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Rimmer PB, Shorttle O. A Surface Hydrothermal Source of Nitriles and Isonitriles. Life (Basel) 2024; 14:498. [PMID: 38672768 PMCID: PMC11051382 DOI: 10.3390/life14040498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 03/22/2024] [Accepted: 03/29/2024] [Indexed: 04/28/2024] Open
Abstract
Giant impacts can generate transient hydrogen-rich atmospheres, reducing atmospheric carbon. The reduced carbon will form hazes that rain out onto the surface and can become incorporated into the crust. Once heated, a large fraction of the carbon is converted into graphite. The result is that local regions of the Hadean crust were plausibly saturated with graphite. We explore the consequences of such a crust for a prebiotic surface hydrothermal vent scenario. We model a surface vent fed by nitrogen-rich volcanic gas from high-temperature magmas passing through graphite-saturated crust. We consider this occurring at pressures of 1-1000bar and temperatures of 1500-1700 ∘C. The equilibrium with graphite purifies the leftover gas, resulting in substantial quantities of nitriles (0.1% HCN and 1ppm HC3N) and isonitriles (0.01% HNC) relevant for prebiotic chemistry. We use these results to predict gas-phase concentrations of methyl isocyanide of ∼1 ppm. Methyl isocyanide can participate in the non-enzymatic activation and ligation of the monomeric building blocks of life, and surface or shallow hydrothermal environments provide its only known equilibrium geochemical source.
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Affiliation(s)
- Paul B. Rimmer
- Cavendish Laboratory, University of Cambridge, JJ Thomson Ave, Cambridge CB3 0HE, UK
| | - Oliver Shorttle
- Institute of Astronomy, University of Cambridge, Cambridge CB3 0HA, UK
- Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK
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2
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Madhusudhan N, Moses JI, Rigby F, Barrier E. Chemical conditions on Hycean worlds. Faraday Discuss 2023; 245:80-111. [PMID: 37530120 DOI: 10.1039/d3fd00075c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
Traditionally, the search for life on exoplanets has been predominantly focused on rocky exoplanets. The recently proposed Hycean worlds have the potential to significantly expand and accelerate the search for life elsewhere. Hycean worlds are a class of habitable sub-Neptunes with planet-wide oceans and H2-rich atmospheres. Their broad range of possible sizes and temperatures lead to a wide habitable zone and high potential for discovery and atmospheric characterization using transit spectroscopy. Over a dozen candidate Hycean planets are already known to be transiting nearby M dwarfs, making them promising targets for atmospheric characterization with the James Webb Space Telescope (JWST). In this work, we investigate possible chemical conditions on a canonical Hycean world, focusing on (a) the present and primordial molecular composition of the atmosphere, and (b) the inventory of bioessential elements for the origin and sustenance of life in the ocean. Based on photochemical and kinetic modeling for a range of conditions, we discuss the possible chemical evolution and observable present-day composition of its atmosphere. In particular, for reduced primordial conditions the early atmospheric evolution passes through a phase that is rich in organic molecules that could provide important feedstock for prebiotic chemistry. We investigate avenues for delivering bioessential metals to the ocean, considering the challenging lack of weathering from a rocky surface and the ocean separated from the rocky core by a thick icy mantle. Based on ocean depths from internal structure modelling and elemental estimates for the early Earth's oceans, we estimate the requirements for bioessential metals in such a planet. We find that the requirements can be met for plausible assumptions about impact history and atmospheric sedimentation, and supplemented by other steady state sources. We discuss the observational prospects for atmospheric characterisation of Hycean worlds with JWST and future directions of this new paradigm in the search for life on exoplanets.
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Affiliation(s)
| | | | - Frances Rigby
- Institute of Astronomy, University of Cambridge, Cambridge, UK.
| | - Edouard Barrier
- Institute of Astronomy, University of Cambridge, Cambridge, UK.
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3
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Armas-Vázquez MZ, González-Espinoza CE, Segura A, Heredia A, Miranda-Rosete A. Impact of M Dwarfs Ultraviolet Radiation on Prebiotic Chemistry: The Case of Adenine. ASTROBIOLOGY 2023; 23:705-722. [PMID: 37115581 DOI: 10.1089/ast.2022.0050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
To date, several exoplanets have been found to orbit within the habitable zone of main sequence M stars (M dwarfs). These stars exhibit different levels of chromospheric activity that produces ultraviolet (UV) radiation. UV may be harmful to life, but it can also trigger reactions of prebiotic importance on the surface of a potentially habitable planet (PHP). We created a code to obtain the adenine yield for a known adenine synthesis route from diaminomaleonitrile (DAMN). We used computational methods to calculate the reaction coefficient rates (photolysis rate J and rate constant K) for the intermediate molecules DAMN, diaminofumaronitrile (DAFN), and 4-aminoimidazole-5-carbonitrile (AICN) of the adenine synthesis route. We used stellar UV sources and a mercury lamp to compare the theoretical results with experiments performed with lamps. The surface UV flux of planets in the habitable zone of two active M dwarfs (Proxima Centauri and AD Leonis) and the prebiotic Earth was calculated using the photochemical model ATMOS, considering a CO2-N2-H2O atmosphere. We obtained UV absorption coefficients for DAMN and DAFN and thermodynamic parameters that are useful for prebiotic chemistry studies. According to our results, experiments using UV lamps may underestimate the photolysis production of molecules of prebiotic importance. Our results indicate that photolysis reactions are fast with a yield of 50% of AICN in 10 s for the young Sun and ∼1 h for Proxima Centauri b. Planets around active M dwarfs may provide the most favorable environment for UV-mediated production of compounds relevant to the origins of life. The kinetic reaction AICN + HCN adenine is the bottleneck of the pathway with reaction rates <10-22 L/(mol·s).
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Affiliation(s)
- M Zulema Armas-Vázquez
- Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México (UNAM), Ciudad de Mexico, Mexico
| | | | - Antígona Segura
- Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México (UNAM), Ciudad de Mexico, Mexico
| | - Alejandro Heredia
- Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México (UNAM), Ciudad de Mexico, Mexico
| | - Arturo Miranda-Rosete
- Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México (UNAM), Ciudad de Mexico, Mexico
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4
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Shapiro AV, Brühl C, Klingmüller K, Steil B, Shapiro AI, Witzke V, Kostogryz N, Gizon L, Solanki SK, Lelieveld J. Metal-rich stars are less suitable for the evolution of life on their planets. Nat Commun 2023; 14:1893. [PMID: 37072387 PMCID: PMC10113254 DOI: 10.1038/s41467-023-37195-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 03/03/2023] [Indexed: 04/20/2023] Open
Abstract
Atmospheric ozone and oxygen protect the terrestrial biosphere against harmful ultraviolet (UV) radiation. Here, we model atmospheres of Earth-like planets hosted by stars with near-solar effective temperatures (5300 to 6300 K) and a broad range of metallicities covering known exoplanet host stars. We show that paradoxically, although metal-rich stars emit substantially less ultraviolet radiation than metal-poor stars, the surface of their planets is exposed to more intense ultraviolet radiation. For the stellar types considered, metallicity has a larger impact than stellar temperature. During the evolution of the universe, newly formed stars have progressively become more metal-rich, exposing organisms to increasingly intense ultraviolet radiation. Our findings imply that planets hosted by stars with low metallicity are the best targets to search for complex life on land.
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Affiliation(s)
- Anna V Shapiro
- Max Planck Institute for Solar System Research, Göttingen, Germany.
| | | | | | | | | | - Veronika Witzke
- Max Planck Institute for Solar System Research, Göttingen, Germany
| | - Nadiia Kostogryz
- Max Planck Institute for Solar System Research, Göttingen, Germany
| | - Laurent Gizon
- Max Planck Institute for Solar System Research, Göttingen, Germany
- Institute for Astrophysics, Georg-August-Universität Göttingen, Göttingen, Germany
- Center for Space Science, NYUAD Institute, New York University Abu Dhabi, Abu Dhabi, UAE
| | - Sami K Solanki
- Max Planck Institute for Solar System Research, Göttingen, Germany
- School of Space Research, Kyung Hee University, Yongin, Republic of Korea
| | - Jos Lelieveld
- Max Planck Institute for Chemistry, Mainz, Germany
- The Cyprus Institute, Climate and Atmosphere Research Center, Nicosia, Cyprus
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5
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On the origins of life's homochirality: Inducing enantiomeric excess with spin-polarized electrons. Proc Natl Acad Sci U S A 2022; 119:e2204765119. [PMID: 35787048 PMCID: PMC9282223 DOI: 10.1073/pnas.2204765119] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Life as we know it is homochiral, but the origins of biological homochirality on early Earth remain elusive. Shallow closed-basin lakes are a plausible prebiotic environment on early Earth, and most are expected to have significant sedimentary magnetite deposits. We hypothesize that ultraviolet (200- to 300-nm) irradiation of magnetite deposits could generate hydrated spin-polarized electrons sufficient to induce enantioselective prebiotic chemistry. Such electrons are potent reducing agents that drive reduction reactions where the spin polarization direction can enantioselectively alter the reaction kinetics. Our estimate of this chiral bias is based on the strong effective spin-orbit coupling observed in the chiral-induced spin selectivity (CISS) effect, as applied to energy differences in reduction reactions for different isomers. In the original CISS experiments, spin-selective electron transmission through a monolayer of double-strand DNA molecules is observed at room temperature-indicating a strong coupling between molecular chirality and electron spin. We propose that the chiral symmetry breaking due to the CISS effect, when applied to reduction chemistry, can induce enantioselective synthesis on the prebiotic Earth and thus facilitate the homochiral assembly of life's building blocks.
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Ranjan S, Kufner CL, Lozano GG, Todd ZR, Haseki A, Sasselov DD. UV Transmission in Natural Waters on Prebiotic Earth. ASTROBIOLOGY 2022; 22:242-262. [PMID: 34939825 PMCID: PMC8968845 DOI: 10.1089/ast.2020.2422] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Ultraviolet (UV) light plays a key role in surficial theories of the origin of life, and numerous studies have focused on constraining the atmospheric transmission of UV radiation on early Earth. However, the UV transmission of the natural waters in which origins-of-life chemistry (prebiotic chemistry) is postulated to have occurred is poorly constrained. In this work, we combine laboratory and literature-derived absorption spectra of potential aqueous-phase prebiotic UV absorbers with literature estimates of their concentrations on early Earth to constrain the prebiotic UV environment in marine and terrestrial natural waters, and we consider the implications for prebiotic chemistry. We find that prebiotic freshwaters were largely transparent in the UV, contrary to assumptions in some models of prebiotic chemistry. Some waters, such as high-salinity waters like carbonate lakes, may be deficient in shortwave (≤220 nm) UV flux. More dramatically, ferrous waters can be strongly UV-shielded, particularly if the Fe2+ forms highly UV-absorbent species such as FeCN64-. Such waters may be compelling venues for UV-averse origin-of-life scenarios but are unfavorable for some UV-dependent prebiotic chemistries. UV light can trigger photochemistry even if attenuated through photochemical transformations of the absorber (e.g., eaq- production from halide irradiation), which may have both constructive and destructive effects for prebiotic syntheses. Prebiotic chemistries that invoke waters that contain such absorbers must self-consistently account for the chemical effects of these transformations. The speciation and abundance of Fe2+ in natural waters on early Earth is a major uncertainty and should be prioritized for further investigation, as it played a major role in UV transmission in prebiotic natural waters.
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Affiliation(s)
- Sukrit Ranjan
- Department of Earth, Atmospheric & Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Department of Physics and Astronomy, Center for Interdisciplinary Exploration and Research in Astrophysics, Northwestern University, Evanston, Illinois, USA
- Blue Marble Space Institute of Science, Seattle, Washington, USA
- Address correspondence to: Sukrit Ranjan, Department of Physics and Astronomy, Center for Interdisciplinary Exploration and Research in Astrophysics, Northwestern University, 1800 Sherman Avenue, 6th Floor, Evanston, IL 60601, USA
| | - Corinna L. Kufner
- Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA
| | | | - Zoe R. Todd
- Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA
- Department of Earth and Space Sciences, University of Washington, Seattle, Washington, USA
| | - Azra Haseki
- Department of Earth, Atmospheric & Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Harvard College, Cambridge, Massachusetts, USA
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7
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Rimmer PB, Thompson SJ, Xu J, Russell DA, Green NJ, Ritson DJ, Sutherland JD, Queloz DP. Timescales for Prebiotic Photochemistry Under Realistic Surface Ultraviolet Conditions. ASTROBIOLOGY 2021; 21:1099-1120. [PMID: 34152196 PMCID: PMC8570677 DOI: 10.1089/ast.2020.2335] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Ultraviolet (UV) light has long been invoked as a source of energy for prebiotic chemical synthesis, but experimental support does not involve sources of UV light that look like the young Sun. Here we experimentally investigate whether the UV flux available on the surface of early Earth, given a favorable atmosphere, can facilitate a variety of prebiotic chemical syntheses. We construct a solar simulator for the UV light of the faint young Sun on the surface of early Earth, called StarLab. We then attempt a series of reactions testing different aspects of a prebiotic chemical scenario involving hydrogen cyanide (HCN), sulfites, and sulfides under the UV light of StarLab, including hypophosphite oxidation by UV light and hydrogen sulfide, photoreduction of HCN with bisulfite, the photoanomerization of α-thiocytidine, the production of a chemical precursor of a potentially prebiotic activating agent (nitroprusside), the photoreduction of thioanhydrouridine and thioanhydroadenosine, and the oxidation of ethanol (EtOH) by photochemically generated hydroxyl radicals. We compare the output of StarLab to the light of the faint young Sun to constrain the timescales over which these reactions would occur on the surface of early Earth. We predict that hypophosphite oxidation, HCN reduction, and photoproduction of nitroprusside would all operate on the surface of early Earth in a matter of days to weeks. The photoanomerization of α-thiocytidine would take months to complete, and the production of oxidation products from hydroxyl radicals would take years. The photoreduction of thioanhydrouridine with hydrogen sulfide did not succeed even after a long period of irradiation, providing a lower limit on the timescale of several years. The photoreduction of thioanhydroadenosine with bisulfite produced 2'-deoxyriboadenosine (dA) on the timescale of days. This suggests the plausibility of the photoproduction of purine deoxyribonucleotides, such as the photoproduction of simple sugars, proceeds more efficiently in the presence of bisulfite.
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Affiliation(s)
- Paul B. Rimmer
- Department of Earth Sciences, University of Cambridge, Cambridge, United Kingdom
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
- Address correspondence to: Paul B. Rimmer, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, United Kingdom
| | | | - Jianfeng Xu
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | | | | | | | | | - Didier P. Queloz
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
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8
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Rivera-Valentín EG, Filiberto J, Lynch KL, Mamajanov I, Lyons TW, Schulte M, Méndez A. Introduction-First Billion Years: Habitability. ASTROBIOLOGY 2021; 21:893-905. [PMID: 34406807 PMCID: PMC8403211 DOI: 10.1089/ast.2020.2314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 12/22/2020] [Indexed: 06/13/2023]
Abstract
The physical processes active during the first billion years (FBY) of Earth's history, such as accretion, differentiation, and impact cratering, provide constraints on the initial conditions that were conducive to the formation and establishment of life on Earth. This motivated the Lunar and Planetary Institute's FBY topical initiative, which was a four-part conference series intended to look at each of these physical processes to study the basic structure and composition of our Solar System that was set during the FBY. The FBY Habitability conference, held in September 2019, was the last in this series and was intended to synthesize the initiative; specifically, to further our understanding of the origins of life, planetary and environmental habitability, and the search for life beyond Earth. The conference included discussions of planetary habitability and the potential emergence of life on bodies within our Solar System, as well as extrasolar systems by applying our knowledge of the Solar System's FBY, and in particular Earth's early history. To introduce this Special Collection, which resulted from work discussed at the conference, we provide a review of the main themes and a synopsis of the FBY Habitability conference.
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Affiliation(s)
| | - Justin Filiberto
- Lunar and Planetary Institute, Universities Space Research Association, Houston, Texas, USA
| | - Kennda L. Lynch
- Lunar and Planetary Institute, Universities Space Research Association, Houston, Texas, USA
| | - Irena Mamajanov
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
| | - Timothy W. Lyons
- Department of Earth and Planetary Sciences, University of California Riverside, Riverside, California, USA
| | - Mitch Schulte
- Planetary Science Division, NASA Headquarters, Washington, District of Columbia, USA
| | - Abel Méndez
- Planetary Habitability Laboratory, University of Puerto Rico Arecibo, Arecibo, Puerto Rico
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9
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Possibilities for an Aerial Biosphere in Temperate Sub Neptune-Sized Exoplanet Atmospheres. UNIVERSE 2021. [DOI: 10.3390/universe7060172] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The search for signs of life through the detection of exoplanet atmosphere biosignature gases is gaining momentum. Yet, only a handful of rocky exoplanet atmospheres are suitable for observation with planned next-generation telescopes. To broaden prospects, we describe the possibilities for an aerial, liquid water cloud-based biosphere in the atmospheres of sub Neptune-sized temperate exoplanets, those receiving Earth-like irradiation from their host stars. One such planet is known (K2-18b) and other candidates are being followed up. Sub Neptunes are common and easier to study observationally than rocky exoplanets because of their larger sizes, lower densities, and extended atmospheres or envelopes. Yet, sub Neptunes lack any solid surface as we know it, so it is worthwhile considering whether their atmospheres can support an aerial biosphere. We review, synthesize, and build upon existing research. Passive microbial-like life particles must persist aloft in a region with liquid water clouds for long enough to metabolize, reproduce, and spread before downward transport to lower altitudes that may be too hot for life of any kind to survive. Dynamical studies are needed to flesh out quantitative details of life particle residence times. A sub Neptune would need to be a part of a planetary system with an unstable asteroid belt in order for meteoritic material to provide nutrients, though life would also need to efficiently reuse and recycle metals. The origin of life may be the most severe limiting challenge. Regardless of the uncertainties, we can keep an open mind to the search for biosignature gases as a part of general observational studies of sub Neptune exoplanets.
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10
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Colville BWF, Powner MW. Selective Prebiotic Synthesis of α‐Threofuranosyl Cytidine by Photochemical Anomerization. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202101376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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11
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Colville BWF, Powner MW. Selective Prebiotic Synthesis of α-Threofuranosyl Cytidine by Photochemical Anomerization. Angew Chem Int Ed Engl 2021; 60:10526-10530. [PMID: 33644959 PMCID: PMC8252090 DOI: 10.1002/anie.202101376] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Indexed: 11/23/2022]
Abstract
The structure of life's first genetic polymer is a question of intense ongoing debate. The “RNA world theory” suggests RNA was life's first nucleic acid. However, ribonucleotides are complex chemical structures, and simpler nucleic acids, such as threose nucleic acid (TNA), can carry genetic information. In principle, nucleic acids like TNA could have played a vital role in the origins of life. The advent of any genetic polymer in life requires synthesis of its monomers. Here we demonstrate a high‐yielding, stereo‐, regio‐ and furanosyl‐selective prebiotic synthesis of threo‐cytidine 3, an essential component of TNA. Our synthesis uses key intermediates and reactions previously exploited in the prebiotic synthesis of the canonical pyrimidine ribonucleoside cytidine 1. Furthermore, we demonstrate that erythro‐specific 2′,3′‐cyclic phosphate synthesis provides a mechanism to photochemically select TNA cytidine. These results suggest that TNA may have coexisted with RNA during the emergence of life.
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Affiliation(s)
- Ben W F Colville
- Department of Chemistry, UCL, 20 Gordon Street, London, WC1H 0AJ, UK
| | - Matthew W Powner
- Department of Chemistry, UCL, 20 Gordon Street, London, WC1H 0AJ, UK
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12
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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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13
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Clark BC, Kolb VM. Macrobiont: Cradle for the Origin of Life and Creation of a Biosphere. Life (Basel) 2020; 10:life10110278. [PMID: 33198206 PMCID: PMC7697624 DOI: 10.3390/life10110278] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 11/09/2020] [Accepted: 11/09/2020] [Indexed: 02/06/2023] Open
Abstract
Although the cellular microorganism is the fundamental unit of biology, the origin of life (OoL) itself is unlikely to have occurred in a microscale environment. The macrobiont (MB) is the macro-scale setting where life originated. Guided by the methodologies of Systems Analysis, we focus on subaerial ponds of scale 3 to 300 m diameter. Within such ponds, there can be substantial heterogeneity, on the vertical, horizontal, and temporal scales, which enable multi-pot prebiotic chemical evolution. Pond size-sensitivities for several figures of merit are mathematically formulated, leading to the expectation that the optimum pond size for the OoL is intermediate, but biased toward smaller sizes. Sensitivities include relative access to nutrients, energy sources, and catalysts, as sourced from geological, atmospheric, hydrospheric, and astronomical contributors. Foreshores, especially with mudcracks, are identified as a favorable component for the success of the macrobiont. To bridge the gap between inanimate matter and a planetary-scale biosphere, five stages of evolution within the macrobiont are hypothesized: prebiotic chemistry → molecular replicator → protocell → macrobiont cell → colonizer cell. Comparison of ponds with other macrobionts, including hydrothermal and meteorite settings, allows a conclusion that more than one possible macrobiont locale could enable an OoL.
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Affiliation(s)
- Benton C. Clark
- Space Science Institute, Boulder, CO 80301, USA
- Correspondence:
| | - Vera M. Kolb
- Department of Chemistry, University of Wisconsin—Parkside, Kenosha, WI 53141, USA;
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14
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Liu Z. Synthesis of Prebiotic Building Blocks by Photochemistry. Chem Res Chin Univ 2020. [DOI: 10.1007/s40242-020-0289-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Testing Earthlike Atmospheric Evolution on Exo-Earths through Oxygen Absorption: Required Sample Sizes and the Advantage of Age-based Target Selection. ACTA ACUST UNITED AC 2020. [DOI: 10.3847/1538-4357/ab8fad] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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16
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Ritson DJ, Mojzsis SJ, Sutherland JD. Supply of phosphate to early Earth by photogeochemistry after meteoritic weathering. NATURE GEOSCIENCE 2020; 13:344-348. [PMID: 32395178 PMCID: PMC7213494 DOI: 10.1038/s41561-020-0556-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 02/19/2020] [Indexed: 05/24/2023]
Abstract
During terrestrial differentiation, the relatively small amount of phosphorus that migrated to the lithosphere was incorporated into igneous rock, predominantly in the form of basic calcium orthophosphate (Ca10(PO4)6(OH,F,Cl)2, apatite). Yet, the highly insoluble nature of calcium apatite presents a significant problem to those contemplating the origin of life given the foundational role of phosphate (PO4 3-) in extant biology and the apparent requirement for PO4 3- as a catalyst, buffer and reagent in prebiotic chemistry. Reduced meteorites such as enstatite chondrites are highly enriched in phosphide minerals, and upon reaction with water these minerals can release phosphorus species of various oxidation states. Here, we demonstrate how reduced phosphorus species can be fully oxidized to PO4 3- simply by the action of ultraviolet light on H2S/HS-. We used low pressure Hg lamps to simulate UV output from the young Sun and 31P NMR spectroscopy to monitor the progress of reactions. Our experimental findings provide a cosmochemically and geochemically plausible means for supply of PO4 3- that was widely available to prebiotic chemistry and nascent life on early Earth, and potentially on other planets.
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Affiliation(s)
- Dougal J. Ritson
- MRC – Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, U.K
| | - Stephen J. Mojzsis
- Department of Geological Sciences, University of Colorado, UCB 399, 2200 Colorado Avenue, Boulder, CO 80309-0399, USA
- Institute for Geological and Geochemical Research, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, 45 Budaörsi Street, H-1112 Budapest, Hungary
| | - John. D. Sutherland
- MRC – Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, U.K
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17
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Longo A, Damer B. Factoring Origin of Life Hypotheses into the Search for Life in the Solar System and Beyond. Life (Basel) 2020; 10:E52. [PMID: 32349245 PMCID: PMC7281141 DOI: 10.3390/life10050052] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/14/2020] [Accepted: 04/22/2020] [Indexed: 01/13/2023] Open
Abstract
Two widely-cited alternative hypotheses propose geological localities and biochemical mechanisms for life's origins. The first states that chemical energy available in submarine hydrothermal vents supported the formation of organic compounds and initiated primitive metabolic pathways which became incorporated in the earliest cells; the second proposes that protocells self-assembled from exogenous and geothermally-delivered monomers in freshwater hot springs. These alternative hypotheses are relevant to the fossil record of early life on Earth, and can be factored into the search for life elsewhere in the Solar System. This review summarizes the evidence supporting and challenging these hypotheses, and considers their implications for the search for life on various habitable worlds. It will discuss the relative probability that life could have emerged in environments on early Mars, on the icy moons of Jupiter and Saturn, and also the degree to which prebiotic chemistry could have advanced on Titan. These environments will be compared to ancient and modern terrestrial analogs to assess their habitability and biopreservation potential. Origins of life approaches can guide the biosignature detection strategies of the next generation of planetary science missions, which could in turn advance one or both of the leading alternative abiogenesis hypotheses.
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Affiliation(s)
- Alex Longo
- National Aeronautics and Space Administration Headquarters, Washington, DC 20546, USA
- Department of Geology, The University of North Carolina, Chapel Hill, NC 27599, USA
| | - Bruce Damer
- Department of Biomolecular Engineering, University of California, Santa Cruz, CA 95064, USA or
- Digital Space Research, Boulder Creek, CA 95006, USA
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Sasselov DD, Grotzinger JP, Sutherland JD. The origin of life as a planetary phenomenon. SCIENCE ADVANCES 2020; 6:eaax3419. [PMID: 32076638 PMCID: PMC7002131 DOI: 10.1126/sciadv.aax3419] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 11/22/2019] [Indexed: 05/03/2023]
Abstract
We advocate an integrative approach between laboratory experiments in prebiotic chemistry and geologic, geochemical, and astrophysical observations to help assemble a robust chemical pathway to life that can be reproduced in the laboratory. The cyanosulfidic chemistry scenario described here was developed by such an integrative iterative process. We discuss how it maps onto evolving planetary surface environments on early Earth and Mars and the value of comparative planetary evolution. The results indicate that Mars can offer direct evidence for geochemical conditions similar to prebiotic Earth, whose early record has been erased. The Jezero crater is now the chosen landing site for NASA's Mars 2020 rover, making this an extraordinary opportunity for a breakthrough in understanding life's origins.
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Affiliation(s)
- Dimitar D. Sasselov
- Department of Astronomy, Harvard University, 60 Garden St., Cambridge, MA 02138, USA
- Corresponding author.
| | - John P. Grotzinger
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - John D. Sutherland
- MRC Laboratory of Molecular Biology, Francis Crick Ave., Cambridge CB2 0QH, UK
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19
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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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20
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Haqq-Misra J. Does the Evolution of Complex Life Depend on the Stellar Spectral Energy Distribution? ASTROBIOLOGY 2019; 19:1292-1299. [PMID: 31429585 DOI: 10.1089/ast.2018.1946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
This article presents the proportional evolutionary time (PET) hypothesis, which posits that the mean time required for the evolution of complex life is a function of stellar mass. The "biological available window" is defined as the region of a stellar spectrum between 200 and 1200 nm that generates free energy for life. Over the ∼4 Gyr history of Earth, the total energy incident at the top of the atmosphere and within the biological available window is ∼1034 J. The hypothesis assumes that the rate of evolution from the origin of life to complex life is proportional to this total energy, which would suggest that planets orbiting other stars should not show signs of complex life if the total energy incident on the planet is below this energy threshold. The PET hypothesis predicts that late K- and M-dwarf stars (M < 0.7 [Formula: see text]) are too young to host any complex life at the present age of the Universe. F-, G-, and early K-dwarf stars (M > 0.7 [Formula: see text]) represent the best targets for the next generation of space telescopes to search for spectroscopic biosignatures indicative of complex life.
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21
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Xu J, Green NJ, Gibard C, Krishnamurthy R, Sutherland JD. Prebiotic phosphorylation of 2-thiouridine provides either nucleotides or DNA building blocks via photoreduction. Nat Chem 2019; 11:457-462. [PMID: 30936523 DOI: 10.1038/s41557-019-0225-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 01/25/2019] [Indexed: 11/09/2022]
Abstract
Breakthroughs in the study of the origin of life have demonstrated how some of the building blocks essential to biology could have been formed under various primordial scenarios, and could therefore have contributed to the chemical evolution of life. Missing building blocks are then sometimes inferred to be products of primitive biosynthesis, which can stretch the limits of plausibility. Here, we demonstrate the synthesis of 2'-deoxy-2-thiouridine, and subsequently 2'-deoxyadenosine and 2-deoxyribose, under prebiotic conditions. 2'-Deoxy-2-thiouridine is produced by photoreduction of 2,2'-anhydro-2-thiouridine, which is in turn formed by phosphorylation of 2-thiouridine-an intermediate of prebiotic RNA synthesis. 2'-Deoxy-2-thiouridine is an effective deoxyribosylating agent and may have functioned as such in either abiotic or proto-enzyme-catalysed pathways to DNA, as demonstrated by its conversion to 2'-deoxyadenosine by reaction with adenine, and 2-deoxyribose by hydrolysis. An alternative prebiotic phosphorylation of 2-thiouridine leads to the formation of its 5'-phosphate, showing that hypotheses in which 2-thiouridine was a key component of early RNA sequences are within the bounds of synthetic credibility.
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Affiliation(s)
- Jianfeng Xu
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | | | - Clémentine Gibard
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
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22
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23
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Lingam M, Loeb A. Relative Likelihood of Success in the Search for Primitive versus Intelligent Extraterrestrial Life. ASTROBIOLOGY 2019; 19:28-39. [PMID: 30556749 DOI: 10.1089/ast.2018.1936] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We estimate the relative likelihood of success in the searches for primitive versus intelligent life on other planets. Taking into account the larger search volume for detectable artificial electromagnetic signals, we conclude that both searches should be performed concurrently, albeit with significantly more funding dedicated to primitive life. Based on the current federal funding allocated to the search for biosignatures, our analysis suggests that the search for extraterrestrial intelligence (SETI) may merit a federal funding level of at least $10 million per year, assuming that the average lifetime of technological species exceeds a millennium.
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Affiliation(s)
- Manasvi Lingam
- Institute for Theory and Computation, Harvard University , Cambridge, Massachusetts
| | - Abraham Loeb
- Institute for Theory and Computation, Harvard University , Cambridge, Massachusetts
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24
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Todd ZR, Szabla R, Szostak JW, Sasselov DD. UV photostability of three 2-aminoazoles with key roles in prebiotic chemistry on the early earth. Chem Commun (Camb) 2019; 55:10388-10391. [PMID: 31380533 DOI: 10.1039/c9cc05265h] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Three related molecules in the 2-aminoazole family are potentially important for prebiotic chemistry: 2-aminooxazole, 2-aminoimidazole, and 2-aminothiazole, which can provide critical functions as an intermediate in nucleotide synthesis, a nucleotide activating agent, and a selective agent, respectively. Here, we examine the wavelength-dependent photodegradation of these three molecules under mid-range UV light (210-290 nm). We then assess the implications of the observed degradation rates for the proposed prebiotic roles of these compounds. We find that all three 2-aminoazoles degrade under UV light, with half lives ranging from ≈7-100 hours under a solar-like spectrum. 2-Aminooxazole is the least photostable, while 2-aminoimidazole is the most photostable. The relative photostabilities are consistent with the order in which these molecules would be used prebiotically: AO is used first to build nucleotides and AI is used last to activate them.
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Affiliation(s)
- Zoe R Todd
- Department of Astronomy, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA.
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Mariani A, Bonfio C, Johnson CM, Sutherland JD. pH-Driven RNA Strand Separation under Prebiotically Plausible Conditions. Biochemistry 2018; 57:6382-6386. [PMID: 30383375 PMCID: PMC6340128 DOI: 10.1021/acs.biochem.8b01080] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Replication of nucleic acids in the absence of genetically encoded enzymes represents a critical process for the emergence of cellular life. Repeated separation of complementary RNA strands is required to achieve multiple cycles of chemical replication, yet thermal denaturation under plausible prebiotic conditions is impaired by the high temperatures required to separate long RNA strands and by concurrent degradation pathways, the latter accelerated by divalent metal ions. Here we show how the melting temperature of oligoribonucleotide duplexes can be tuned by changes in pH, enabling the separation of RNA strands at moderate temperatures. At the same time, the risk of phosphodiester bond cleavage is reduced under the acid denaturation conditions herein described, both in the presence and in the absence of divalent metal ions. Through a combination of ultraviolet and circular dichroism thermal studies and gel electrophoresis, we demonstrate the relevance of geological pH oscillations in the context of the RNA strand separation problem. Our results reveal new insights in the field of prebiotic chemistry, supporting plausible geochemical scenarios in which non-enzymatic RNA replication might have taken place.
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Affiliation(s)
- Angelica Mariani
- MRC Laboratory of Molecular Biology , Francis Crick Avenue, Cambridge Biomedical Campus , Cambridge CB2 0QH , U.K
| | - Claudia Bonfio
- MRC Laboratory of Molecular Biology , Francis Crick Avenue, Cambridge Biomedical Campus , Cambridge CB2 0QH , U.K
| | - Christopher M Johnson
- MRC Laboratory of Molecular Biology , Francis Crick Avenue, Cambridge Biomedical Campus , Cambridge CB2 0QH , U.K
| | - John D Sutherland
- MRC Laboratory of Molecular Biology , Francis Crick Avenue, Cambridge Biomedical Campus , Cambridge CB2 0QH , U.K
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