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Abstract
Thresholds are widespread in origin of life scenarios, from the emergence of chirality, to the appearance of vesicles, of autocatalysis, all the way up to Darwinian evolution. Here, we analyze the “error threshold,” which poses a condition for sustaining polymer replication, and generalize the threshold approach to other properties of prebiotic systems. Thresholds provide theoretical predictions, prescribe experimental tests, and integrate interdisciplinary knowledge. The coupling between systems and their environment determines how thresholds can be crossed, leading to different categories of prebiotic transitions. Articulating multiple thresholds reveals evolutionary properties in prebiotic scenarios. Overall, thresholds indicate how to assess, revise, and compare origin of life scenarios.
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Affiliation(s)
- Cyrille Jeancolas
- Laboratoire de Biochimie, UMR CNRS-ESPCI 8231 Chimie Biologie Innovation, PSL University, ESPCI Paris, 10 rue Vauquelin, 75005 Paris, France.,Laboratoire d'Anthropologie Sociale, Collège de France, 52 rue du Cardinal Lemoine, 75005 Paris, France
| | - Christophe Malaterre
- Département de Philosophie and Centre de Recherche Interuniversitaire sur la Science et la Technologie (CIRST), Université du Québec à Montréal (UQAM), 455 boulevard René-Lévesque Est, Montréal, QC H3C 3P8, Canada
| | - Philippe Nghe
- Laboratoire de Biochimie, UMR CNRS-ESPCI 8231 Chimie Biologie Innovation, PSL University, ESPCI Paris, 10 rue Vauquelin, 75005 Paris, France
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2
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Abstract
The chemistry of abiotic nucleotide synthesis of RNA and DNA in the context of their prebiotic origins on early earth is a continuing challenge. How did (or how can) the nucleotides form and assemble from the small molecule inventories and under conditions that prevailed on early earth 3.5-4 billion years ago? This review provides a background and up-to-date progress that will allow the reader to judge where the field stands currently and what remains to be achieved. We start with a brief primer on the biological synthesis of nucleotides, followed by an extensive focus on the prebiotic formation of the components of nucleotides-either via the synthesis of ribose and the canonical nucleobases and then joining them together or by building both the conjoined sugar and nucleobase, part-by-part-toward the ultimate goal of forming RNA and DNA by polymerization. The review will emphasize that there are-and will continue to be-many more questions than answers from the synthetic, mechanistic, and analytical perspectives. We wrap up the review with a cautionary note in this context about coming to conclusions as to whether the problem of chemistry of prebiotic nucleotide synthesis has been solved.
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Affiliation(s)
- Mahipal Yadav
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States.,NSF-NASA Center for Chemical Evolution, Atlanta, Georgia 30332, United States
| | - Ravi Kumar
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States.,NSF-NASA Center for Chemical Evolution, Atlanta, Georgia 30332, United States
| | - Ramanarayanan Krishnamurthy
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States.,NSF-NASA Center for Chemical Evolution, Atlanta, Georgia 30332, United States
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3
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Baú JPT, Villafañe-Barajas SA, da Costa ACS, Negrón-Mendoza A, Colín-Garcia M, Zaia DAM. Adenine Adsorbed onto Montmorillonite Exposed to Ionizing Radiation: Essays on Prebiotic Chemistry. ASTROBIOLOGY 2020; 20:26-38. [PMID: 31549853 DOI: 10.1089/ast.2018.1909] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Most adsorption and radiolysis experiments related to prebiotic chemistry studies are performed in distilled water or sodium chloride solutions. However, distilled water and sodium chloride solutions do not represent the composition of the primitive seas of Earth. In this work, an artificial seawater with ion abundances Mg2+ > Ca2+ >> Na+ ≈ K+ and SO42- >> Cl- was used, one that is different from the average composition of seawater today. This artificial seawater is named seawater 4.0 Ga, since it better represents the composition of the major constituents of seawater of primitive Earth. The radiolysis of adenine adsorbed onto montmorillonite was studied. The most important result is that adenine is adsorbed onto montmorillonite, when it is dissolved in artificial seawater 4.0 Ga, and the clay protects adenine against gamma radiation decomposition. However, desorption of adenine from montmorillonite was possible only with 0.10 mol L-1 of KOH. This result indicates that adenine was strongly bonded to montmorillonite. Fourier transform infrared spectroscopy showed that NH2 group and electrostatic interactions, between negatively charged montmorillonite and positively charged adenine, are responsible for adsorption of adenine onto montmorillonite. In addition, X-ray diffractograms showed that adenine enters in the interlayer space of montmorillonite.
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Affiliation(s)
- João Paulo T Baú
- Laboratório de Química Prebiótica, Departamento de Química-CCE, Universidade Estadual de Londrina, Londrina, Brasil
| | - Sául A Villafañe-Barajas
- Posgrado en Ciencias de la Tierra, Universidad Nacional Autónoma de México, Ciudad Universitaria, México
| | | | - Alicia Negrón-Mendoza
- Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Ciudad Universitaria, México
| | - María Colín-Garcia
- Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, México
| | - Dimas A M Zaia
- Laboratório de Química Prebiótica, Departamento de Química-CCE, Universidade Estadual de Londrina, Londrina, Brasil
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4
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Campbell TD, Febrian R, McCarthy JT, Kleinschmidt HE, Forsythe JG, Bracher PJ. Prebiotic condensation through wet-dry cycling regulated by deliquescence. Nat Commun 2019; 10:4508. [PMID: 31586058 PMCID: PMC6778215 DOI: 10.1038/s41467-019-11834-1] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 07/26/2019] [Indexed: 12/16/2022] Open
Abstract
Wet-dry cycling is widely regarded as a means of driving condensation reactions under prebiotic conditions to generate mixtures of prospective biopolymers. A criticism of this model is its reliance on unpredictable rehydration events, like rainstorms. Here, we report the ability of deliquescent minerals to mediate the oligomerization of glycine during iterative wet-dry cycles. The reaction mixtures evaporate to dryness at high temperatures and spontaneously reacquire water vapor to form aqueous solutions at low temperatures. Deliquescent mixtures can foster yields of oligomerization over ten-fold higher than non-deliquescent controls. The deliquescent mixtures tightly regulate their moisture content, which is crucial, as too little water precludes dissolution of the reactants while too much water favors hydrolysis over condensation. The model also suggests a potential reason why life evolved to favor the enrichment of potassium: so living systems could acquire and retain sufficient water to serve as a solvent for biochemical reactions.
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Affiliation(s)
- Thomas D Campbell
- Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, St. Louis, Missouri, 63103, USA
| | - Rio Febrian
- Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, St. Louis, Missouri, 63103, USA
| | - Jack T McCarthy
- Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, St. Louis, Missouri, 63103, USA
| | - Holly E Kleinschmidt
- Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, St. Louis, Missouri, 63103, USA
| | - Jay G Forsythe
- Department of Chemistry and Biochemistry, College of Charleston, 66 George Street, Charleston, South Carolina, 29424, USA
| | - Paul J Bracher
- Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, St. Louis, Missouri, 63103, USA.
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5
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Mariscal C, Barahona A, Aubert-Kato N, Aydinoglu AU, Bartlett S, Cárdenas ML, Chandru K, Cleland C, Cocanougher BT, Comfort N, Cornish-Bowden A, Deacon T, Froese T, Giovannelli D, Hernlund J, Hut P, Kimura J, Maurel MC, Merino N, Moreno A, Nakagawa M, Peretó J, Virgo N, Witkowski O, James Cleaves H. Hidden Concepts in the History and Philosophy of Origins-of-Life Studies: a Workshop Report. ORIGINS LIFE EVOL B 2019; 49:111-145. [PMID: 31399826 DOI: 10.1007/s11084-019-09580-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 06/12/2019] [Indexed: 12/11/2022]
Abstract
In this review, we describe some of the central philosophical issues facing origins-of-life research and provide a targeted history of the developments that have led to the multidisciplinary field of origins-of-life studies. We outline these issues and developments to guide researchers and students from all fields. With respect to philosophy, we provide brief summaries of debates with respect to (1) definitions (or theories) of life, what life is and how research should be conducted in the absence of an accepted theory of life, (2) the distinctions between synthetic, historical, and universal projects in origins-of-life studies, issues with strategies for inferring the origins of life, such as (3) the nature of the first living entities (the "bottom up" approach) and (4) how to infer the nature of the last universal common ancestor (the "top down" approach), and (5) the status of origins of life as a science. Each of these debates influences the others. Although there are clusters of researchers that agree on some answers to these issues, each of these debates is still open. With respect to history, we outline several independent paths that have led to some of the approaches now prevalent in origins-of-life studies. These include one path from early views of life through the scientific revolutions brought about by Linnaeus (von Linn.), Wöhler, Miller, and others. In this approach, new theories, tools, and evidence guide new thoughts about the nature of life and its origin. We also describe another family of paths motivated by a" circularity" approach to life, which is guided by such thinkers as Maturana & Varela, Gánti, Rosen, and others. These views echo ideas developed by Kant and Aristotle, though they do so using modern science in ways that produce exciting avenues of investigation. By exploring the history of these ideas, we can see how many of the issues that currently interest us have been guided by the contexts in which the ideas were developed. The disciplinary backgrounds of each of these scholars has influenced the questions they sought to answer, the experiments they envisioned, and the kinds of data they collected. We conclude by encouraging scientists and scholars in the humanities and social sciences to explore ways in which they can interact to provide a deeper understanding of the conceptual assumptions, structure, and history of origins-of-life research. This may be useful to help frame future research agendas and bring awareness to the multifaceted issues facing this challenging scientific question.
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Affiliation(s)
- Carlos Mariscal
- Department of Philosophy, Ecology, Evolution, and Conservation Biology (EECB) Program, and Integrative Neuroscience Program, University of Nevada, Reno (UNR), Reno, Nevada, USA
| | - Ana Barahona
- Department of Evolutionary Biology, School of Sciences, UNAM, 04510, CDMX, Coyoacán, Mexico
| | - Nathanael Aubert-Kato
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, 152-8551, Japan
- Department of Information Sciences, Ochanomizu University, Bunkyoku, Otsuka, 2-1-1, Tokyo, 112-0012, Japan
| | - Arsev Umur Aydinoglu
- Blue Marble Space Institute of Science, Washington, DC, 20011, USA
- Science and Technology Policies Department, Middle East Technical University (METU), 06800, Ankara, Turkey
| | - Stuart Bartlett
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, 152-8551, Japan
- Division of Geological and Planetary Sciences, California Institute of Technology, 1200 E California Blvd, Pasadena, CA, 91125, USA
| | | | - Kuhan Chandru
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, 152-8551, Japan
- Space Science Centre (ANGKASA), Institute of Climate Change, Level 3, Research Complex, National University of Malaysia, 43600, UKM Bangi, Selangor, Malaysia
- Department of Physical Chemistry, University of Chemistry and Technology, Prague, Technicka 5, 16628, Prague, 6, Dejvice, Czech Republic
| | - Carol Cleland
- Department of Philosophy, University of Colorado, Boulder, Colorado, USA
| | - Benjamin T Cocanougher
- Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, 20147, USA
- Department of Zoology, University of Cambridge, Cambridge, CB2 3EJ, UK
| | - Nathaniel Comfort
- Department of the History of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | | | - Terrence Deacon
- Department of Anthropology & Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
| | - Tom Froese
- Institute for Applied Mathematics and Systems Research (IIMAS), National Autonomous University of Mexico (UNAM), 04510, Mexico City, Mexico
- Centre for the Sciences of Complexity (C3), National Autonomous University of Mexico (UNAM), 04510, Mexico City, Mexico
| | - Donato Giovannelli
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, 152-8551, Japan
- Institute for Advanced Study, Princeton, NJ, 08540, USA
- Department of Marine and Coastal Science, Rutgers University, 71 Dudley Rd, New Brunswick, NJ, 08901, USA
- YHouse, Inc., NY, 10159, New York, USA
- Department of Biology, University of Naples "Federico II", Via Cinthia, 80156, Naples, Italy
| | - John Hernlund
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, 152-8551, Japan
| | - Piet Hut
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, 152-8551, Japan
- Institute for Advanced Study, Princeton, NJ, 08540, USA
| | - Jun Kimura
- Department of Earth and Space Science, Osaka University, Machikaneyama-Chou 1-1, Toyonaka City, Osaka, 560-0043, Japan
| | | | - Nancy Merino
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, 152-8551, Japan
- Department of Earth Sciences, University of Southern California, California, Los Angeles, 90089, USA
| | - Alvaro Moreno
- Department of Logic and Philosophy of Science, IAS-Research Centre for Life, Mind and Society, University of the Basque Country, Avenida de Tolosa 70, 20018, Donostia-San Sebastian, Spain
| | - Mayuko Nakagawa
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, 152-8551, Japan
| | - Juli Peretó
- Department of Biochemistry and Molecular Biology, University of Valéncia and Institute for Integrative Systems Biology I2SysBio (University of Valéncia-CSIC), València, Spain
| | - Nathaniel Virgo
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, 152-8551, Japan
- Max Planck Institute for Mathematics in the Sciences, Leipzig, Germany
- European Centre for Living Technology, Venice, Italy
| | - Olaf Witkowski
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, 152-8551, Japan
- Institute for Advanced Study, Princeton, NJ, 08540, USA
| | - H James Cleaves
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, 152-8551, Japan.
- Blue Marble Space Institute of Science, Washington, DC, 20011, USA.
- Institute for Advanced Study, Princeton, NJ, 08540, USA.
- European Centre for Living Technology, Venice, Italy.
- Center for Chemical Evolution, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
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6
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Campbell T, Febrian R, Kleinschmidt HE, Smith KA, Bracher PJ. Quantitative Analysis of Glycine Oligomerization by Ion-Pair Chromatography. ACS OMEGA 2019; 4:12745-12752. [PMID: 31460397 PMCID: PMC6681977 DOI: 10.1021/acsomega.9b01492] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 07/12/2019] [Indexed: 06/10/2023]
Abstract
This paper describes a method for the quantitative analysis of mixtures of glycine and its oligomers by ion-pair high-performance liquid chromatography (IP-HPLC), with a particular focus on applications in origins-of-life research. We demonstrate the identification of glycine oligomers (Gly n ) up to 14 residues long-the approximate detectable limit of their solubility in water-and measurement of the concentration of these species in the product mixture of an oligomerization reaction. The molar response factors for higher oligomers of glycine-which are impractical to obtain as pure samples-are extrapolated from direct analysis of pure standards of n = 3-6, which established a clear linear trend. We compare and contrast our method to those in previous reports with respect to accuracy and practicality. While the data reported here are specific to the analysis of oligomers of glycine, the approach should be applicable to the design of methods for the analysis of oligomerization of other amino acids.
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7
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Biscans A. Exploring the Emergence of RNA Nucleosides and Nucleotides on the Early Earth. Life (Basel) 2018; 8:life8040057. [PMID: 30404133 PMCID: PMC6316623 DOI: 10.3390/life8040057] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 10/31/2018] [Accepted: 11/03/2018] [Indexed: 01/02/2023] Open
Abstract
Understanding how life began is one of the most fascinating problems to solve. By approaching this enigma from a chemistry perspective, the goal is to define what series of chemical reactions could lead to the synthesis of nucleotides, amino acids, lipids, and other cellular components from simple feedstocks under prebiotically plausible conditions. It is well established that evolution of life involved RNA which plays central roles in both inheritance and catalysis. In this review, we present historically important and recently published articles aimed at understanding the emergence of RNA nucleosides and nucleotides on the early Earth.
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Affiliation(s)
- Annabelle Biscans
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, 01605 MA, USA.
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8
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Campbell TD, Hart CA, Febrian R, Cheneler ML, Bracher PJ. The opposite effect of K+ and Na+ on the hydrolysis of linear and cyclic dipeptides. Tetrahedron Lett 2018. [DOI: 10.1016/j.tetlet.2018.04.073] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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9
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Keil L, Hartmann M, Lanzmich S, Braun D. Probing of molecular replication and accumulation in shallow heat gradients through numerical simulations. Phys Chem Chem Phys 2018; 18:20153-9. [PMID: 27153345 DOI: 10.1039/c6cp00577b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
How can living matter arise from dead matter? All known living systems are built around information stored in RNA and DNA. To protect this information against molecular degradation and diffusion, the second law of thermodynamics imposes the need for a non-equilibrium driving force. Following a series of successful experiments using thermal gradients, we have shown that heat gradients across sub-millimetre pores can drive accumulation, replication, and selection of ever longer molecules, implementing all the necessary parts for Darwinian evolution. For these lab experiments to proceed with ample speed, however, the temperature gradients have to be quite steep, reaching up to 30 K per 100 μm. Here we use computer simulations based on experimental data to show that 2000-fold shallower temperature gradients - down to 100 K over one metre - can still drive the accumulation of protobiomolecules. This finding opens the door for various environments to potentially host the origins of life: volcanic, water-vapour, or hydrothermal settings. Following the trajectories of single molecules in simulation, we also find that they are subjected to frequent temperature oscillations inside these pores, facilitating e.g. template-directed replication mechanisms. The tilting of the pore configuration is the central strategy to achieve replication in a shallow temperature gradient. Our results suggest that shallow thermal gradients across porous rocks could have facilitated the formation of evolutionary machines, significantly increasing the number of potential sites for the origin of life on young rocky planets.
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Affiliation(s)
- Lorenz Keil
- Systems Biophysics, Physics Department, Nanosystems Initiative Munich and Center for NanoScience, Ludwig-Maximilians-Universität München, Amalienstraße 54, 80799 München, Germany.
| | - Michael Hartmann
- Systems Biophysics, Physics Department, Nanosystems Initiative Munich and Center for NanoScience, Ludwig-Maximilians-Universität München, Amalienstraße 54, 80799 München, Germany.
| | - Simon Lanzmich
- Systems Biophysics, Physics Department, Nanosystems Initiative Munich and Center for NanoScience, Ludwig-Maximilians-Universität München, Amalienstraße 54, 80799 München, Germany.
| | - Dieter Braun
- Systems Biophysics, Physics Department, Nanosystems Initiative Munich and Center for NanoScience, Ludwig-Maximilians-Universität München, Amalienstraße 54, 80799 München, Germany.
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10
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Menor-Salván C. From the Dawn of Organic Chemistry to Astrobiology: Urea as a Foundational Component in the Origin of Nucleobases and Nucleotides. PREBIOTIC CHEMISTRY AND CHEMICAL EVOLUTION OF NUCLEIC ACIDS 2018. [DOI: 10.1007/978-3-319-93584-3_4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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11
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Qiao H, Hu N, Bai J, Ren L, Liu Q, Fang L, Wang Z. Encapsulation of Nucleic Acids into Giant Unilamellar Vesicles by Freeze-Thaw: a Way Protocells May Form. ORIGINS LIFE EVOL B 2017; 47:499-510. [PMID: 27807660 DOI: 10.1007/s11084-016-9527-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 10/19/2016] [Indexed: 12/27/2022]
Abstract
Protocells are believed to consist of a lipid membrane and encapsulated nucleic acid. As the lipid membrane is impermeable to macromolecules like nucleic acids, the processes by which nucleic acids become encapsulated inside lipid membrane compartments are still unknown. In this paper, a freeze-thaw method was modified and applied to giant unilamellar vesicles (GUVs) and deoxyribonucleic acid (DNA) in mixed solution resulting in the efficient encapsulation of 6.4 kb plasmid DNA and similar length linear DNA into GUVs. The mechanism of encapsulation was followed by observing the effect of freeze-thaw temperatures on GUV morphological change, DNA encapsulation and ice crystal formation, and analyzing their correlation. Following ice crystal formation, the shape of spherical GUVs was altered and membrane integrity was damaged and this was found to be a necessary condition for encapsulation. Heating alone had no effects on DNA encapsulation, but was helpful for restoring the spherical shape and membrane integrity of GUVs damaged during freezing. These results suggested that freeze-thaw could promote the encapsulation of DNA into GUVs by a mechanism: the vesicle membrane was breached by ice crystal formation during freezing, DNA entered into damaged GUVs through these membrane gaps and was encapsulated after the membrane was resealed during the thawing process. The process described herein therefore describes a simple way for the encapsulation of nucleic acids and potentially other macromolecules into lipid vesicles, a process by which early protocells might have formed.
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Affiliation(s)
- Hai Qiao
- State Key Laboratory of Ultrasound Engineering in Medicine Co-Founed by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Biomedical Engineering, College of Biomedical Engineering, Chongqing Medical University, P. O. Box 153, No.1 Yixueyuan Road, Yuzhong District, Chongqing, 400016, People's Republic of China
| | - Na Hu
- State Key Laboratory of Ultrasound Engineering in Medicine Co-Founed by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Biomedical Engineering, College of Biomedical Engineering, Chongqing Medical University, P. O. Box 153, No.1 Yixueyuan Road, Yuzhong District, Chongqing, 400016, People's Republic of China
| | - Jin Bai
- State Key Laboratory of Ultrasound Engineering in Medicine Co-Founed by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Biomedical Engineering, College of Biomedical Engineering, Chongqing Medical University, P. O. Box 153, No.1 Yixueyuan Road, Yuzhong District, Chongqing, 400016, People's Republic of China
| | - Lili Ren
- State Key Laboratory of Ultrasound Engineering in Medicine Co-Founed by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Biomedical Engineering, College of Biomedical Engineering, Chongqing Medical University, P. O. Box 153, No.1 Yixueyuan Road, Yuzhong District, Chongqing, 400016, People's Republic of China
| | - Qing Liu
- State Key Laboratory of Ultrasound Engineering in Medicine Co-Founed by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Biomedical Engineering, College of Biomedical Engineering, Chongqing Medical University, P. O. Box 153, No.1 Yixueyuan Road, Yuzhong District, Chongqing, 400016, People's Republic of China
| | - Liaoqiong Fang
- State Key Laboratory of Ultrasound Engineering in Medicine Co-Founed by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Biomedical Engineering, College of Biomedical Engineering, Chongqing Medical University, P. O. Box 153, No.1 Yixueyuan Road, Yuzhong District, Chongqing, 400016, People's Republic of China.
| | - Zhibiao Wang
- State Key Laboratory of Ultrasound Engineering in Medicine Co-Founed by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Biomedical Engineering, College of Biomedical Engineering, Chongqing Medical University, P. O. Box 153, No.1 Yixueyuan Road, Yuzhong District, Chongqing, 400016, People's Republic of China.
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12
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Jamshidi MP, MacDonald MJ, Beauchemin AM. On the Ability of Formaldehyde to Act as a Tethering Catalyst in Water. ORIGINS LIFE EVOL B 2017; 47:405-412. [PMID: 28474281 DOI: 10.1007/s11084-017-9538-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Accepted: 04/20/2017] [Indexed: 10/19/2022]
Abstract
The low concentration issue is a fundamental challenge when it comes to prebiotic chemistry, as macromolecular systems need to be assembled via intermolecular reactions, and this is inherently difficult in dilute solutions. This is especially true when the reactions are challenging, and reactions that proceeded more rapidly could have dictated chemical evolution. Herein we establish that formaldehyde is capable of catalyzing, via temporary intramolecularity, a challenging reaction in water at low concentrations, thus providing an alternative to other approaches that can either lead to higher concentrations or higher effective molarities.
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Affiliation(s)
- Mohammad P Jamshidi
- Center for Catalysis Research and Innovation, Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie, Ottawa, ON, K1N 6N5, Canada
| | - Melissa J MacDonald
- Center for Catalysis Research and Innovation, Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie, Ottawa, ON, K1N 6N5, Canada
| | - André M Beauchemin
- Center for Catalysis Research and Innovation, Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie Curie, Ottawa, ON, K1N 6N5, Canada.
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13
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Foldamer hypothesis for the growth and sequence differentiation of prebiotic polymers. Proc Natl Acad Sci U S A 2017; 114:E7460-E7468. [PMID: 28831002 DOI: 10.1073/pnas.1620179114] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
It is not known how life originated. It is thought that prebiotic processes were able to synthesize short random polymers. However, then, how do short-chain molecules spontaneously grow longer? Also, how would random chains grow more informational and become autocatalytic (i.e., increasing their own concentrations)? We study the folding and binding of random sequences of hydrophobic ([Formula: see text]) and polar ([Formula: see text]) monomers in a computational model. We find that even short hydrophobic polar (HP) chains can collapse into relatively compact structures, exposing hydrophobic surfaces. In this way, they act as primitive versions of today's protein catalysts, elongating other such HP polymers as ribosomes would now do. Such foldamer catalysts are shown to form an autocatalytic set, through which short chains grow into longer chains that have particular sequences. An attractive feature of this model is that it does not overconverge to a single solution; it gives ensembles that could further evolve under selection. This mechanism describes how specific sequences and conformations could contribute to the chemistry-to-biology (CTB) transition.
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14
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Bera PP, Stein T, Head-Gordon M, Lee TJ. Mechanisms of the Formation of Adenine, Guanine, and Their Analogues in UV-Irradiated Mixed NH 3:H 2O Molecular Ices Containing Purine. ASTROBIOLOGY 2017; 17:771-785. [PMID: 28708419 PMCID: PMC5734622 DOI: 10.1089/ast.2016.1614] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We investigated the formation mechanisms of the nucleobases adenine and guanine and the nucleobase analogues hypoxanthine, xanthine, isoguanine, and 2,6-diaminopurine in a UV-irradiated mixed 10:1 H2O:NH3 ice seeded with precursor purine by using ab initio and density functional theory computations. Our quantum chemical investigations suggest that a multistep reaction mechanism involving purine cation, hydroxyl and amino radicals, together with water and ammonia, explains the experimentally obtained products in an independent study. The relative abundances of these products appear to largely follow from relative thermodynamic stabilities. The key role of the purine cation is likely to be the reason why purine is not functionalized in pure ammonia ice, where cations are promptly neutralized by free electrons from NH3 ionization. Amine group addition to purine is slightly favored over hydroxyl group attachment based on energetics, but hydroxyl is much more abundant due to higher abundance of H2O. The amino group is preferentially attached to the 6 position, giving 6-aminopurine, that is, adenine, while the hydroxyl group is preferentially attached to the 2 position, leading to 2-hydroxypurine. A second substitution by hydroxyl or amino group occurs at either the 6 or the 2 position depending on the first substitution. Given that H2O is far more abundant than NH3 in the experimentally studied ices (as well as based on interstellar abundances), xanthine and isoguanine are expected to be the most abundant bi-substituted photoproducts. Key Words: Astrophysical ice-Abiotic organic synthesis-Nucleic acids-Origin of life-RNA world. Astrobiology 17, 771-785.
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Affiliation(s)
- Partha P. Bera
- NASA Ames Research Center, Moffett Field, Mountain View, CA, USA
- Bay Area Environmental Research Institute, Petaluma, CA, USA
| | - Tamar Stein
- University of California, Berkeley, CA, USA
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Martin Head-Gordon
- University of California, Berkeley, CA, USA
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Timothy J. Lee
- NASA Ames Research Center, Moffett Field, Mountain View, CA, USA
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15
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Li BJ, EI-Nachef C, Beauchemin AM. Organocatalysis using aldehydes: the development and improvement of catalytic hydroaminations, hydrations and hydrolyses. Chem Commun (Camb) 2017; 53:13192-13204. [DOI: 10.1039/c7cc07352f] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Aldehydes as organocatalysts? Simple aldehydes achieve difficult intermolecular reactions by exploiting temporary intramolecularity and inducing electrophilic activation.
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Affiliation(s)
- Bin-Jie Li
- Centre for Catalysis Research and Innovation
- Department of Chemistry and Biomolecular Sciences
- University of Ottawa
- Ottawa
- Canada
| | - Claudia EI-Nachef
- Centre for Catalysis Research and Innovation
- Department of Chemistry and Biomolecular Sciences
- University of Ottawa
- Ottawa
- Canada
| | - André M. Beauchemin
- Centre for Catalysis Research and Innovation
- Department of Chemistry and Biomolecular Sciences
- University of Ottawa
- Ottawa
- Canada
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16
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Abstract
Understanding how life arose is a fundamental problem of biology. Much progress has been made by adopting a synthetic and mechanistic perspective on originating life. We present a current view of the biochemistry of the origin of life, focusing on issues surrounding the emergence of an RNA World in which RNA dominated informational and functional roles. There is cause for optimism on this difficult problem: the prebiotic chemical inventory may not have been as nightmarishly complex as previously thought; the catalytic repertoire of ribozymes continues to expand, approaching the goal of self-replicating RNA; encapsulation in protocells provides evolutionary and biophysical advantages. Nevertheless, major issues remain unsolved, such as the origin of a genetic code. Attention to this field is particularly timely given the accelerating discovery and characterization of exoplanets.
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17
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Domagal-Goldman SD, Wright KE, Adamala K, Arina de la Rubia L, Bond J, Dartnell LR, Goldman AD, Lynch K, Naud ME, Paulino-Lima IG, Singer K, Walther-Antonio M, Abrevaya XC, Anderson R, Arney G, Atri D, Azúa-Bustos A, Bowman JS, Brazelton WJ, Brennecka GA, Carns R, Chopra A, Colangelo-Lillis J, Crockett CJ, DeMarines J, Frank EA, Frantz C, de la Fuente E, Galante D, Glass J, Gleeson D, Glein CR, Goldblatt C, Horak R, Horodyskyj L, Kaçar B, Kereszturi A, Knowles E, Mayeur P, McGlynn S, Miguel Y, Montgomery M, Neish C, Noack L, Rugheimer S, Stüeken EE, Tamez-Hidalgo P, Imari Walker S, Wong T. The Astrobiology Primer v2.0. ASTROBIOLOGY 2016; 16:561-653. [PMID: 27532777 PMCID: PMC5008114 DOI: 10.1089/ast.2015.1460] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 06/06/2016] [Indexed: 05/09/2023]
Affiliation(s)
- Shawn D Domagal-Goldman
- 1 NASA Goddard Space Flight Center , Greenbelt, Maryland, USA
- 2 Virtual Planetary Laboratory , Seattle, Washington, USA
| | - Katherine E Wright
- 3 University of Colorado at Boulder , Colorado, USA
- 4 Present address: UK Space Agency, UK
| | - Katarzyna Adamala
- 5 Department of Genetics, Cell Biology and Development, University of Minnesota , Minneapolis, Minnesota, USA
| | | | - Jade Bond
- 7 Department of Physics, University of New South Wales , Sydney, Australia
| | | | | | - Kennda Lynch
- 10 Division of Biological Sciences, University of Montana , Missoula, Montana, USA
| | - Marie-Eve Naud
- 11 Institute for research on exoplanets (iREx) , Université de Montréal, Montréal, Canada
| | - Ivan G Paulino-Lima
- 12 Universities Space Research Association , Mountain View, California, USA
- 13 Blue Marble Space Institute of Science , Seattle, Washington, USA
| | - Kelsi Singer
- 14 Southwest Research Institute , Boulder, Colorado, USA
| | | | - Ximena C Abrevaya
- 16 Instituto de Astronomía y Física del Espacio (IAFE) , UBA-CONICET, Ciudad Autónoma de Buenos Aires, Argentina
| | - Rika Anderson
- 17 Department of Biology, Carleton College , Northfield, Minnesota, USA
| | - Giada Arney
- 18 University of Washington Astronomy Department and Astrobiology Program , Seattle, Washington, USA
| | - Dimitra Atri
- 13 Blue Marble Space Institute of Science , Seattle, Washington, USA
| | | | - Jeff S Bowman
- 19 Lamont-Doherty Earth Observatory, Columbia University , Palisades, New York, USA
| | | | | | - Regina Carns
- 22 Polar Science Center, Applied Physics Laboratory, University of Washington , Seattle, Washington, USA
| | - Aditya Chopra
- 23 Planetary Science Institute, Research School of Earth Sciences, Research School of Astronomy and Astrophysics, The Australian National University , Canberra, Australia
| | - Jesse Colangelo-Lillis
- 24 Earth and Planetary Science, McGill University , and the McGill Space Institute, Montréal, Canada
| | | | - Julia DeMarines
- 13 Blue Marble Space Institute of Science , Seattle, Washington, USA
| | | | - Carie Frantz
- 27 Department of Geosciences, Weber State University , Ogden, Utah, USA
| | - Eduardo de la Fuente
- 28 IAM-Departamento de Fisica, CUCEI , Universidad de Guadalajara, Guadalajara, México
| | - Douglas Galante
- 29 Brazilian Synchrotron Light Laboratory , Campinas, Brazil
| | - Jennifer Glass
- 30 School of Earth and Atmospheric Sciences, Georgia Institute of Technology , Atlanta, Georgia , USA
| | | | | | - Colin Goldblatt
- 33 School of Earth and Ocean Sciences, University of Victoria , Victoria, Canada
| | - Rachel Horak
- 34 American Society for Microbiology , Washington, DC, USA
| | | | - Betül Kaçar
- 36 Harvard University , Organismic and Evolutionary Biology, Cambridge, Massachusetts, USA
| | - Akos Kereszturi
- 37 Research Centre for Astronomy and Earth Sciences , Hungarian Academy of Sciences, Budapest, Hungary
| | - Emily Knowles
- 38 Johnson & Wales University , Denver, Colorado, USA
| | - Paul Mayeur
- 39 Rensselaer Polytechnic Institute , Troy, New York, USA
| | - Shawn McGlynn
- 40 Earth Life Science Institute, Tokyo Institute of Technology , Tokyo, Japan
| | - Yamila Miguel
- 41 Laboratoire Lagrange, UMR 7293, Université Nice Sophia Antipolis , CNRS, Observatoire de la Côte d'Azur, Nice, France
| | | | - Catherine Neish
- 43 Department of Earth Sciences, The University of Western Ontario , London, Canada
| | - Lena Noack
- 44 Royal Observatory of Belgium , Brussels, Belgium
| | - Sarah Rugheimer
- 45 Department of Astronomy, Harvard University , Cambridge, Massachusetts, USA
- 46 University of St. Andrews , St. Andrews, UK
| | - Eva E Stüeken
- 47 University of Washington , Seattle, Washington, USA
- 48 University of California , Riverside, California, USA
| | | | - Sara Imari Walker
- 13 Blue Marble Space Institute of Science , Seattle, Washington, USA
- 50 School of Earth and Space Exploration and Beyond Center for Fundamental Concepts in Science, Arizona State University , Tempe, Arizona, USA
| | - Teresa Wong
- 51 Department of Earth and Planetary Sciences, Washington University in St. Louis , St. Louis, Missouri, USA
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18
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Bera PP, Nuevo M, Materese CK, Sandford SA, Lee TJ. Mechanisms for the formation of thymine under astrophysical conditions and implications for the origin of life. J Chem Phys 2016; 144:144308. [PMID: 27083722 PMCID: PMC5809119 DOI: 10.1063/1.4945745] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Nucleobases are the carriers of the genetic information in ribonucleic acid and deoxyribonucleic acid (DNA) for all life on Earth. Their presence in meteorites clearly indicates that compounds of biological importance can form via non-biological processes in extraterrestrial environments. Recent experimental studies have shown that the pyrimidine-based nucleobases uracil and cytosine can be easily formed from the ultraviolet irradiation of pyrimidine in H2O-rich ice mixtures that simulate astrophysical processes. In contrast, thymine, which is found only in DNA, is more difficult to form under the same experimental conditions, as its formation usually requires a higher photon dose. Earlier quantum chemical studies confirmed that the reaction pathways were favorable provided that several H2O molecules surrounded the reactants. However, the present quantum chemical study shows that the formation of thymine is limited because of the inefficiency of the methylation of pyrimidine and its oxidized derivatives in an H2O ice, as supported by the laboratory studies. Our results constrain the formation of thymine in astrophysical environments and thus the inventory of organic molecules delivered to the early Earth and have implications for the role of thymine and DNA in the origin of life.
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Affiliation(s)
- Partha P. Bera
- Space Science and Astrobiology Division, NASA Ames Research Center, Moffett Field, California 94035, USA
- Bay Area Environmental Research Institute, Petaluma, California 94952, USA
| | - Michel Nuevo
- Space Science and Astrobiology Division, NASA Ames Research Center, Moffett Field, California 94035, USA
- Bay Area Environmental Research Institute, Petaluma, California 94952, USA
| | - Christopher K. Materese
- Space Science and Astrobiology Division, NASA Ames Research Center, Moffett Field, California 94035, USA
- Bay Area Environmental Research Institute, Petaluma, California 94952, USA
| | - Scott A. Sandford
- Space Science and Astrobiology Division, NASA Ames Research Center, Moffett Field, California 94035, USA
| | - Timothy J. Lee
- Space Science and Astrobiology Division, NASA Ames Research Center, Moffett Field, California 94035, USA
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19
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Bregestovski PD. “RNA World”, a highly improbable scenario of the origin and early evolution of life on earth. J EVOL BIOCHEM PHYS+ 2015. [DOI: 10.1134/s0022093015010111] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Sandford SA, Bera PP, Lee TJ, Materese CK, Nuevo M. Photosynthesis and photo-stability of nucleic acids in prebiotic extraterrestrial environments. Top Curr Chem (Cham) 2015; 356:123-64. [PMID: 24500331 PMCID: PMC5737941 DOI: 10.1007/128_2013_499] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Laboratory experiments have shown that the UV photo-irradiation of low-temperature ices of astrophysical interest leads to the formation of organic molecules, including molecules important for biology such as amino acids, quinones, and amphiphiles. When pyrimidine is introduced into these ices, the products of irradiation include the nucleobases uracil, cytosine, and thymine, the informational sub-units of DNA and RNA, as well as some of their isomers. The formation of these compounds, which has been studied both experimentally and theoretically, requires a succession of additions of OH, NH₂, and CH₃groups to pyrimidine. Results show that H₂O ice plays key roles in the formation of the nucleobases, as an oxidant, as a matrix in which reactions can take place, and as a catalyst that assists proton abstraction from intermediate compounds. As H₂O is also the most abundant icy component in most cold astrophysical environments, it probably plays the same roles in space in the formation of biologically relevant compounds. Results also show that although the formation of uracil and cytosine from pyrimidine in ices is fairly straightforward, the formation of thymine is not. This is mostly due to the fact that methylation is a limiting step for its formation, particularly in H₂O-rich ices, where methylation must compete with oxidation. The relative inefficiency of the abiotic formation of thymine to that of uracil and cytosine, together with the fact that thymine has not been detected in meteorites, are not inconsistent with the RNA world hypothesis. Indeed, a lack of abiotically produced thymine delivered to the early Earth may have forced the choice for an RNA world, in which only uracil and cytosine are needed, but not thymine.
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Affiliation(s)
- Scott A Sandford
- Space Science and Astrobiology Division, NASA Ames Research Center, MS 245-6, Moffett Field, CA, 94035, USA,
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21
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Davila AF, McKay CP. Chance and necessity in biochemistry: implications for the search for extraterrestrial biomarkers in Earth-like environments. ASTROBIOLOGY 2014; 14:534-40. [PMID: 24867145 PMCID: PMC4060776 DOI: 10.1089/ast.2014.1150] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
In this paper, we examine a restricted subset of the question of possible alien biochemistries. That is, we look into how different life might be if it emerged in environments similar to that required for life on Earth. We advocate a principle of chance and necessity in biochemistry. According to this principle, biochemistry is in some fundamental way the sum of two processes: there is an aspect of biochemistry that is an endowment from prebiotic processes, which represents the necessity, plus an aspect that is invented by the process of evolution, which represents the chance. As a result, we predict that life originating in extraterrestrial Earth-like environments will share biochemical motifs that can be traced back to the prebiotic world but will also have intrinsic biochemical traits that are unlikely to be duplicated elsewhere as they are combinatorially path-dependent. Effective and objective strategies to search for biomarkers, and evidence for a second genesis, on planets with Earth-like environments can be built based on this principle.
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Affiliation(s)
- Alfonso F. Davila
- Carl Sagan Center at the SETI Institute, Mountain View, California
- Space Science and Astrobiology Division, NASA Ames Research Center, Moffett Field, California
| | - Christopher P. McKay
- Space Science and Astrobiology Division, NASA Ames Research Center, Moffett Field, California
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22
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Kluska M, Prukała D, Prukała W, Kondrzycka-Dąda A, Komasińska M, Małkiewicz K. SUCCESSFUL SEPARATION AND DETERMINATION OF ISOMERS OF CYTOSINE DERIVATIVES FOR HPLC. J LIQ CHROMATOGR R T 2014. [DOI: 10.1080/10826076.2013.828304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Mariusz Kluska
- a Institute of Chemistry , Siedlce University of Natural Sciences and Humanities , Siedlce , Poland
| | - Dorota Prukała
- b Faculty of Chemistry, Adam Mickiewicz University , Poznan , Poland
| | - Wiesław Prukała
- b Faculty of Chemistry, Adam Mickiewicz University , Poznan , Poland
| | | | | | - Konrad Małkiewicz
- d Department of Conservative Dentistry , Medical University of Warsaw , Warsaw , Poland
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23
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Ruiz-Mirazo K, Briones C, de la Escosura A. Prebiotic Systems Chemistry: New Perspectives for the Origins of Life. Chem Rev 2013; 114:285-366. [DOI: 10.1021/cr2004844] [Citation(s) in RCA: 563] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Kepa Ruiz-Mirazo
- Biophysics
Unit (CSIC-UPV/EHU), Leioa, and Department of Logic and Philosophy
of Science, University of the Basque Country, Avenida de Tolosa 70, 20080 Donostia−San Sebastián, Spain
| | - Carlos Briones
- Department
of Molecular Evolution, Centro de Astrobiología (CSIC−INTA, associated to the NASA Astrobiology Institute), Carretera de Ajalvir, Km 4, 28850 Torrejón de Ardoz, Madrid, Spain
| | - Andrés de la Escosura
- Organic
Chemistry Department, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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24
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Tang Q, Guo Z, Li Q. A quantum chemical study of the structures, stability, and spectroscopy of halogen- and hydrogen-boned complexes between cyanoacetaldehyde and hypochlorous acids. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2013; 121:157-163. [PMID: 24239758 DOI: 10.1016/j.saa.2013.10.088] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 10/15/2013] [Indexed: 06/02/2023]
Abstract
The complexes of cyanoacetaldehyde and hypohalous acid (HOX, X=Cl, Br, and I) have been investigated. They can form six different structures (A, B, C, D, E, and F), the former three structures are mainly combined through a N(O)⋯X halogen bond and the latter three structures are maintained mainly by a N(O)⋯H hydrogen bond, although other weaker interactions are also present in most structures. The hydrogen-bonded structures are more stable than the respective halogen-bonded structures. The O-H and O-X bonds in the halogen- and hydrogen-bonded complexes are lengthened and show an observed red shift, while those in the weaker secondary interactions are contracted and display a small blue shift. The orbital interactions in NBO analysis and the electron densities in AIM analysis provide useful and reliable information for the strength of each type of interaction in different structures.
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Affiliation(s)
- Qingjie Tang
- College of Material Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China; Hebei North University, Zhangjiakou 075000, People's Republic of China
| | - Zhenfu Guo
- Hebei North University, Zhangjiakou 075000, People's Republic of China
| | - Qingzhong Li
- The Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Yantai University, Yantai 264005, People's Republic of China.
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25
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Materese CK, Nuevo M, Bera PP, Lee TJ, Sandford SA. Thymine and other prebiotic molecules produced from the ultraviolet photo-irradiation of pyrimidine in simple astrophysical ice analogs. ASTROBIOLOGY 2013; 13:948-962. [PMID: 24143868 DOI: 10.1089/ast.2013.1044] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The informational subunits of RNA or DNA consist of substituted N-heterocyclic compounds that fall into two groups: those based on purine (C₅H₄N₄) (adenine and guanine) and those based on pyrimidine (C₄H₄N₂) (uracil, cytosine, and thymine). Although not yet detected in the interstellar medium, N-heterocycles, including the nucleobase uracil, have been reported in carbonaceous chondrites. Recent laboratory experiments and ab initio calculations have shown that the irradiation of pyrimidine in ices containing H₂O, NH₃, or both leads to the abiotic production of substituted pyrimidines, including the nucleobases uracil and cytosine. In this work, we studied the methylation and oxidation of pyrimidine in CH₃OH:pyrimidine, H₂O:CH₃OH:pyrimidine, CH₄:pyrimidine, and H₂O:CH₄:pyrimidine ices irradiated with UV photons under astrophysically relevant conditions. The nucleobase thymine was detected in the residues from some of the mixtures. Our results suggest that the abundance of abiotic thymine produced by ice photolysis and delivered to the early Earth may have been significantly lower than that of uracil. Insofar as the delivery of extraterrestrial molecules was important for early biological chemistry on early Earth, these results suggest that there was more uracil than thymine available for emergent life, a scenario consistent with the RNA world hypothesis.
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Affiliation(s)
- Christopher K Materese
- 1 NASA Ames Research Center , Space Science and Astrobiology Division, Moffett Field, California
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26
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Prebiotic chemistry: geochemical context and reaction screening. Life (Basel) 2013; 3:331-45. [PMID: 25369745 PMCID: PMC4187135 DOI: 10.3390/life3020331] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 04/17/2013] [Accepted: 04/18/2013] [Indexed: 11/23/2022] Open
Abstract
The origin of life on Earth is widely believed to have required the reactions of organic compounds and their self- and/or environmental organization. What those compounds were remains open to debate, as do the environment in and process or processes by which they became organized. Prebiotic chemistry is the systematic organized study of these phenomena. It is difficult to study poorly defined phenomena, and research has focused on producing compounds and structures familiar to contemporary biochemistry, which may or may not have been crucial for the origin of life. Given our ignorance, it may be instructive to explore the extreme regions of known and future investigations of prebiotic chemistry, where reactions fail, that will relate them to or exclude them from plausible environments where they could occur. Come critical parameters which most deserve investigation are discussed.
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27
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Menor-Salván C, Marín-Yaseli MR. A New Route for the Prebiotic Synthesis of Nucleobases and Hydantoins in Water/Ice Solutions Involving the Photochemistry of Acetylene. Chemistry 2013; 19:6488-97. [DOI: 10.1002/chem.201204313] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 02/15/2013] [Indexed: 11/11/2022]
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28
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Cleaves HJ, Michalkova Scott A, Hill FC, Leszczynski J, Sahai N, Hazen R. Mineral-organic interfacial processes: potential roles in the origins of life. Chem Soc Rev 2012; 41:5502-25. [PMID: 22743683 DOI: 10.1039/c2cs35112a] [Citation(s) in RCA: 169] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Life is believed to have originated on Earth ∼4.4-3.5 Ga ago, via processes in which organic compounds supplied by the environment self-organized, in some geochemical environmental niches, into systems capable of replication with hereditary mutation. This process is generally supposed to have occurred in an aqueous environment and, likely, in the presence of minerals. Mineral surfaces present rich opportunities for heterogeneous catalysis and concentration which may have significantly altered and directed the process of prebiotic organic complexification leading to life. We review here general concepts in prebiotic mineral-organic interfacial processes, as well as recent advances in the study of mineral surface-organic interactions of potential relevance to understanding the origin of life.
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Affiliation(s)
- H James Cleaves
- Blue Marble Space Institute of Science, Washington, DC 20016, USA
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29
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Menor-Salván C, Marín-Yaseli MR. Prebiotic chemistry in eutectic solutions at the water-ice matrix. Chem Soc Rev 2012; 41:5404-15. [PMID: 22660387 DOI: 10.1039/c2cs35060b] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A crystalline ice matrix at subzero temperatures can maintain a liquid phase where organic solutes and salts concentrate to form eutectic solutions. This concentration effect converts the confined reactant solutions in the ice matrix, sometimes making condensation and polymerisation reactions occur more favourably. These reactions occur at significantly high rates from a prebiotic chemistry standpoint, and the labile products can be protected from degradation. The experimental study of the synthesis of nitrogen heterocycles at the ice-water system showed the efficiency of this scenario and could explain the origin of nucleobases in the inner Solar System bodies, including meteorites and extra-terrestrial ices, and on the early Earth. The same conditions can also favour the condensation of monomers to form ribonucleic acid and peptides. Together with the synthesis of these monomers, the ice world (i.e., the chemical evolution in the range between the freezing point of water and the limit of stability of liquid brines, 273 to 210 K) is an under-explored experimental model in prebiotic chemistry.
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Affiliation(s)
- César Menor-Salván
- Centro de Astrobiología (INTA-CSIC), INTA, E-28850 Torrejón de Ardoz, Spain.
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30
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Møllendal H, Margulès L, Motiyenko RA, Larsen NW, Guillemin JC. Rotational Spectrum and Conformational Composition of Cyanoacetaldehyde, a Compound of Potential Prebiotic and Astrochemical Interest. J Phys Chem A 2012; 116:4047-56. [DOI: 10.1021/jp212306z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Harald Møllendal
- Centre for Theoretical and Computational
Chemistry (CTCC), Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO 0315 Oslo, Norway
| | - Laurent Margulès
- Laboratoire de Physique des
Lasers, Atomes, et Molécules, UMR CNRS 8523, Université de Lille I, F-59655 Villeneuve d’Ascq Cédex,
France
| | - Roman A. Motiyenko
- Laboratoire de Physique des
Lasers, Atomes, et Molécules, UMR CNRS 8523, Université de Lille I, F-59655 Villeneuve d’Ascq Cédex,
France
| | - Niels Wessel Larsen
- Department of Chemistry, University of Copenhagen, The H. C. Ørsted Institute,
Universitetsparken 5, DK 2100 Copenhagen Ø, Denmark
| | - Jean-Claude Guillemin
- Sciences Chimiques de Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, Avenue du Général Leclerc, CS 50837,
35708 Rennes Cedex 7, France
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Nuevo M, Milam SN, Sandford SA. Nucleobases and prebiotic molecules in organic residues produced from the ultraviolet photo-irradiation of pyrimidine in NH(3) and H(2)O+NH(3) ices. ASTROBIOLOGY 2012; 12:295-314. [PMID: 22519971 DOI: 10.1089/ast.2011.0726] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Although not yet identified in the interstellar medium (ISM), N-heterocycles including nucleobases-the information subunits of DNA and RNA-are present in carbonaceous chondrites, which indicates that molecules of biological interest can be formed in non-terrestrial environments via abiotic pathways. Recent laboratory experiments and ab initio calculations have already shown that the irradiation of pyrimidine in pure H(2)O ices leads to the formation of a suite of oxidized pyrimidine derivatives, including the nucleobase uracil. In the present work, NH(3):pyrimidine and H(2)O:NH(3):pyrimidine ice mixtures with different relative proportions were irradiated with UV photons under astrophysically relevant conditions. Liquid- and gas-chromatography analysis of the resulting organic residues has led to the detection of the nucleobases uracil and cytosine, as well as other species of prebiotic interest such as urea and small amino acids. The presence of these molecules in organic residues formed under abiotic conditions supports scenarios in which extraterrestrial organics that formed in space and were subsequently delivered to telluric planets via comets and meteorites could have contributed to the inventory of molecules that triggered the first biological reactions on their surfaces.
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Affiliation(s)
- Michel Nuevo
- NASA Ames Research Center, Space Science Division, Moffett Field, California 94035, USA
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Wang T, Bowie JH. Can cytosine, thymine and uracil be formed in interstellar regions? A theoretical study. Org Biomol Chem 2012; 10:652-62. [DOI: 10.1039/c1ob06352a] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Abstract
Recent synthetic approaches to understanding the origin of life have yielded insights into plausible pathways for the emergence of the first cells. Here we review current experiments with implications for the origin of life, emphasizing the ability of unexpected physical processes to facilitate the self-assembly and self-replication of the first biological systems. These laboratory efforts have uncovered novel physical mechanisms for the emergence of homochirality; the concentration and purification of prebiotic building blocks; and the ability of the first cells to assemble, grow, divide, and acquire greater complexity. In the absence of evolved biochemical capabilities, such physical processes likely played an essential role in early biology.
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Affiliation(s)
- Itay Budin
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114-2696, USA
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35
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Demongeot J. Biological boundaries and biological age. Acta Biotheor 2009; 57:397-418. [PMID: 19907923 DOI: 10.1007/s10441-009-9087-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Accepted: 09/16/2009] [Indexed: 11/28/2022]
Abstract
The chronologic age classically used in demography is often unable to give useful information about which exact stage in development or aging processes has reached an organism. Hence, we propose here to explain in some applications for what reason the chronologic age fails in explaining totally the observed state of an organism, which leads to propose a new notion, the biological age. This biological age is essentially determined by the number of divisions before the Hayflick's limit the tissue or mitochondrion in a critical organ (in the sense where its loss causes the death of the whole organism) has already used for its development and adult phases. We give a precise definition of the biological age of an organ based on the Hayflick's limit of its cells and we introduce a desynchronization index (the cell entropy) for some critical tissues or membranes, which are mainly skin, intestinal endothelium, alveoli epithelium and mitochondrial inner membrane. In these actively metabolising interface tissues or membranes, there is a rapid turnover of cells, of their cytoplasmic constituents such as proteins, and of membrane lipids. The boundaries corresponding to these tissues, cells or membranes have vital functions of interface with the environment (protection, homeothermy, nutrition and respiration) and have a rapid turnover (the total cell renewal time is in mice equal to 3 weeks for the skin, 1.5 day for the intestine, 4 months for the alveolae and 11 days for mitochondrial inner membrane) conditioning their biological age. The biological age of a tissue is made of two major components: (1) first, its embryonic age based on the distance (in number of divisions) between the birth date of its first differentiated cell and the time until it reaches its final boundary at the end of its development and (2) second, its adult age whose complement until its death is just the lapse of time made of the sum of remaining cell cycle durations authorized by its Hayflick's limit. From this definition, we calculate the global biological lifespan of an organism and revisit notions like demographic survival curves, duration and synchrony of cell cycles, living boundaries from proto-cells to organs, and embryonic and adult phases duration.
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Affiliation(s)
- Jacques Demongeot
- TIMC-IMAG, UMR CNRS 5525, Team AGIM(3), Faculty of Medicine of Grenoble, University J. Fourier, 38700, La Tronche, France.
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Ruiz-Bermejo M, Rogero C, Menor-Salván C, Osuna-Esteban S, Martín-Gago J, Veintemillas-Verdaguer S. Thermal Wet Decomposition of Prussian Blue: Implications for Prebiotic Chemistry. Chem Biodivers 2009; 6:1309-22. [DOI: 10.1002/cbdv.200900024] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Precambrian lunar volcanic protolife. Int J Mol Sci 2009; 10:2681-2721. [PMID: 19582224 PMCID: PMC2705511 DOI: 10.3390/ijms10062681] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Revised: 05/28/2009] [Accepted: 06/03/2009] [Indexed: 11/20/2022] Open
Abstract
Five representative terrestrial analogs of lunar craters are detailed relevant to Precambrian fumarolic activity. Fumarolic fluids contain the ingredients for protolife. Energy sources to derive formaldehyde, amino acids and related compounds could be by flow charging, charge separation and volcanic shock. With no photodecomposition in shadow, most fumarolic fluids at 40 K would persist over geologically long time periods. Relatively abundant tungsten would permit creation of critical enzymes, Fischer-Tropsch reactions could form polycyclic aromatic hydrocarbons and soluble volcanic polyphosphates would enable assembly of nucleic acids. Fumarolic stimuli factors are described. Orbital and lander sensors specific to protolife exploration including combined Raman/laser-induced breakdown spectrocsopy are evaluated.
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Horn A, Møllendal H, Guillemin JC. A Quantum Chemical Study of the Generation of a Potential Prebiotic Compound, Cyanoacetaldehyde, and Related Sulfur Containing Species. J Phys Chem A 2008; 112:11009-16. [DOI: 10.1021/jp805357w] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anne Horn
- Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway, and Sciences Chimiques de Rennes, École Nationale Supérieure de Chimie de Rennes-CNRS, F-35700 Rennes, France
| | - Harald Møllendal
- Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway, and Sciences Chimiques de Rennes, École Nationale Supérieure de Chimie de Rennes-CNRS, F-35700 Rennes, France
| | - Jean-Claude Guillemin
- Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway, and Sciences Chimiques de Rennes, École Nationale Supérieure de Chimie de Rennes-CNRS, F-35700 Rennes, France
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Monnard PA, Ziock H. Eutectic Phase in Water-Ice: A Self-Assembled Environment Conducive to Metal-Catalyzed Non-Enzymatic RNA Polymerization. Chem Biodivers 2008; 5:1521-1539. [DOI: 10.1002/cbdv.200890141] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Abstract
The demonstration that ribosomal peptide synthesis is a ribozyme-catalyzed reaction makes it almost certain that there was once an RNA World. The central problem for origin-of-life studies, therefore, is to understand how a protein-free RNA World became established on the primitive Earth. We first review the literature on the prebiotic synthesis of the nucleotides, the nonenzymatic synthesis and copying of polynucleotides, and the selection of ribozyme catalysts of a kind that might have facilitated polynucleotide replication. This leads to a brief outline of the Molecular Biologists' Dream, an optimistic scenario for the origin of the RNA World. In the second part of the review we point out the many unresolved problems presented by the Molecular Biologists' Dream. This in turn leads to a discussion of genetic systems simpler than RNA that might have "invented" RNA. Finally, we review studies of prebiotic membrane formation.
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Abstract
Recent studies support an earlier suggestion that, if adenine was formed prebiotically on the primitive earth, eutectic freezing of hydrogen cyanide solutions is likely to have been important. Here we revisit the suggestion that the synthesis of adenine may have involved the photochemical conversion of the tetramer of hydrogen cyanide in eutectic solution to 4-amino-5-cyano-imidazole. This would make possible a reaction sequence that does not require the presence of free ammonia. It is further suggested that the reaction of cyanoacetylene with cyanate in eutectic solution to give cytosine might have proceeded in parallel with adenine synthesis.
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Affiliation(s)
- Leslie E Orgel
- The Salk Institute for Biological Studies, San Diego, CA, USA.
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Martin W, Russell MJ. On the origins of cells: a hypothesis for the evolutionary transitions from abiotic geochemistry to chemoautotrophic prokaryotes, and from prokaryotes to nucleated cells. Philos Trans R Soc Lond B Biol Sci 2003; 358:59-83; discussion 83-5. [PMID: 12594918 PMCID: PMC1693102 DOI: 10.1098/rstb.2002.1183] [Citation(s) in RCA: 401] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
All life is organized as cells. Physical compartmentation from the environment and self-organization of self-contained redox reactions are the most conserved attributes of living things, hence inorganic matter with such attributes would be life's most likely forebear. We propose that life evolved in structured iron monosulphide precipitates in a seepage site hydrothermal mound at a redox, pH and temperature gradient between sulphide-rich hydrothermal fluid and iron(II)-containing waters of the Hadean ocean floor. The naturally arising, three-dimensional compartmentation observed within fossilized seepage-site metal sulphide precipitates indicates that these inorganic compartments were the precursors of cell walls and membranes found in free-living prokaryotes. The known capability of FeS and NiS to catalyse the synthesis of the acetyl-methylsulphide from carbon monoxide and methylsulphide, constituents of hydrothermal fluid, indicates that pre-biotic syntheses occurred at the inner surfaces of these metal-sulphide-walled compartments, which furthermore restrained reacted products from diffusion into the ocean, providing sufficient concentrations of reactants to forge the transition from geochemistry to biochemistry. The chemistry of what is known as the RNA-world could have taken place within these naturally forming, catalyticwalled compartments to give rise to replicating systems. Sufficient concentrations of precursors to support replication would have been synthesized in situ geochemically and biogeochemically, with FeS (and NiS) centres playing the central catalytic role. The universal ancestor we infer was not a free-living cell, but rather was confined to the naturally chemiosmotic, FeS compartments within which the synthesis of its constituents occurred. The first free-living cells are suggested to have been eubacterial and archaebacterial chemoautotrophs that emerged more than 3.8 Gyr ago from their inorganic confines. We propose that the emergence of these prokaryotic lineages from inorganic confines occurred independently, facilitated by the independent origins of membrane-lipid biosynthesis: isoprenoid ether membranes in the archaebacterial and fatty acid ester membranes in the eubacterial lineage. The eukaryotes, all of which are ancestrally heterotrophs and possess eubacterial lipids, are suggested to have arisen ca. 2 Gyr ago through symbiosis involving an autotrophic archaebacterial host and a heterotrophic eubacterial symbiont, the common ancestor of mitochondria and hydrogenosomes. The attributes shared by all prokaryotes are viewed as inheritances from their confined universal ancestor. The attributes that distinguish eubacteria and archaebacteria, yet are uniform within the groups, are viewed as relics of their phase of differentiation after divergence from the non-free-living universal ancestor and before the origin of the free-living chemoautotrophic lifestyle. The attributes shared by eukaryotes with eubacteria and archaebacteria, respectively, are viewed as inheritances via symbiosis. The attributes unique to eukaryotes are viewed as inventions specific to their lineage. The origin of the eukaryotic endomembrane system and nuclear membrane are suggested to be the fortuitous result of the expression of genes for eubacterial membrane lipid synthesis by an archaebacterial genetic apparatus in a compartment that was not fully prepared to accommodate such compounds, resulting in vesicles of eubacterial lipids that accumulated in the cytosol around their site of synthesis. Under these premises, the most ancient divide in the living world is that between eubacteria and archaebacteria, yet the steepest evolutionary grade is that between prokaryotes and eukaryotes.
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Affiliation(s)
- William Martin
- Institut für Botanik III, Heinrich-Heine Universitaet Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany.
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Abstract
Cyanoacetylene is an earlier intermediate in a proposed prebiotic synthesis of cytosine, while cyanoacetaldehyde is a later intermediate. There is no scientific basis for the claim that cyanoacetaldehyde is more plausibly prebiotic than cyanoacetylene in this context.
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Affiliation(s)
- Leslie E Orgel
- The Salk Institute for Biological Studies, La Jolla, CA, USA.
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Shapiro R. Comments on 'concentration by evaporation and the prebiotic synthesis of cytosine'. ORIGINS LIFE EVOL B 2002; 32:275-8. [PMID: 12227431 DOI: 10.1023/a:1016582308525] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The claim by Nelson et al. (2001) that the reaction of cyanoacetaldehyde and urea provides 'an efficient prebiotic synthesis' of cytosine is disputed. The authors have not dealt with the important points presented in a criticism of this reaction (Shapiro, 1999): (1) The reactants undergo side reactions with common nucleophiles that appear to proceed more rapidly than cytosine formation, and (2) No reactions have been described thus far that would produce cytosine at a rate sufficient to compensate for its decomposition by deamination, and permit accumulation over extended periods of time. Instead, Nelson et al. have conducted 'drying-down' experiments, in an effort to simulate evaporations on the early Earth, but the design of these experiments is flawed. The initial reactant concentrations are much higher than might be expected in a natural setting, and potentially interfering substances such as glycine, cyanide and thiols have been excluded. 'Drying beaches and drying lagoons' have been invoked as sites for such a reaction but no effort has been made to describe the characteristics of such sites or to estimate their frequency with reference to the present Earth. In the absence of contradictory data, the conclusion put forward in Shapiro (1999) remains valid: 'It was quite unlikely that cytosine played a role in the origin of life'.
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Affiliation(s)
- Robert Shapiro
- Department of Chemistry, New York University, NY 10003-6688, USA.
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Kanavarioti A, Monnard PA, Deamer DW. Eutectic phases in ice facilitate nonenzymatic nucleic acid synthesis. ASTROBIOLOGY 2001; 1:271-281. [PMID: 12448990 DOI: 10.1089/15311070152757465] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Polymeric compounds similar to oligonucleotides are relevant to the origin of life and particularly to the concept of an RNA world. Although short oligomers of RNA can be synthesized nonenzymatically under laboratory conditions by second-order reactions in concentrated solutions, there is no consensus on how these polymers could have been synthesized de novo on the early Earth from dilute solutions of monomers. To address this question in the context of an RNA world, we have explored ice eutectic phases as a reaction medium. When an aqueous solution freezes, the solutes become concentrated in the spaces between the ice crystals. The increased concentration offsets the effect of the lower temperature and accelerates the reaction. Here we show that in the presence of metal ions in dilute solutions, frozen samples of phosphoimidazolide-activated uridine react within days at -18 degrees C to form oligouridylates up to 11 bases long. Product yields typically exceed 90%, and approximately 30% of the oligomers include one or more 3'-5' linkages. These conditions facilitate not only the notoriously difficult oligouridylate synthesis, but also the oligomerization of activated cytidylate, adenylate, and guanylate. To our knowledge, this represents the first report to indicate that ice matrices on the early Earth may have accelerated certain prebiotic polymerization reactions.
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Affiliation(s)
- A Kanavarioti
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, CA, USA.
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