1
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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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2
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Welsch F, Kervio E, Tremmel P, Richert C. Prolinyl Nucleotides Drive Enzyme-Free Genetic Copying of RNA. Angew Chem Int Ed Engl 2023; 62:e202307591. [PMID: 37382466 DOI: 10.1002/anie.202307591] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 06/30/2023]
Abstract
Proline is one of the proteinogenic amino acids. It is found in all kingdoms of life. It also has remarkable activity as an organocatalyst and is of structural importance in many folded polypeptides. Here, we show that prolinyl nucleotides with a phosphoramidate linkage are active building blocks in enzyme- and ribozyme-free copying of RNA in the presence of monosubstituted imidazoles as organocatalysts. Both dinucleotides and mononucleotides are incorporated at the terminus of RNA primers in aqueous buffer, as instructed by the template sequence, in up to eight consecutive extension steps. Our results show that condensation products of amino acids and ribonucleotides can act like nucleoside triphosphates in media devoid of enzymes or ribozymes. Prolinyl nucleotides are metastable building blocks, readily activated by catalysts, helping to explain why the combination of α-amino acids and nucleic acids was selected in molecular evolution.
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Affiliation(s)
- Franziska Welsch
- Institute of Organic Chemistry, University of Stuttgart, 70569, Stuttgart, Germany
| | - Eric Kervio
- Institute of Organic Chemistry, University of Stuttgart, 70569, Stuttgart, Germany
| | - Peter Tremmel
- Institute of Organic Chemistry, University of Stuttgart, 70569, Stuttgart, Germany
| | - Clemens Richert
- Institute of Organic Chemistry, University of Stuttgart, 70569, Stuttgart, Germany
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3
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Whitaker D, Powner MW. Prebiotic synthesis and triphosphorylation of 3'-amino-TNA nucleosides. Nat Chem 2022; 14:766-774. [PMID: 35778563 DOI: 10.1038/s41557-022-00982-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 05/23/2022] [Indexed: 12/22/2022]
Abstract
Nucleosides are essential to the emergence of life, and so their synthesis is a key challenge for prebiotic chemistry. Although amino-nucleosides have enhanced reactivity in water compared with ribonucleosides, they are assumed to be prebiotically irrelevant due to perceived difficulties with their selective formation. Here we demonstrate that 3'-amino-TNA nucleosides (TNA, threose nucleic acid) are formed diastereoselectively and regiospecifically from prebiotic feedstocks in four high-yielding steps. Phosphate provides an unexpected resolution, leading to spontaneous purification of the genetically relevant threo-isomer. Furthermore, 3'-amino-TNA nucleosides are shown to be phosphorylated directly in water, under mild conditions with cyclic trimetaphosphate, forming a nucleoside triphosphate (NTP) in a manner not feasible for canonical nucleosides. Our results suggest 3'-amino-TNA nucleosides may have been present on the early Earth, and the ease with which these NTPs form, alongside the inherent selectivity for the Watson-Crick base-pairing threo-monomer, warrants further study of the role they could play during the emergence of life.
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Affiliation(s)
- Daniel Whitaker
- Department of Chemistry, University College London, London, UK
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4
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Bose S, Hodgson DRW. Stereoselective Syntheses of 3'-Hydroxyamino- and 3'-Methoxyamino-2',3'-Dideoxynucleosides. Org Lett 2019; 21:9084-9088. [PMID: 31668079 PMCID: PMC7007280 DOI: 10.1021/acs.orglett.9b03474] [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: 11/30/2022]
Abstract
![]()
Aminonucleosides
are used as key motifs in medicinal and bioconjugate
chemistry; however, existing strategies toward 3′-hypernucleophilic
amine systems do not readily deliver deoxyribo-configured
products. We report diastereoselective syntheses of deoxyribo- and deoxyxylo-configured 3′-hydroxyamino-
and 3′-methoxyamino-nucelosides from 3′-imine intermediates.
The presence or absence of the 5′-hydroxyl-group protection
dictates facial selectivity via inter- or intramolecular delivery
of hydride from BH3 (borane). Protecting group screening
gave one access to previously unknown 3′-methoxyamino-deoxyguanosine
derivatives.
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Affiliation(s)
- Sritama Bose
- Durham University , Department of Chemistry , Lower Mountjoy, Stockton Road , Durham , DH1 3LE , United Kingdom
| | - David R W Hodgson
- Durham University , Department of Chemistry , Lower Mountjoy, Stockton Road , Durham , DH1 3LE , United Kingdom
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5
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Sosson M, Pfeffer D, Richert C. Enzyme-free ligation of dimers and trimers to RNA primers. Nucleic Acids Res 2019; 47:3836-3845. [PMID: 30869145 PMCID: PMC6486630 DOI: 10.1093/nar/gkz160] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 02/25/2019] [Accepted: 02/28/2019] [Indexed: 01/19/2023] Open
Abstract
The template-directed formation of phosphodiester bonds between two nucleic acid components is a pivotal process in biology. To induce such a reaction in the absence of enzymes is a challenge. This challenge has been met for the extension of a primer with mononucleotides, but the ligation of short oligonucleotides (dimers or trimers) has proven difficult. Here we report a method for ligating dimers and trimers of ribonucleotides using in situ activation in aqueous buffer. All 16 different dimers and two trimers were tested. Binding studies by NMR showed low millimolar dissociation constants for complexes between representative dimers and hairpins mimicking primer-template duplexes, confirming that a weak template effect is not the cause of the poor ligating properties of these short oligomers. Rather, cyclization was found to compete with ligation, with up to 90% of dimer being converted to the cyclic form during the course of an assay. This side reaction is strongly sequence dependent and more pronounced for dimers than for trimers. Under optimized reaction conditions, high yields were observed with strongly pairing purines at the 3'-terminus. These results show that short oligomers of ribonucleotides are competent reactants in enzyme-free copying.
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Affiliation(s)
- Marilyne Sosson
- Institute of Organic Chemistry, University of Stuttgart, 70569 Stuttgart, Germany
| | - Daniel Pfeffer
- Institute of Organic Chemistry, University of Stuttgart, 70569 Stuttgart, Germany
| | - Clemens Richert
- Institute of Organic Chemistry, University of Stuttgart, 70569 Stuttgart, Germany
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6
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Conway LP, Mikkola S, O'Donoghue AC, Hodgson DRW. The synthesis, conformation and hydrolytic stability of an N,S-bridging thiophosphoramidate analogue of thymidylyl-3',5'-thymidine. Org Biomol Chem 2018; 14:7361-7. [PMID: 27417455 DOI: 10.1039/c6ob01270a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A 3'-N,5'-S-bridging thiophosphoramidate analogue of thymidylyl-3',5'-thymidine was synthesised under aqueous conditions. (1)H NMR conformational measurements show that the 3'-N-substituted deoxyribose ring is biased towards the 'north', RNA-like conformation. Rate constants for hydrolysis of the analogue were measured at 90 °C in the pH range 1.3-10.9. The pH-log kobs profile displays a pH-independent region between approximately pH 7 and 10 (t1/2 ∼13 days). Under acidic conditions, kobs displays a first order dependence on [H3O(+)].
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Affiliation(s)
- Louis P Conway
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, UK.
| | - Satu Mikkola
- Department of Chemistry, University of Turku, Vatselankatu 2, 20014 Turku, Finland
| | | | - David R W Hodgson
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, UK.
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7
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Sosson M, Richert C. Enzyme-free genetic copying of DNA and RNA sequences. Beilstein J Org Chem 2018; 14:603-617. [PMID: 29623122 PMCID: PMC5870163 DOI: 10.3762/bjoc.14.47] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 02/20/2018] [Indexed: 11/23/2022] Open
Abstract
The copying of short DNA or RNA sequences in the absence of enzymes is a fascinating reaction that has been studied in the context of prebiotic chemistry. It involves the incorporation of nucleotides at the terminus of a primer and is directed by base pairing. The reaction occurs in aqueous medium and leads to phosphodiester formation after attack of a nucleophilic group of the primer. Two aspects of this reaction will be discussed in this review. One is the activation of the phosphate that drives what is otherwise an endergonic reaction. The other is the improved mechanistic understanding of enzyme-free primer extension that has led to a quantitative kinetic model predicting the yield of the reaction over the time course of an assay. For a successful modeling of the reaction, the strength of the template effect, the inhibitory effect of spent monomers, and the rate constants of the chemical steps have to be determined experimentally. While challenges remain for the high fidelity copying of long stretches of DNA or RNA, the available data suggest that enzyme-free primer extension is a more powerful reaction than previously thought.
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Affiliation(s)
- Marilyne Sosson
- Institute of Organic Chemistry, University of Stuttgart, 70569 Stuttgart, Germany
| | - Clemens Richert
- Institute of Organic Chemistry, University of Stuttgart, 70569 Stuttgart, Germany
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8
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Insight into the mechanism of nonenzymatic RNA primer extension from the structure of an RNA-GpppG complex. Proc Natl Acad Sci U S A 2017; 114:7659-7664. [PMID: 28673998 DOI: 10.1073/pnas.1704006114] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The nonenzymatic copying of RNA templates with imidazole-activated nucleotides is a well-studied model for the emergence of RNA self-replication during the origin of life. We have recently discovered that this reaction can proceed through the formation of an imidazolium-bridged dinucleotide intermediate that reacts rapidly with the primer. To gain insight into the relationship between the structure of this intermediate and its reactivity, we cocrystallized an RNA primer-template complex with a close analog of the intermediate, the triphosphate-bridged guanosine dinucleotide GpppG, and solved a high-resolution X-ray structure of the complex. The structure shows that GpppG binds the RNA template through two Watson-Crick base pairs, with the primer 3'-hydroxyl oriented to attack the 5'-phosphate of the adjacent G residue. Thus, the GpppG structure suggests that the bound imidazolium-bridged dinucleotide intermediate would be preorganized to react with the primer by in-line SN2 substitution. The structures of bound GppG and GppppG suggest that the length and flexibility of the 5'-5' linkage are important for optimal preorganization of the complex, whereas the position of the 5'-phosphate of bound pGpG explains the slow rate of oligonucleotide ligation reactions. Our studies provide a structural interpretation for the observed reactivity of the imidazolium-bridged dinucleotide intermediate in nonenzymatic RNA primer extension.
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9
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Kim YH, Oh JH, Lytton-Jean AKR, Lee JS. Pyridine: a Denaturant or Stabilizer of Spherical Nucleic Acids? Anal Chem 2017; 89:4581-4586. [DOI: 10.1021/acs.analchem.7b00005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Yoon Hyuck Kim
- Department
of Materials Science and Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Ju-Hwan Oh
- Department
of Materials Science and Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
| | - Abigail K. R. Lytton-Jean
- David
H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Jae-Seung Lee
- Department
of Materials Science and Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea
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10
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Tam CP, Fahrenbach AC, Björkbom A, Prywes N, Izgu EC, Szostak JW. Downstream Oligonucleotides Strongly Enhance the Affinity of GMP to RNA Primer-Template Complexes. J Am Chem Soc 2017; 139:571-574. [PMID: 28055190 PMCID: PMC7547879 DOI: 10.1021/jacs.6b09760] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Indexed: 11/29/2022]
Abstract
Origins of life hypotheses often invoke a transitional phase of nonenzymatic template-directed RNA replication prior to the emergence of ribozyme-catalyzed copying of genetic information. Here, using NMR and ITC, we interrogate the binding affinity of guanosine 5'-monophosphate (GMP) for primer-template complexes when either another GMP, or a helper oligonucleotide, can bind downstream. Binding of GMP to a primer-template complex cannot be significantly enhanced by the possibility of downstream monomer binding, because the affinity of the downstream monomer is weaker than that of the first monomer. Strikingly, GMP binding affinity can be enhanced by ca. 2 orders of magnitude when a helper oligonucleotide is stably bound downstream of the monomer binding site. We compare these thermodynamic parameters to those previously reported for T7 RNA polymerase-mediated replication to help address questions of binding affinity in related nonenzymatic processes.
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Affiliation(s)
- Chun Pong Tam
- 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 Chemistry and Chemical Biology, Harvard
University, 12 Oxford
Street, Cambridge, Massachusetts 02138, United States
| | - Albert C. Fahrenbach
- 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
- Earth
Life Science Institute, Tokyo Institute of Technology, 2-12-1-IE-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan
| | - Anders Björkbom
- 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 Biosciences, Åbo Akademi University, Åbo FI-20520, Finland
| | - Noam Prywes
- 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 Chemistry and Chemical Biology, Harvard
University, 12 Oxford
Street, Cambridge, Massachusetts 02138, United States
| | - Enver Cagri Izgu
- 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
- Department
of Chemistry and Chemical Biology, Harvard
University, 12 Oxford
Street, Cambridge, Massachusetts 02138, United States
- Earth
Life Science Institute, Tokyo Institute of Technology, 2-12-1-IE-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan
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11
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Kervio E, Sosson M, Richert C. The effect of leaving groups on binding and reactivity in enzyme-free copying of DNA and RNA. Nucleic Acids Res 2016; 44:5504-14. [PMID: 27235418 PMCID: PMC4937335 DOI: 10.1093/nar/gkw476] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 05/06/2016] [Accepted: 05/09/2016] [Indexed: 01/29/2023] Open
Abstract
The template-directed incorporation of nucleotides at the terminus of a growing primer is the basis of the transmission of genetic information. Nature uses polymerases-catalyzed reactions, but enzyme-free versions exist that employ nucleotides with organic leaving groups. The leaving group affects yields, but it was not clear whether inefficient extensions are due to poor binding, low reactivity toward the primer, or rapid hydrolysis. We have measured the binding of a total of 15 different activated nucleotides to DNA or RNA sequences. Further, we determined rate constants for the chemical step of primer extension involving methylimidazolides or oxyazabenzotriazolides of deoxynucleotides or ribonucleotides. Binding constants range from 10 to >500 mM and rate constants from 0.1 to 370 M(-1) h(-1) For aminoterminal primers, a fast covalent step and slow hydrolysis are the main factors leading to high yields. For monomers with weakly pairing bases, the leaving group can improve binding significantly. A detailed mechanistic picture emerges that explains why some enzyme-free primer extensions occur in high yield, while others remain recalcitrant to copying without enzymatic catalysis. A combination of tight binding and rapid extension, coupled with slow hydrolysis induces efficient enzyme-free copying.
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Affiliation(s)
- Eric Kervio
- Institute of Organic Chemistry, University of Stuttgart, 70569 Stuttgart, Germany
| | - Marilyne Sosson
- Institute of Organic Chemistry, University of Stuttgart, 70569 Stuttgart, Germany
| | - Clemens Richert
- Institute of Organic Chemistry, University of Stuttgart, 70569 Stuttgart, Germany
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12
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Plöger TA, von Kiedrowski G. A self-replicating peptide nucleic acid. Org Biomol Chem 2015; 12:6908-14. [PMID: 25065957 DOI: 10.1039/c4ob01168f] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
While the non-enzymatic ligation and template-directed synthesis of peptide nucleic acids (PNA) have been reported since 1995, a case of self-replication of PNA has not been achieved yet. Here, we present evidence for autocatalytic feedback in a template directed synthesis of a self-complementary hexa-PNA from two trimeric building blocks. The course of the reaction was monitored in the presence of increasing initial concentrations of the product by RP-HPLC. Kinetic modeling with the SimFit program revealed parabolic growth characteristics. The observed template effect, as well as the rate of ligation, was significantly influenced by nucleophilic catalysts, pH value, and uncharged co-solvents. Systematic optimization of the reaction conditions allowed us to increase the autocatalytic efficiency of the system by two orders of magnitude. Our findings contribute to the hypothesis that PNA may have served as a primordial genetic molecule and was involved in a potential precursor of a RNA world.
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Affiliation(s)
- Tobias A Plöger
- Ruhr-Universität Bochum, Chair of Organic Chemistry I - Bioorganic Chemistry, 44780 Bochum, Germany.
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13
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Barbeyron R, Martin AR, Jean-Jacques Vasseur JJV, Michael Smietana MS. DNA-templated borononucleic acid self assembly: a study of minimal complexity. RSC Adv 2015. [DOI: 10.1039/c5ra20767c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The minimal degree of sequence complexity needed for DNA-templated self-assembly of bifunctional oligonucleotides able to form internucleosidic boronate linkages has been studied.
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Affiliation(s)
- Renaud Barbeyron
- Institut des Biomolécules Max Mousseron
- UMR 5247 CNRS
- Université de Montpellier
- 34095 Montpellier
- France
| | - Anthony R. Martin
- Institut des Biomolécules Max Mousseron
- UMR 5247 CNRS
- Université de Montpellier
- 34095 Montpellier
- France
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14
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Barbeyron R, Vasseur JJ, Smietana M. pH-controlled DNA- and RNA-templated assembly of short oligomers. Chem Sci 2015; 6:542-547. [PMID: 28936308 PMCID: PMC5588539 DOI: 10.1039/c4sc03028a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 10/24/2014] [Indexed: 01/04/2023] Open
Abstract
In the area of artificial genetics the development of non-enzymatic self-organization of synthetic building blocks is critical for both providing biopolymers with extended functions and understanding prebiotic processes. While reversibility is believed to have played a major role in early functional genetic materials, we previously reported an efficient DNA-templated ligation of suitably designed 5'-end boronic acid and 3'-end ribonucleosidic half-sequences. Here, we report the enzyme-free and activation-free DNA- and RNA-templated assembly of bifunctional hexamers. The reversible assembly was found to be regio- and sequence specific and the stabilities of the resulting duplexes were compared to their nicked counterparts. To go further with our understanding of this unprecedented process we also examined an auto-templated duplex self-assembly representing a key step toward the evolution of sequence-defined synthetic polymers.
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Affiliation(s)
- Renaud Barbeyron
- Institut des Biomolécules Max Mousseron (IBMM) UMR 5247 CNRS-Université Montpellier 1 et Université Montpellier 2 , Place Bataillon , 34095 Montpellier , France . ;
| | - Jean-Jacques Vasseur
- Institut des Biomolécules Max Mousseron (IBMM) UMR 5247 CNRS-Université Montpellier 1 et Université Montpellier 2 , Place Bataillon , 34095 Montpellier , France . ;
| | - Michael Smietana
- Institut des Biomolécules Max Mousseron (IBMM) UMR 5247 CNRS-Université Montpellier 1 et Université Montpellier 2 , Place Bataillon , 34095 Montpellier , France . ;
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15
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Kervio E, Claasen B, Steiner UE, Richert C. The strength of the template effect attracting nucleotides to naked DNA. Nucleic Acids Res 2014; 42:7409-20. [PMID: 24875480 PMCID: PMC4066754 DOI: 10.1093/nar/gku314] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The transmission of genetic information relies on Watson–Crick base pairing between nucleoside phosphates and template bases in template–primer complexes. Enzyme-free primer extension is the purest form of the transmission process, without any chaperon-like effect of polymerases. This simple form of copying of sequences is intimately linked to the origin of life and provides new opportunities for reading genetic information. Here, we report the dissociation constants for complexes between (deoxy)nucleotides and template–primer complexes, as determined by nuclear magnetic resonance and the inhibitory effect of unactivated nucleotides on enzyme-free primer extension. Depending on the sequence context, Kd′s range from 280 mM for thymidine monophosphate binding to a terminal adenine of a hairpin to 2 mM for a deoxyguanosine monophosphate binding in the interior of a sequence with a neighboring strand. Combined with rate constants for the chemical step of extension and hydrolytic inactivation, our quantitative theory explains why some enzyme-free copying reactions are incomplete while others are not. For example, for GMP binding to ribonucleic acid, inhibition is a significant factor in low-yielding reactions, whereas for amino-terminal DNA hydrolysis of monomers is critical. Our results thus provide a quantitative basis for enzyme-free copying.
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Affiliation(s)
- Eric Kervio
- Institute for Organic Chemistry, University of Stuttgart, 70569 Stuttgart, Germany
| | - Birgit Claasen
- Institute for Organic Chemistry, University of Stuttgart, 70569 Stuttgart, Germany
| | - Ulrich E Steiner
- Fachbereich Chemie, Universität Konstanz, 78457 Konstanz, Germany
| | - Clemens Richert
- Institute for Organic Chemistry, University of Stuttgart, 70569 Stuttgart, Germany
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16
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Abstract
The complexity of even the simplest known life forms makes efforts to synthesize living cells from inanimate components seem like a daunting task. However, recent progress toward the creation of synthetic cells, ranging from simple protocells to artificial cells approaching the complexity of bacteria, suggests that the synthesis of life is now a realistic goal. Protocell research, fueled by advances in the biophysics of primitive membranes and the chemistry of nucleic acid replication, is providing new insights into the origin of cellular life. Parallel efforts to construct more complex artificial cells, incorporating translational machinery and protein enzymes, are providing information about the requirements for protein-based life. We discuss recent advances and remaining challenges in the synthesis of artificial cells, the possibility of creating new forms of life distinct from existing biology, and the promise of this research for gaining a deeper understanding of the nature of living systems.
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Affiliation(s)
- J Craig Blain
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114; ,
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17
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Patzke V, McCaskill JS, von Kiedrowski G. DNA mit 3′-5′-Disulfid-Verknüpfung - schnelle chemische Ligation durch isosteren Ersatz. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201310644] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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18
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Patzke V, McCaskill JS, von Kiedrowski G. DNA with 3'-5'-disulfide links--rapid chemical ligation through isosteric replacement. Angew Chem Int Ed Engl 2014; 53:4222-6. [PMID: 24623660 DOI: 10.1002/anie.201310644] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2013] [Revised: 01/28/2014] [Indexed: 11/11/2022]
Abstract
Efforts to chemically ligate oligonucleotides, without resorting to biochemical enzymes, have led to a multitude of synthetic analogues, and have extended oligomer ligation to reactions of novel oligonucleotides, peptides, and hybrids such as PNA.1 Key requirements for potential diagnostic tools not based on PCR include a fast templated chemical DNA ligation method that exhibits high pairing selectivity, and a sensitive detection method. Here we report on a solid-phase synthesis of oligonucleotides containing 5'- or 3'-mercapto-dideoxynucleotides and their chemical ligations, yielding 3'-5'-disulfide bonds as a replacement for 3'-5'-phosphodiester units. Employing a system designed for fluorescence monitoring, we demonstrate one of the fastest ligation reactions with half-lives on the order of seconds. The nontemplated ligation reaction is efficiently suppressed by the choice of DNA modification and the 3'-5' orientation of the activation site. The influence of temperature on the templated reaction is shown.
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Affiliation(s)
- Volker Patzke
- Lehrstuhl für Bioorganische Chemie, Ruhr-Universität Bochum, 44780 Bochum (Germany).
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19
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Blain JC, Ricardo A, Szostak JW. Synthesis and nonenzymatic template-directed polymerization of 2'-amino-2'-deoxythreose nucleotides. J Am Chem Soc 2014; 136:2033-9. [PMID: 24409991 PMCID: PMC4105081 DOI: 10.1021/ja411950n] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
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Threose nucleic acid (TNA) is a potential
alternative genetic material
that may have played a role in the early evolution of life. We have
developed a novel synthesis of 2′-amino modified TNA nucleosides
(2′-NH2-TNA) based on a cycloaddition reaction between
a glycal and an azodicarboxylate, followed by direct nucleosidation
of the cycloadduct. Using this route, we synthesized the thymine and
guanine 2′-NH2-TNA nucleosides in seven steps with
24% and 12% overall yield, respectively. We then phosphorylated the
guanine nucleoside on the 3′-hydroxyl, activated the phosphate
as the 2-methylimidazolide, and tested the ability of the activated
nucleotide to copy C4 RNA, DNA, and TNA templates by nonenzymatic
primer extension. We measured pseudo-first-order rate constants for
the first nucleotide addition step of 1.5, 0.97, and 0.57 h–1 on RNA, DNA, and TNA templates, respectively, at pH 7.5 and 4 °C
with 150 mM NaCl, 100 mM N-(hydroxylethyl)imidazole
catalyst, and 5 mM activated nucleotide. The activated nucleotide
hydrolyzed with a rate constant of 0.39 h–1, causing
the polymerization reaction to stall before complete template copying
could be achieved. These extension rates are more than 1 order of
magnitude slower than those for amino-sugar ribonucleotides under
the same conditions, and copying of the TNA template, which best represented
a true self-copying reaction, was the slowest of all. The poor kinetics
of 2′-NH2-TNA template copying could give insight
into why TNA was ultimately not used as a genetic material by biological
systems.
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Affiliation(s)
- J Craig Blain
- Howard Hughes Medical Institute and 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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20
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Zhang S, Blain JC, Zielinska D, Gryaznov SM, Szostak JW. Fast and accurate nonenzymatic copying of an RNA-like synthetic genetic polymer. Proc Natl Acad Sci U S A 2013; 110:17732-7. [PMID: 24101473 PMCID: PMC3816440 DOI: 10.1073/pnas.1312329110] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recent advances suggest that it may be possible to construct simple artificial cells from two subsystems: a self-replicating cell membrane and a self-replicating genetic polymer. Although multiple pathways for the growth and division of model protocell membranes have been characterized, no self-replicating genetic material is yet available. Nonenzymatic template-directed synthesis of RNA with activated ribonucleotide monomers has led to the copying of short RNA templates; however, these reactions are generally slow (taking days to weeks) and highly error prone. N3'-P5'-linked phosphoramidate DNA (3'-NP-DNA) is similar to RNA in its overall duplex structure, and is attractive as an alternative to RNA because the high reactivity of its corresponding monomers allows rapid and efficient copying of all four nucleobases on homopolymeric RNA and DNA templates. Here we show that both homopolymeric and mixed-sequence 3'-NP-DNA templates can be copied into complementary 3'-NP-DNA sequences. G:T and A:C wobble pairing leads to a high error rate, but the modified nucleoside 2-thiothymidine suppresses wobble pairing. We show that the 2-thiothymidine modification increases both polymerization rate and fidelity in the copying of a 3'-NP-DNA template into a complementary strand of 3'-NP-DNA. Our results suggest that 3'-NP-DNA has the potential to serve as the genetic material of artificial biological systems.
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Affiliation(s)
- Shenglong Zhang
- Howard Hughes Medical Institute and
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA 02114; and
| | - J. Craig Blain
- Howard Hughes Medical Institute and
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA 02114; and
| | - Daria Zielinska
- Department of Nucleic Acid Chemistry, Geron Corporation, Menlo Park, CA 94025
| | - Sergei M. Gryaznov
- Department of Nucleic Acid Chemistry, Geron Corporation, Menlo Park, CA 94025
| | - Jack W. Szostak
- Howard Hughes Medical Institute and
- Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA 02114; and
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21
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Sliding over the blocks in enzyme-free RNA copying--one-pot primer extension in ice. PLoS One 2013; 8:e75617. [PMID: 24058695 PMCID: PMC3776762 DOI: 10.1371/journal.pone.0075617] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 08/15/2013] [Indexed: 12/02/2022] Open
Abstract
Template-directed polymerization of RNA in the absence of enzymes is the basis for an information transfer in the ‘RNA-world’ hypothesis and in novel nucleic acid based technology. Previous investigations established that only cytidine rich strands are efficient templates in bulk aqueous solutions while a few specific sequences completely block the extension of hybridized primers. We show that a eutectic water/ice system can support Pb2+/Mg2+-ion catalyzed extension of a primer across such sequences, i.e. AA, AU and AG, in a one-pot synthesis. Using mixtures of imidazole activated nucleotide 5′-monophosphates, the two first “blocking” residues could be passed during template-directed polymerization, i.e., formation of triply extended products containing a high fraction of faithful copies was demonstrated. Across the AG sequence, a mismatch sequence was formed in similar amounts to the correct product due to U·G wobble pairing. Thus, the template-directed extension occurs both across pyrimidine and purine rich sequences and insertions of pyrimidines did not inhibit the subsequent insertions. Products were mainly formed with 2′-5′-phosphodiester linkages, however, the abundance of 3′–5′-linkages was higher than previously reported for pyrimidine insertions. When enzyme-free, template-directed RNA polymerization is performed in a eutectic water ice environment, various intrinsic reaction limitations observed in bulk solution can then be overcome.
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22
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Kaiser A, Richert C. Nucleotide-based copying of nucleic acid sequences without enzymes. J Org Chem 2013; 78:793-9. [PMID: 23327991 DOI: 10.1021/jo3025779] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Chemical primer extension is the enzyme-free incorporation of nucleotides at the end of an oligonucleotide, directed by a template. The reaction mimics the copying of sequences during replication but relies on recognition and reactivity of nucleic acids alone. Copying is low-yielding, particularly for long RNA. Hydrolysis of active esters and inhibition through hydrolysis products have been identified as factors that prevent high yields, and approaches to overcoming them have culminated in successful template-directed solid-phase syntheses for RNA and phosphoramidate DNA.
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Affiliation(s)
- Andreas Kaiser
- Institute for Organic Chemistry, University of Stuttgart, 70569 Stuttgart, Germany
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23
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Zhang S, Zhang N, Blain JC, Szostak JW. Synthesis of N3'-P5'-linked phosphoramidate DNA by nonenzymatic template-directed primer extension. J Am Chem Soc 2013; 135:924-32. [PMID: 23252395 PMCID: PMC3548433 DOI: 10.1021/ja311164j] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
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A fast and accurate pathway for nonenzymatic RNA replication
would
simplify models for the emergence of the RNA world from the prebiotic
chemistry of the early earth. However, numerous difficulties stand
in the way of an experimental demonstration of effective nonenzymatic
RNA replication. To gain insight into the necessary properties of
potentially self-replicating informational polymers, we have studied
several model systems based on amino–sugar nucleotides. Here
we describe the synthesis of N3′–P5′-linked phosphoramidate
DNA (3′-NP-DNA) by the template-directed polymerization of
activated 3′-amino-2′,3′-dideoxyribonucleotides.
3′-NP-DNA is an interesting model because of its very RNA-like
A-type duplex conformation and because activated 3′-amino-2′,3′-dideoxyribonucleotides
are much more reactive than the corresponding activated ribonucleotides.
In contrast to our previous studies with 2′-amino-2′,3′-dideoxyribonucleotides
(for which G and C but not A and T exhibit efficient template copying),
we have found that all four canonical 3′-amino-2′,3′-dideoxyribonucleotides
(G, C, A, and T) polymerize efficiently on RNA templates. RNA templates
are generally superior to DNA templates, and oligo-ribo-T templates
are superior to oligo-ribo-U templates, which are the least efficient
of the RNA homopolymer templates. We have also found that activation
of 3′-aminonucleotides with 2-methylimidazole results in a
ca. 10-fold higher polymerization rate relative to activation with
imidazole, an observation that parallels earlier findings with ribonucleotides.
We discuss the implications of our experiments for the possibility
of self-replication in the 3′-NP-DNA and RNA systems.
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Affiliation(s)
- Shenglong Zhang
- Howard Hughes Medical Institute and Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, USA
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24
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Kaiser A, Spies S, Lommel T, Richert C. Template-Directed Synthesis in 3′- and 5′-Direction with Reversible Termination. Angew Chem Int Ed Engl 2012; 51:8299-303. [DOI: 10.1002/anie.201203859] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Indexed: 01/21/2023]
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25
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Kaiser A, Spies S, Lommel T, Richert C. Template-Directed Synthesis in 3′- and 5′-Direction with Reversible Termination. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201203859] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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26
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Evolution of functional nucleic acids in the presence of nonheritable backbone heterogeneity. Proc Natl Acad Sci U S A 2011; 108:13492-7. [PMID: 21825162 DOI: 10.1073/pnas.1107113108] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Multiple lines of evidence support the hypothesis that the early evolution of life was dominated by RNA, which can both transfer information from generation to generation through replication directed by base-pairing, and carry out biochemical activities by folding into functional structures. To understand how life emerged from prebiotic chemistry we must therefore explain the steps that led to the emergence of the RNA world, and in particular, the synthesis of RNA. The generation of pools of highly pure ribonucleotides on the early Earth seems unlikely, but the presence of alternative nucleotides would support the assembly of nucleic acid polymers containing nonheritable backbone heterogeneity. We suggest that homogeneous monomers might not have been necessary if populations of heterogeneous nucleic acid molecules could evolve reproducible function. For such evolution to be possible, function would have to be maintained despite the repeated scrambling of backbone chemistry from generation to generation. We have tested this possibility in a simplified model system, by using a T7 RNA polymerase variant capable of transcribing nucleic acids that contain an approximately 11 mixture of deoxy- and ribonucleotides. We readily isolated nucleotide-binding aptamers by utilizing an in vitro selection process that shuffles the order of deoxy- and ribonucleotides in each round. We describe two such RNA/DNA mosaic nucleic acid aptamers that specifically bind ATP and GTP, respectively. We conclude that nonheritable variations in nucleic acid backbone structure may not have posed an insurmountable barrier to the emergence of functionality in early nucleic acids.
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27
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Martin AR, Barvik I, Luvino D, Smietana M, Vasseur JJ. Dynamic and Programmable DNA-Templated Boronic Ester Formation. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201007170] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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28
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Martin AR, Barvik I, Luvino D, Smietana M, Vasseur JJ. Dynamic and programmable DNA-templated boronic ester formation. Angew Chem Int Ed Engl 2011; 50:4193-6. [PMID: 21445950 DOI: 10.1002/anie.201007170] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 02/14/2011] [Indexed: 11/08/2022]
Affiliation(s)
- Anthony R Martin
- Institut des Biomolécules Max Mousseron (IBMM), UMR 5247 CNRS-Universités Montpellier 1 et 2, Place Bataillon, 34095 Montpellier, France
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29
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Spencer SM, Lin L, Chiang CF, Peng Z, Hesketh P, Salon J, Huang Z. Direct and rapid detection of RNAs on a novel RNA microchip. Chembiochem 2010; 11:1378-82. [PMID: 20549757 DOI: 10.1002/cbic.201000170] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Sarah M Spencer
- Department of Chemistry, Georgia State University, Atlanta, GA 30303 USA
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30
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Röthlingshöfer M, Richert C. Chemical primer extension at submillimolar concentration of deoxynucleotides. J Org Chem 2010; 75:3945-52. [PMID: 20364862 DOI: 10.1021/jo1002467] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Template-directed primer extension usually requires a polymerase, nucleoside triphosphates, and magnesium ions as cofactors. Enzyme-free, chemical primer extensions are known for preactivated nucleotides at millimolar concentrations. Based on a screen of carbodiimides, heterocyclic catalysts, and reactions conditions, we now show that near-quantitative primer conversion can be achieved at submillimolar concentration of any of the four deoxynucleotides (dAMP, dCMP, dGMP and dTMP). The new protocol relies on in situ activation with EDC and 1-methylimidazole and a magnesium-free buffer that was tested successfully for different sequence motifs. The method greatly simplifies chemical primer extension assays, further reduces the cost of such assays, and demonstrates the potential of the in situ activation approach.
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Affiliation(s)
- Manuel Röthlingshöfer
- Institute for Organic Chemistry, University of Karlsruhe/K.I.T., 76131 Karlsruhe, Germany
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31
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Bell NM, Wong R, Micklefield J. A non-enzymatic, DNA template-directed morpholino primer extension approach. Chemistry 2010; 16:2026-30. [PMID: 20087911 DOI: 10.1002/chem.200902237] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Neil M Bell
- School of Chemistry, The University of Manchester, Manchester Interdisciplinary Biocentre, 131 Princess Street, Manchester M1 7ND, UK
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32
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Abstract
Understanding the origin of cellular life on Earth requires the discovery of plausible pathways for the transition from complex prebiotic chemistry to simple biology, defined as the emergence of chemical assemblies capable of Darwinian evolution. We have proposed that a simple primitive cell, or protocell, would consist of two key components: a protocell membrane that defines a spatially localized compartment, and an informational polymer that allows for the replication and inheritance of functional information. Recent studies of vesicles composed of fatty-acid membranes have shed considerable light on pathways for protocell growth and division, as well as means by which protocells could take up nutrients from their environment. Additional work with genetic polymers has provided insight into the potential for chemical genome replication and compatibility with membrane encapsulation. The integration of a dynamic fatty-acid compartment with robust, generalized genetic polymer replication would yield a laboratory model of a protocell with the potential for classical Darwinian biological evolution, and may help to evaluate potential pathways for the emergence of life on the early Earth. Here we discuss efforts to devise such an integrated protocell model.
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Affiliation(s)
- Jason P Schrum
- Howard Hughes Medical Institute, Department of Molecular Biology and the Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
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33
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Rajamani S, Ichida JK, Antal T, Treco DA, Leu K, Nowak MA, Szostak JW, Chen IA. Effect of stalling after mismatches on the error catastrophe in nonenzymatic nucleic acid replication. J Am Chem Soc 2010; 132:5880-5. [PMID: 20359213 PMCID: PMC2857888 DOI: 10.1021/ja100780p] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Indexed: 11/28/2022]
Abstract
The frequency of errors during genome replication limits the amount of functionally important information that can be passed on from generation to generation. During the origin of life, mutation rates are thought to have been quite high, raising a classic chicken-and-egg paradox: could nonenzymatic replication propagate sequences accurately enough to allow for the emergence of heritable function? Here we show that the theoretical limit on genomic information content may increase substantially as a consequence of dramatically slowed polymerization after mismatches. As a result of postmismatch stalling, accurate copies of a template tend to be completed more rapidly than mutant copies and the accurate copies can therefore begin a second round of replication more quickly. To quantify this effect, we characterized an experimental model of nonenzymatic, template-directed nucleic acid polymerization. We found that most mismatches decrease the rate of primer extension by more than 2 orders of magnitude relative to a matched (Watson-Crick) control. A chemical replication system with this property would be able to propagate sequences long enough to have function. Our study suggests that the emergence of functional sequences during the origin of life would be possible even in the face of the high intrinsic error rates of chemical replication.
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34
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Kim EK, Switzer C. Nonenzymatic oligomerization of activated nucleotides on hairpin templates. ACTA ACUST UNITED AC 2010; Chapter 3:Unit3.18. [PMID: 20013784 DOI: 10.1002/0471142700.nc0318s39] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This unit describes a protocol for nonenzymatic oligomerization of activated ribonucleotides on DNA hairpins appended by templates containing threofuranosyl nucleic acid (TNA). TNA-cytidylate templates effectively promote oligomerization of 2-MeImpG, and give 3',5'-linked oligomerization products predominantly, with good base-pairing fidelity. Although the rates of oligomerization depend on TNA content, after 3 days of incubation, oligomerization products are apparent, and full-length products are present after 10 days. Characterization of product phosphodiester bond regiochemistry is accomplished by digestion with RNase T1. Additionally, exposure of oligomerization products to calf intestinal alkaline phosphatase enables detection of any endcapping due to pyrophosphate formation. Base-pairing fidelity is assessed by challenging the template to oligomerize 2-MeImpA. The protocols described for nonenzymatic, template-directed synthesis in this unit are applicable to oligomerization of activated monomers on templates of different compositions, with respect to both base identity and polymer backbone.
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Affiliation(s)
- Eun-Kyong Kim
- Department of Chemistry, University of California, Riverside, California, USA
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35
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Sheng J, Hassan AEA, Huang Z. Synthesis of the first tellurium-derivatized oligonucleotides for structural and functional studies. Chemistry 2010; 15:10210-6. [PMID: 19691067 DOI: 10.1002/chem.200900774] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We report here the first synthesis of Te-nucleoside phosphoramidites and Te-modified oligonucleotides. We protected the 2'-tellurium functionality by alkylation and found that the Te functionality is compatible with solid-phase synthesis and that the Te oligonucleotides are stable during deprotection and purification. In addition, the redox properties of the Te functionalities have been explored. We found that the telluride and telluoxide DNAs are interchangeable by redox reactions. At elevated temperature, the Te-DNA can also be site-specifically fragmented oxidatively or reductively when 2'-TePh functionality is present, whereas elimination of the nucleobase is observed in the presence of 2'-TeMe. Moreover, the stability of the DNA duplexes derivatized with the Te functionalities has been investigated. Our Te derivatization of nucleic acids provides a novel approach for investigating DNA damage as well as for structure and function studies of nucleic acids and their protein complexes.
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Affiliation(s)
- Jia Sheng
- Department of Chemistry, Georgia State University, 50 Decatur Street, Atlanta, GA 30303-3083, USA
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36
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Gaynor JW, Piperakis MM, Fisher J, Cosstick R. Reverse-direction (5'-->3') synthesis of oligonucleotides containing a 3'-S-phosphorothiolate linkage and 3'-terminal 3'-thionucleosides. Org Biomol Chem 2010; 8:1463-70. [PMID: 20204222 DOI: 10.1039/b923545k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of oligodeoxynucleotides containing 3'-thionucleosides has been explored using a reverse-direction (5'-->3') approach, based on nucleoside monomers which contain a trityl- or dimethoxytrityl-protected 3'-thiol and a 5'-O-phosphoramidite. These monomers are relatively simple to prepare as trityl-based protecting groups were introduced selectively at a 3'-thiol in preference to a 5'-hydroxyl group. As an alternative approach, trityl group migration could be induced from the 5'-oxygen to the 3'-thiol function. 5'-->3' Synthesis of oligonucleotides gave relatively poor yields for the internal incorporation of 3'-thionucleosides [to give a 3'-S-phosphorothiolate (3'-SP) linkage] and multiple 3'-SP modifications could not be introduced by this method. However, the reverse direction approach provided an efficient route to oligonucleotides terminating with a 3'-thionucleoside. The direct synthesis of these thio-terminating oligomers has not previously been reported and the methods described are applicable to 2'-deoxy-3'-thionucleosides derived from thymine, cytosine and adenine.
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Affiliation(s)
- James W Gaynor
- Department of Chemistry, University of Liverpool, Crown Street, Liverpool, UK L69 7ZD
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37
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Schrum JP, Ricardo A, Krishnamurthy M, Blain JC, Szostak JW. Efficient and rapid template-directed nucleic acid copying using 2'-amino-2',3'-dideoxyribonucleoside-5'-phosphorimidazolide monomers. J Am Chem Soc 2009; 131:14560-70. [PMID: 19757789 PMCID: PMC2759813 DOI: 10.1021/ja906557v] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The development of a sequence-general nucleic acid copying system is an essential step in the assembly of a synthetic protocell, an autonomously replicating spatially localized chemical system capable of spontaneous Darwinian evolution. Previously described nonenzymatic template-copying experiments have validated the concept of nonenzymatic replication, but have not yet achieved robust, sequence-general polynucleotide replication. The 5'-phosphorimidazolides of the 2'-amino-2',3'-dideoxyribonucleotides are attractive as potential monomers for such a system because they polymerize by forming 2'-->5' linkages, which are favored in nonenzymatic polymerization reactions using similarly activated ribonucleotides on RNA templates. Furthermore, the 5'-activated 2'-amino nucleotides do not cyclize. We recently described the rapid and efficient nonenzymatic copying of a DNA homopolymer template (dC(15)) encapsulated within fatty acid vesicles using 2'-amino-2',3'-dideoxyguanosine-5'-phosphorimidazolide as the activated monomer. However, to realize a true Darwinian system, the template-copying chemistry must be able to copy most sequences and their complements to allow for the transmission of information from generation to generation. Here, we describe the copying of a series of nucleic acid templates using 2'-amino-2',3'-dideoxynucleotide-5'-phosphorimidazolides. Polymerization reactions proceed rapidly to completion on short homopolymer RNA and LNA templates, which favor an A-type duplex geometry. We show that more efficiently copied sequences are generated by replacing the adenine nucleobase with diaminopurine, and uracil with C5-(1-propynyl)uracil. Finally, we explore the copying of longer, mixed-sequence RNA templates to assess the sequence-general copying ability of 2'-amino-2',3'-dideoxynucleoside-5'-phosphorimidazolides. Our results are a significant step forward in the realization of a self-replicating genetic polymer compatible with protocell template copying and suggest that N2'-->P5'-phosphoramidate DNA may have the potential to function as a self-replicating system.
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Affiliation(s)
- Jason P Schrum
- Howard Hughes Medical Institute and Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Harvard Medical School, Boston, Massachusetts 02114, USA
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38
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Grossmann TN, Seitz O. Nucleic acid templated reactions: consequences of probe reactivity and readout strategy for amplified signaling and sequence selectivity. Chemistry 2009; 15:6723-30. [PMID: 19496097 DOI: 10.1002/chem.200900025] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
DNA- and RNA-templated chemical reactions can serve as a diagnostic means for the detection of nucleic acids. Reaction schemes that allow amplified detection are of high interest for polymerase chain reaction (PCR)-free DNA and RNA diagnosis. These reactions typically draw upon the catalytic activity of the template, which is able to trigger the conversion of many signaling molecules per template molecule. However, the design of reactive probes that allow both sensitive and selective nucleic acid detection is a challenge and requires insight into three major parameters: a) reactivity of functional groups involved, b) affinity of probes for the template, and c) the readout system. In this study we used peptide nucleic acid (PNA)-based probes to investigate in detail the signaling power and the selectivity of a transfer reaction derived from a native chemical ligation. We show that subtle variations of the thioesters involved had a tremendous impact on the sensitivity and selectivity of the reaction system. The results suggest that reactions at turnover conditions require low rates of non-templated reaction pathways to provide high target selectivity and sensitivity. On the other hand, very high rates of templated reactions should be avoided to allow mismatched probe-template complexes to dissociate prior to bond formation. Furthermore, the temperature dependence of the DNA-catalyzed transfer reaction was studied and provided insight into crucial strand-exchange processes. Further improvements of selective signaling were achieved through a new readout based on pyrene-transfer reactions. This method reduces background signals and enables significant increases in the signaling rates compared with previous fluorescence-based methods.
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Affiliation(s)
- Tom N Grossmann
- Institut für Chemie der Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
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Loakes D, Holliger P. Darwinian chemistry: towards the synthesis of a simple cell. MOLECULAR BIOSYSTEMS 2009; 5:686-94. [PMID: 19562107 DOI: 10.1039/b904024b] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The total synthesis of a simple cell is in many ways the ultimate challenge in synthetic biology. Outlined eight years ago in a visionary article by Szostak et al. (J. W. Szostak, D. P. Bartel and P. L. Luisi, Nature, 2001, 409, 387), the chances of success seemed remote. However, recent progress in nucleic acid chemistry, directed evolution and membrane biophysics have brought the prospect of a simple synthetic cell with life-like properties such as growth, division, heredity and evolution within reach. Success in this area will not only revolutionize our understanding of abiogenesis but provide a fertile test-bed for models of prebiotic chemistry and early evolution. Last but not least, a robust "living" protocell may provide a versatile and safe chassis for embedding synthetic devices and systems.
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Affiliation(s)
- David Loakes
- Medical Research Council, Laboratory of Molecular Biology, Hills Road, Cambridge, CB2 0QH, UK
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Eisenhuth R, Richert C. Convenient syntheses of 3'-amino-2',3'-dideoxynucleosides, their 5'-monophosphates, and 3'-aminoterminal oligodeoxynucleotide primers. J Org Chem 2009; 74:26-37. [PMID: 19053612 DOI: 10.1021/jo8018889] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
5'-Protected 3'-amino-2',3'-dideoxynucleosides containing any of the four canonical nucleobases (A/C/G/T) were prepared via azides in five to six steps, starting from deoxynucleosides. For pyrimidines, the synthetic route involved nucleophilic opening of anhydronucleosides. For purines, an in situ oxidation/reduction sequence, followed by a Mitsunobu reaction with diphenyl-2-pyridylphosphine and sodium azide, provided the 3'-azidonucleosides in high yield and purity. For solid-phase synthesis of aminoterminal oligonucleotides, aminonucleosides were linked to controlled pore glass through a novel hexafluoroglutaric acid linker. These supports gave 3'-aminoterminal primers in high yield and purity via conventional DNA chain assembly and one-step deprotection/release with aqueous ammonia. Primers thus prepared were successfully tested in enzyme-free chemical primer extension, an inexpensive methodology for genotyping and labeling. Protected 5'-monophosphates of 3'-amino-2',3'-dideoxynucleosides were also prepared, providing starting materials for the preparation of labeled or photolably protected monomers for chemical primer extension.
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Affiliation(s)
- Ralf Eisenhuth
- Institute for Organic Chemistry, University of Karlsruhe (TH), 76131 Karlsruhe, Germany
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