1
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Mittal S, Nisler C, Szostak JW. Simulations predict preferred Mg 2+ coordination in a nonenzymatic primer-extension reaction center. Biophys J 2024; 123:1579-1591. [PMID: 38702884 PMCID: PMC11214020 DOI: 10.1016/j.bpj.2024.04.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 04/24/2024] [Accepted: 04/30/2024] [Indexed: 05/06/2024] Open
Abstract
The mechanism by which genetic information was copied prior to the evolution of ribozymes is of great interest because of its importance to the origin of life. The most effective known process for the nonenzymatic copying of an RNA template is primer extension by a two-step pathway in which 2-aminoimidazole-activated nucleotides first react with each other to form an imidazolium-bridged intermediate that subsequently reacts with the primer. Reaction kinetics, structure-activity relationships, and X-ray crystallography have provided insight into the overall reaction mechanism, but many puzzles remain. In particular, high concentrations of Mg2+ are required for efficient primer extension, but the mechanism by which Mg2+ accelerates primer extension remains unknown. By analogy with the mechanism of DNA and RNA polymerases, a role for Mg2+ in facilitating the deprotonation of the primer 3'-hydroxyl is often assumed, but no catalytic metal ion is seen in crystal structures of the primer-extension complex. To explore the potential effects of Mg2+ binding in the reaction center, we performed atomistic molecular dynamics simulations of a series of modeled complexes in which a Mg2+ ion was placed in the reaction center with inner-sphere coordination with different sets of functional groups. Our simulations suggest that coordination of a Mg2+ ion with both O3' of the terminal primer nucleotide and the pro-Sp nonbridging oxygen of the reactive phosphate of an imidazolium-bridged dinucleotide would help to pre-organize the structure of the primer/template substrate complex to favor the primer-extension reaction. Our results suggest that the catalytic metal ion may play an important role in overcoming electrostatic repulsion between a deprotonated O3' and the reactive phosphate of the bridged dinucleotide and lead to testable predictions of the mode of Mg2+ binding that is most relevant to catalysis of primer extension.
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Affiliation(s)
- Shriyaa Mittal
- Howard Hughes Medical Institute, Department of Molecular Biology, Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts; Department of Genetics, Harvard Medical School, Boston, Massachusetts
| | - Collin Nisler
- Howard Hughes Medical Institute, Department of Chemistry, University of Chicago, Chicago, Illinois
| | - Jack W Szostak
- Howard Hughes Medical Institute, Department of Molecular Biology, Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts; Department of Genetics, Harvard Medical School, Boston, Massachusetts; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts; Howard Hughes Medical Institute, Department of Chemistry, University of Chicago, Chicago, Illinois.
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2
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Jia X, Zhang SJ, Zhou L, Szostak J. Constraints on the emergence of RNA through non-templated primer extension with mixtures of potentially prebiotic nucleotides. Nucleic Acids Res 2024; 52:5451-5464. [PMID: 38726871 PMCID: PMC11162797 DOI: 10.1093/nar/gkae355] [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: 01/19/2024] [Revised: 04/10/2024] [Accepted: 04/22/2024] [Indexed: 06/11/2024] Open
Abstract
The emergence of RNA on the early Earth is likely to have been influenced by chemical and physical processes that acted to filter out various alternative nucleic acids. For example, UV photostability is thought to have favored the survival of the canonical nucleotides. In a recent proposal for the prebiotic synthesis of the building blocks of RNA, ribonucleotides share a common pathway with arabino- and threo-nucleotides. We have therefore investigated non-templated primer extension with 2-aminoimidazole-activated forms of these alternative nucleotides to see if the synthesis of the first oligonucleotides might have been biased in favor of RNA. We show that non-templated primer extension occurs predominantly through 5'-5' imidazolium-bridged dinucleotides, echoing the mechanism of template-directed primer extension. Ribo- and arabino-nucleotides exhibited comparable rates and yields of non-templated primer extension, whereas threo-nucleotides showed lower reactivity. Competition experiments confirmed the bias against the incorporation of threo-nucleotides. The incorporation of an arabino-nucleotide at the end of the primer acts as a chain terminator and blocks subsequent extension. These biases, coupled with potentially selective prebiotic synthesis, and the templated copying that is known to favour the incorporation of ribonucleotides, provide a plausible model for the effective exclusion of arabino- and threo-nucleotides from primordial oligonucleotides.
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Affiliation(s)
- Xiwen Jia
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA 02114, USA
- Howard Hughes Medical Institute, Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA
| | - Stephanie J Zhang
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA 02114, USA
| | - Lijun Zhou
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Penn Institute for RNA Innovation, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jack W Szostak
- Howard Hughes Medical Institute, Department of Chemistry, The University of Chicago, Chicago, IL 60637, USA
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3
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Callaghan KL, Sherrell PC, Ellis AV. The Impact of Activating Agents on Non-Enzymatic Nucleic Acid Extension Reactions. Chembiochem 2024; 25:e202300859. [PMID: 38282207 DOI: 10.1002/cbic.202300859] [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: 12/20/2023] [Revised: 01/21/2024] [Accepted: 01/28/2024] [Indexed: 01/30/2024]
Abstract
Non-enzymatic template-directed primer extension is increasingly being studied for the production of RNA and DNA. These reactions benefit from producing RNA or DNA in an aqueous, protecting group free system, without the need for expensive enzymes. However, these primer extension reactions suffer from a lack of fidelity, low reaction rates, low overall yields, and short primer extension lengths. This review outlines a detailed mechanistic pathway for non-enzymatic template-directed primer extension and presents a review of the thermodynamic driving forces involved in entropic templating. Through the lens of entropic templating, the rate and fidelity of a reaction are shown to be intrinsically linked to the reactivity of the activating agent used. Thus, a strategy is discussed for the optimization of non-enzymatic template-directed primer extension, providing a path towards cost-effective in vitro synthesis of RNA and DNA.
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Affiliation(s)
- Kimberley L Callaghan
- Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Peter C Sherrell
- Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria, 3010, Australia
- School of Science, RMIT University, Melbourne, Victoria, 3000, Australia
| | - Amanda V Ellis
- Department of Chemical Engineering, The University of Melbourne, Parkville, Victoria, 3010, Australia
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4
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Cohen ZR, Ding D, Zhou L, DasGupta S, Haas S, Sinclair KP, Todd ZR, Black RA, Szostak JW, Catling DC. Natural soda lakes provide compatible conditions for RNA and membrane function that could have enabled the origin of life. PNAS NEXUS 2024; 3:pgae084. [PMID: 38505692 PMCID: PMC10949909 DOI: 10.1093/pnasnexus/pgae084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 01/31/2024] [Indexed: 03/21/2024]
Abstract
The origin of life likely occurred within environments that concentrated cellular precursors and enabled their co-assembly into cells. Soda lakes (those dominated by Na+ ions and carbonate species) can concentrate precursors of RNA and membranes, such as phosphate, cyanide, and fatty acids. Subsequent assembly of RNA and membranes into cells is a long-standing problem because RNA function requires divalent cations, e.g. Mg2+, but Mg2+ disrupts fatty acid membranes. The low solubility of Mg-containing carbonates limits soda lakes to moderate Mg2+ concentrations (∼1 mM), so we investigated whether both RNAs and membranes function within these lakes. We collected water from Last Chance Lake and Goodenough Lake in Canada. Because we sampled after seasonal evaporation, the lake water contained ∼1 M Na+ and ∼1 mM Mg2+ near pH 10. In the laboratory, nonenzymatic, RNA-templated polymerization of 2-aminoimidazole-activated ribonucleotides occurred at comparable rates in lake water and standard laboratory conditions (50 mM MgCl2, pH 8). Additionally, we found that a ligase ribozyme that uses oligonucleotide substrates activated with 2-aminoimidazole was active in lake water after adjusting pH from ∼10 to 9. We also observed that decanoic acid and decanol assembled into vesicles in a dilute solution that resembled lake water after seasonal rains, and that those vesicles retained encapsulated solutes despite salt-induced flocculation when the external solution was replaced with dry-season lake water. By identifying compatible conditions for nonenzymatic and ribozyme-catalyzed RNA assembly, and for encapsulation by membranes, our results suggest that soda lakes could have enabled cellular life to emerge on Earth, and perhaps elsewhere.
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Affiliation(s)
- Zachary R Cohen
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
- Astrobiology Program, University of Washington, Seattle, WA 98195, USA
| | - Dian Ding
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Lijun Zhou
- Department of Biochemistry and Biophysics and Penn Institute for RNA Innovation, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Saurja DasGupta
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Sebastian Haas
- Astrobiology Program, University of Washington, Seattle, WA 98195, USA
- Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195, USA
| | - Kimberly P Sinclair
- Astrobiology Program, University of Washington, Seattle, WA 98195, USA
- Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195, USA
| | - Zoe R Todd
- Astrobiology Program, University of Washington, Seattle, WA 98195, USA
- Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195, USA
- Department of Chemistry and Department of Astronomy, University of Wisconsin, Madison, WI 53706, USA
| | - Roy A Black
- Department of Chemistry, University of Washington, Seattle, WA 98195, USA
- Astrobiology Program, University of Washington, Seattle, WA 98195, USA
| | - Jack W Szostak
- Howard Hughes Medical Institute, Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
| | - David C Catling
- Astrobiology Program, University of Washington, Seattle, WA 98195, USA
- Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195, USA
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5
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Ding D, Fang Z, Kim SC, O’Flaherty DK, Jia X, Stone TB, Zhou L, Szostak JW. Unusual Base Pair between Two 2-Thiouridines and Its Implication for Nonenzymatic RNA Copying. J Am Chem Soc 2024; 146:3861-3871. [PMID: 38293747 PMCID: PMC10870715 DOI: 10.1021/jacs.3c11158] [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: 10/09/2023] [Revised: 01/05/2024] [Accepted: 01/08/2024] [Indexed: 02/01/2024]
Abstract
2-Thiouridine (s2U) is a nucleobase modification that confers enhanced efficiency and fidelity both on modern tRNA codon translation and on nonenzymatic and ribozyme-catalyzed RNA copying. We have discovered an unusual base pair between two 2-thiouridines that stabilizes an RNA duplex to a degree that is comparable to that of a native A:U base pair. High-resolution crystal structures indicate similar base-pairing geometry and stacking interactions in duplexes containing s2U:s2U compared to those with U:U pairs. Notably, the C═O···H-N hydrogen bond in the U:U pair is replaced with a C═S···H-N hydrogen bond in the s2U:s2U base pair. The thermodynamic stability of the s2U:s2U base pair suggested that this self-pairing might lead to an increased error frequency during nonenzymatic RNA copying. However, competition experiments show that s2U:s2U base-pairing induces only a low level of misincorporation during nonenzymatic RNA template copying because the correct A:s2U base pair outcompetes the slightly weaker s2U:s2U base pair. In addition, even if an s2U is incorrectly incorporated, the addition of the next base is greatly hindered. This strong stalling effect would further increase the effective fidelity of nonenzymatic RNA copying with s2U. Our findings suggest that s2U may enhance the rate and extent of nonenzymatic copying with only a minimal cost in fidelity.
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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
| | - Ziyuan Fang
- Howard
Hughes Medical Institute, Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Seohyun Chris Kim
- 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
| | - Derek K. O’Flaherty
- Department
of Chemistry, College of Engineering and Physical Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Xiwen Jia
- 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
| | - Talbot B. Stone
- Department
of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Penn
Institute for RNA Innovation, University
of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Lijun Zhou
- Department
of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Penn
Institute for RNA Innovation, University
of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Jack W. Szostak
- Howard
Hughes Medical Institute, Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
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6
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Dantsu Y, Zhang Y, Zhang W. Insight into the structures of unusual base pairs in RNA complexes containing a primer/template/adenosine ligand. RSC Chem Biol 2023; 4:942-951. [PMID: 37920395 PMCID: PMC10619131 DOI: 10.1039/d3cb00137g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 08/29/2023] [Indexed: 11/04/2023] Open
Abstract
In the prebiotic RNA world, the self-replication of RNA without enzymes can be achieved through the utilization of 2-aminoimidazole activated nucleotides as efficient substrates. The mechanism of RNA nonenzymatic polymerization has been extensively investigated biophysically and structurally by using the model of an RNA primer/template complex which is bound by the imidazolium-bridged or triphosphate-bridged diguanosine intermediate. However, beyond the realm of the guanosine substrate, the structural insight into how alternative activated nucleotides bind and interact with the RNA primer/template complex remains unexplored, which is important for understanding the low reactivity of adenosine and uridine substrates in RNA primer extension, as well as its relationship with the structures. Here we use crystallography as a method and determine a series of high-resolution structures of RNA primer/template complexes bound by ApppG, a close analog of the dinucleotide intermediate containing adenosine and guanosine. The structures show that ApppG ligands bind to the RNA template through both Watson-Crick and noncanonical base pairs, with the primer 3'-OH group far from the adjacent phosphorus atom of the incoming substrate. The structures indicate that when adenosine is included in the imidazolium-bridged intermediate, the complexes are likely preorganized in a suboptimal conformation, making it difficult for the primer to in-line attack the substrate. Moreover, by co-crystallizing the RNA primer/template with chemically activated adenosine and guanosine monomers, we successfully observe the slow formation of the imidazolium-bridged intermediate (Ap-AI-pG) and the preorganized structure for RNA primer extension. Overall, our studies offer a structural explanation for the slow rate of RNA primer extension when using adenosine-5'-phosphoro-2-aminoimidazolide as a substrate during nonenzymatic polymerization.
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Affiliation(s)
- Yuliya Dantsu
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine Indianapolis IN 46202 USA
| | - Ying Zhang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine Indianapolis IN 46202 USA
| | - Wen Zhang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine Indianapolis IN 46202 USA
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7
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Park SJ, Callaghan KL, Ellis AV. Role of helicity in the nonenzymatic template-directed primer extension of DNA. Org Biomol Chem 2023; 21:6702-6706. [PMID: 37555399 DOI: 10.1039/d3ob01179h] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
Complexing a DNA primer with an RNA template showed improved nonenzymatic template-directed primer extension, attributed to a shift in the DNA helicity from a B-type towards an A-type helix. A 2-fold (deoxyadenosine) and 4.5-fold (deoxycytidine) increase in conversion from initial DNA primer to a primer + 1 nucleotide product was observed.
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Affiliation(s)
- Sung Joon Park
- School of Chemical and Biomedical Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Kimberley Laura Callaghan
- School of Chemical and Biomedical Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Amanda Vera Ellis
- School of Chemical and Biomedical Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia.
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8
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Okita H, Kondo S, Murayama K, Asanuma H. Rapid Chemical Ligation of DNA and Acyclic Threoninol Nucleic Acid ( aTNA) for Effective Nonenzymatic Primer Extension. J Am Chem Soc 2023; 145:17872-17880. [PMID: 37466125 PMCID: PMC10436273 DOI: 10.1021/jacs.3c04979] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Indexed: 07/20/2023]
Abstract
Previously, nonenzymatic primer extension reaction of acyclic l-threoninol nucleic acid (L-aTNA) was achieved in the presence of N-cyanoimidazole (CNIm) and Mn2+; however, the reaction conditions were not optimized and a mechanistic insight was not sufficient. Herein, we report investigation of the kinetics and reaction mechanism of the chemical ligation of L-aTNA to L-aTNA and of DNA to DNA. We found that Cd2+, Ni2+, and Co2+ accelerated ligation of both L-aTNA and DNA and that the rate-determining step was activation of the phosphate group. The activation was enhanced by duplex formation between a phosphorylated L-aTNA fragment and template, resulting in unexpectedly more effective L-aTNA ligation than DNA ligation. Under optimized conditions, an 8-mer L-aTNA primer could be elongated by ligation to L-aTNA trimers to produce a 29-mer full-length oligomer with 60% yield within 2 h at 4 °C. This highly effective chemical ligation system will allow construction of artificial genomes, robust DNA nanostructures, and xeno nucleic acids for use in selection methods. Our findings also shed light on the possible pre-RNA world.
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Affiliation(s)
- Hikari Okita
- Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
| | - Shuto Kondo
- Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
| | - Keiji Murayama
- Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
| | - Hiroyuki Asanuma
- Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
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9
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Ding D, Zhang SJ, Szostak JW. Enhanced nonenzymatic RNA copying with in-situ activation of short oligonucleotides. Nucleic Acids Res 2023:7184164. [PMID: 37247941 PMCID: PMC10359593 DOI: 10.1093/nar/gkad439] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 04/28/2023] [Accepted: 05/10/2023] [Indexed: 05/31/2023] Open
Abstract
The nonenzymatic copying of RNA is thought to have been necessary for the transition between prebiotic chemistry and ribozyme-catalyzed RNA replication in the RNA World. We have previously shown that a potentially prebiotic nucleotide activation pathway based on phospho-Passerini chemistry can lead to the efficient synthesis of 2-aminoimidazole activated mononucleotides when carried out under freeze-thaw cycling conditions. Such activated nucleotides react with each other to form 5'-5' 2-aminoimidazolium bridged dinucleotides, enabling template-directed primer extension to occur within the same reaction mixture. However, mononucleotides linked to oligonucleotides by a 5'-5' 2-aminoimidazolium bridge are superior substrates for nonenzymatic primer extension; their higher intrinsic reactivity and their higher template affinity enable faster template copying at lower substrate concentrations. Here we show that eutectic phase phospho-Passerini chemistry efficiently activates short oligonucleotides and promotes the formation of monomer-bridged-oligonucleotide species during freeze-thaw cycles. We then demonstrate that in-situ generated monomer-bridged-oligonucleotides lead to efficient nonenzymatic template copying in the same reaction mixture. Our demonstration that multiple steps in the pathway from activation chemistry to RNA copying can occur together in a single complex environment simplifies this aspect of the origin of life.
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Affiliation(s)
- Dian Ding
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA02138, USA
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA02114, USA
| | - Stephanie J Zhang
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA02138, USA
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA02114, USA
| | - Jack W Szostak
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA02138, USA
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA02114, USA
- Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA02115, USA
- Howard Hughes Medical Institute, Department of Chemistry, The University of Chicago, Chicago, IL60637, USA
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10
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Slootbeek AD, van Haren MHI, Smokers IBA, Spruijt E. Growth, replication and division enable evolution of coacervate protocells. Chem Commun (Camb) 2022; 58:11183-11200. [PMID: 36128910 PMCID: PMC9536485 DOI: 10.1039/d2cc03541c] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Accepted: 09/13/2022] [Indexed: 11/21/2022]
Abstract
Living and proliferating cells undergo repeated cycles of growth, replication and division, all orchestrated by complex molecular networks. How a minimal cell cycle emerged and helped primitive cells to evolve remains one of the biggest mysteries in modern science, and is an active area of research in chemistry. Protocells are cell-like compartments that recapitulate features of living cells and may be seen as the chemical ancestors of modern life. While compartmentalization is not strictly required for primitive, open-ended evolution of self-replicating systems, it gives such systems a clear identity by setting the boundaries and it can help them overcome three major obstacles of dilution, parasitism and compatibility. Compartmentalization is therefore widely considered to be a central hallmark of primitive life, and various types of protocells are actively investigated, with the ultimate goal of developing a protocell capable of autonomous proliferation by mimicking the well-known cell cycle of growth, replication and division. We and others have found that coacervates are promising protocell candidates in which chemical building blocks required for life are naturally concentrated, and chemical reactions can be selectively enhanced or suppressed. This feature article provides an overview of how growth, replication and division can be realized with coacervates as protocells and what the bottlenecks are. Considerations are given for designing chemical networks in coacervates that can lead to sustained growth, selective replication and controlled division, in a way that they are linked together like in the cell cycle. Ultimately, such a system may undergo evolution by natural selection of certain phenotypes, leading to adaptation and the gain of new functions, and we end with a brief discussion of the opportunities for coacervates to facilitate this.
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Affiliation(s)
- Annemiek D Slootbeek
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
| | - Merlijn H I van Haren
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
| | - Iris B A Smokers
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
| | - Evan Spruijt
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
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11
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Núñez-Villanueva D, Hunter CA. H-Bond Templated Oligomer Synthesis Using a Covalent Primer. J Am Chem Soc 2022; 144:17307-17316. [PMID: 36082527 PMCID: PMC9501907 DOI: 10.1021/jacs.2c08119] [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] [Indexed: 11/29/2022]
Abstract
![]()
Template-directed synthesis of nucleic acids in the polymerase
chain reaction is based on the use of a primer, which is elongated
in the replication process. The attachment of a high affinity primer
to the end of a template chain has been implemented for templating
the synthesis of triazole oligomers. A covalent ester base-pair was
used to attach a primer to a mixed sequence template. The resulting
primed template has phenol recognition units on the template, which
can form noncovalent base-pairs with phosphine oxide monomers via
H-bonding, and an alkyne group on the primer, which can react with
the azide group on a phosphine oxide monomer. Competition reactions
between azides bearing phosphine oxide and phenol recognition groups
were used to demonstrate a substantial template effect, due to H-bonding
interactions between the phenols on the template and phosphine oxides
on the azide. The largest rate acceleration was observed when a phosphine
oxide 2-mer was used, because this compound binds to the template
with a higher affinity than compounds that can only make one H-bond.
The 31P NMR spectrum of the product duplex shows that the
H-bonds responsible for the template effect are present in the product,
and this result indicates that the covalent ester base-pairs and noncovalent
H-bonded base-pairs developed here are geometrically compatible. Following
the templated reaction, it is possible to regenerate the template
and liberate the copy strand by hydrolysis of the ester base-pair
used to attach the primer, thus completing a formal replication cycle.
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Affiliation(s)
- Diego Núñez-Villanueva
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Christopher A Hunter
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
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12
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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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13
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Freeze-thaw cycles enable a prebiotically plausible and continuous pathway from nucleotide activation to nonenzymatic RNA copying. Proc Natl Acad Sci U S A 2022; 119:e2116429119. [PMID: 35446612 PMCID: PMC9169909 DOI: 10.1073/pnas.2116429119] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The replication of RNA without the aid of evolved enzymes may have enabled the inheritance of useful molecular functions during the origin of life. Template-directed RNA copying is a posited step in RNA replication. Key steps on the path to copying of RNA templates have been studied in isolation, including chemical nucleotide activation, generation of a key reactive intermediate, and template-directed polymerization. Here we report a prebiotically plausible scenario under which these reactions can happen together under mutually compatible conditions. Thus, this pathway could potentially have operated in nature without the complicating requirement for exchange of materials between distinct environments. Nonenzymatic template-directed RNA copying using chemically activated nucleotides is thought to have played a key role in the emergence of genetic information on the early Earth. A longstanding question concerns the number and nature of different environments that might have been necessary to enable all of the steps from nucleotide synthesis to RNA copying. Here we explore three sequential steps from this overall pathway: nucleotide activation, synthesis of imidazolium-bridged dinucleotides, and template-directed RNA copying. We find that all three steps can take place in one reaction mixture undergoing multiple freeze-thaw cycles. Recent experiments have demonstrated a potentially prebiotic methyl isocyanide-based nucleotide activation chemistry. However, the original version of this approach is incompatible with nonenzymatic RNA copying because the high required concentration of the imidazole activating group prevents the accumulation of the essential imidazolium-bridged dinucleotide. Here we report that ice eutectic phase conditions facilitate not only the methyl isocyanide-based activation of ribonucleotide 5′-monophosphates with stoichiometric 2-aminoimidazole, but also the subsequent conversion of these activated mononucleotides into imidazolium-bridged dinucleotides. Furthermore, this one-pot approach is compatible with template-directed RNA copying in the same reaction mixture. Our results suggest that the simple and common environmental fluctuation of freeze-thaw cycles could have played an important role in prebiotic nucleotide activation and nonenzymatic RNA copying.
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14
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Roberts SJ, Liu Z, Sutherland JD. Potentially Prebiotic Synthesis of Aminoacyl-RNA via a Bridging Phosphoramidate-Ester Intermediate. J Am Chem Soc 2022; 144:4254-4259. [PMID: 35230111 PMCID: PMC9097472 DOI: 10.1021/jacs.2c00772] [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] [Indexed: 11/28/2022]
Abstract
![]()
Translation
according to the genetic code is made possible by selectivity
both in aminoacylation of tRNA and in anticodon/codon recognition.
In extant biology, tRNAs are selectively aminoacylated by enzymes
using high-energy intermediates, but how this might have been achieved
prior to the advent of protein synthesis has been a largely unanswered
question in prebiotic chemistry. We have now elucidated a novel, prebiotically
plausible stereoselective aminoacyl-RNA synthesis, which starts from
RNA-amino acid phosphoramidates and proceeds via phosphoramidate-ester
intermediates that subsequently undergo conversion to aminoacyl-esters
by mild acid hydrolysis. The chemistry avoids the intermediacy of
high-energy mixed carboxy-phosphate anhydrides and is greatly favored
under eutectic conditions, which also potentially allow for the requisite
pH fluctuation through the variable solubility of CO2 in
solid/liquid water.
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Affiliation(s)
- Samuel J Roberts
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, U.K
| | - Ziwei Liu
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, U.K
| | - John D Sutherland
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, U.K
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15
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Ding D, Zhou L, Giurgiu C, Szostak JW. Kinetic explanations for the sequence biases observed in the nonenzymatic copying of RNA templates. Nucleic Acids Res 2021; 50:35-45. [PMID: 34893864 PMCID: PMC8754633 DOI: 10.1093/nar/gkab1202] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 11/17/2021] [Accepted: 12/08/2021] [Indexed: 11/15/2022] Open
Abstract
The identification of nonenzymatic pathways for nucleic acid replication is a key challenge in understanding the origin of life. We have previously shown that nonenzymatic RNA primer extension using 2-aminoimidazole (2AI) activated nucleotides occurs primarily through an imidazolium-bridged dinucleotide intermediate. The reactive nature and preorganized structure of the intermediate increase the efficiency of primer extension but remain insufficient to drive extensive copying of RNA templates containing all four canonical nucleotides. To understand the factors that limit RNA copying, we synthesized all ten 2AI-bridged dinucleotide intermediates and measured the kinetics of primer extension in a model system. The affinities of the ten dinucleotides for the primer/template/helper complexes vary by over 7,000-fold, consistent with nearest neighbor energetic predictions. Surprisingly, the reaction rates at saturating intermediate concentrations still vary by over 15-fold, with the most weakly binding dinucleotides exhibiting a lower maximal reaction rate. Certain noncanonical nucleotides can decrease sequence dependent differences in affinity and primer extension rate, while monomers bridged to short oligonucleotides exhibit enhanced binding and reaction rates. We suggest that more uniform binding and reactivity of imidazolium-bridged intermediates may lead to the ability to copy arbitrary template sequences under prebiotically plausible conditions.
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Affiliation(s)
- Dian Ding
- Howard Hughes Medical Institute, Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, USA.,Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA
| | - Lijun Zhou
- Howard Hughes Medical Institute, Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, USA.,Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, USA
| | - Constantin Giurgiu
- Howard Hughes Medical Institute, Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, USA.,Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA
| | - Jack W Szostak
- Howard Hughes Medical Institute, Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, USA.,Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA.,Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, USA
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16
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Giurgiu C, Fang Z, Aitken HRM, Kim SC, Pazienza L, Mittal S, Szostak JW. Structure–Activity Relationships in Nonenzymatic Template‐Directed RNA Synthesis. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202109714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Constantin Giurgiu
- Howard Hughes Medical Institute Department of Molecular Biology, and Center for Computational and Integrative Biology Massachusetts General Hospital Boston MA 02114 USA
- Department of Chemistry and Chemical Biology Harvard University Cambridge MA 02138 USA
| | - Ziyuan Fang
- Howard Hughes Medical Institute Department of Molecular Biology, and Center for Computational and Integrative Biology Massachusetts General Hospital Boston MA 02114 USA
- Department of Genetics Harvard Medical School Boston MA 02115 USA
| | - Harry R. M. Aitken
- Howard Hughes Medical Institute Department of Molecular Biology, and Center for Computational and Integrative Biology Massachusetts General Hospital Boston MA 02114 USA
- Department of Genetics Harvard Medical School Boston MA 02115 USA
| | - Seohyun Chris Kim
- Howard Hughes Medical Institute Department of Molecular Biology, and Center for Computational and Integrative Biology Massachusetts General Hospital Boston MA 02114 USA
- Department of Genetics Harvard Medical School Boston MA 02115 USA
| | - Lydia Pazienza
- Howard Hughes Medical Institute Department of Molecular Biology, and Center for Computational and Integrative Biology Massachusetts General Hospital Boston MA 02114 USA
- Department of Chemistry and Chemical Biology Harvard University Cambridge MA 02138 USA
| | - Shriyaa Mittal
- Howard Hughes Medical Institute Department of Molecular Biology, and Center for Computational and Integrative Biology Massachusetts General Hospital Boston MA 02114 USA
- Department of Chemistry and Chemical Biology Harvard University Cambridge MA 02138 USA
| | - Jack W. Szostak
- Howard Hughes Medical Institute Department of Molecular Biology, and Center for Computational and Integrative Biology Massachusetts General Hospital Boston MA 02114 USA
- Department of Chemistry and Chemical Biology Harvard University Cambridge MA 02138 USA
- Department of Genetics Harvard Medical School Boston MA 02115 USA
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17
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Giurgiu C, Fang Z, Aitken HRM, Kim SC, Pazienza L, Mittal S, Szostak JW. Structure-Activity Relationships in Nonenzymatic Template-Directed RNA Synthesis. Angew Chem Int Ed Engl 2021; 60:22925-22932. [PMID: 34428345 PMCID: PMC8490286 DOI: 10.1002/anie.202109714] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Indexed: 11/11/2022]
Abstract
The template-directed synthesis of RNA played an important role in the transition from prebiotic chemistry to the beginnings of RNA based life, but the mechanism of RNA copying chemistry is incompletely understood. We measured the kinetics of template copying with a set of primers with modified 3'-nucleotides and determined the crystal structures of these modified nucleotides in the context of a primer/template/substrate-analog complex. pH-rate profiles and solvent isotope effects show that deprotonation of the primer 3'-hydroxyl occurs prior to the rate limiting step, the attack of the alkoxide on the activated phosphate of the incoming nucleotide. The analogs with a 3 E ribose conformation show the fastest formation of 3'-5' phosphodiester bonds. Among those derivatives, the reaction rate is strongly correlated with the electronegativity of the 2'-substituent. We interpret our results in terms of differences in steric bulk and charge distribution in the ground vs. transition states.
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Affiliation(s)
- Constantin Giurgiu
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, 02114, USA.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Ziyuan Fang
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, 02114, USA.,Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
| | - Harry R M Aitken
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, 02114, USA.,Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
| | - Seohyun Chris Kim
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, 02114, USA.,Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
| | - Lydia Pazienza
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, 02114, USA.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Shriyaa Mittal
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, 02114, USA.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Jack W Szostak
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, 02114, USA.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA.,Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
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18
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Jiménez EI, Gibard C, Krishnamurthy R. Prebiotic Phosphorylation and Concomitant Oligomerization of Deoxynucleosides to form DNA. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202015910] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Eddy I. Jiménez
- The Department of Chemistry The Scripps Research Institute 10550 North Torrey Pines Road La Jolla CA 92037 USA
| | - Clémentine Gibard
- The Department of Chemistry The Scripps Research Institute 10550 North Torrey Pines Road La Jolla CA 92037 USA
| | - Ramanarayanan Krishnamurthy
- The Department of Chemistry The Scripps Research Institute 10550 North Torrey Pines Road La Jolla CA 92037 USA
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19
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Jiménez EI, Gibard C, Krishnamurthy R. Prebiotic Phosphorylation and Concomitant Oligomerization of Deoxynucleosides to form DNA. Angew Chem Int Ed Engl 2021; 60:10775-10783. [PMID: 33325148 DOI: 10.1002/anie.202015910] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Indexed: 12/14/2022]
Abstract
Recent demonstrations of RNA-DNA chimeras (RDNA) enabling RNA and DNA replication, coupled with prebiotic co-synthesis of deoxyribo- and ribo-nucleotides, have resurrected the hypothesis of co-emergence of RNA and DNA. As further support, we show that diamidophosphate (DAP) with 2-aminoimidazole (amido)phosphorylates and oligomerizes deoxynucleosides to form DNA-under conditions similar to those of ribonucleosides. The pyrimidine deoxynucleoside 5'-O-amidophosphates are formed in good (≈60 %) yields. Intriguingly, the presence of pyrimidine deoxynucleos(t)ides increased the yields of purine deoxynucleotides (≈20 %). Concomitantly, oligomerization (≈18-31 %) is observed with predominantly 3',5'-phosphodiester DNA linkages, and some (<5 %) pyrophosphates. Combined with previous observations of DAP-mediated chemistries and the constructive role of RDNA chimeras, the results reported here help set the stage for systematic investigation of a systems chemistry approach of RNA-DNA coevolution.
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Affiliation(s)
- Eddy I Jiménez
- The Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Clémentine Gibard
- The Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Ramanarayanan Krishnamurthy
- The Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA
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20
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Moelling K, Broecker F. Viroids and the Origin of Life. Int J Mol Sci 2021; 22:ijms22073476. [PMID: 33800543 PMCID: PMC8036462 DOI: 10.3390/ijms22073476] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/24/2021] [Accepted: 03/24/2021] [Indexed: 11/16/2022] Open
Abstract
Viroids are non-coding circular RNA molecules with rod-like or branched structures. They are often ribozymes, characterized by catalytic RNA. They can perform many basic functions of life and may have played a role in evolution since the beginning of life on Earth. They can cleave, join, replicate, and undergo Darwinian evolution. Furthermore, ribozymes are the essential elements for protein synthesis of cellular organisms as parts of ribosomes. Thus, they must have preceded DNA and proteins during evolution. Here, we discuss the current evidence for viroids or viroid-like RNAs as a likely origin of life on Earth. As such, they may also be considered as models for life on other planets or moons in the solar system as well as on exoplanets.
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Affiliation(s)
- Karin Moelling
- Institute of Medical Microbiology, University of Zurich, Gloriastr 30, 8006 Zurich, Switzerland
- Max Planck Institute for molecular Genetics, Ihnestr. 63-73, 14195 Berlin, Germany
- Correspondence: ; Tel.: +49-(172)-3274306
| | - Felix Broecker
- Vaxxilon Deutschland GmbH, Magnusstr. 11, 12489 Berlin, Germany;
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21
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Kim SC, O'Flaherty DK, Giurgiu C, Zhou L, Szostak JW. The Emergence of RNA from the Heterogeneous Products of Prebiotic Nucleotide Synthesis. J Am Chem Soc 2021; 143:3267-3279. [PMID: 33636080 DOI: 10.1021/jacs.0c12955] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recent advances in prebiotic chemistry are beginning to outline plausible pathways for the synthesis of the canonical ribonucleotides and their assembly into oligoribonucleotides. However, these reaction pathways suggest that many noncanonical nucleotides are likely to have been generated alongside the standard ribonucleotides. Thus, the oligomerization of prebiotically synthesized nucleotides is likely to have led to a highly heterogeneous collection of oligonucleotides comprised of a wide range of types of nucleotides connected by a variety of backbone linkages. How then did relatively homogeneous RNA emerge from this primordial heterogeneity? Here we focus on nonenzymatic template-directed primer extension as a process that would have strongly enriched for homogeneous RNA over the course of multiple cycles of replication. We review the effects on copying the kinetics of nucleotides with altered nucleobase and sugar moieties, when they are present as activated monomers and when they are incorporated into primer and template oligonucleotides. We also discuss three variations in backbone connectivity, all of which are nonheritable and regenerate native RNA upon being copied. The kinetic superiority of RNA synthesis suggests that nonenzymatic copying served as a chemical selection mechanism that allowed relatively homogeneous RNA to emerge from a complex mixture of prebiotically synthesized nucleotides and oligonucleotides.
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Affiliation(s)
- Seohyun Chris Kim
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Derek K O'Flaherty
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Constantin Giurgiu
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Lijun Zhou
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Jack W Szostak
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States.,Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, United States
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22
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Zhang W, Kim SC, Tam CP, Lelyveld VS, Bala S, Chaput JC, Szostak JW. Structural interpretation of the effects of threo-nucleotides on nonenzymatic template-directed polymerization. Nucleic Acids Res 2021; 49:646-656. [PMID: 33347562 PMCID: PMC7826252 DOI: 10.1093/nar/gkaa1215] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/25/2020] [Accepted: 12/17/2020] [Indexed: 11/13/2022] Open
Abstract
The prebiotic synthesis of ribonucleotides is likely to have been accompanied by the synthesis of noncanonical nucleotides including the threo-nucleotide building blocks of TNA. Here, we examine the ability of activated threo-nucleotides to participate in nonenzymatic template-directed polymerization. We find that primer extension by multiple sequential threo-nucleotide monomers is strongly disfavored relative to ribo-nucleotides. Kinetic, NMR and crystallographic studies suggest that this is due in part to the slow formation of the imidazolium-bridged TNA dinucleotide intermediate in primer extension, and in part because of the greater distance between the attacking RNA primer 3'-hydroxyl and the phosphate of the incoming threo-nucleotide intermediate. Even a single activated threo-nucleotide in the presence of an activated downstream RNA oligonucleotide is added to the primer 10-fold more slowly than an activated ribonucleotide. In contrast, a single activated threo-nucleotide at the end of an RNA primer or in an RNA template results in only a modest decrease in the rate of primer extension, consistent with the minor and local structural distortions revealed by crystal structures. Our results are consistent with a model in which heterogeneous primordial oligonucleotides would, through cycles of replication, have given rise to increasingly homogeneous RNA strands.
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Affiliation(s)
- Wen Zhang
- Howard Hughes Medical Institute and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Genetics, Harvard Medical School, Boston, MA 02114, USA.,Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Seohyun Chris Kim
- Howard Hughes Medical Institute and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Chun Pong Tam
- Howard Hughes Medical Institute and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Victor S Lelyveld
- Howard Hughes Medical Institute and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Genetics, Harvard Medical School, Boston, MA 02114, USA
| | - Saikat Bala
- Department of Chemistry and of Pharmaceutical Sciences, University of California, Irvine, CA 92697, USA
| | - John C Chaput
- Department of Chemistry and of Pharmaceutical Sciences, University of California, Irvine, CA 92697, USA
| | - Jack W Szostak
- Howard Hughes Medical Institute and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA 02114, USA.,Department of Genetics, Harvard Medical School, Boston, MA 02114, USA.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
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23
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Song EY, Jiménez EI, Lin H, Le Vay K, Krishnamurthy R, Mutschler H. Prebiotically Plausible RNA Activation Compatible with Ribozyme-Catalyzed Ligation. Angew Chem Int Ed Engl 2021; 60:2952-2957. [PMID: 33128282 PMCID: PMC7898671 DOI: 10.1002/anie.202010918] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 10/29/2020] [Indexed: 01/04/2023]
Abstract
RNA-catalyzed RNA ligation is widely believed to be a key reaction for primordial biology. However, since typical chemical routes towards activating RNA substrates are incompatible with ribozyme catalysis, it remains unclear how prebiotic systems generated and sustained pools of activated building blocks needed to form increasingly larger and complex RNA. Herein, we demonstrate in situ activation of RNA substrates under reaction conditions amenable to catalysis by the hairpin ribozyme. We found that diamidophosphate (DAP) and imidazole drive the formation of 2',3'-cyclic phosphate RNA mono- and oligonucleotides from monophosphorylated precursors in frozen water-ice. This long-lived activation enables iterative enzymatic assembly of long RNAs. Our results provide a plausible scenario for the generation of higher-energy substrates required to fuel ribozyme-catalyzed RNA synthesis in the absence of a highly evolved metabolism.
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Affiliation(s)
- Emilie Yeonwha Song
- Max Planck Institute of BiochemistryAm Klopferspitz 1882152MartinsriedGermany
| | - Eddy Ivanhoe Jiménez
- Department of ChemistryThe Scripps Research Institute10550 North Torrey Pines RoadLa JollaCA92037USA
| | - Huacan Lin
- Department of ChemistryThe Scripps Research Institute10550 North Torrey Pines RoadLa JollaCA92037USA
| | - Kristian Le Vay
- Max Planck Institute of BiochemistryAm Klopferspitz 1882152MartinsriedGermany
| | | | - Hannes Mutschler
- Max Planck Institute of BiochemistryAm Klopferspitz 1882152MartinsriedGermany
- Technical University DortmundOtto-Hahn-Strasse 4a44227DortmundGermany
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24
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Radakovic A, Wright TH, Lelyveld VS, Szostak JW. A Potential Role for Aminoacylation in Primordial RNA Copying Chemistry. Biochemistry 2021; 60:477-488. [PMID: 33523633 PMCID: PMC9634692 DOI: 10.1021/acs.biochem.0c00943] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Aminoacylated tRNAs
are the substrates for ribosomal protein synthesis
in all branches of life, implying an ancient origin for aminoacylation
chemistry. In the 1970s, Orgel and colleagues reported potentially
prebiotic routes to aminoacylated nucleotides and their RNA-templated
condensation to form amino acid-bridged dinucleotides. However, it
is unclear whether such reactions would have aided or impeded non-enzymatic
RNA replication. Determining whether aminoacylated RNAs could have
been advantageous in evolution prior to the emergence of protein synthesis
remains a key challenge. We therefore tested the ability of aminoacylated
RNA to participate in both templated primer extension and ligation
reactions. We find that at low magnesium concentrations that favor
fatty acid-based protocells, these reactions proceed orders of magnitude
more rapidly than when initiated from the cis-diol
of unmodified RNA. We further demonstrate that amino acid-bridged
RNAs can act as templates in a subsequent round of copying. Our results
suggest that aminoacylation facilitated non-enzymatic RNA replication,
thus outlining a potentially primordial functional link between aminoacylation
chemistry and RNA replication.
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Affiliation(s)
- Aleksandar Radakovic
- Howard Hughes Medical Institute, 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, Boston, Massachusetts 02115, United States
| | - Tom H Wright
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, United States
| | - Victor S Lelyveld
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, United States
| | - Jack W Szostak
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, United States
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25
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Namani T, Snyder S, Eagan JM, Bevilacqua PC, Wesdemiotis C, Sahai N. Amino Acid Specific Nonenzymatic Montmorillonite‐Promoted RNA Polymerization. CHEMSYSTEMSCHEM 2021. [DOI: 10.1002/syst.202000060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Trishool Namani
- School of Polymer Science and Polymer Engineering The University of Akron Akron OH 44325 USA
| | - Savannah Snyder
- Department of Chemistry The University of Akron Akron OH 44325 USA
| | - James M. Eagan
- School of Polymer Science and Polymer Engineering The University of Akron Akron OH 44325 USA
| | - Philip C. Bevilacqua
- Department of Chemistry and Biochemistry Department of Microbiology and Molecular Biology Center for RNA Molecular Biology Pennsylvania State University University Park Pennsylvania PA 16802 USA
| | | | - Nita Sahai
- School of Polymer Science and Polymer Engineering The University of Akron Akron OH 44325 USA
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26
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Zhou L, Ding D, Szostak JW. The virtual circular genome model for primordial RNA replication. RNA (NEW YORK, N.Y.) 2021; 27:1-11. [PMID: 33028653 PMCID: PMC7749632 DOI: 10.1261/rna.077693.120] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 10/02/2020] [Indexed: 05/13/2023]
Abstract
We propose a model for the replication of primordial protocell genomes that builds upon recent advances in the nonenzymatic copying of RNA. We suggest that the original genomes consisted of collections of oligonucleotides beginning and ending at all possible positions on both strands of one or more virtual circular sequences. Replication is driven by feeding with activated monomers and by the activation of monomers and oligonucleotides in situ. A fraction of the annealed configurations of the protocellular oligonucleotides would allow for template-directed oligonucleotide growth by primer extension or ligation. Rearrangements of these annealed configurations, driven either by environmental fluctuations or occurring spontaneously, would allow for continued oligonucleotide elongation. Assuming that shorter oligonucleotides were more abundant than longer ones, replication of the entire genome could occur by the growth of all oligonucleotides by as little as one nucleotide on average. We consider possible scenarios that could have given rise to such protocell genomes, as well as potential routes to the emergence of catalytically active ribozymes and thus the more complex cells of the RNA World.
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Affiliation(s)
- Lijun Zhou
- Howard Hughes Medical Institute, Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Dian Ding
- Howard Hughes Medical Institute, Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Jack W Szostak
- Howard Hughes Medical Institute, Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
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27
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Song EY, Jiménez EI, Lin H, Le Vay K, Krishnamurthy R, Mutschler H. Präbiotisch plausible RNA‐Aktivierung kompatibel mit ribozymkatalysierter Ligation. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202010918] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Emilie Yeonwha Song
- Max Planck Institute of Biochemistry Am Klopferspitz 18 82152 Martinsried Deutschland
| | - Eddy Ivanhoe Jiménez
- Department of Chemistry The Scripps Research Institute 10550 North Torrey Pines Road La Jolla CA 92037 USA
| | - Huacan Lin
- Department of Chemistry The Scripps Research Institute 10550 North Torrey Pines Road La Jolla CA 92037 USA
| | - Kristian Le Vay
- Max Planck Institute of Biochemistry Am Klopferspitz 18 82152 Martinsried Deutschland
| | | | - Hannes Mutschler
- Max Planck Institute of Biochemistry Am Klopferspitz 18 82152 Martinsried Deutschland
- TU Dortmund University Otto-Hahn-Straße 4a 44227 Dortmund Deutschland
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28
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Zhou L, O'Flaherty DK, Szostak JW. Template-Directed Copying of RNA by Non-enzymatic Ligation. Angew Chem Int Ed Engl 2020; 59:15682-15687. [PMID: 32558121 PMCID: PMC7496532 DOI: 10.1002/anie.202004934] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 06/04/2020] [Indexed: 12/12/2022]
Abstract
The non-enzymatic replication of the primordial genetic material is thought to have enabled the evolution of early forms of RNA-based life. However, the replication of oligonucleotides long enough to encode catalytic functions is problematic due to the low efficiency of template copying with mononucleotides. We show that template-directed ligation can assemble long RNAs from shorter oligonucleotides, which would be easier to replicate. The rate of ligation can be greatly enhanced by employing a 3'-amino group at the 3'-end of each oligonucleotide, in combination with an N-alkyl imidazole organocatalyst. These modifications enable the copying of RNA templates by the multistep ligation of tetranucleotide building blocks, as well as the assembly of long oligonucleotides using short splint oligonucleotides. We also demonstrate the formation of long oligonucleotides inside model prebiotic vesicles, which suggests a potential route to the assembly of artificial cells capable of evolution.
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Affiliation(s)
- Lijun Zhou
- Howard Hughes Medical InstituteDepartment of Molecular BiologyCenter for Computational and Integrative BiologyMassachusetts General HospitalBostonMA02114 (USA), E
| | - Derek K. O'Flaherty
- Howard Hughes Medical InstituteDepartment of Molecular BiologyCenter for Computational and Integrative BiologyMassachusetts General HospitalBostonMA02114 (USA), E
- Present address: Alnylam PharmaceuticalsCambridgeMA02142USA
| | - Jack W. Szostak
- Howard Hughes Medical InstituteDepartment of Molecular BiologyCenter for Computational and Integrative BiologyMassachusetts General HospitalBostonMA02114 (USA), E
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29
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Zhang SJ, Duzdevich D, Szostak JW. Potentially Prebiotic Activation Chemistry Compatible with Nonenzymatic RNA Copying. J Am Chem Soc 2020; 142:14810-14813. [PMID: 32794700 PMCID: PMC9594304 DOI: 10.1021/jacs.0c05300] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
![]()
The nonenzymatic replication of ribonucleic
acid (RNA) may have
enabled the propagation of genetic information during the origin of
life. RNA copying can be initiated in the laboratory with chemically
activated nucleotides, but continued copying requires a source of
chemical energy for in situ nucleotide activation.
Recent work has illuminated a potentially prebiotic cyanosulfidic
chemistry that activates nucleotides, but its application to nonenzymatic
RNA copying had not been demonstrated. Here, we report a novel pathway
that activates RNA nucleotides in a manner compatible with template-directed
nonenzymatic copying. We show that this pathway, which we refer to
as bridge-forming activation, selectively yields the reactive imidazolium-bridged
dinucleotide intermediate required for copying. Our results will enable
more realistic simulations of RNA propagation based on continuous in situ nucleotide activation.
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Affiliation(s)
- Stephanie J Zhang
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Daniel Duzdevich
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States
| | - Jack W Szostak
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States.,Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States
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30
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Zhou L, O'Flaherty DK, Szostak JW. Template‐Directed Copying of RNA by Non‐enzymatic Ligation. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202004934] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Lijun Zhou
- Howard Hughes Medical Institute Department of Molecular Biology Center for Computational and Integrative Biology Massachusetts General Hospital Boston MA 02114 (USA), E
| | - Derek K. O'Flaherty
- Howard Hughes Medical Institute Department of Molecular Biology Center for Computational and Integrative Biology Massachusetts General Hospital Boston MA 02114 (USA), E
- Present address: Alnylam Pharmaceuticals Cambridge MA 02142 USA
| | - Jack W. Szostak
- Howard Hughes Medical Institute Department of Molecular Biology Center for Computational and Integrative Biology Massachusetts General Hospital Boston MA 02114 (USA), E
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31
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Duzdevich D, Carr CE, Szostak JW. Deep sequencing of non-enzymatic RNA primer extension. Nucleic Acids Res 2020; 48:e70. [PMID: 32427335 PMCID: PMC7337528 DOI: 10.1093/nar/gkaa400] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 04/02/2020] [Accepted: 05/05/2020] [Indexed: 12/02/2022] Open
Abstract
Life emerging in an RNA world is expected to propagate RNA as hereditary information, requiring some form of primitive replication without enzymes. Non-enzymatic template-directed RNA primer extension is a model of the copying step in this posited form of replication. The sequence space accessed by primer extension dictates potential pathways to self-replication and, eventually, ribozymes. Which sequences can be accessed? What is the fidelity of the reaction? Does the recently illuminated mechanism of primer extension affect the distribution of sequences that can be copied? How do sequence features respond to experimental conditions and prebiotically relevant contexts? To help answer these and related questions, we here introduce a deep-sequencing methodology for studying RNA primer extension. We have designed and vetted special RNA constructs for this purpose, honed a protocol for sample preparation and developed custom software that analyzes sequencing data. We apply this new methodology to proof-of-concept controls, and demonstrate that it works as expected and reports on key features of the sequences accessed by primer extension.
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Affiliation(s)
- Daniel Duzdevich
- Department of Molecular Biology, Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Christopher E Carr
- Department of Molecular Biology, Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jack W Szostak
- Department of Molecular Biology, Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA 02114, USA
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
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32
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Selective prebiotic formation of RNA pyrimidine and DNA purine nucleosides. Nature 2020; 582:60-66. [PMID: 32494078 DOI: 10.1038/s41586-020-2330-9] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 04/16/2020] [Indexed: 11/08/2022]
Abstract
The nature of the first genetic polymer is the subject of major debate1. Although the 'RNA world' theory suggests that RNA was the first replicable information carrier of the prebiotic era-that is, prior to the dawn of life2,3-other evidence implies that life may have started with a heterogeneous nucleic acid genetic system that included both RNA and DNA4. Such a theory streamlines the eventual 'genetic takeover' of homogeneous DNA from RNA as the principal information-storage molecule, but requires a selective abiotic synthesis of both RNA and DNA building blocks in the same local primordial geochemical scenario. Here we demonstrate a high-yielding, completely stereo-, regio- and furanosyl-selective prebiotic synthesis of the purine deoxyribonucleosides: deoxyadenosine and deoxyinosine. Our synthesis uses key intermediates in the prebiotic synthesis of the canonical pyrimidine ribonucleosides (cytidine and uridine), and we show that, once generated, the pyrimidines persist throughout the synthesis of the purine deoxyribonucleosides, leading to a mixture of deoxyadenosine, deoxyinosine, cytidine and uridine. These results support the notion that purine deoxyribonucleosides and pyrimidine ribonucleosides may have coexisted before the emergence of life5.
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33
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Kim SC, Zhou L, Zhang W, O'Flaherty DK, Rondo-Brovetto V, Szostak JW. A Model for the Emergence of RNA from a Prebiotically Plausible Mixture of Ribonucleotides, Arabinonucleotides, and 2'-Deoxynucleotides. J Am Chem Soc 2020; 142:2317-2326. [PMID: 31913615 PMCID: PMC7577264 DOI: 10.1021/jacs.9b11239] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
![]()
The abiotic synthesis of ribonucleotides
is thought to have been
an essential step toward the emergence of the RNA world. However,
it is likely that the prebiotic synthesis of ribonucleotides was accompanied
by the simultaneous synthesis of arabinonucleotides, 2′-deoxyribonucleotides,
and other variations on the canonical nucleotides. In order to understand
how relatively homogeneous RNA could have emerged from such complex
mixtures, we have examined the properties of arabinonucleotides and
2′-deoxyribonucleotides in nonenzymatic template-directed primer
extension reactions. We show that nonenzymatic primer extension with
activated arabinonucleotides is much less efficient than with activated
ribonucleotides, and furthermore that once an arabinonucleotide is
incorporated, continued primer extension is strongly inhibited. As
previously shown, 2′-deoxyribonucleotides are also less efficiently
incorporated in primer extension reactions, but the difference is
more modest. Experiments with mixtures of nucleotides suggest that
the coexistence of ribo- and arabinonucleotides does not impede the
copying of RNA templates. Moreover, chimeric oligoribonucleotides
containing 2′-deoxy- or arabinonucleotides are effective templates
for RNA synthesis. We propose that the initial genetic polymers were
random sequence chimeric oligonucleotides formed by untemplated polymerization,
but that template copying chemistry favored RNA synthesis; multiple
rounds of replication may have led to pools of oligomers composed
mainly of RNA.
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Affiliation(s)
- Seohyun Chris Kim
- Howard Hughes Medical Institute, 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
| | - Lijun Zhou
- Howard Hughes Medical Institute, 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
| | - Wen Zhang
- Howard Hughes Medical Institute, 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
| | - Derek K O'Flaherty
- Howard Hughes Medical Institute, 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
| | - Valeria Rondo-Brovetto
- Howard Hughes Medical Institute, 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
- Howard Hughes Medical Institute, 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
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34
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Fairbanks BD, Culver HR, Mavila S, Bowman CN. Towards High-Efficiency Synthesis of Xenonucleic Acids. TRENDS IN CHEMISTRY 2020. [DOI: 10.1016/j.trechm.2019.06.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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35
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Wright TH, Giurgiu C, Zhang W, Radakovic A, O'Flaherty DK, Zhou L, Szostak JW. Prebiotically Plausible "Patching" of RNA Backbone Cleavage through a 3'-5' Pyrophosphate Linkage. J Am Chem Soc 2019; 141:18104-18112. [PMID: 31651170 PMCID: PMC7577263 DOI: 10.1021/jacs.9b08237] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
![]()
Achieving multiple cycles of RNA
replication within a model protocell
would be a critical step toward demonstrating a path from prebiotic
chemistry to cellular biology. Any model for early life based on an
“RNA world” must account for RNA strand cleavage and
hydrolysis, which would degrade primitive genetic information and
lead to an accumulation of truncated, phosphate-terminated strands.
We show here that cleavage of the phosphodiester backbone is not an
end point for RNA replication. Instead, 3′-phosphate-terminated
RNA strands can participate in template-directed copying reactions
with activated ribonucleotide monomers. These reactions form a pyrophosphate
linkage, the stability of which we have characterized in the context
of RNA copying chemistry. The presence of free magnesium cations results
in cleavage of the pyrophosphate bond within minutes. However, we
found that the pyrophosphate bond is relatively stable within an RNA
duplex and in the presence of chelated magnesium. We show that, under
these conditions, pyrophosphate-linked RNA can act as a template for
the polymerization of ribonucleotides into canonical 3′–5′
phosphodiester-linked RNA. We suggest that primer extension of 3′-phosphate-terminated
RNA followed by template-directed copying represents a plausible nonenzymatic
pathway for the salvage and recovery of genetic information following
strand cleavage.
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Affiliation(s)
- Tom H Wright
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology , Massachusetts General Hospital , 185 Cambridge Street , Boston , Massachusetts 02114 , United States
| | - Constantin Giurgiu
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology , Massachusetts General Hospital , 185 Cambridge Street , Boston , Massachusetts 02114 , United States
| | - Wen Zhang
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology , Massachusetts General Hospital , 185 Cambridge Street , Boston , Massachusetts 02114 , United States
| | - Aleksandar Radakovic
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology , Massachusetts General Hospital , 185 Cambridge Street , Boston , Massachusetts 02114 , United States
| | - Derek K O'Flaherty
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology , Massachusetts General Hospital , 185 Cambridge Street , Boston , Massachusetts 02114 , United States
| | - Lijun Zhou
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology , Massachusetts General Hospital , 185 Cambridge Street , Boston , Massachusetts 02114 , United States
| | - Jack W Szostak
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology , Massachusetts General Hospital , 185 Cambridge Street , Boston , Massachusetts 02114 , United States
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36
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Zhang W, Pal A, Ricardo A, Szostak JW. Template-Directed Nonenzymatic Primer Extension Using 2-Methylimidazole-Activated Morpholino Derivatives of Guanosine and Cytidine. J Am Chem Soc 2019; 141:12159-12166. [PMID: 31298852 PMCID: PMC7547883 DOI: 10.1021/jacs.9b06453] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Efforts to develop self-replicating nucleic acids have led to insights into the origin of life and have also suggested potential pathways to the design of artificial life forms based on non-natural nucleic acids. The template-directed nonenzymatic polymerization of activated ribonucleotide monomers is generally slow because of the relatively weak nucleophilicity of the primer 3'-hydroxyl. To circumvent this problem, several nucleic acids based on amino-sugar nucleotides have been studied, and as expected, the more-nucleophilic amine generally results in faster primer extension. Extending this logic, we have chosen to study morpholino nucleic acid (MoNA), because the secondary amine of the morpholino-nucleotides is expected to be highly nucleophilic. We describe the synthesis of 2-methylimidazole-activated MoNA monomers from their corresponding ribonucleoside 5'-monophosphates and the synthesis of an RNA primer with a terminal MoNA nucleotide. We show that the activated G and C MoNA monomers enable rapid and efficient extension of the morpholino-terminated primer on homopolymeric and mixed-sequenced RNA templates. Our results show that MoNA is a non-natural informational polymer that is worthy of further study as a candidate self-replicating material.
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Affiliation(s)
- Weicheng Zhang
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology , Massachusetts General Hospital , Boston , Massachusetts 02114 , United States
| | - Ayan Pal
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology , Massachusetts General Hospital , Boston , Massachusetts 02114 , United States
| | - Alonso Ricardo
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology , Massachusetts General Hospital , Boston , Massachusetts 02114 , United States
| | - Jack W Szostak
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology , Massachusetts General Hospital , Boston , Massachusetts 02114 , United States
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37
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Walton T, Zhang W, Li L, Tam CP, Szostak JW. The Mechanism of Nonenzymatic Template Copying with Imidazole-Activated Nucleotides. Angew Chem Int Ed Engl 2019; 58:10812-10819. [PMID: 30908802 DOI: 10.1002/anie.201902050] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Indexed: 11/10/2022]
Abstract
The emergence of the replication of RNA oligonucleotides was a critical step in the origin of life. An important model for the study of nonenzymatic template copying, which would be a key part of any such pathway, involves the reaction of ribonucleoside-5'-phosphorimidazolides with an RNA primer/template complex. The mechanism by which the primer becomes extended by one nucleotide was assumed to be a classical in-line nucleophilic-substitution reaction in which the 3'-hydroxyl of the primer attacks the phosphate of the incoming activated monomer with displacement of the imidazole leaving group. Surprisingly, this simple model has turned out to be incorrect, and the dominant pathway has now been shown to involve the reaction of two activated nucleotides with each other to form a 5'-5'-imidazolium bridged dinucleotide intermediate. Here we review the discovery of this unexpected intermediate, and the chemical, kinetic, and structural evidence for its role in template copying chemistry.
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Affiliation(s)
- Travis Walton
- Howard Hughes Medical Institute and Dept. of Molecular Biology, Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Wen Zhang
- Howard Hughes Medical Institute and Dept. of Molecular Biology, Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Li Li
- Howard Hughes Medical Institute and Dept. of Molecular Biology, Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Chun Pong Tam
- Howard Hughes Medical Institute and Dept. of Molecular Biology, Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, 02114, USA.,Dept. of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA.,Present address: Moderna Inc., Cambridge, MA, 02139, USA
| | - Jack W Szostak
- Howard Hughes Medical Institute and Dept. of Molecular Biology, Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA, 02114, USA.,Dept. of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA
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38
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Walton T, Zhang W, Li L, Tam CP, Szostak JW. The Mechanism of Nonenzymatic Template Copying with Imidazole‐Activated Nucleotides. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201902050] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Travis Walton
- Howard Hughes Medical Institute and Dept. of Molecular Biology Center for Computational and Integrative Biology Massachusetts General Hospital Boston MA 02114 USA
| | - Wen Zhang
- Howard Hughes Medical Institute and Dept. of Molecular Biology Center for Computational and Integrative Biology Massachusetts General Hospital Boston MA 02114 USA
| | - Li Li
- Howard Hughes Medical Institute and Dept. of Molecular Biology Center for Computational and Integrative Biology Massachusetts General Hospital Boston MA 02114 USA
| | - Chun Pong Tam
- Howard Hughes Medical Institute and Dept. of Molecular Biology Center for Computational and Integrative Biology Massachusetts General Hospital Boston MA 02114 USA
- Dept. of Chemistry and Chemical Biology Harvard University Cambridge MA 02138 USA
- Present address: Moderna Inc. Cambridge MA 02139 USA
| | - Jack W. Szostak
- Howard Hughes Medical Institute and Dept. of Molecular Biology Center for Computational and Integrative Biology Massachusetts General Hospital Boston MA 02114 USA
- Dept. of Chemistry and Chemical Biology Harvard University Cambridge MA 02138 USA
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39
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O'Flaherty DK, Zhou L, Szostak JW. Nonenzymatic Template-Directed Synthesis of Mixed-Sequence 3'-NP-DNA up to 25 Nucleotides Long Inside Model Protocells. J Am Chem Soc 2019; 141:10481-10488. [PMID: 31180644 PMCID: PMC7547854 DOI: 10.1021/jacs.9b04858] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Efficiently copying mixed-sequence oligonucleotide templates nonenzymatically is a long-standing problem both with respect to the origin of life, and with regard to bottom up efforts to synthesize artificial living systems. Here we report an efficient and sequence-general nonenzymatic process in which RNA templates direct the synthesis of a complementary strand composed of N3'→P5' phosphoramidate DNA (3'-NP-DNA) using 3'-amino-2',3'-dideoxyribonucleotides activated with 2-aminoimidazole. Using only the four canonical nucleobases (A, G, C, and T) of modern DNA, we demonstrate the chemical copying of a variety of mixed-sequence RNA templates, both in solution and within model protocells, into complementary 3'-NP-DNA strands. Templates up to 25 nucleotides long were chemically transcribed with an average stepwise yield of 96-97%. The nonenzymatic template-directed generation of primer extension products long enough to encode active ribozymes and/or aptamers inside model protocells suggests possible routes to the synthesis of evolving cellular systems.
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Affiliation(s)
- Derek K O'Flaherty
- Howard Hughes Medical Institute, 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
| | - Lijun Zhou
- Howard Hughes Medical Institute, 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
- Howard Hughes Medical Institute, 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 Chemistry and Chemical Biology , Harvard University , 12 Oxford Street , Cambridge , Massachusetts 02138 , United States
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40
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Petkowski JJ, Bains W, Seager S. Natural Products Containing 'Rare' Organophosphorus Functional Groups. Molecules 2019; 24:E866. [PMID: 30823503 PMCID: PMC6429109 DOI: 10.3390/molecules24050866] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 02/13/2019] [Accepted: 02/22/2019] [Indexed: 12/25/2022] Open
Abstract
Phosphorous-containing molecules are essential constituents of all living cells. While the phosphate functional group is very common in small molecule natural products, nucleic acids, and as chemical modification in protein and peptides, phosphorous can form P⁻N (phosphoramidate), P⁻S (phosphorothioate), and P⁻C (e.g., phosphonate and phosphinate) linkages. While rare, these moieties play critical roles in many processes and in all forms of life. In this review we thoroughly categorize P⁻N, P⁻S, and P⁻C natural organophosphorus compounds. Information on biological source, biological activity, and biosynthesis is included, if known. This review also summarizes the role of phosphorylation on unusual amino acids in proteins (N- and S-phosphorylation) and reviews the natural phosphorothioate (P⁻S) and phosphoramidate (P⁻N) modifications of DNA and nucleotides with an emphasis on their role in the metabolism of the cell. We challenge the commonly held notion that nonphosphate organophosphorus functional groups are an oddity of biochemistry, with no central role in the metabolism of the cell. We postulate that the extent of utilization of some phosphorus groups by life, especially those containing P⁻N bonds, is likely severely underestimated and has been largely overlooked, mainly due to the technological limitations in their detection and analysis.
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Affiliation(s)
- Janusz J Petkowski
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Mass. Ave., Cambridge, MA 02139, USA.
| | - William Bains
- Rufus Scientific, 37 The Moor, Melbourn, Royston, Herts SG8 6ED, UK.
| | - Sara Seager
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Mass. Ave., Cambridge, MA 02139, USA.
- Department of Physics, Massachusetts Institute of Technology, 77 Mass. Ave., Cambridge, MA 02139, USA.
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, 77 Mass. Ave., Cambridge, MA 02139, USA.
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41
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Abstract
Central to the “RNA world” hypothesis of the origin of life is the emergence of an RNA catalyst capable of RNA replication. However, possible replicase ribozymes are quite complex and were likely predated by simpler non-enzymatic replication reactions. The templated polymerisation of phosphorimidazolide (Imp) activated ribonucleotides currently appears as the most tractable route to both generate and replicate short RNA oligomer pools from which a replicase could emerge. Herein we demonstrate the rapid assembly of complex ribozymes from such Imp-activated RNA fragment pools. Specifically, we show assembly of a newly selected minimal RNA polymerase ribozyme variant (150 nt) by RNA templated ligation of 5’-2-methylimidazole-activated RNA oligomers <30 nucleotides long. Our results provide support for the possibility that complex RNA structures could have emerged from pools of activated RNA oligomers and outlines a path for the transition from non-enzymatic/chemical to enzymatic RNA replication.
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Affiliation(s)
- Falk Wachowius
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH (UK)
| | - Philipp Holliger
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH (UK)
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42
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Walton T, Pazienza L, Szostak JW. Template-Directed Catalysis of a Multistep Reaction Pathway for Nonenzymatic RNA Primer Extension. Biochemistry 2018; 58:755-762. [PMID: 30566332 PMCID: PMC7547881 DOI: 10.1021/acs.biochem.8b01156] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
![]()
Before
the advent of polymerase enzymes, the copying of genetic
material during the origin of life may have involved the nonenzymatic
polymerization of RNA monomers that are more reactive than the biological
nucleoside triphosphates. Activated RNA monomers such as nucleotide
5′-phosphoro-2-aminoimidazolides spontaneously form an imidazolium-bridged
dinucleotide intermediate that undergoes rapid nonenzymatic template-directed
primer extension. However, it is unknown whether the intermediate
can form on the template or only in solution and whether the intermediate
is prone to hydrolysis when bound to the template or reacts preferentially
with the primer. Here we show that an activated monomer can first
bind the template and then form an imidazolium-bridged intermediate
by reacting with a 2-aminoimidazole-activated downstream oligonucleotide.
We have also characterized the partition of the template-bound intermediate
between hydrolysis and primer extension. In the presence of the catalytic
metal ion Mg2+, >90% of the template-bound intermediate
reacts with the adjacent primer to generate the primer extension product
while less than 10% reacts with competing water. Our results indicate
that an RNA template can catalyze a multistep phosphodiester bond
formation pathway while minimizing hydrolysis with a specificity reminiscent
of an enzyme-catalyzed reaction.
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Affiliation(s)
- Travis Walton
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology , Massachusetts General Hospital , Boston , Massachusetts 02114 , United States
| | - Lydia Pazienza
- Department of Chemistry and Chemical Biology , Harvard University , 12 Oxford Street , Cambridge , Massachusetts 02138 , United States
| | - Jack W Szostak
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology , Massachusetts General Hospital , Boston , Massachusetts 02114 , United States.,Department of Chemistry and Chemical Biology , Harvard University , 12 Oxford Street , Cambridge , Massachusetts 02138 , United States
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43
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Benner SA. Prebiotic plausibility and networks of paradox-resolving independent models. Nat Commun 2018; 9:5173. [PMID: 30538230 PMCID: PMC6290000 DOI: 10.1038/s41467-018-07274-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 10/19/2018] [Indexed: 11/09/2022] Open
Abstract
The plausibility of any model in science comes from the extent of its interconnections to other models that are grounded in different premises and reasoning. Focusing research on paradoxes in those models, logic whereby they appear to generate unacceptable conclusions from seemingly indisputable premises, helps find those interconnections.
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Affiliation(s)
- Steven A Benner
- Foundation for Applied Molecular Evolution, Westheimer Institute for Science and Technology, 13709 Progress Blvd., Alachua, FL, 32615, USA.
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44
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Inosine, but none of the 8-oxo-purines, is a plausible component of a primordial version of RNA. Proc Natl Acad Sci U S A 2018; 115:13318-13323. [PMID: 30509978 PMCID: PMC6310819 DOI: 10.1073/pnas.1814367115] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The RNA world hypothesis assumes the abiotic synthesis of nucleotides, as well as their participation in nonenzymatic RNA replication. Whereas prebiotic syntheses of the canonical purine nucleotides remain inefficient, a prebiotically plausible route to the 8-oxo-purines has been reported. Although these noncanonical purine nucleotides are known to engage in non-Watson–Crick pairing with their canonical purine counterparts, their behavior in nonenzymatic RNA copying has not been evaluated. Our study indicates that none of the 8-oxo-purines behaves as a suitable substrate for nonenzymatic RNA copying. However, inosine turns out to exhibit reasonable rates and fidelities in RNA copying reactions. We propose that inosine could have served as a surrogate for guanosine in the early emergence of life. The emergence of primordial RNA-based life would have required the abiotic synthesis of nucleotides, and their participation in nonenzymatic RNA replication. Although considerable progress has been made toward potentially prebiotic syntheses of the pyrimidine nucleotides (C and U) and their 2-thio variants, efficient routes to the canonical purine nucleotides (A and G) remain elusive. Reported syntheses are low yielding and generate a large number of undesired side products. Recently, a potentially prebiotic pathway to 8-oxo-adenosine and 8-oxo-inosine has been demonstrated, raising the question of the suitability of the 8-oxo-purines as substrates for prebiotic RNA replication. Here we show that the 8-oxo-purine nucleotides are poor substrates for nonenzymatic RNA primer extension, both as activated monomers and when present in the template strand; their presence at the end of a primer also strongly reduces the rate and fidelity of primer extension. To provide a proper comparison with 8-oxo-inosine, we also examined primer extension reactions with inosine, and found that inosine exhibits surprisingly rapid and accurate nonenzymatic RNA copying. We propose that inosine, which can be derived from adenosine by deamination, could have acted as a surrogate for G in the earliest stages of the emergence of life.
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45
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Mavila S, Worrell BT, Culver HR, Goldman TM, Wang C, Lim CH, Domaille DW, Pattanayak S, McBride MK, Musgrave CB, Bowman CN. Dynamic and Responsive DNA-like Polymers. J Am Chem Soc 2018; 140:13594-13598. [DOI: 10.1021/jacs.8b09105] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Sudheendran Mavila
- Department of Chemical and Biological Engineering, University of Colorado−Boulder, Boulder, Colorado 80309, United States
| | - Brady T. Worrell
- Department of Chemical and Biological Engineering, University of Colorado−Boulder, Boulder, Colorado 80309, United States
| | - Heidi R. Culver
- Department of Chemical and Biological Engineering, University of Colorado−Boulder, Boulder, Colorado 80309, United States
| | - Trevor M. Goldman
- Department of Chemical and Biological Engineering, University of Colorado−Boulder, Boulder, Colorado 80309, United States
| | - Chen Wang
- Department of Chemical and Biological Engineering, University of Colorado−Boulder, Boulder, Colorado 80309, United States
| | - Chern-Hooi Lim
- Department of Chemical and Biological Engineering, University of Colorado−Boulder, Boulder, Colorado 80309, United States
| | - Dylan W. Domaille
- Department of Chemical and Biological Engineering, University of Colorado−Boulder, Boulder, Colorado 80309, United States
| | - Sankha Pattanayak
- Department of Chemical and Biological Engineering, University of Colorado−Boulder, Boulder, Colorado 80309, United States
| | - Matthew K. McBride
- Department of Chemical and Biological Engineering, University of Colorado−Boulder, Boulder, Colorado 80309, United States
| | - Charles B. Musgrave
- Department of Chemical and Biological Engineering, University of Colorado−Boulder, Boulder, Colorado 80309, United States
| | - Christopher N. Bowman
- Department of Chemical and Biological Engineering, University of Colorado−Boulder, Boulder, Colorado 80309, United States
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46
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Abstract
The general notion of an "RNA world" is that, in the early development of life on the Earth, genetic continuity was assured by the replication of RNA, and RNA molecules were the chief agents of catalytic function. Assuming that all of the components of RNA were available in some prebiotic locale, these components could have assembled into activated nucleotides that condensed to form RNA polymers, setting the stage for the chemical replication of polynucleotides through RNA-templated RNA polymerization. If a sufficient diversity of RNAs could be copied with reasonable rate and fidelity, then Darwinian evolution would begin with RNAs that facilitated their own reproduction enjoying a selective advantage. The concept of a "protocell" refers to a compartment where replication of the primitive genetic material took place and where primitive catalysts gave rise to products that accumulated locally for the benefit of the replicating cellular entity. Replication of both the protocell and its encapsulated genetic material would have enabled natural selection to operate based on the differential fitness of competing cellular entities, ultimately giving rise to modern cellular life.
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Affiliation(s)
- Gerald F Joyce
- The Salk Institute for Biological Studies, La Jolla, California 92037
| | - Jack W Szostak
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114
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47
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Yarus M. Eighty routes to a ribonucleotide world; dispersion and stringency in the decisive selection. RNA (NEW YORK, N.Y.) 2018; 24:1041-1055. [PMID: 29785967 PMCID: PMC6049501 DOI: 10.1261/rna.066761.118] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 05/10/2018] [Indexed: 06/08/2023]
Abstract
We examine the initial emergence of genetics; that is, of an inherited chemical capability. The crucial actors are ribonucleotides, occasionally meeting in a prebiotic landscape. Previous work identified six influential variables during such random ribonucleotide pooling. Geochemical pools can be in periodic danger (e.g., from tides) or constant danger (e.g., from unfavorable weather). Such pools receive Gaussian nucleotide amounts sporadically, at random times, or get varying substrates simultaneously. Pools use cross-templated RNA synthesis (5'-5' product from 5'-3' template) or para-templated (5'-5' product from 5'-5' template) synthesis. Pools can undergo mild or strong selection, and be recently initiated (early) or late in age. Considering >80 combinations of these variables, selection calculations identify a superior route. Most likely, an early, sporadically fed, cross-templating pool in constant danger, receiving ≥1 mM nucleotides while under strong selection for a coenzyme-like product, will host selection of the first encoded biochemical functions. Predominantly templated products emerge from a critical event, the starting bloc selection, which exploits inevitable differences among early pools. Favorable selection has a simple rationale; it is increased by product dispersion (SD/mean), by selection intensity (mild or strong), or by combining these factors as stringency, reciprocal fraction of pools selected (1/sfsel). To summarize: chance utility, acting via a preference for disperse, templated coenzyme-like dinucleotides, uses stringent starting bloc selection to quickly establish majority encoded/genetic expression. Despite its computational origin, starting bloc selection is largely independent of specialized assumptions. This ribodinucleotide route to inheritance may also have facilitated 5'-3' chemical RNA replication.
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Affiliation(s)
- Michael Yarus
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, Colorado 80309-0347, USA
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48
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Marmelstein AM, Morgan JAM, Penkert M, Rogerson DT, Chin JW, Krause E, Fiedler D. Pyrophosphorylation via selective phosphoprotein derivatization. Chem Sci 2018; 9:5929-5936. [PMID: 30079207 PMCID: PMC6050540 DOI: 10.1039/c8sc01233d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 06/08/2018] [Indexed: 01/13/2023] Open
Abstract
An important step in elucidating the function of protein post-translational modifications (PTMs) is gaining access to site-specifically modified, homogeneous samples for biochemical characterization. Protein pyrophosphorylation is a poorly characterized PTM, and here a chemical approach to obtain pyrophosphoproteins is reported. Photo-labile phosphorimidazolide reagents were developed for selective pyrophosphorylation, affinity-capture, and release of pyrophosphoproteins. Kinetic analysis of the reaction revealed rate constants between 9.2 × 10-3 to 0.58 M-1 s-1, as well as a striking proclivity of the phosphorimidazolides to preferentially react with phosphate monoesters over other nucleophilic side chains. Besides enabling the characterization of pyrophosphorylation on protein function, this work highlights the utility of phosphoryl groups as handles for selective protein modification for a variety of applications, such as phosphoprotein bioconjugation and enrichment.
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Affiliation(s)
- Alan M Marmelstein
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie , Robert-Rössle Str. 10 , 13125 Berlin , Germany .
- Department of Chemistry , Princeton University , Washington Road , Princeton , New Jersey 08544 , USA
| | - Jeremy A M Morgan
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie , Robert-Rössle Str. 10 , 13125 Berlin , Germany .
| | - Martin Penkert
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie , Robert-Rössle Str. 10 , 13125 Berlin , Germany .
- Institut für Chemie , Humboldt Universität zu Berlin , Brook-Taylor-Str. 2 , 12489 Berlin , Germany
| | - Daniel T Rogerson
- Medical Research Council Laboratory of Molecular Biology , Francis Crick Avenue , Cambridge , UK
| | - Jason W Chin
- Medical Research Council Laboratory of Molecular Biology , Francis Crick Avenue , Cambridge , UK
| | - Eberhard Krause
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie , Robert-Rössle Str. 10 , 13125 Berlin , Germany .
| | - Dorothea Fiedler
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie , Robert-Rössle Str. 10 , 13125 Berlin , Germany .
- Institut für Chemie , Humboldt Universität zu Berlin , Brook-Taylor-Str. 2 , 12489 Berlin , Germany
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49
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Chaput JC. Visualizing primer extension without enzymes. eLife 2018; 7:e37926. [PMID: 29851382 PMCID: PMC5980227 DOI: 10.7554/elife.37926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 05/25/2018] [Indexed: 12/02/2022] Open
Abstract
X-ray crystallography has been used to observe the synthesis of RNA in the absence of enzymes with atomic resolution.
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Affiliation(s)
- John C Chaput
- Department of Pharmaceutical SciencesUniversity of California, IrvineIrvineUnited States
- Department of ChemistryUniversity of California, IrvineIrvineUnited States
- Department of Molecular Biology & BiochemistryUniversity of California, IrvineIrvineUnited States
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50
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Zhang W, Walton T, Li L, Szostak JW. Crystallographic observation of nonenzymatic RNA primer extension. eLife 2018; 7:36422. [PMID: 29851379 PMCID: PMC5980232 DOI: 10.7554/elife.36422] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 04/26/2018] [Indexed: 12/31/2022] Open
Abstract
The importance of genome replication has inspired detailed crystallographic studies of enzymatic DNA/RNA polymerization. In contrast, the mechanism of nonenzymatic polymerization is less well understood, despite its critical role in the origin of life. Here we report the direct observation of nonenzymatic RNA primer extension through time-resolved crystallography. We soaked crystals of an RNA primer-template-dGMP complex with guanosine-5′-phosphoro-2-aminoimidazolide for increasing times. At early times we see the activated ribonucleotides bound to the template, followed by formation of the imidazolium-bridged dinucleotide intermediate. At later times, we see a new phosphodiester bond forming between the primer and the incoming nucleotide. The intermediate is pre-organized because of the constraints of base-pairing with the template and hydrogen bonding between the imidazole amino group and both flanking phosphates. Our results provide atomic-resolution insight into the mechanism of nonenzymatic primer extension, and set the stage for further structural dissection and optimization of the RNA copying process. Enzymes speed up chemical reactions that are essential to life. Most enzymes are proteins, but some are molecules of ribonucleic acid or RNA. Like DNA, RNA is made from a chain of building blocks called nucleotides. In modern organisms, protein-based enzymes build RNAs by linking nucleotides together, while the building blocks of proteins are linked by an RNA-based enzyme at the heart of a structure called a ribosome. The earliest life on Earth most likely relied only on RNA-based enzymes, but during the emergence of life, scientists believe that RNA molecules must have replicated spontaneously before dedicated RNA-based enzymes had evolved. How RNA could replicate without enzymes has been a puzzle for decades. Recently, scientists discovered a previously unsuspected chemical intermediate that forms during the process, and hypothesized that this molecule’s special structure is what enables the chemical reaction that adds new nucleotides to a growing strand of RNA. To test this hypothesis, Zhang et al. diffused free RNA nucleotides into a crystalized complex containing template strands of RNA attached to short pieces of RNA called primers, which kick-start replication. Then, the crystals were frozen at various intervals and viewed using X-rays. This allowed Zhang et al. to observe the structural changes that occurred over time as the compounds reacted. The approach first revealed that the free nucleotides had paired with complementary nucleotides on the RNA template strands. Then, pairs of free nucleotides reacted with each other to form the intermediate. Finally, the intermediate reacted with the primer, forming a new bond that connects the RNA primer to one of the nucleotides of the intermediate, while the other nucleotide of the intermediate was released as a free nucleotide. This experiment confirms that the specific structure of the intermediate molecule promotes RNA replication without help from enzymes. These findings will benefit chemists and biologists who study how RNA evolves and replicates. Future research building upon this work will deepen scientific understanding of the environmental conditions that were required for life to appear on Earth.
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Affiliation(s)
- Wen Zhang
- Department of Molecular Biology, Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, United States.,Department of Genetics, Harvard Medical School, Boston, United States.,Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, United States
| | - Travis Walton
- Department of Molecular Biology, Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, United States.,Department of Genetics, Harvard Medical School, Boston, United States.,Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, United States
| | - Li Li
- Department of Molecular Biology, Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, United States.,Department of Genetics, Harvard Medical School, Boston, United States.,Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, United States
| | - Jack W Szostak
- Department of Molecular Biology, Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, United States.,Department of Genetics, Harvard Medical School, Boston, United States.,Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, United States
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