1
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Williamson MP. Autocatalytic Selection as a Driver for the Origin of Life. Life (Basel) 2024; 14:590. [PMID: 38792611 PMCID: PMC11122578 DOI: 10.3390/life14050590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 04/29/2024] [Accepted: 05/02/2024] [Indexed: 05/26/2024] Open
Abstract
Darwin's theory of evolution by natural selection was revolutionary because it provided a mechanism by which variation could be selected. This mechanism can only operate on living systems and thus cannot be applied to the origin of life. Here, we propose a viable alternative mechanism for prebiotic systems: autocatalytic selection, in which molecules catalyze reactions and processes that lead to increases in their concentration. Crucially, this provides a driver for increases in concentrations of molecules to a level that permits prebiotic metabolism. We show how this can produce high levels of amino acids, sugar phosphates, nucleotides and lipids and then lead on to polymers. Our outline is supported by a set of guidelines to support the identification of the most likely prebiotic routes. Most of the steps in this pathway are already supported by experimental results. These proposals generate a coherent and viable set of pathways that run from established Hadean geochemistry to the beginning of life.
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Affiliation(s)
- Mike P Williamson
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
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2
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Goldford JE, Smith HB, Longo LM, Wing BA, McGlynn SE. Primitive purine biosynthesis connects ancient geochemistry to modern metabolism. Nat Ecol Evol 2024; 8:999-1009. [PMID: 38519634 DOI: 10.1038/s41559-024-02361-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 02/06/2024] [Indexed: 03/25/2024]
Abstract
An unresolved question in the origin and evolution of life is whether a continuous path from geochemical precursors to the majority of molecules in the biosphere can be reconstructed from modern-day biochemistry. Here we identified a feasible path by simulating the evolution of biosphere-scale metabolism, using only known biochemical reactions and models of primitive coenzymes. We find that purine synthesis constitutes a bottleneck for metabolic expansion, which can be alleviated by non-autocatalytic phosphoryl coupling agents. Early phases of the expansion are enriched with enzymes that are metal dependent and structurally symmetric, supporting models of early biochemical evolution. This expansion trajectory suggests distinct hypotheses regarding the tempo, mode and timing of metabolic pathway evolution, including a late appearance of methane metabolisms and oxygenic photosynthesis consistent with the geochemical record. The concordance between biological and geological analyses suggests that this trajectory provides a plausible evolutionary history for the vast majority of core biochemistry.
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Affiliation(s)
- Joshua E Goldford
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA.
- Physics of Living Systems, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Blue Marble Space Institute of Science, Seattle, WA, USA.
| | - Harrison B Smith
- Blue Marble Space Institute of Science, Seattle, WA, USA
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
| | - Liam M Longo
- Blue Marble Space Institute of Science, Seattle, WA, USA
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan
| | - Boswell A Wing
- Department of Geological Sciences, University of Colorado, Boulder, CO, USA
| | - Shawn Erin McGlynn
- Blue Marble Space Institute of Science, Seattle, WA, USA.
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, Japan.
- Biofunctional Catalyst Research Team, RIKEN Center for Sustainable Resource Science, Wako, Japan.
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3
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Di Giulio M. Theories of the origin of the genetic code: Strong corroboration for the coevolution theory. Biosystems 2024; 239:105217. [PMID: 38663520 DOI: 10.1016/j.biosystems.2024.105217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 04/16/2024] [Accepted: 04/18/2024] [Indexed: 04/29/2024]
Abstract
I analyzed all the theories and models of the origin of the genetic code, and over the years, I have considered the main suggestions that could explain this origin. The conclusion of this analysis is that the coevolution theory of the origin of the genetic code is the theory that best captures the majority of observations concerning the organization of the genetic code. In other words, the biosynthetic relationships between amino acids would have heavily influenced the origin of the organization of the genetic code, as supported by the coevolution theory. Instead, the presence in the genetic code of physicochemical properties of amino acids, which have also been linked to the physicochemical properties of anticodons or codons or bases by stereochemical and physicochemical theories, would simply be the result of natural selection. More explicitly, I maintain that these correlations between codons, anticodons or bases and amino acids are in fact the result not of a real correlation between amino acids and codons, for example, but are only the effect of the intervention of natural selection. Specifically, in the genetic code table we expect, for example, that the most similar codons - that is, those that differ by only one base - will have more similar physicochemical properties. Therefore, the 64 codons of the genetic code table ordered in a certain way would also represent an ordering of some of their physicochemical properties. Now, a study aimed at clarifying which physicochemical property of amino acids has influenced the allocation of amino acids in the genetic code has established that the partition energy of amino acids has played a role decisive in this. Indeed, under some conditions, the genetic code was found to be approximately 98% optimized on its columns. In this same work, it was shown that this was most likely the result of the action of natural selection. If natural selection had truly allocated the amino acids in the genetic code in such a way that similar amino acids also have similar codons - this, not through a mechanism of physicochemical interaction between, for example, codons and amino acids - then it might turn out that even different physicochemical properties of codons (or anticodons or bases) show some correlation with the physicochemical properties of amino acids, simply because the partition energy of amino acids is correlated with other physicochemical properties of amino acids. It is very likely that this would inevitably lead to a correlation between codons (or anticodons or bases) and amino acids. In other words, since the codons (anticodons or bases) are ordered in the genetic code, that is to say, some of their physicochemical properties should also be ordered by a similar order, and given that the amino acids would also appear to have been ordered in the genetic code by selection natural, then it should inevitably turn out that there is a correlation between, for example, the hydrophobicity of anticodons and that of amino acids. Instead, the intervention of natural selection in organizing the genetic code would appear to be highly compatible with the main mechanism of structuring the genetic code as supported by the coevolution theory. This would make the coevolution theory the only plausible explanation for the origin of the genetic code.
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Affiliation(s)
- Massimo Di Giulio
- The Ionian School, Early Evolution of Life Department, Genetic Code and tRNA Origin Laboratory, Via Roma 19, 67030, Alfedena, L'Aquila, Italy.
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4
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Di Giulio M. The time of appearance of the genetic code. Biosystems 2024; 237:105159. [PMID: 38373543 DOI: 10.1016/j.biosystems.2024.105159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 02/13/2024] [Accepted: 02/16/2024] [Indexed: 02/21/2024]
Abstract
I support the hypothesis that the origin of the genetic code occurred simultaneously with the evolution of cellularity. That is to say, I favour the hypothesis that the origin of the genetic code is a very, very late event in the history of life on Earth. I corroborate this hypothesis with observations favouring the progenote's stage for the Last Universal Common Ancestor (LUCA), for the ancestor of bacteria and that of archaea. Indeed, these progenotic stages would imply that - at that time - the origin of the genetic code was still ongoing simply because this origin would fall within the very definition of progenote. Therefore, if the evolution of cellularity had truly been coeval with the origin of the genetic code - at least in its terminal part - then this would favour theories such as the coevolution theory of the origin of the genetic code because this theory would postulate that this origin must have occurred in extremely complex protocellular conditions and not concerning stereochemical or physicochemical interactions having to do with other stages of the origin of life. In this sense, the coevolution theory would be corroborated while the stereochemical and physicochemical theories would be damaged. Therefore, the origin of the genetic code would be linked to the origin of the cell and not to the origin of life as sometimes asserted. Therefore, I will discuss the late hypothesis of the origin of the genetic code in the context of the theories proposed to explain this origin and more generally of its implications for the early evolution of life.
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Affiliation(s)
- Massimo Di Giulio
- The Ionian School, Early Evolution of Life Department, Genetic Code and tRNA Origin Laboratory, Via Roma 19, 67030, Alfedena, L'Aquila, Italy.
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5
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Douglas J, Bouckaert R, Carter CW, Wills P. Enzymic recognition of amino acids drove the evolution of primordial genetic codes. Nucleic Acids Res 2024; 52:558-571. [PMID: 38048305 PMCID: PMC10810186 DOI: 10.1093/nar/gkad1160] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 10/28/2023] [Accepted: 11/20/2023] [Indexed: 12/06/2023] Open
Abstract
How genetic information gained its exquisite control over chemical processes needed to build living cells remains an enigma. Today, the aminoacyl-tRNA synthetases (AARS) execute the genetic codes in all living systems. But how did the AARS that emerged over three billion years ago as low-specificity, protozymic forms then spawn the full range of highly-specific enzymes that distinguish between 22 diverse amino acids? A phylogenetic reconstruction of extant AARS genes, enhanced by analysing modular acquisitions, reveals six AARS with distinct bacterial, archaeal, eukaryotic, or organellar clades, resulting in a total of 36 families of AARS catalytic domains. Small structural modules that differentiate one AARS family from another played pivotal roles in discriminating between amino acid side chains, thereby expanding the genetic code and refining its precision. The resulting model shows a tendency for less elaborate enzymes, with simpler catalytic domains, to activate amino acids that were not synthesised until later in the evolution of the code. The most probable evolutionary route for an emergent amino acid type to establish a place in the code was by recruiting older, less specific AARS, rather than adapting contemporary lineages. This process, retrofunctionalisation, differs from previously described mechanisms through which amino acids would enter the code.
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Affiliation(s)
- Jordan Douglas
- Department of Physics, The University of Auckland, New Zealand
- Centre for Computational Evolution, The University of Auckland, New Zealand
| | - Remco Bouckaert
- Centre for Computational Evolution, The University of Auckland, New Zealand
- School of Computer Science, The University of Auckland, New Zealand
| | - Charles W Carter
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, USA
| | - Peter R Wills
- Department of Physics, The University of Auckland, New Zealand
- Centre for Computational Evolution, The University of Auckland, New Zealand
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6
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Russell MJ. A self-sustaining serpentinization mega-engine feeds the fougerite nanoengines implicated in the emergence of guided metabolism. Front Microbiol 2023; 14:1145915. [PMID: 37275164 PMCID: PMC10236563 DOI: 10.3389/fmicb.2023.1145915] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 03/22/2023] [Indexed: 06/07/2023] Open
Abstract
The demonstration by Ivan Barnes et al. that the serpentinization of fresh Alpine-type ultramafic rocks results in the exhalation of hot alkaline fluids is foundational to the submarine alkaline vent theory (AVT) for life's emergence to its 'improbable' thermodynamic state. In AVT, such alkaline fluids ≤ 150°C, bearing H2 > CH4 > HS--generated and driven convectively by a serpentinizing exothermic mega-engine operating in the ultramafic crust-exhale into the iron-rich, CO2> > > NO3--bearing Hadean ocean to result in hydrothermal precipitate mounds comprising macromolecular ferroferric-carbonate oxyhydroxide and minor sulfide. As the nanocrystalline minerals fougerite/green rust and mackinawite (FeS), they compose the spontaneously precipitated inorganic membranes that keep the highly contrasting solutions apart, thereby maintaining redox and pH disequilibria. They do so in the form of fine chimneys and chemical gardens. The same disequilibria drive the reduction of CO2 to HCOO- or CO, and the oxidation of CH4 to a methyl group-the two products reacting to form acetate in a sequence antedating the 'energy-producing' acetyl coenzyme-A pathway. Fougerite is a 2D-layered mineral in which the hydrous interlayers themselves harbor 2D solutions, in effect constricted to ~ 1D by preferentially directed electron hopping/tunneling, and proton Gröthuss 'bucket-brigading' when subject to charge. As a redox-driven nanoengine or peristaltic pump, fougerite forces the ordered reduction of nitrate to ammonium, the amination of pyruvate and oxalate to alanine and glycine, and their condensation to short peptides. In turn, these peptides have the flexibility to sequester the founding inorganic iron oxyhydroxide, sulfide, and pyrophosphate clusters, to produce metal- and phosphate-dosed organic films and cells. As the feed to the hydrothermal mound fails, the only equivalent sustenance on offer to the first autotrophs is the still mildly serpentinizing upper crust beneath. While the conditions here are very much less bountiful, they do offer the similar feed and disequilibria the survivors are accustomed to. Sometime during this transition, a replicating non-ribosomal guidance system is discovered to provide the rules to take on the incrementally changing surroundings. The details of how these replicating apparatuses emerged are the hard problem, but by doing so the progenote archaea and bacteria could begin to colonize what would become the deep biosphere. Indeed, that the anaerobic nitrate-respiring methanotrophic archaea and the deep-branching Acetothermia presently comprise a portion of that microbiome occupying serpentinizing rocks offers circumstantial support for this notion. However, the inescapable, if jarring conclusion is drawn that, absent fougerite/green rust, there would be no structured channelway to life.
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Affiliation(s)
- Michael J. Russell
- Dipartimento di Chimica, Università degli Studi di Torino, Torino, Italy
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7
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Harrison SA, Webb WL, Rammu H, Lane N. Prebiotic Synthesis of Aspartate Using Life's Metabolism as a Guide. Life (Basel) 2023; 13:life13051177. [PMID: 37240822 DOI: 10.3390/life13051177] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 04/29/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
A protometabolic approach to the origins of life assumes that the conserved biochemistry of metabolism has direct continuity with prebiotic chemistry. One of the most important amino acids in modern biology is aspartic acid, serving as a nodal metabolite for the synthesis of many other essential biomolecules. Aspartate's prebiotic synthesis is complicated by the instability of its precursor, oxaloacetate. In this paper, we show that the use of the biologically relevant cofactor pyridoxamine, supported by metal ion catalysis, is sufficiently fast to offset oxaloacetate's degradation. Cu2+-catalysed transamination of oxaloacetate by pyridoxamine achieves around a 5% yield within 1 h, and can operate across a broad range of pH, temperature, and pressure. In addition, the synthesis of the downstream product β-alanine may also take place in the same reaction system at very low yields, directly mimicking an archaeal synthesis route. Amino group transfer supported by pyridoxal is shown to take place from aspartate to alanine, but the reverse reaction (alanine to aspartate) shows a poor yield. Overall, our results show that the nodal metabolite aspartate and related amino acids can indeed be synthesised via protometabolic pathways that foreshadow modern metabolism in the presence of the simple cofactor pyridoxamine and metal ions.
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Affiliation(s)
- Stuart A Harrison
- Centre for Life's Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - William L Webb
- Centre for Life's Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Hanadi Rammu
- Centre for Life's Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Nick Lane
- Centre for Life's Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
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8
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Halpern A, Bartsch LR, Ibrahim K, Harrison SA, Ahn M, Christodoulou J, Lane N. Biophysical Interactions Underpin the Emergence of Information in the Genetic Code. Life (Basel) 2023; 13:life13051129. [PMID: 37240774 DOI: 10.3390/life13051129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 04/25/2023] [Accepted: 04/30/2023] [Indexed: 05/28/2023] Open
Abstract
The genetic code conceals a 'code within the codons', which hints at biophysical interactions between amino acids and their cognate nucleotides. Yet, research over decades has failed to corroborate systematic biophysical interactions across the code. Using molecular dynamics simulations and NMR, we have analysed interactions between the 20 standard proteinogenic amino acids and 4 RNA mononucleotides in 3 charge states. Our simulations show that 50% of amino acids bind best with their anticodonic middle base in the -1 charge state common to the backbone of RNA, while 95% of amino acids interact most strongly with at least 1 of their codonic or anticodonic bases. Preference for the cognate anticodonic middle base was greater than 99% of randomised assignments. We verify a selection of our results using NMR, and highlight challenges with both techniques for interrogating large numbers of weak interactions. Finally, we extend our simulations to a range of amino acids and dinucleotides, and corroborate similar preferences for cognate nucleotides. Despite some discrepancies between the predicted patterns and those observed in biology, the existence of weak stereochemical interactions means that random RNA sequences could template non-random peptides. This offers a compelling explanation for the emergence of genetic information in biology.
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Affiliation(s)
- Aaron Halpern
- UCL Centre for Life's Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Lilly R Bartsch
- UCL Centre for Life's Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Kaan Ibrahim
- UCL Centre for Life's Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Stuart A Harrison
- UCL Centre for Life's Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Minkoo Ahn
- Department of Structural and Molecular Biology, Institute of Structural and Molecular Biology (ISMB), University College London, London WC1E 6BT, UK
| | - John Christodoulou
- Department of Structural and Molecular Biology, Institute of Structural and Molecular Biology (ISMB), University College London, London WC1E 6BT, UK
| | - Nick Lane
- UCL Centre for Life's Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
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9
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Metal ion availability and homeostasis as drivers of metabolic evolution and enzyme function. Curr Opin Genet Dev 2022; 77:101987. [PMID: 36183585 DOI: 10.1016/j.gde.2022.101987] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 08/25/2022] [Accepted: 08/29/2022] [Indexed: 01/27/2023]
Abstract
Metal ions are potent catalysts and have been available for cellular biochemistry at all stages of evolution. Growing evidence suggests that metal catalysis was critical for the origin of the very first metabolic reactions. With approximately 80% of modern metabolic pathways being dependent on metal ions, metallocatalysis and homeostasis continue to be essential for intracellular metabolic networks and physiology. However, the genetic network that controls metal ion homeostasis and the impact of metal availability on metabolism is poorly understood. Here, we review recent work on gene and protein evolution relevant for better understanding metal ion biology and its role in metabolism. We highlight the importance of analysing the origin and evolution of enzyme catalysis in the context of catalytically relevant metal ions, summarise unanswered questions essential for developing a comprehensive understanding of metal ion homeostasis and advocate for the consideration of metal ion properties and availability in the design and directed evolution of novel enzymes and pathways.
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10
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Nunes Palmeira R, Colnaghi M, Harrison SA, Pomiankowski A, Lane N. The limits of metabolic heredity in protocells. Proc Biol Sci 2022; 289:20221469. [PMID: 36350219 PMCID: PMC9653231 DOI: 10.1098/rspb.2022.1469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The universal core of metabolism could have emerged from thermodynamically favoured prebiotic pathways at the origin of life. Starting with H
2
and CO
2
, the synthesis of amino acids and mixed fatty acids, which self-assemble into protocells, is favoured under warm anoxic conditions. Here, we address whether it is possible for protocells to evolve greater metabolic complexity, through positive feedbacks involving nucleotide catalysis. Using mathematical simulations to model metabolic heredity in protocells, based on branch points in protometabolic flux, we show that nucleotide catalysis can indeed promote protocell growth. This outcome only occurs when nucleotides directly catalyse CO
2
fixation. Strong nucleotide catalysis of other pathways (e.g. fatty acids and amino acids) generally unbalances metabolism and slows down protocell growth, and when there is competition between catalytic functions cell growth collapses. Autocatalysis of nucleotide synthesis can promote growth but only if nucleotides also catalyse CO
2
fixation; autocatalysis alone leads to the accumulation of nucleotides at the expense of CO
2
fixation and protocell growth rate. Our findings offer a new framework for the emergence of greater metabolic complexity, in which nucleotides catalyse broad-spectrum processes such as CO
2
fixation, hydrogenation and phosphorylation important to the emergence of genetic heredity at the origin of life.
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Affiliation(s)
- Raquel Nunes Palmeira
- Department of Computer Science, Engineering Building, Malet Place, University College London, WC1E 7JG, UK
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Marco Colnaghi
- Department of Computer Science, Engineering Building, Malet Place, University College London, WC1E 7JG, UK
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Stuart A. Harrison
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Andrew Pomiankowski
- Department of Computer Science, Engineering Building, Malet Place, University College London, WC1E 7JG, UK
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | - Nick Lane
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
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11
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Pinna S, Kunz C, Halpern A, Harrison SA, Jordan SF, Ward J, Werner F, Lane N. A prebiotic basis for ATP as the universal energy currency. PLoS Biol 2022; 20:e3001437. [PMID: 36194581 PMCID: PMC9531788 DOI: 10.1371/journal.pbio.3001437] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 08/30/2022] [Indexed: 11/07/2022] Open
Abstract
ATP is universally conserved as the principal energy currency in cells, driving metabolism through phosphorylation and condensation reactions. Such deep conservation suggests that ATP arose at an early stage of biochemical evolution. Yet purine synthesis requires 6 phosphorylation steps linked to ATP hydrolysis. This autocatalytic requirement for ATP to synthesize ATP implies the need for an earlier prebiotic ATP equivalent, which could drive protometabolism before purine synthesis. Why this early phosphorylating agent was replaced, and specifically with ATP rather than other nucleoside triphosphates, remains a mystery. Here, we show that the deep conservation of ATP might reflect its prebiotic chemistry in relation to another universally conserved intermediate, acetyl phosphate (AcP), which bridges between thioester and phosphate metabolism by linking acetyl CoA to the substrate-level phosphorylation of ADP. We confirm earlier results showing that AcP can phosphorylate ADP to ATP at nearly 20% yield in water in the presence of Fe3+ ions. We then show that Fe3+ and AcP are surprisingly favoured. A wide range of prebiotically relevant ions and minerals failed to catalyse ADP phosphorylation. From a panel of prebiotic phosphorylating agents, only AcP, and to a lesser extent carbamoyl phosphate, showed any significant phosphorylating potential. Critically, AcP did not phosphorylate any other nucleoside diphosphate. We use these data, reaction kinetics, and molecular dynamic simulations to infer a possible mechanism. Our findings might suggest that the reason ATP is universally conserved across life is that its formation is chemically favoured in aqueous solution under mild prebiotic conditions.
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Affiliation(s)
- Silvana Pinna
- Centre for Life’s Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, Darwin Building, London, United Kingdom
| | - Cäcilia Kunz
- Centre for Life’s Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, Darwin Building, London, United Kingdom
| | - Aaron Halpern
- Centre for Life’s Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, Darwin Building, London, United Kingdom
| | - Stuart A. Harrison
- Centre for Life’s Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, Darwin Building, London, United Kingdom
| | - Sean F. Jordan
- Centre for Life’s Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, Darwin Building, London, United Kingdom
| | - John Ward
- Department of Biochemical Engineering, University College London, London, United Kingdom
| | - Finn Werner
- Institute for Structural and Molecular Biology, University College London, Darwin Building, London, United Kingdom
| | - Nick Lane
- Centre for Life’s Origins and Evolution (CLOE), Department of Genetics, Evolution and Environment, University College London, Darwin Building, London, United Kingdom
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