding mode of modern tRNA molecules that carry amino acids or peptidyl moieties. Using quantum mechanics and crystal coordinates, this work studies the question of whether the putative protoribosome has properties necessary to function as an evolutionary precursor to the modern ribosome. The quantum model used in the calculations is density functional theory--B3LYP/3-21G*, implemented using the kernel energy method to make the computations practical and efficient. It occurs that the necessary conditions that would characterize a practicable protoribosome--namely (i) energetic structural stability and (ii) energetically stable attachment to substrates--are both well satisfied.
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38
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A Vestige of an RNA Apparatus With Ribozyme Capabilities Embedded and Functions Within the Modern Ribosome. SOCIAL AND ECOLOGICAL INTERACTIONS IN THE GALAPAGOS ISLANDS 2013. [DOI: 10.1007/978-1-4614-6732-8_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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39
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Egel R. Life's Order, Complexity, Organization, and Its Thermodynamic-Holistic Imperatives. Life (Basel) 2012; 2:323-63. [PMID: 25371269 PMCID: PMC4187152 DOI: 10.3390/life2040323] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 10/30/2012] [Accepted: 11/05/2012] [Indexed: 12/17/2022] Open
Abstract
In memoriam Jeffrey S. Wicken (1942-2002)-the evolutionarily minded biochemist, who in the 1970/80s strived for a synthesis of biological and physical theories to fathom the tentative origins of life. Several integrative concepts are worth remembering from Wicken's legacy. (i) Connecting life's origins and complex organization to a preexisting physical world demands a thermodynamically sound transition. (ii) Energetic 'charging' of the prebiosphere must precede the emergence of biological organization. (iii) Environmental energy gradients are exploited progressively, approaching maximum interactive structure and minimum dissipation. (iv) Dynamic self-assembly of prebiotic organic matter is driven by hydrophobic tension between water and amphiphilic building blocks, such as aggregating peptides from non-polar amino acids and base stacking in nucleic acids. (v) The dynamics of autocatalytic self-organization are facilitated by a multiplicity of weak interactions, such as hydrogen bonding, within and between macromolecular assemblies. (vi) The coevolution of (initially uncoded) proteins and nucleic acids in energy-coupled and metabolically active so-called 'microspheres' is more realistic as a kinetic transition model of primal biogenesis than 'hypercycle replication' theories for nucleic acid replicators on their own. All these considerations blend well with the current understanding that sunlight UV-induced photo-electronic excitation of colloidal metal sulfide particles appears most suitable as a prebiotic driver of organic synthesis reactions, in tight cooperation with organic, phase-separated, catalytic 'microspheres'. On the 'continuist vs. miraculist' schism described by Iris Fry for origins-of-life considerations (Table 1), Wicken was a fervent early protagonist of holistic 'continuist' views and agenda.
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Affiliation(s)
- Richard Egel
- Department of Biology, University of Copenhagen Biocenter, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark.
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Mulkidjanian AY, Bychkov AY, Dibrova DV, Galperin MY, Koonin EV. Open questions on the origin of life at anoxic geothermal fields. ORIGINS LIFE EVOL B 2012; 42:507-16. [PMID: 23132762 PMCID: PMC3997052 DOI: 10.1007/s11084-012-9315-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 08/28/2012] [Indexed: 10/27/2022]
Abstract
We have recently reconstructed the 'hatcheries' of the first cells by combining geochemical analysis with phylogenomic scrutiny of the inorganic ion requirements of universal components of modern cells (Mulkidjanian et al. Proc Natl Acad Sci U S A 109:E821-830, 2012). These ubiquitous, and by inference primordial, proteins and functional systems show affinity to and functional requirement for K⁺, Zn²⁺, Mn²⁺, and phosphate. Thus, protocells must have evolved in habitats with a high K⁺/Na⁺ ratio and relatively high concentrations of Zn, Mn and phosphorous compounds. Geochemical reconstruction shows that the ionic composition conducive to the origin of cells could not have existed in marine settings but is compatible with emissions of vapor-dominated zones of inland geothermal systems. Under an anoxic, CO₂-dominated atmosphere, the ionic composition of pools of cool, condensed vapor at anoxic geothermal fields would resemble the internal milieu of modern cells. Such pools would be lined with porous silicate minerals mixed with metal sulfides and enriched in K⁺ ions and phosphorous compounds. Here we address some questions that have appeared in print after the publication of our anoxic geothermal field scenario. We argue that anoxic geothermal fields, which were identified as likely cradles of life by using a top-down approach and phylogenomics analysis, could provide geochemical conditions similar to those which were suggested as most conducive for the emergence of life by the chemists who pursuit the complementary bottom-up strategy.
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Affiliation(s)
- Armen Y Mulkidjanian
- School of Physics, University of Osnabrueck, Barbarastrasse 7, 49076 Osnabrueck, Germany.
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Mulkidjanian AY, Bychkov AY, Dibrova DV, Galperin MY, Koonin EV. Origin of first cells at terrestrial, anoxic geothermal fields. Proc Natl Acad Sci U S A 2012; 109:E821-30. [PMID: 22331915 PMCID: PMC3325685 DOI: 10.1073/pnas.1117774109] [Citation(s) in RCA: 216] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
All cells contain much more potassium, phosphate, and transition metals than modern (or reconstructed primeval) oceans, lakes, or rivers. Cells maintain ion gradients by using sophisticated, energy-dependent membrane enzymes (membrane pumps) that are embedded in elaborate ion-tight membranes. The first cells could possess neither ion-tight membranes nor membrane pumps, so the concentrations of small inorganic molecules and ions within protocells and in their environment would equilibrate. Hence, the ion composition of modern cells might reflect the inorganic ion composition of the habitats of protocells. We attempted to reconstruct the "hatcheries" of the first cells by combining geochemical analysis with phylogenomic scrutiny of the inorganic ion requirements of universal components of modern cells. These ubiquitous, and by inference primordial, proteins and functional systems show affinity to and functional requirement for K(+), Zn(2+), Mn(2+), and phosphate. Thus, protocells must have evolved in habitats with a high K(+)/Na(+) ratio and relatively high concentrations of Zn, Mn, and phosphorous compounds. Geochemical reconstruction shows that the ionic composition conducive to the origin of cells could not have existed in marine settings but is compatible with emissions of vapor-dominated zones of inland geothermal systems. Under the anoxic, CO(2)-dominated primordial atmosphere, the chemistry of basins at geothermal fields would resemble the internal milieu of modern cells. The precellular stages of evolution might have transpired in shallow ponds of condensed and cooled geothermal vapor that were lined with porous silicate minerals mixed with metal sulfides and enriched in K(+), Zn(2+), and phosphorous compounds.
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Affiliation(s)
- Armen Y. Mulkidjanian
- School of Physics, University of Osnabrück, D-49069 Osnabrück, Germany
- A. N. Belozersky Institute of Physico-Chemical Biology and Schools of
| | | | - Daria V. Dibrova
- School of Physics, University of Osnabrück, D-49069 Osnabrück, Germany
- Bioengineering and Bioinformatics, Moscow State University, Moscow 119992, Russia; and
| | - Michael Y. Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894
| | - Eugene V. Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894
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Egel R. Primal eukaryogenesis: on the communal nature of precellular States, ancestral to modern life. Life (Basel) 2012; 2:170-212. [PMID: 25382122 PMCID: PMC4187143 DOI: 10.3390/life2010170] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 12/29/2011] [Accepted: 01/11/2012] [Indexed: 02/08/2023] Open
Abstract
This problem-oriented, exploratory and hypothesis-driven discourse toward the unknown combines several basic tenets: (i) a photo-active metal sulfide scenario of primal biogenesis in the porespace of shallow sedimentary flats, in contrast to hot deep-sea hydrothermal vent conditions; (ii) an inherently complex communal system at the common root of present life forms; (iii) a high degree of internal compartmentalization at this communal root, progressively resembling coenocytic (syncytial) super-cells; (iv) a direct connection from such communal super-cells to proto-eukaryotic macro-cell organization; and (v) multiple rounds of micro-cellular escape with streamlined reductive evolution-leading to the major prokaryotic cell lines, as well as to megaviruses and other viral lineages. Hopefully, such nontraditional concepts and approaches will contribute to coherent and plausible views about the origins and early life on Earth. In particular, the coevolutionary emergence from a communal system at the common root can most naturally explain the vast discrepancy in subcellular organization between modern eukaryotes on the one hand and both archaea and bacteria on the other.
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Affiliation(s)
- Richard Egel
- Department of Biology, University of Copenhagen Biocenter, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark.
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Krupkin M, Matzov D, Tang H, Metz M, Kalaora R, Belousoff MJ, Zimmerman E, Bashan A, Yonath A. A vestige of a prebiotic bonding machine is functioning within the contemporary ribosome. Philos Trans R Soc Lond B Biol Sci 2012; 366:2972-8. [PMID: 21930590 PMCID: PMC3158926 DOI: 10.1098/rstb.2011.0146] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Based on the presumed capability of a prebiotic pocket-like entity to accommodate substrates whose stereochemistry enables the creation of chemical bonds, it is suggested that a universal symmetrical region identified within all contemporary ribosomes originated from an entity that we term the ‘proto-ribosome’. This ‘proto-ribosome’ could have evolved from an earlier machine that was capable of performing essential tasks in the RNA world, called here the ‘pre-proto-ribosome’, which was adapted for producing proteins.
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Affiliation(s)
- Miri Krupkin
- Weizmann Institute of Science, Rehovot 76100, Israel
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Fox GE, Tran Q, Yonath A. An exit cavity was crucial to the polymerase activity of the early ribosome. ASTROBIOLOGY 2012; 12:57-60. [PMID: 22191510 PMCID: PMC3264961 DOI: 10.1089/ast.2011.0692] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The emergence of an RNA entity capable of synthesizing peptides was a key prebiotic development. It is hypothesized that a precursor of the modern ribosomal exit tunnel was associated with this RNA entity (e.g., "protoribosome" or "bonding entity") from the earliest time and played an essential role. Various compounds that can bind and activate amino acids, including extremely short RNA chains carrying amino acids, and possibly di- or tripeptides, would have associated with the internal cavity of the protoribosome. This cavity hosts the site for peptide bond formation and adjacent to it a relatively elongated feature that could have evolved to the modern ribosomal exit tunnel, as it is wide enough to allow passage of an oligopeptide. When two of the compounds carrying amino acids or di- or tripeptides (to which we refer, for simplicity, as small aminoacylated RNAs) were in proximity within the heart of the protoribosome, a peptide bond could form spontaneously. The growing peptide would enter the nearby cavity and would not disrupt the attachment of the substrates to the protoribosome or interfere with the subsequent attachment of additional small aminoacylated RNAs. Additionally, the presence of the peptide in the cavity would increase the lifetime of the oligopeptide in the protoribosome. Thus, subsequent addition of another amino acid would be more likely than detachment from the protoribosome, and synthesis could continue. The early ability to synthesize peptides may have resulted in an abbreviated RNA World.
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Affiliation(s)
- George E. Fox
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, USA
| | - Quyen Tran
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, USA
| | - Ada Yonath
- Structural Biology Department, Weizmann Institute of Science, Rehovot, Israel
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Parenteau J, Durand M, Morin G, Gagnon J, Lucier JF, Wellinger RJ, Chabot B, Elela SA. Introns within ribosomal protein genes regulate the production and function of yeast ribosomes. Cell 2011; 147:320-31. [PMID: 22000012 DOI: 10.1016/j.cell.2011.08.044] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 07/05/2011] [Accepted: 08/22/2011] [Indexed: 12/13/2022]
Abstract
In budding yeast, the most abundantly spliced pre-mRNAs encode ribosomal proteins (RPs). To investigate the contribution of splicing to ribosome production and function, we systematically eliminated introns from all RP genes to evaluate their impact on RNA expression, pre-rRNA processing, cell growth, and response to stress. The majority of introns were required for optimal cell fitness or growth under stress. Most introns are found in duplicated RP genes, and surprisingly, in the majority of cases, deleting the intron from one gene copy affected the expression of the other in a nonreciprocal manner. Consistently, 70% of all duplicated genes were asymmetrically expressed, and both introns and gene deletions displayed copy-specific phenotypic effects. Together, our results indicate that splicing in yeast RP genes mediates intergene regulation and implicate the expression ratio of duplicated RP genes in modulating ribosome function.
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Affiliation(s)
- Julie Parenteau
- Laboratoire de génomique fonctionnelle de l'Université de Sherbrooke, Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Québec, Canada
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Dunn IS. RNA templating of molecular assembly and covalent modification patterning in early molecular evolution and modern biosystems. J Theor Biol 2011; 284:32-41. [PMID: 21703277 DOI: 10.1016/j.jtbi.2011.06.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 05/23/2011] [Accepted: 06/08/2011] [Indexed: 10/18/2022]
Abstract
The Direct RNA Template (DRT) hypothesis proposes that an early stage of genetic code evolution involved RNA molecules acting as stereochemical recognition templates for assembly of specific amino acids in sequence-ordered arrays, providing a framework for directed covalent peptide bond formation. It is hypothesized here that modern biological precedents may exist for RNA-based structural templating with functional analogies to hypothetical DRT systems. Beyond covalent molecular assembly, an extension of the DRT concept can include RNA molecules acting as dynamic structural template guides for the specific non-covalent assembly of multi-subunit complexes, equivalent to structural assembly chaperones. However, despite numerous precedents for RNA molecules acting as scaffolds for protein complexes, true RNA-mediated assembly chaperoning appears to be absent in modern biosystems. Another level of function with parallels to a DRT system is possible if RNA structural motifs dynamically guided specific patterns of catalytic modifications within multiple target sites in a pre-formed polymer or macromolecular complex. It is suggested that this type of structural RNA templating could logically play a functional role in certain areas of biology, one of which is the glycome of complex organisms. If any such RNA templating processes are shown to exist, they would share no necessary evolutionary relationships with events during early molecular evolution, but may promote understanding of the practical limits of biological RNA functions now and in the ancient RNA World. Awareness of these formal possibilities may also assist in the current search for functions of extensive non-coding RNAs in complex organisms, or for efforts towards artificial rendering of DRT systems.
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Affiliation(s)
- Ian S Dunn
- CytoCure LLC, 100 Cummings Center, Beverly, MA 01915, USA.
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Rakauskaite R, Dinman JD. Mutations of highly conserved bases in the peptidyltransferase center induce compensatory rearrangements in yeast ribosomes. RNA (NEW YORK, N.Y.) 2011; 17:855-864. [PMID: 21441349 PMCID: PMC3078735 DOI: 10.1261/rna.2593211] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 02/18/2011] [Indexed: 05/30/2023]
Abstract
Molecular dynamics simulation identified three highly conserved rRNA bases in the large subunit of the ribosome that form a three-dimensional (3D) "gate" that induces pausing of the aa-tRNA acceptor stem during accommodation into the A-site. A nearby fourth base contacting the "tryptophan finger" of yeast protein L3, which is involved in the coordinating elongation factor recruitment to the ribosome with peptidyltransfer, is also implicated in this process. To better understand the functional importance of these bases, single base substitutions as well as deletions at all four positions were constructed and expressed as the sole forms of ribosomes in yeast Saccharomyces cerevisiae. None of the mutants had strong effects on cell growth, translational fidelity, or on the interactions between ribosomes and tRNAs. However, the mutants did promote strong effects on cell growth in the presence of translational inhibitors, and differences in viability between yeast and Escherichia coli mutants at homologous positions suggest new targets for antibacterial therapeutics. Mutant ribosomes also promoted changes in 25S rRNA structure, all localized to the core of peptidyltransferase center (i.e., the proto-ribosome area). We suggest that a certain degree of structural plasticity is built into the ribosome, enabling it to ensure accurate translation of the genetic code while providing it with the flexibility to adapt and evolve.
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Affiliation(s)
- Rasa Rakauskaite
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742, USA
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Abstract
The modern ribosome was largely formed at the time of the last common ancestor, LUCA. Hence its earliest origins likely lie in the RNA world. Central to its development were RNAs that spawned the modern tRNAs and a symmetrical region deep within the large ribosomal RNA, (rRNA), where the peptidyl transferase reaction occurs. To understand pre-LUCA developments, it is argued that events that are coupled in time are especially useful if one can infer a likely order in which they occurred. Using such timing events, the relative age of various proteins and individual regions within the large rRNA are inferred. An examination of the properties of modern ribosomes strongly suggests that the initial peptides made by the primitive ribosomes were likely enriched for l-amino acids, but did not completely exclude d-amino acids. This has implications for the nature of peptides made by the first ribosomes. From the perspective of ribosome origins, the immediate question regarding coding is when did it arise rather than how did the assignments evolve. The modern ribosome is very dynamic with tRNAs moving in and out and the mRNA moving relative to the ribosome. These movements may have become possible as a result of the addition of a template to hold the tRNAs. That template would subsequently become the mRNA, thereby allowing the evolution of the code and making an RNA genome useful. Finally, a highly speculative timeline of major events in ribosome history is presented and possible future directions discussed.
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Affiliation(s)
- George E Fox
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204-5001, USA.
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Davidovich C, Belousoff M, Wekselman I, Shapira T, Krupkin M, Zimmerman E, Bashan A, Yonath A. The Proto-Ribosome: an ancient nano-machine for peptide bond formation. Isr J Chem 2010. [PMID: 26207070 DOI: 10.1002/ijch.201000012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The ribosome is a ribozyme whose active site, the peptidyl transferase center (PTC) is situated within a highly conserved universal symmetrical region that connects all ribosomal functional centers involved in amino-acid polymerization. The linkage between this elaborate architecture and A-site tRNA position revealed that the A to P-site passage of the tRNA 3' terminus during protein synthesis is performed by a rotary motion, synchronized with the overall tRNA/mRNA sideways movement and Guided by the PTC. This rotary motion leads to suitable stereochemistry for peptide bond formation as well as for substrate mediated catalysis. Analysis of the substrate binding modes to ribosomes led to the hypothesis that the ancient ribosome produced single peptide bonds and non-coded chains, potentially in a similar manner to the modern PTC. Later in evolution, a mechanism, enabling some type of decoding genetic control triggered the emergence of the small ribosomal subunit or part of it. This seems to be the result of the appearance of reaction products that could have evolved after polypeptides capable of enzymatic function were generated sporadically, while an ancient stable RNA fold was converted into an old version of a tRNA molecule. As in the contemporary ribosome the symmetry relates only the backbone fold and nucleotides orientations but not nucleotide sequences, it emphasizes the superiority of functional requirement over sequence conservation, and indicates that the PTC may have evolved by gene fusion or gene duplication.
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Affiliation(s)
- Chen Davidovich
- Department of Structural Biology, Weizmann Inst., 76100 Rehovot, Israel
| | - Matthew Belousoff
- Department of Structural Biology, Weizmann Inst., 76100 Rehovot, Israel
| | - Itai Wekselman
- Department of Structural Biology, Weizmann Inst., 76100 Rehovot, Israel
| | - Tal Shapira
- Department of Structural Biology, Weizmann Inst., 76100 Rehovot, Israel
| | - Miri Krupkin
- Department of Structural Biology, Weizmann Inst., 76100 Rehovot, Israel
| | - Ella Zimmerman
- Department of Structural Biology, Weizmann Inst., 76100 Rehovot, Israel
| | - Anat Bashan
- Department of Structural Biology, Weizmann Inst., 76100 Rehovot, Israel
| | - Ada Yonath
- Department of Structural Biology, Weizmann Inst., 76100 Rehovot, Israel
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Yonath A. Winterschlafende Bären, Antibiotika und die Evolution des Ribosoms (Nobel-Aufsatz). Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201001297] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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