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Bian T, Pei Y, Gao S, Zhou S, Sun X, Dong M, Song J. Xeno Nucleic Acids as Functional Materials: From Biophysical Properties to Application. Adv Healthc Mater 2024:e2401207. [PMID: 39036821 DOI: 10.1002/adhm.202401207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 06/14/2024] [Indexed: 07/23/2024]
Abstract
Xeno nucleic acid (XNA) are artificial nucleic acids, in which the chemical composition of the sugar moiety is changed. These modifications impart distinct physical and chemical properties to XNAs, leading to changes in their biological, chemical, and physical stability. Additionally, these alterations influence the binding dynamics of XNAs to their target molecules. Consequently, XNAs find expanded applications as functional materials in diverse fields. This review provides a comprehensive summary of the distinctive biophysical properties exhibited by various modified XNAs and explores their applications as innovative functional materials in expanded fields.
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Affiliation(s)
- Tianyuan Bian
- Academy of Medical Engineering and Translational Medicine (AMT), Tianjin University, Tianjin, 300072, China
- Hangzhou Institute of Medicine, Chinese Academy of Sciences, Hangzhou, 310022, China
| | - Yufeng Pei
- Hangzhou Institute of Medicine, Chinese Academy of Sciences, Hangzhou, 310022, China
| | - Shitao Gao
- Hangzhou Institute of Medicine, Chinese Academy of Sciences, Hangzhou, 310022, China
- College of Materials Science and Engineering, Zhejiang University of Technology, ChaoWang Road 18, HangZhou, 310014, China
| | - Songtao Zhou
- Hangzhou Institute of Medicine, Chinese Academy of Sciences, Hangzhou, 310022, China
| | - Xinyu Sun
- Hangzhou Institute of Medicine, Chinese Academy of Sciences, Hangzhou, 310022, China
- Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Mingdong Dong
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus C, Aarhus, DK-8000, Denmark
| | - Jie Song
- Hangzhou Institute of Medicine, Chinese Academy of Sciences, Hangzhou, 310022, China
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2
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Shechner DM. Architecture of an RNA polymerase ribozyme illuminates the RNA World. Trends Genet 2024; 40:291-292. [PMID: 38485607 PMCID: PMC11003837 DOI: 10.1016/j.tig.2024.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 02/29/2024] [Indexed: 04/11/2024]
Abstract
'Ribo-organisms' of the primordial RNA World would have needed ribozymes that catalyze RNA replication. McRae, Wan, Kristoffersen et al. recently revealed how these RNA replicases might have functioned by solving the structure of an artificial polymerase ribozyme. This work illustrates how complex RNA structures evolve, with implications for the origins of life.
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Affiliation(s)
- David M Shechner
- Department of Pharmacology, University of Washington, Seattle, WA, USA; Institute for Stem Cell and Regenerative Medicine, Seattle, WA, USA; Brotman Baty Institute for Precision Medicine, Seattle, WA, USA.
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3
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Paschek K, Lee M, Semenov DA, Henning TK. Prebiotic Vitamin B 3 Synthesis in Carbonaceous Planetesimals. Chempluschem 2024; 89:e202300508. [PMID: 37847591 DOI: 10.1002/cplu.202300508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/11/2023] [Accepted: 10/12/2023] [Indexed: 10/19/2023]
Abstract
Aqueous chemistry within carbonaceous planetesimals is promising for synthesizing prebiotic organic matter essential to all life. Meteorites derived from these planetesimals delivered these life building blocks to the early Earth, potentially facilitating the origins of life. Here, we studied the formation of vitamin B3 as it is an important precursor of the coenzyme NAD(P)(H), which is essential for the metabolism of all life as we know it. We propose a new reaction mechanism based on known experiments in the literature that explains the synthesis of vitamin B3. It combines the sugar precursors glyceraldehyde or dihydroxyacetone with the amino acids aspartic acid or asparagine in aqueous solution without oxygen or other oxidizing agents. We performed thermochemical equilibrium calculations to test the thermodynamic favorability. The predicted vitamin B3 abundances resulting from this new pathway were compared with measured values in asteroids and meteorites. We conclude that competition for reactants and decomposition by hydrolysis are necessary to explain the prebiotic content of meteorites. In sum, our model fits well into the complex network of chemical pathways active in this environment.
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Affiliation(s)
- Klaus Paschek
- Max Planck Institute for Astronomy, Königstuhl 17, D-69117, Heidelberg, Germany
| | - Mijin Lee
- Max Planck Institute for Astronomy, Königstuhl 17, D-69117, Heidelberg, Germany
| | - Dmitry A Semenov
- Max Planck Institute for Astronomy, Königstuhl 17, D-69117, Heidelberg, Germany
- Department of Chemistry, Ludwig Maximilian University of Munich, Butenandtstraße 5-13, House F, D-81377, Munich, Germany
| | - Thomas K Henning
- Max Planck Institute for Astronomy, Königstuhl 17, D-69117, Heidelberg, Germany
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4
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McRae EKS, Wan CJK, Kristoffersen EL, Hansen K, Gianni E, Gallego I, Curran JF, Attwater J, Holliger P, Andersen ES. Cryo-EM structure and functional landscape of an RNA polymerase ribozyme. Proc Natl Acad Sci U S A 2024; 121:e2313332121. [PMID: 38207080 PMCID: PMC10801858 DOI: 10.1073/pnas.2313332121] [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: 08/09/2023] [Accepted: 11/29/2023] [Indexed: 01/13/2024] Open
Abstract
The emergence of an RNA replicase capable of self-replication is considered an important stage in the origin of life. RNA polymerase ribozymes (PR) - including a variant that uses trinucleotide triphosphates (triplets) as substrates - have been created by in vitro evolution and are the closest functional analogues of the replicase, but the structural basis for their function is poorly understood. Here we use single-particle cryogenic electron microscopy (cryo-EM) and high-throughput mutation analysis to obtain the structure of a triplet polymerase ribozyme (TPR) apoenzyme and map its functional landscape. The cryo-EM structure at 5-Å resolution reveals the TPR as an RNA heterodimer comprising a catalytic subunit and a noncatalytic, auxiliary subunit, resembling the shape of a left hand with thumb and fingers at a 70° angle. The two subunits are connected by two distinct kissing-loop (KL) interactions that are essential for polymerase function. Our combined structural and functional data suggest a model for templated RNA synthesis by the TPR holoenzyme, whereby heterodimer formation and KL interactions preorganize the TPR for optimal primer-template duplex binding, triplet substrate discrimination, and templated RNA synthesis. These results provide a better understanding of TPR structure and function and should aid the engineering of more efficient PRs.
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Affiliation(s)
- Ewan K. S. McRae
- Interdisciplinary Nanoscience Center, Department of Molecular Biology and Genetics, Aarhus University, Aarhus8000, Denmark
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council, Laboratory of Molecular Biology, CambridgeCB2 0QH, United Kingdom
| | - Christopher J. K. Wan
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council, Laboratory of Molecular Biology, CambridgeCB2 0QH, United Kingdom
| | - Emil L. Kristoffersen
- Interdisciplinary Nanoscience Center, Department of Molecular Biology and Genetics, Aarhus University, Aarhus8000, Denmark
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council, Laboratory of Molecular Biology, CambridgeCB2 0QH, United Kingdom
| | - Kalinka Hansen
- Interdisciplinary Nanoscience Center, Department of Molecular Biology and Genetics, Aarhus University, Aarhus8000, Denmark
| | - Edoardo Gianni
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council, Laboratory of Molecular Biology, CambridgeCB2 0QH, United Kingdom
| | - Isaac Gallego
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council, Laboratory of Molecular Biology, CambridgeCB2 0QH, United Kingdom
| | - Joseph F. Curran
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council, Laboratory of Molecular Biology, CambridgeCB2 0QH, United Kingdom
| | - James Attwater
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council, Laboratory of Molecular Biology, CambridgeCB2 0QH, United Kingdom
| | - Philipp Holliger
- Division of Protein and Nucleic Acid Chemistry, Medical Research Council, Laboratory of Molecular Biology, CambridgeCB2 0QH, United Kingdom
| | - Ebbe S. Andersen
- Interdisciplinary Nanoscience Center, Department of Molecular Biology and Genetics, Aarhus University, Aarhus8000, Denmark
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5
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Luo Y, Liang M, Yu C, Ma W. Circular at the very beginning: on the initial genomes in the RNA world. RNA Biol 2024; 21:17-31. [PMID: 39016036 PMCID: PMC11259081 DOI: 10.1080/15476286.2024.2380130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2024] [Indexed: 07/18/2024] Open
Abstract
It is likely that an RNA world existed in early life, when RNA played both the roles of the genome and functional molecules, thereby undergoing Darwinian evolution. However, even with only one type of polymer, it seems quite necessary to introduce a labour division concerning these two roles because folding is required for functional molecules (ribozymes) but unfavourable for the genome (as a template in replication). Notably, while ribozymes tend to have adopted a linear form for folding without constraints, a circular form, which might have been topologically hindered in folding, seems more suitable for an RNA template. Another advantage of involving a circular genome could have been to resist RNA's end-degradation. Here, we explore the scenario of a circular RNA genome plus linear ribozyme(s) at the precellular stage of the RNA world through computer modelling. The results suggest that a one-gene scene could have been 'maintained', albeit with rather a low efficiency for the circular genome to produce the ribozyme, which required precise chain-break or chain-synthesis. This strict requirement may have been relieved by introducing a 'noncoding' sequence into the genome, which had the potential to derive a second gene through mutation. A two-gene scene may have 'run well' with the two corresponding ribozymes promoting the replication of the circular genome from different respects. Circular genomes with more genes might have arisen later in RNA-based protocells. Therefore, circular genomes, which are common in the modern living world, may have had their 'root' at the very beginning of life.
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Affiliation(s)
- Yufan Luo
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Minglun Liang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
| | - Chunwu Yu
- College of Computer Sciences, Wuhan University, Wuhan, China
| | - Wentao Ma
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China
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6
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Sabat N, Stämpfli A, Flamme M, Hanlon S, Bisagni S, Sladojevich F, Püntener K, Hollenstein M. Artificial nucleotide codons for enzymatic DNA synthesis. Chem Commun (Camb) 2023; 59:14547-14550. [PMID: 37987464 DOI: 10.1039/d3cc04933g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Herein, we report the high-yielding solid-phase synthesis of unmodified and chemically modified trinucleotide triphosphates (dN3TPs). These synthetic codons can be used for enzymatic DNA synthesis provided their scaffold is stabilized with phosphorothioate units. Enzymatic synthesis with three rather than one letter nucleotides will be useful to produce xenonucleic acids (XNAs) and for in vitro selection of modified functional nucleic acids.
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Affiliation(s)
- Nazarii Sabat
- Institut Pasteur, Université Paris Cité, CNRS UMR3523, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, 28, rue du Docteur Roux, 75724 Paris Cedex 15, France.
| | - Andreas Stämpfli
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Marie Flamme
- Institut Pasteur, Université Paris Cité, CNRS UMR3523, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, 28, rue du Docteur Roux, 75724 Paris Cedex 15, France.
| | - Steven Hanlon
- Pharmaceutical Division, Synthetic Molecules Technical Development, Process Chemistry & Catalysis, F. Hoffmann-La Roche Ltd, Basel 4070, Switzerland
| | - Serena Bisagni
- Pharmaceutical Division, Synthetic Molecules Technical Development, Process Chemistry & Catalysis, F. Hoffmann-La Roche Ltd, Basel 4070, Switzerland
| | - Filippo Sladojevich
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 4070, Basel, Switzerland
| | - Kurt Püntener
- Pharmaceutical Division, Synthetic Molecules Technical Development, Process Chemistry & Catalysis, F. Hoffmann-La Roche Ltd, Basel 4070, Switzerland
| | - Marcel Hollenstein
- Institut Pasteur, Université Paris Cité, CNRS UMR3523, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, 28, rue du Docteur Roux, 75724 Paris Cedex 15, France.
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7
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Ma X, Zhang Y, Huang K, Zhu L, Xu W. Multifunctional rolling circle transcription-based nanomaterials for advanced drug delivery. Biomaterials 2023; 301:122241. [PMID: 37451000 DOI: 10.1016/j.biomaterials.2023.122241] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 06/21/2023] [Accepted: 07/06/2023] [Indexed: 07/18/2023]
Abstract
As the up-and-comer in the development of RNA nanotechnology, RNA nanomaterials based on functionalized rolling circle transcription (RCT) have become promising carriers for drug production and delivery. This is due to RCT technology can self-produce polyvalent tandem nucleic acid prodrugs for intervention in intracellular gene expression and protein production. RNA component strands participating in de novo assembly enable RCT-based nanomaterials to exhibit good mechanical properties, biostability, and biocompatibility as delivery carriers. The biostability makes it to suitable for thermodynamically/kinetically favorable assembly, enzyme resistance and efficient expression in vivo. Controllable RCT system combined with polymers enables customizable and adjustable size, shape, structure, and stoichiometry of RNA building materials, which provide groundwork for the delivery of advanced drugs. Here, we review the assembly strategies and the dynamic regulation of RCT-based nanomaterials, summarize its functional properties referring to the bottom-up design philosophy, and describe its advancements in tumor gene therapy, synergistic chemotherapy, and immunotherapy. Last, we elaborate on the unique and practical value of RCT-based nanomaterials, namely "self-production and self-sale", and their potential challenges in nanotechnology, material science and biomedicine.
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Affiliation(s)
- Xuan Ma
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083, China; College of Food Science and Nutrition Engineering, China Agricultural University, Beijing, 100083, China
| | - Yangzi Zhang
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083, China; College of Food Science and Nutrition Engineering, China Agricultural University, Beijing, 100083, China
| | - Kunlun Huang
- College of Food Science and Nutrition Engineering, China Agricultural University, Beijing, 100083, China
| | - Longjiao Zhu
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083, China
| | - Wentao Xu
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083, China; College of Food Science and Nutrition Engineering, China Agricultural University, Beijing, 100083, China.
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8
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Ding D, Zhou L, Mittal S, Szostak JW. Experimental Tests of the Virtual Circular Genome Model for Nonenzymatic RNA Replication. J Am Chem Soc 2023; 145:7504-7515. [PMID: 36963403 PMCID: PMC10080680 DOI: 10.1021/jacs.3c00612] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2023]
Abstract
The virtual circular genome (VCG) model was proposed as a means of going beyond template copying to indefinite cycles of nonenzymatic RNA replication during the origin of life. In the VCG model, the protocellular genome is a collection of short oligonucleotides that map to both strands of a virtual circular sequence. Replication is driven by templated nonenzymatic primer extensions on a subset of kinetically trapped partially base-paired configurations, followed by the shuffling of these configurations to enable continued oligonucleotide elongation. Here, we describe initial experimental studies of the feasibility of the VCG model for replication. We designed a small 12-nucleotide model VCG and synthesized all 247 oligonucleotides of lengths 2 to 12 corresponding to this genome. We experimentally monitored the fate of individual labeled primers in the pool of VCG oligonucleotides following the addition of activated nucleotides and investigated the effect of factors such as oligonucleotide length, concentration, composition, and temperature on the extent of primer extension. We observe a surprisingly prolonged equilibration process in the VCG system that enables a considerable extent of reaction. We find that environmental fluctuations would be essential for continuous templated extension of the entire VCG system since the shortest oligonucleotides can only bind to templates at low temperatures, while the longest oligonucleotides require high-temperature spikes to escape from inactive configurations. Finally, we demonstrate that primer extension is significantly enhanced when the mix of VCG oligonucleotides is preactivated. We discuss the necessity of ongoing in situ activation chemistry for continuous and accurate VCG replication.
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Affiliation(s)
- Dian Ding
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, United States
| | - Lijun Zhou
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, United States
- Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Shriyaa Mittal
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, United States
- Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Jack W Szostak
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, United States
- Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
- Howard Hughes Medical Institute, Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
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9
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Salditt A, Karr L, Salibi E, Le Vay K, Braun D, Mutschler H. Ribozyme-mediated RNA synthesis and replication in a model Hadean microenvironment. Nat Commun 2023; 14:1495. [PMID: 36932102 PMCID: PMC10023712 DOI: 10.1038/s41467-023-37206-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 03/06/2023] [Indexed: 03/19/2023] Open
Abstract
Enzyme-catalyzed replication of nucleic acid sequences is a prerequisite for the survival and evolution of biological entities. Before the advent of protein synthesis, genetic information was most likely stored in and replicated by RNA. However, experimental systems for sustained RNA-dependent RNA-replication are difficult to realise, in part due to the high thermodynamic stability of duplex products and the low chemical stability of catalytic RNAs. Using a derivative of a group I intron as a model for an RNA replicase, we show that heated air-water interfaces that are exposed to a plausible CO2-rich atmosphere enable sense and antisense RNA replication as well as template-dependent synthesis and catalysis of a functional ribozyme in a one-pot reaction. Both reactions are driven by autonomous oscillations in salt concentrations and pH, resulting from precipitation of acidified dew droplets, which transiently destabilise RNA duplexes. Our results suggest that an abundant Hadean microenvironment may have promoted both replication and synthesis of functional RNAs.
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Affiliation(s)
- Annalena Salditt
- Systems Biophysics and Center for NanoScience (CeNS), Ludwig Maximilian University Munich, Geschwister-Scholl-Platz 1, 80539, Munich, Germany
| | - Leonie Karr
- Systems Biophysics and Center for NanoScience (CeNS), Ludwig Maximilian University Munich, Geschwister-Scholl-Platz 1, 80539, Munich, Germany
| | - Elia Salibi
- Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Str. 4a, 44227, Dortmund, Germany
| | - Kristian Le Vay
- Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Str. 4a, 44227, Dortmund, Germany
| | - Dieter Braun
- Systems Biophysics and Center for NanoScience (CeNS), Ludwig Maximilian University Munich, Geschwister-Scholl-Platz 1, 80539, Munich, Germany.
| | - Hannes Mutschler
- Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Str. 4a, 44227, Dortmund, Germany.
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10
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Towards an RNA/Peptides World by the Direct RNA Template Mechanism: The Emergence of Membrane-Stabilizing Peptides in RNA-Based Protocells. Life (Basel) 2023; 13:life13020523. [PMID: 36836881 PMCID: PMC9966593 DOI: 10.3390/life13020523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 01/29/2023] [Accepted: 02/06/2023] [Indexed: 02/17/2023] Open
Abstract
How functional peptides may have arisen is a significant problem for the scenario of the RNA world. An attractive idea, the direct RNA template (DRT) hypothesis, proposes that RNA molecules can bind amino acids specifically and promote the synthesis of corresponding peptides, thereby starting the RNA/peptides world. To investigate the plausibility of this idea, we modeled the emergence of a "membrane-stabilizing peptide" in RNA-based protocells-such a peptide was suggested to have appeared early in the RNA world based on experimental evidence. The computer simulation demonstrated that the protocells containing the "RNA gene" encoding this peptide may spread in the system owing to the peptide's function. The RNA gene may either originate de novo in protocells or emerge in protocells already containing ribozymes-here we adopt a nucleotide synthetase ribozyme as an example. Furthermore, interestingly, we show that a "nucleotide synthetase peptide" encoded by RNA (also via the DRT mechanism) may substitute the nucleotide synthetase ribozyme in evolution, which may represent how "functional-takeover" in the RNA world could have occurred. Overall, we conclude that the transition from the RNA world towards an RNA/peptides world may well have been mediated by the DRT mechanism. Remarkably, the successful modeling on the emergence of membrane-stabilizing peptide in RNA-based protocells is per se significant, which may imply a "promising" way for peptides to enter the RNA world, especially considering the weak interaction between RNA and the membrane in chemistry.
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11
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Pavlinova P, Lambert CN, Malaterre C, Nghe P. Abiogenesis through gradual evolution of autocatalysis into template-based replication. FEBS Lett 2023; 597:344-379. [PMID: 36203246 DOI: 10.1002/1873-3468.14507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 09/20/2022] [Accepted: 09/29/2022] [Indexed: 11/11/2022]
Abstract
How life emerged from inanimate matter is one of the most intriguing questions posed to modern science. Central to this research are experimental attempts to build systems capable of Darwinian evolution. RNA catalysts (ribozymes) are a promising avenue, in line with the RNA world hypothesis whereby RNA pre-dated DNA and proteins. Since evolution in living organisms relies on template-based replication, the identification of a ribozyme capable of replicating itself (an RNA self-replicase) has been a major objective. However, no self-replicase has been identified to date. Alternatively, autocatalytic systems involving multiple RNA species capable of ligation and recombination may enable self-reproduction. However, it remains unclear how evolution could emerge in autocatalytic systems. In this review, we examine how experimentally feasible RNA reactions catalysed by ribozymes could implement the evolutionary properties of variation, heredity and reproduction, and ultimately allow for Darwinian evolution. We propose a gradual path for the emergence of evolution, initially supported by autocatalytic systems leading to the later appearance of RNA replicases.
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Affiliation(s)
- Polina Pavlinova
- Laboratoire de Biophysique et Evolution, UMR CNRS-ESPCI 8231 Chimie Biologie Innovation, PSL University, Paris, France
| | - Camille N Lambert
- Laboratoire de Biophysique et Evolution, UMR CNRS-ESPCI 8231 Chimie Biologie Innovation, PSL University, Paris, France
| | - Christophe Malaterre
- Laboratory of Philosophy of Science (LAPS) and Centre Interuniversitaire de Recherche sur la Science et la Technologie (CIRST), Université du Québec à Montréal (UQAM), Canada
| | - Philippe Nghe
- Laboratoire de Biophysique et Evolution, UMR CNRS-ESPCI 8231 Chimie Biologie Innovation, PSL University, Paris, France
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12
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Toward understanding the emergence of life: A dual function of the system of nucleotides in the metabolically closed autopoietic organization. Biosystems 2023; 224:104837. [PMID: 36649884 DOI: 10.1016/j.biosystems.2023.104837] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 01/05/2023] [Accepted: 01/10/2023] [Indexed: 01/15/2023]
Abstract
General structure of metabolism includes the reproduction of catalysts that govern metabolism. In this structure, the system becomes autopoietic in the sense of Maturana and Varela, and it is closed to efficient causation as defined by Robert Rosen. The autopoietic maintenance and operation of the catalysts takes place via the set of free nucleotides while the synthesis of catalysts occurs via the information encoded by the set of nucleotides arranged in polymers of RNA and DNA. Both energy charge and genetic information use the components of the same pool of nucleoside triphosphates, which is equilibrated by thermodynamic buffering enzymes such as nucleoside diphosphate kinase and adenylate kinase. This occurs in a way that the system becomes internally stable and metabolically closed, which initially could be realized at the level of ribozymes catalyzing basic metabolic reactions as well as own reproduction. The function of ATP, GTP, UTP, and CTP is dual, as these species participate both in the general metabolism as free nucleotides and in the transfer of genetic information via covalent polymerization to nucleic acids. The changes in their pools directly impact both bioenergetic pathways and nucleic acid turnover. Here we outline the concept of metabolic closure of biosystems grounded in the dual function of nucleotide coenzymes that serve both as energetic and informational molecules and through this duality generate the autopoietic performance and the ability for codepoietic evolutionary transformations of living systems starting from the emergence of prebiotic systems.
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13
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Demongeot J, Thellier M. Primitive Oligomeric RNAs at the Origins of Life on Earth. Int J Mol Sci 2023; 24:ijms24032274. [PMID: 36768599 PMCID: PMC9916791 DOI: 10.3390/ijms24032274] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 01/18/2023] [Accepted: 01/21/2023] [Indexed: 01/26/2023] Open
Abstract
There are several theories on the origin of life, which differ by choosing the preponderant factor of emergence: main function (autocatalysis versus replication), initial location (black smokers versus ponds) or first molecule (RNA versus DNA). Among the two last ones, the first assumes that an RNA world involving a collaboration of small RNAs with amino-acids pre-existed and the second that DNA-enzyme-lipid complexes existed first. The debate between these classic theories is not closed and the arguments for one or the other of these theories have recently fueled a debate in which the two have a high degree of likelihood. It therefore seems interesting to propose a third intermediate way, based on the existence of an RNA that may have existed before the latter stages postulated by these theories, and therefore may be the missing link towards a common origin of them. To search for a possible ancestral structure, we propose as candidate a small RNA existing in ring or hairpin form in the early stages of life, which could have acted as a "proto-ribosome" by favoring the synthesis of the first peptides. Remnants of this putative candidate RNA exist in molecules nowadays involved in the ribosomal factory, the concentrations of these relics depending on the seniority of these molecules within the translation process.
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Affiliation(s)
- Jacques Demongeot
- Faculty of Medicine, Université Grenoble Alpes, Laboratory AGEIS EA 7407 Tools for e-Gnosis Medical, 38700 Grenoble, France
- Correspondence:
| | - Michel Thellier
- Académie des Sciences, Section Biologie Integrative, 75006 Paris, France
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14
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Rolling Circles as a Means of Encoding Genes in the RNA World. Life (Basel) 2022; 12:life12091373. [PMID: 36143408 PMCID: PMC9505818 DOI: 10.3390/life12091373] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/17/2022] [Accepted: 08/23/2022] [Indexed: 11/25/2022] Open
Abstract
The rolling circle mechanism found in viroids and some RNA viruses is a likely way that replication could have begun in the RNA World. Here, we consider simulations of populations of protocells, each containing multiple copies of rolling circle RNAs that can replicate non-enzymatically. The mechanism requires the presence of short self-cleaving ribozymes such as hammerheads, which can cleave and re-circularize RNA strands. A rolling circle must encode a hammerhead and the complement of a hammerhead, so that both plus and minus strands can cleave. Thus, the minimal functional length is twice the length of the hammerhead sequence. Selection for speed of replication will tend to reduce circles to this minimum length. However, if sequence errors occur when copying the hammerhead sequence, this prevents cleavage at one point, but still allows cleavage on the next passage around the rolling circle. Thus, there is a natural doubling mechanism that creates strands that are multiple times the length of the minimal sequence. This can provide space for the origin of new genes with beneficial functions. We show that if a beneficial gene appears in this new space, the longer sequence with the beneficial function can be selected, even though it replicates more slowly. This provides a route for the evolution of longer circles encoding multiple genes.
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15
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Chamanian P, Higgs PG. Computer simulations of Template-Directed RNA Synthesis driven by temperature cycling in diverse sequence mixtures. PLoS Comput Biol 2022; 18:e1010458. [PMID: 36001640 PMCID: PMC9447872 DOI: 10.1371/journal.pcbi.1010458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 09/06/2022] [Accepted: 07/31/2022] [Indexed: 11/24/2022] Open
Abstract
We present simulations of non-enzymatic template-directed RNA synthesis that incorporate primer extension, ligation, melting, and reannealing. Strand growth occurs over multiple heating/cooling cycles, producing strands of several hundred nucleotides in length, starting with random oligomers of 4 to 10 nucleotides. A strand typically grows by only 1 or 2 nucleotides in each cycle. Therefore, a strand is copied from many different templates, not from one specific complementary strand. A diverse sequence mixture is produced, and there is no exact copying of sequences, even if single base additions are fully accurate (no mutational errors). It has been proposed that RNA systems may contain a virtual circular genome, in which sequences partially overlap in a way that is mutually catalytic. We show that virtual circles do not emerge naturally in our simulations, and that a system initiated with a virtual circle can only maintain itself if there are no mutational errors and there is no input of new sequences formed by random polymerization. Furthermore, if a virtual sequence and its complement contain repeated short words, new sequences can be produced that were not on the original virtual circle. Therefore the virtual circle sequence cannot maintain itself. Functional sequences with secondary structures contain complementary words on opposite sides of stem regions. Both these words are repeated in the complementary sequence; hence, functional sequences cannot be encoded on a virtual circle. Additionally, we consider sequence replication in populations of protocells. We suppose that functional ribozymes benefit the cell which contains them. Nevertheless, scrambling of sequences occurs, and the functional sequence is not maintained, even when under positive selection. The earliest form of RNA replication may have been non-enzymatic, without requiring polymerase ribozymes. Non-enzymatic replication forms double strands that are unlikely to separate unless melting is driven by temperature cycling. However, re-annealing of existing strands occurs rapidly on cooling, and this prevents subsequent cycles of copying if there are multiple copies of similar sequences. In contrast, if there is a diverse mixture of sequences, partially matching sequences can reanneal in configurations that allow continued strand growth. We show that this allows continued synthesis of populations of random sequences that are quite long. We test the idea that a virtual circular genome could exist in such a mixture. We show that a virtual genome does not arise spontaneously and that it cannot be maintained except in unrealistic ideal cases. We conclude that functional sequence information cannot be encoded on the fragments of a virtual circle.
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Affiliation(s)
- Pouyan Chamanian
- Origins Institute and Dept of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Paul G. Higgs
- Origins Institute and Dept of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
- * E-mail:
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16
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Roy S, Sengupta S. The Effect of Environment on the Evolution and Proliferation of Protocells of Increasing Complexity. LIFE (BASEL, SWITZERLAND) 2022; 12:life12081227. [PMID: 36013406 PMCID: PMC9410160 DOI: 10.3390/life12081227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/01/2022] [Accepted: 08/10/2022] [Indexed: 11/16/2022]
Abstract
The formation, growth, division and proliferation of protocells containing RNA strands is an important step in ensuring the viability of a mixed RNA-lipid world. Experiments and computer simulations indicate that RNA encapsulated inside protocells can favor the protocell, promoting its growth while protecting the system from being over-run by selfish RNA sequences. Recent work has also shown that the rolling-circle replication mechanism can be harnessed to ensure the rapid growth of RNA strands and the probabilistic emergence and proliferation of protocells with functionally diverse ribozymes. Despite these advances in our understanding of a primordial RNA-lipid world, key questions remain about the ideal environment for the formation of protocells and its role in regulating the proliferation of functionally complex protocells. The hot spring hypothesis suggests that mineral-rich regions near hot springs, subject to dry-wet cycles, provide an ideal environment for the origin of primitive protocells. We develop a computational model to study protocellular evolution in such environments that are distinguished by the occurrence of three distinct phases, a wet phase, followed by a gel phase, and subsequently by a dry phase. We determine the conditions under which protocells containing multiple types of ribozymes can evolve and proliferate in such regions. We find that diffusion in the gel phase can inhibit the proliferation of complex protocells with the extent of inhibition being most significant when a small fraction of protocells is eliminated during environmental cycling. Our work clarifies how the environment can shape the evolution and proliferation of complex protocells.
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17
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Hassenkam T, Deamer D. Visualizing RNA polymers produced by hot wet-dry cycling. Sci Rep 2022; 12:10098. [PMID: 35739144 PMCID: PMC9226162 DOI: 10.1038/s41598-022-14238-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 06/03/2022] [Indexed: 11/24/2022] Open
Abstract
It is possible that the transition from abiotic systems to life relied on RNA polymers that served as ribozyme-like catalysts and for storing genetic information. The source of such polymers is uncertain, but previous investigations reported that wet–dry cycles simulating prebiotic hot springs provide sufficient energy to drive condensation reactions of mononucleotides to form oligomers and polymers. The aim of the study reported here was to verify this claim and visualize the products prepared from solutions composed of single mononucleotides and 1:1 mixture of two mononucleotides. Therefore, we designed experiments that allowed comparisons of all such mixtures representing six combinations of the four mononucleotides of RNA. We observed irregular stringy patches and crystal strands when wet-dry cycling was performed at room temperature (20 °C). However, when the same solutions were exposed to wet–dry cycles at 80 °C, we observed what appeared to be true polymers. Their thickness was consistent with RNA-like products composed of covalently bonded monomers, while irregular strings and crystal segments of mononucleotides dried or cycled at room temperature were consistent with structures assembled and stabilized by weak hydrogen bonds. In a few instances we observed rings with short polymer attachments. These observations are consistent with previous claims of polymerization during wet–dry cycling. We conclude that RNA-like polymers and rings could have been synthesized non-enzymatically in freshwater hot springs on the prebiotic Earth with sizes sufficient to fold into ribozymes and genetic molecules required for life to begin.
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Affiliation(s)
- Tue Hassenkam
- Globe Institute, University of Copenhagen, 1350, Copenhagen, Denmark.
| | - David Deamer
- Department of Biomolecular Engineering, University of California, Santa Cruz, Santa Cruz, CA, 95064, USA.
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