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Molland DP, Rhyu IB, Wade J, Schnell JR. Bivalent Surface Attachment via Cysteine Thiol Results in Efficient and Stereoselective Abiotic Peptide Synthesis. JACS AU 2025; 5:1922-1931. [PMID: 40313818 PMCID: PMC12041950 DOI: 10.1021/jacsau.5c00153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2025] [Revised: 03/21/2025] [Accepted: 03/25/2025] [Indexed: 05/03/2025]
Abstract
Surface-catalyzed peptide bond formation may have been an important source of peptides for abiogenesis, but model peptide synthesis reactions using the consensus set of 10 abiotic amino acids give only modest rates of peptide bond formation. Additionally, the peptides are typically limited in length to a small number of amino acids and stereoselective amino acid incorporation is weak or absent. An abiotic route for the high-yield synthesis of cysteine from serine was recently reported by Foden et al. (Science 2020, 370, 865-869), indicating that, in some environments, prebiotic cysteine may also have been available. Here, we show that the presence of cysteine dramatically increases the yields of surface-catalyzed peptide synthesis reactions in a hydrothermal vent solvent model containing achiral silicate minerals and that the reaction exhibits a strong stereoselective bias toward l-cysteine. Solid state NMR confirmed that cysteine associates bivalently with silicates at alkaline pH via both the carboxylate and the sulfur groups. Polarization-resolved IRRAS indicates that the bivalent adsorption stereospecifically orients the reactive amino group, providing a mechanism for stereoselective incorporation of l-cysteine. Stereoselective rates of peptide bond formation in surface-catalyzed peptide bond formation are expected to occur for any amino acid able to form sufficiently strong side chain-silicate interactions at alkaline pH. The high nucleophilicity of the thiol group produces unusually high reaction rates and stereoselectivity in such reactions, in addition to conferring transition metal ion binding to the peptide products. The potential benefits of reactive sulfur species for abiogenesis suggest that they may be useful biosignatures in the search for habitable extraterrestrial environments.
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Affiliation(s)
- Daniel P. Molland
- Department
of Biochemistry, University of Oxford, South Parks Road, OX1 3QU Oxford, U.K.
| | - Isabella B. Rhyu
- Department
of Biochemistry, University of Oxford, South Parks Road, OX1 3QU Oxford, U.K.
| | - Jon Wade
- Department
of Earth Sciences, University of Oxford, South Parks Road, OX1 3AN Oxford, U.K.
| | - Jason R. Schnell
- Department
of Biochemistry, University of Oxford, South Parks Road, OX1 3QU Oxford, U.K.
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2
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Wipf S, Mabey P, Urso RG, Wolf S, Stok A, Ricco AJ, Quinn RC, Mattioda AL, Jones NC, Hoffmann SV, Cottin H, Chaput D, Ehrenfreund P, Elsaesser A. Photochemical Evolution of Alanine in Association with the Martian Soil Analog Montmorillonite: Insights Derived from Experiments Conducted on the International Space Station. ASTROBIOLOGY 2025; 25:97-114. [PMID: 39869065 DOI: 10.1089/ast.2024.0034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2025]
Abstract
The Photochemistry on the Space Station (PSS) experiment was part of the European Space Agency's EXPOSE-R2 mission and was conducted on the International Space Station from 2014 to 2016. The PSS experiment investigated the properties of montmorillonite clay as a protective shield against degradation of organic compounds that were exposed to elevated levels of ultraviolet (UV) radiation in space. Additionally, we examined the potential for montmorillonite to catalyze UV-induced breakdown of the amino acid alanine and its potential to trap the resulting photochemical byproducts within its interlayers. We tested pure alanine thin films, alanine thin films protected from direct UV exposure by a thin cover layer of montmorillonite, and an intimate combination of the two substances forming an organoclay. The samples were exposed to space conditions for 15.5 months and then returned to Earth for detailed analysis. Concurrent ground-control experiments subjected identical samples to simulated solar light irradiation. Fourier-transform infrared (FTIR) spectroscopy quantified molecular changes by comparing spectra obtained before and after exposure for both the space and ground-control samples. To more deeply understand the photochemical processes influencing the stability of irradiated alanine molecules, we performed an additional experiment using time-resolved FTIR spectroscopy for a second set of ground samples exposed to simulated solar light. Our collective experiments reveal that montmorillonite clay exhibits a dual, configuration-dependent effect on the stability of alanine: while a thin cover layer of the clay provides UV shielding that slows degradation, an intimate mixture of clay and amino acid hastens the photochemical decomposition of alanine by promoting certain chemical reactions. This observation is important to understand the preservation of amino acids in specific extraterrestrial environments, such as Mars: cover mineral layer depths of several millimeters are required to effectively shield organics from the harmful effects of UV radiation. We also explored the role of carbon dioxide (CO2), a byproduct of alanine photolysis, as a tracer of the amino acid. CO2 can be trapped within clay interlayers, particularly in clays with small interlayer ions such as sodium. Our studies emphasize the multifaceted interactions between montmorillonite clay and alanine under nonterrestrial conditions; thus, they contribute valuable insights to broader astrobiological research questions.
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Affiliation(s)
- Severin Wipf
- Experimental Biophysics and Space Sciences, Department of Physics, Freie Universitaet Berlin, Berlin, Germany
| | - Paul Mabey
- Experimental Biophysics and Space Sciences, Department of Physics, Freie Universitaet Berlin, Berlin, Germany
| | | | - Sebastian Wolf
- Experimental Biophysics and Space Sciences, Department of Physics, Freie Universitaet Berlin, Berlin, Germany
| | - Arthur Stok
- Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | | | | | | | - Nykola C Jones
- Department of Physics and Astronomy, ISA, Aarhus University, Aarhus, Denmark
| | - Søren V Hoffmann
- Department of Physics and Astronomy, ISA, Aarhus University, Aarhus, Denmark
| | - Hervé Cottin
- Univ Paris Est Creteil and Université Paris Cité, France
| | - Didier Chaput
- Centre Spatial de Toulouse, Centre National d'Etudes Spatiales (CNES), Toulouse cedex 9, France
| | - Pascale Ehrenfreund
- Space Policy Institute, George Washington University, Washington, District of Columbia, USA
- Laboratory for Astrophysics, Leiden Observatory, Leiden University, Leiden, The Netherlands
| | - Andreas Elsaesser
- Experimental Biophysics and Space Sciences, Department of Physics, Freie Universitaet Berlin, Berlin, Germany
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3
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Cao C, Qiu X, Yang Z, Jin Y. New insights into the evolution and function of the UMAMIT (USUALLY MULTIPLE ACIDS MOVE IN AND OUT TRANSPORTER) gene family. JOURNAL OF PLANT RESEARCH 2025; 138:3-17. [PMID: 39531163 DOI: 10.1007/s10265-024-01596-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2024] [Accepted: 10/31/2024] [Indexed: 11/16/2024]
Abstract
UMAMIT proteins have been known as key players in amino acid transport. In Arabidopsis, functions of several UMAMITs have been characterized, but their precise mechanism, evolutionary history and functional divergence remain elusive. In this study, we conducted phylogenetic analysis of the UMAMIT gene family across key species in the evolutionary history of plants, ranging from algae to angiosperms. Our findings indicate that UMAMIT proteins underwent a substantial expansion from algae to angiosperms, accompanied by the stabilization of the EamA (the main domain of UMAMIT) structure. Phylogenetic studies suggest that UMAMITs may have originated from green algae and be divided into four subfamilies. These proteins first diversified in bryophytes and subsequently experienced gene duplication events in seed plants. Subfamily I was potentially associated with amino acid transport in seeds. Regarding subcellular localization, UMAMITs were predominantly localized in the plasma membrane and chloroplasts. However, members from clade 8 in subfamily III exhibited specific localization in the tonoplast. These members may have multiple functions, such as plant disease resistance and root development. Furthermore, our protein structure prediction revealed that the four-helix bundle motif is crucial in controlling the UMAMIT switch for exporting amino acid. We hypothesize that the specific amino acids in the amino acid binding region determine the type of amino acids being transported. Additionally, subfamily II contains genes that are specifically expressed in reproductive organs and roots in angiosperms, suggesting neofunctionalization. Our study highlights the evolutionary complexity of UMAMITs and underscores their crucial role in the adaptation and diversification of seed plants.
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Affiliation(s)
- Chenhao Cao
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Xinbao Qiu
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Zhongnan Yang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Yue Jin
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China.
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4
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Wehbi S, Wheeler A, Morel B, Manepalli N, Minh BQ, Lauretta DS, Masel J. Order of amino acid recruitment into the genetic code resolved by last universal common ancestor's protein domains. Proc Natl Acad Sci U S A 2024; 121:e2410311121. [PMID: 39665745 DOI: 10.1073/pnas.2410311121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Accepted: 11/13/2024] [Indexed: 12/13/2024] Open
Abstract
The current "consensus" order in which amino acids were added to the genetic code is based on potentially biased criteria, such as the absence of sulfur-containing amino acids from the Urey-Miller experiment which lacked sulfur. More broadly, abiotic abundance might not reflect biotic abundance in the organisms in which the genetic code evolved. Here, we instead identify which protein domains date to the last universal common ancestor (LUCA) and then infer the order of recruitment from deviations of their ancestrally reconstructed amino acid frequencies from the still-ancient post-LUCA controls. We find that smaller amino acids were added to the code earlier, with no additional predictive power in the previous consensus order. Metal-binding (cysteine and histidine) and sulfur-containing (cysteine and methionine) amino acids were added to the genetic code much earlier than previously thought. Methionine and histidine were added to the code earlier than expected from their molecular weights and glutamine later. Early methionine availability is compatible with inferred early use of S-adenosylmethionine and early histidine with its purine-like structure and the demand for metal binding. Even more ancient protein sequences-those that had already diversified into multiple distinct copies prior to LUCA-have significantly higher frequencies of aromatic amino acids (tryptophan, tyrosine, phenylalanine, and histidine) and lower frequencies of valine and glutamic acid than single-copy LUCA sequences. If at least some of these sequences predate the current code, then their distinct enrichment patterns provide hints about earlier, alternative genetic codes.
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Affiliation(s)
- Sawsan Wehbi
- Genetics Graduate Interdisciplinary Program, University of Arizona, Tucson, AZ 85721
| | - Andrew Wheeler
- Genetics Graduate Interdisciplinary Program, University of Arizona, Tucson, AZ 85721
| | - Benoit Morel
- Computational Molecular Evolution Group, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
| | - Nandini Manepalli
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721
| | - Bui Quang Minh
- School of Computing, Australian National University, Canberra, ACT, Australia
| | - Dante S Lauretta
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721
| | - Joanna Masel
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721
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5
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Codispoti S, Yamaguchi T, Makarov M, Giacobelli VG, Mašek M, Kolář MH, Sanchez Rocha AC, Fujishima K, Zanchetta G, Hlouchová K. The interplay between peptides and RNA is critical for protoribosome compartmentalization and stability. Nucleic Acids Res 2024; 52:12689-12700. [PMID: 39340303 PMCID: PMC11551759 DOI: 10.1093/nar/gkae823] [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: 02/01/2024] [Revised: 09/04/2024] [Accepted: 09/10/2024] [Indexed: 09/30/2024] Open
Abstract
The ribosome, owing to its exceptional conservation, harbours a remarkable molecular fossil known as the protoribosome. It surrounds the peptidyl transferase center (PTC), responsible for peptide bond formation. While previous studies have demonstrated the PTC activity in RNA alone, our investigation reveals the intricate roles of the ribosomal protein fragments (rPeptides) within the ribosomal core. This research highlights the significance of rPeptides in stability and coacervation of two distinct protoribosomal evolutionary stages. The 617nt 'big' protoribosome model, which associates with rPeptides specifically, exhibits a structurally defined and rigid nature, further stabilized by the peptides. In contrast, the 136nt 'small' model, previously linked to peptidyltransferase activity, displays greater structural flexibility. While this construct interacts with rPeptides with lower specificity, they induce coacervation of the 'small' protoribosome across a wide concentration range, which is concomitantly dependent on the RNA sequence and structure. Moreover, these conditions protect RNA from degradation. This phenomenon suggests a significant evolutionary advantage in the RNA-protein interaction at the early stages of ribosome evolution. The distinct properties of the two protoribosomal stages suggest that rPeptides initially provided compartmentalization and prevented RNA degradation, preceding the emergence of specific RNA-protein interactions crucial for the ribosomal structural integrity.
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Affiliation(s)
- Simone Codispoti
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università di Milano, Segrate 20054, Italy
| | - Tomoko Yamaguchi
- Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, Prague 12800, Czech Republic
| | - Mikhail Makarov
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, Prague 12800, Czech Republic
| | - Valerio G Giacobelli
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, Prague 12800, Czech Republic
| | - Martin Mašek
- Department of Physical Chemistry, University of Chemistry and Technology, Technicka 5, 16628 Prague, Czech Republic
| | - Michal H Kolář
- Department of Physical Chemistry, University of Chemistry and Technology, Technicka 5, 16628 Prague, Czech Republic
| | | | - Kosuke Fujishima
- Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
- Graduate School of Media and Governance, Keio University, 5322 Endo, Fujisawa 252-0882, Japan
| | - Giuliano Zanchetta
- Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università di Milano, Segrate 20054, Italy
| | - Klára Hlouchová
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, Prague 12800, Czech Republic
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo n. 2, Prague 16610, Czech Republic
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6
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Su M, Roberts SJ, Sutherland JD. RNA-directed peptide synthesis across a nicked loop. Nucleic Acids Res 2024; 52:11415-11422. [PMID: 39164017 PMCID: PMC11514466 DOI: 10.1093/nar/gkae702] [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: 06/08/2024] [Revised: 07/23/2024] [Accepted: 08/06/2024] [Indexed: 08/22/2024] Open
Abstract
Ribosomal translation at the origin of life requires controlled aminoacylation to produce mono-aminoacyl esters of tRNAs. Herein, we show that transient annealing of short RNA oligo:amino acid mixed anhydrides to an acceptor strand enables the sequential transfer of aminoacyl residues to the diol of an overhang, first forming aminoacyl esters then peptidyl esters. Using N-protected aminoacyl esters prevents unwanted peptidyl ester formation in this manner. However, N-acyl-aminoacyl transfer is not stereoselective.
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Affiliation(s)
- Meng Su
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Samuel J Roberts
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - John D Sutherland
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
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7
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Esposito J, Kakar J, Khokhar T, Noll-Walker T, Omar F, Christen A, James Cleaves H, Sandora M. Comparing the complexity of written and molecular symbolic systems. Biosystems 2024; 244:105297. [PMID: 39154841 DOI: 10.1016/j.biosystems.2024.105297] [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: 03/24/2024] [Revised: 08/11/2024] [Accepted: 08/11/2024] [Indexed: 08/20/2024]
Abstract
Symbolic systems (SSs) are uniquely products of living systems, such that symbolism and life may be inextricably intertwined phenomena. Within a given SS, there is a range of symbol complexity over which signaling is functionally optimized. This range exists relative to a complex and potentially infinitely large background of latent, unused symbol space. Understanding how symbol sets sample this latent space is relevant to diverse fields including biochemistry and linguistics. We quantitatively explored the graphic complexity of two biosemiotic systems: genetically encoded amino acids (GEAAs) and written language. Molecular and graphical notions of complexity are highly correlated for GEAAs and written language. Symbol sets are generally neither minimally nor maximally complex relative to their latent spaces, but exist across an objectively definable distribution, with the GEAAs having especially low complexity. The selection pressures guiding these disparate systems are explicable by symbol production and disambiguation efficiency. These selection pressures may be universal, offer a quantifiable metric for comparison, and suggest that all life in the Universe may discover optimal symbol set complexity distributions with respect to their latent spaces. If so, the "complexity" of individual components of SSs may not be as strong a biomarker as symbol set complexity distribution.
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Affiliation(s)
- Julia Esposito
- Blue Marble Space Institute of Science, Seattle, WA, USA
| | - Jyotika Kakar
- Blue Marble Space Institute of Science, Seattle, WA, USA; Department of Computer Engineering, University of Mumbai, MH, India
| | - Tasneem Khokhar
- Blue Marble Space Institute of Science, Seattle, WA, USA; Department of Physics and Astronomy, University of California, Irvine, CA, USA
| | | | - Fatima Omar
- Blue Marble Space Institute of Science, Seattle, WA, USA; Jodrell Bank Centre for Astrophysics, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Anna Christen
- Blue Marble Space Institute of Science, Seattle, WA, USA
| | - H James Cleaves
- Department of Chemistry, Howard University, Washington, DC, 20059, USA; Blue Marble Space Institute of Science, Seattle, WA, USA; Earth-Life Science Institute, Tokyo Institute of Technology, Meguro-ku, Tokyo, Japan.
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8
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Abstract
How did specific useful protein sequences arise from simpler molecules at the origin of life? This seemingly needle-in-a-haystack problem has remarkably close resemblance to the old Protein Folding Problem, for which the solution is now known from statistical physics. Based on the logic that Origins must have come only after there was an operative evolution mechanism-which selects on phenotype, not genotype-we give a perspective that proteins and their folding processes are likely to have been the primary driver of the early stages of the origin of life.
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Affiliation(s)
- Charles D. Kocher
- Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY11794
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY11794
| | - Ken A. Dill
- Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY11794
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY11794
- Department of Chemistry, Stony Brook University, Stony Brook, NY11794
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9
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Hlouchová K. Peptides En Route from Prebiotic to Biotic Catalysis. Acc Chem Res 2024; 57:2027-2037. [PMID: 39016062 PMCID: PMC11308367 DOI: 10.1021/acs.accounts.4c00137] [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: 02/29/2024] [Revised: 05/24/2024] [Accepted: 07/03/2024] [Indexed: 07/18/2024]
Abstract
In the quest to understand prebiotic catalysis, different molecular entities, mainly minerals, metal ions, organic cofactors, and ribozymes, have been implied as key players. Of these, inorganic and organic cofactors have gained attention for their ability to catalyze a wide array of reactions central to modern metabolism and frequently participate in these reactions within modern enzymes. Nevertheless, bridging the gap between prebiotic and modern metabolism remains a fundamental question in the origins of life. In this Account, peptides are investigated as a potential bridge linking prebiotic catalysis by minerals/cofactors to enzymes that dominate modern life's chemical reactions. Before ribosomal synthesis emerged, peptides of random sequences were plausible on early Earth. This was made possible by different sources of amino acid delivery and synthesis, as well as their condensation under a variety of conditions. Early peptides and proteins probably exhibited distinct compositions, enriched in small aliphatic and acidic residues. An increase in abundance of amino acids with larger side chains and canonical basic groups was most likely dependent on the emergence of their more challenging (bio)synthesis. Pressing questions thus arise: how did this composition influence the early peptide properties, and to what extent could they contribute to early metabolism? Recent research from our group and colleagues shows that highly acidic peptides/proteins comprising only the presumably "early" amino acids are in fact competent at secondary structure formation and even possess adaptive folding characteristics such as spontaneous refoldability and chaperone independence to achieve soluble structures. Moreover, we showed that highly acidic proteins of presumably "early" composition can still bind RNA by utilizing metal ions as cofactors to bridge carboxylate and phosphoester functional groups. And finally, ancient organic cofactors were shown to be capable of binding to sequences from amino acids considered prebiotically plausible, supporting their folding properties and providing functional groups, which would nominate them as catalytic hubs of great prebiotic relevance. These findings underscore the biochemical plausibility of an early peptide/protein world devoid of more complex amino acids yet collaborating with other catalytic species. Drawing from the mechanistic properties of protein-cofactor catalysis, it is speculated here that the early peptide/protein-cofactor ensemble could facilitate a similar range of chemical reactions, albeit with lower catalytic rates. This hypothesis invites a systematic experimental test. Nonetheless, this Account does not exclude other scenarios of prebiotic-to-biotic catalysis or prioritize any specific pathways of prebiotic syntheses. The objective is to examine peptide availability, composition, and functional potential among the various factors involved in the emergence of early life.
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Affiliation(s)
- Klára Hlouchová
- Department
of Cell Biology, Faculty of Science, Charles
University, Prague 12800, Czech Republic
- Institute
of Organic Chemistry and Biochemistry, Czech
Academy of Sciences, Prague 16610, Czech Republic
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10
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Wei W, Chu F, Chen G, Zhou S, Sun C, Feng H, Pan Y. Prebiotic Formation of Peptides Through Bubbling and Arc Plasma. Chemistry 2024; 30:e202401809. [PMID: 38802327 DOI: 10.1002/chem.202401809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Revised: 05/26/2024] [Accepted: 05/27/2024] [Indexed: 05/29/2024]
Abstract
The abiotic synthesis of peptides, widely regarded as one of the key chemical reactions on the prebiotic Earth, is thermodynamically constrained in solution. Herein, a simulation of the lightning phenomenon on the sea surface using bubble bursting and arc plasma under ambient conditions enables dipeptide formation of six amino acids with conversion ratios ranging from 2.6 % to 25.5 %. Additionally, we observed the formation of biologically active tripeptides and investigated the stereoselectivity of the dipeptide formation reaction. By utilizing a mixture of 20 amino acids in the reaction, 102 possible dipeptides were generated. These results establish experimental constructions to mimic achievable prebiotic conditions and provide a credible pathway for endogenous biopolymer synthesis on prebiotic Earth.
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Affiliation(s)
- Wei Wei
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Fengjian Chu
- College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Guanru Chen
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Shiwen Zhou
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Cuirong Sun
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Hongru Feng
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Yuanjiang Pan
- Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
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11
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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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12
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Marshall LK, Fahrenbach AC, Thordarson P. RNA-Binding Peptides Inspired by the RNA Recognition Motif. ACS Chem Biol 2024; 19:243-248. [PMID: 38314708 DOI: 10.1021/acschembio.3c00694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
β-Hairpin peptides with RNA-binding sequences mimicking the central two β-strands of the RNA recognition motif (RRM) protein domain have been observed to bind in a 2:1 fashion to a series of RNA homooligonucleotides in aqueous solution (PBS buffer, pH 7.40) with binding energies (-27 to -35 kJ mol-1) similar to those of full-size protein RRMs. The peptides display mild selectivities with respect to the binding of the different homooligomers. Binding studies in 500 mM magnesium chloride suggest that the complex formation is not predominantly driven by Coulombic attraction. These peptides represent a starting point for further studies of non-Coulombic binding of RNA by peptides and proteins, which is important in the context of contemporary biology, potential therapeutic applications, and prebiotic peptide-RNA interactions.
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13
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Skene KR. Systems theory, thermodynamics and life: Integrated thinking across ecology, organization and biological evolution. Biosystems 2024; 236:105123. [PMID: 38244715 DOI: 10.1016/j.biosystems.2024.105123] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Revised: 01/15/2024] [Accepted: 01/15/2024] [Indexed: 01/22/2024]
Abstract
In this paper we explore the relevance and integration of system theory and thermodynamics in terms of the Earth system. It is proposed that together, these fields explain the evolution, organization, functionality and directionality of life on Earth. We begin by summarizing historical and current thinking on the definition of life itself. We then investigate the evidence for a single unit of life. Given that any definition of life and its levels of organization are intertwined, we explore how the Earth system is structured and functions from an energetic perspective, by outlining relevant thermodynamic theory relating to molecular, metabolic, cellular, individual, population, species, ecosystem and biome organization. We next investigate the fundamental relationships between systems theory and thermodynamics in terms of the Earth system, examining the key characteristics of self-assembly, self-organization (including autonomy), emergence, non-linearity, feedback and sub-optimality. Finally, we examine the relevance of systems theory and thermodynamics with reference to two specific aspects: the tempo and directionality of evolution and the directional and predictable process of ecological succession. We discuss the importance of the entropic drive in understanding altruism, multicellularity, mutualistic and antagonistic relationships and how maximum entropy production theory may explain patterns thought to evidence the intermediate disturbance hypothesis.
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Affiliation(s)
- Keith R Skene
- Biosphere Research Institute, Angus, United Kingdom.
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14
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Yarus M. Ordering events in a developing genetic code. RNA Biol 2024; 21:1-8. [PMID: 38169326 PMCID: PMC10766418 DOI: 10.1080/15476286.2023.2299615] [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] [Revised: 12/18/2023] [Accepted: 12/20/2023] [Indexed: 01/05/2024] Open
Abstract
Preexisting partial genetic codes can fuse to evolve towards the complete Standard Genetic Code (SGC). Such code fusion provides a path of 'least selection', readily generating precursor codes that resemble the SGC. Consequently, such least selections produce the SGC via minimal, thus rapid, change. Optimal code evolution therefore requires delayed wobble. Early wobble encoding slows code evolution, very specifically diminishing the most likely SGC precursors: near-complete, accurate codes which are the products of code fusions. In contrast: given delayed wobble, the SGC can emerge from a truncation selection/evolutionary radiation based on proficient fused coding.
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Affiliation(s)
- Michael Yarus
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO, USA
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15
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Brown SM, Mayer-Bacon C, Freeland S. Xeno Amino Acids: A Look into Biochemistry as We Do Not Know It. Life (Basel) 2023; 13:2281. [PMID: 38137883 PMCID: PMC10744825 DOI: 10.3390/life13122281] [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: 10/30/2023] [Revised: 11/18/2023] [Accepted: 11/20/2023] [Indexed: 12/24/2023] Open
Abstract
Would another origin of life resemble Earth's biochemical use of amino acids? Here, we review current knowledge at three levels: (1) Could other classes of chemical structure serve as building blocks for biopolymer structure and catalysis? Amino acids now seem both readily available to, and a plausible chemical attractor for, life as we do not know it. Amino acids thus remain important and tractable targets for astrobiological research. (2) If amino acids are used, would we expect the same L-alpha-structural subclass used by life? Despite numerous ideas, it is not clear why life favors L-enantiomers. It seems clearer, however, why life on Earth uses the shortest possible (alpha-) amino acid backbone, and why each carries only one side chain. However, assertions that other backbones are physicochemically impossible have relaxed into arguments that they are disadvantageous. (3) Would we expect a similar set of side chains to those within the genetic code? Many plausible alternatives exist. Furthermore, evidence exists for both evolutionary advantage and physicochemical constraint as explanatory factors for those encoded by life. Overall, as focus shifts from amino acids as a chemical class to specific side chains used by post-LUCA biology, the probable role of physicochemical constraint diminishes relative to that of biological evolution. Exciting opportunities now present themselves for laboratory work and computing to explore how changing the amino acid alphabet alters the universe of protein folds. Near-term milestones include: (a) expanding evidence about amino acids as attractors within chemical evolution; (b) extending characterization of other backbones relative to biological proteins; and (c) merging computing and laboratory explorations of structures and functions unlocked by xeno peptides.
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16
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Katoh T, Suga H. A comprehensive analysis of translational misdecoding pattern and its implication on genetic code evolution. Nucleic Acids Res 2023; 51:10642-10652. [PMID: 37638759 PMCID: PMC10602915 DOI: 10.1093/nar/gkad707] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 07/19/2023] [Accepted: 08/19/2023] [Indexed: 08/29/2023] Open
Abstract
The universal genetic code is comprised of 61 sense codons, which are assigned to 20 canonical amino acids. However, the evolutionary basis for the highly conserved mapping between amino acids and their codons remains incompletely understood. A possible selective pressure of evolution would be minimization of deleterious effects caused by misdecoding. Here we comprehensively analyzed the misdecoding pattern of 61 codons against 19 noncognate amino acids where an arbitrary amino acid was omitted, and revealed the following two rules. (i) If the second codon base is U or C, misdecoding is frequently induced by mismatches at the first and/or third base, where any mismatches are widely tolerated; whereas misdecoding with the second-base mismatch is promoted by only U-G or C-A pair formation. (ii) If the second codon base is A or G, misdecoding is promoted by only G-U or U-G pair formation at the first or second position. In addition, evaluation of functional/structural diversities of amino acids revealed that less diverse amino acid sets are assigned at codons that induce more frequent misdecoding, and vice versa, so as to minimize deleterious effects of misdecoding in the modern genetic code.
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Affiliation(s)
- Takayuki Katoh
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hiroaki Suga
- Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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17
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Yarus M. The Genetic Code Assembles via Division and Fusion, Basic Cellular Events. Life (Basel) 2023; 13:2069. [PMID: 37895450 PMCID: PMC10608286 DOI: 10.3390/life13102069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/04/2023] [Accepted: 10/07/2023] [Indexed: 10/29/2023] Open
Abstract
Standard Genetic Code (SGC) evolution is quantitatively modeled in up to 2000 independent coding 'environments'. Environments host multiple codes that may fuse or divide, with division yielding identical descendants. Code division may be selected-sophisticated gene products could be required for an orderly separation that preserves the coding. Several unforeseen results emerge: more rapid evolution requires unselective code division rather than its selective form. Combining selective and unselective code division, with/without code fusion, with/without independent environmental coding tables, and with/without wobble defines 25 = 32 possible pathways for SGC evolution. These 32 possible histories are compared, specifically, for evolutionary speed and code accuracy. Pathways differ greatly, for example, by ≈300-fold in time to evolve SGC-like codes. Eight of thirty-two pathways employing code division evolve quickly. Four of these eight that combine fusion and division also unite speed and accuracy. The two most precise, swiftest paths; thus the most likely routes to the SGC are similar, differing only in fusion with independent environmental codes. Code division instead of fusion with unrelated codes implies that exterior codes can be dispensable. Instead, a single ancestral code that divides and fuses can initiate fully encoded peptide biosynthesis. Division and fusion create a 'crescendo of competent coding', facilitating the search for the SGC and also assisting the advent of otherwise uniformly disfavored wobble coding. Code fusion can unite multiple codon assignment mechanisms. However, via code division and fusion, an SGC can emerge from a single primary origin via familiar cellular events.
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Affiliation(s)
- Michael Yarus
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
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18
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Carr CE, Ramírez-Colón JL, Duzdevich D, Lee S, Taniguchi M, Ohshiro T, Komoto Y, Soderblom JM, Zuber MT. Solid-State Single-Molecule Sensing with the Electronic Life-Detection Instrument for Enceladus/Europa (ELIE). ASTROBIOLOGY 2023; 23:1056-1070. [PMID: 37782210 DOI: 10.1089/ast.2022.0119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Growing evidence of the potential habitability of Ocean Worlds across our solar system is motivating the advancement of technologies capable of detecting life as we know it-sharing a common ancestry or physicochemical origin with life on Earth-or don't know it, representing a distinct emergence of life different than our one known example. Here, we propose the Electronic Life-detection Instrument for Enceladus/Europa (ELIE), a solid-state single-molecule instrument payload that aims to search for life based on the detection of amino acids and informational polymers (IPs) at the parts per billion to trillion level. As a first proof-of-principle in a laboratory environment, we demonstrate the single-molecule detection of the amino acid L-proline at a 10 μM concentration in a compact system. Based on ELIE's solid-state quantum electronic tunneling sensing mechanism, we further propose the quantum property of the HOMO-LUMO gap (energy difference between a molecule's highest energy-occupied molecular orbital and lowest energy-unoccupied molecular orbital) as a novel metric to assess amino acid complexity. Finally, we assess the potential of ELIE to discriminate between abiotically and biotically derived α-amino acid abundance distributions to reduce the false positive risk for life detection. Nanogap technology can also be applied to the detection of nucleobases and short sequences of IPs such as, but not limited to, RNA and DNA. Future missions may utilize ELIE to target preserved biosignatures on the surface of Mars, extant life in its deep subsurface, or life or its biosignatures in a plume, surface, or subsurface of ice moons such as Enceladus or Europa. One-Sentence Summary: A solid-state nanogap can determine the abundance distribution of amino acids, detect nucleic acids, and shows potential for detecting life as we know it and life as we don't know it.
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Affiliation(s)
- Christopher E Carr
- Daniel Guggenheim School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - José L Ramírez-Colón
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Daniel Duzdevich
- Massachusetts General Hospital, Department of Molecular Biology, Boston, Massachusetts, USA
- Howard Hughes Medical Institute, Boston, Massachusetts, USA
- Current address: Department of Chemistry, University of Chicago, Chicago, Illinois, USA
| | - Sam Lee
- MIT Department of Electrical Engineering and Computer Science, Cambridge, Massachusetts, USA
| | - Masateru Taniguchi
- Osaka University, Institute of Scientific and Industrial Research, Osaka, Japan
| | - Takahito Ohshiro
- Osaka University, Institute of Scientific and Industrial Research, Osaka, Japan
| | - Yuki Komoto
- Osaka University, Institute of Scientific and Industrial Research, Osaka, Japan
| | - Jason M Soderblom
- MIT Department of Earth, Atmospheric and Planetary Sciences, Cambridge, Massachusetts, USA
| | - M T Zuber
- MIT Department of Earth, Atmospheric and Planetary Sciences, Cambridge, Massachusetts, USA
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19
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Allen JL, Sanders TJ, Horvat J, Lewis RA, Rule KC. Determination of Vibrational Modes of l-Alanine Single Crystals by a Combination of Terahertz Spectroscopy Measurements and Density Functional Calculations. PHYSICAL REVIEW LETTERS 2023; 130:226901. [PMID: 37327443 DOI: 10.1103/physrevlett.130.226901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 03/17/2023] [Indexed: 06/18/2023]
Abstract
Density-functional theory may be used to predict both the frequency and the dipole moment of the fundamental oscillations of molecular crystals. Suitably polarized photons at those frequencies excite such oscillations. Thus, in principle, terahertz spectroscopy may confirm the calculated fundamental modes of amino acids. However, reports to date have multiple shortcomings: (a) material of uncertain purity and morphology and diluted in a binder material is employed; (b) consequently, vibrations along all crystal axes are excited simultaneously; (c) data are restricted to room temperature, where resonances are broad and the background dominant; and (d) comparison with theory has been unsatisfactory (in part because the theory assumes zero temperature). Here, we overcome all four obstacles, in reporting detailed low-temperature polarized THz spectra of single-crystal l-alanine, assigning vibrational modes using density-functional theory, and comparing the calculated dipole moment vector direction to the electric field polarization of the measured spectra. Our direct and detailed comparison of theory with experiment corrects previous mode assignments for l-alanine, and reveals unreported modes, previously obscured by closely spaced spectral absorptions. The fundamental modes are thereby determined.
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Affiliation(s)
- J L Allen
- Institute for Superconducting and Electronic Materials and School of Physics, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - T J Sanders
- Institute for Superconducting and Electronic Materials and School of Physics, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - J Horvat
- Institute for Superconducting and Electronic Materials and School of Physics, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - R A Lewis
- Institute for Superconducting and Electronic Materials and School of Physics, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - K C Rule
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Wales 2234, Australia
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20
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Brown SM, Voráček V, Freeland S. What Would an Alien Amino Acid Alphabet Look Like and Why? ASTROBIOLOGY 2023; 23:536-549. [PMID: 37022727 DOI: 10.1089/ast.2022.0107] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Life on Earth builds genetically encoded proteins by using a standard alphabet of just 20 L-α-amino acids, although many others were available to life's origins and early evolution. To better understand the causes of this foundational evolutionary outcome, we extend previous analyses which have identified a highly unusual distribution of biophysical properties within the set used by life. Specifically, we use a heuristic search algorithm to identify other sets of amino acids, from a library of plausible alternatives, that emulate life's signature. We find that a subset of amino acids seems predisposed to forming such sets. We present other examples of such alphabets under various assumptions, along with analysis and reasoning about why each might be simplistic. We do so to introduce the central, open question that remains: while fundamental biophysics related to protein folding can potentially reduce a library of 1054 possible amino acid alphabets by 7 orders of magnitude, the framework of assumptions that does so leaves a further 1045 possibilities. It is therefore tempting to ask what additional assumptions can further reduce these 45 orders of magnitude? We thus conclude with a focus on library and alphabet construction as a useful target for subsequent research that may help future science speak with more confidence about what an alien amino acid alphabet would look like and why.
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Affiliation(s)
- Sean M Brown
- Department of Biological Sciences, University of Maryland, Baltimore County, Maryland, USA
| | - Václav Voráček
- Department of Computer Science, University of Tübingen, Tübingen, Germany
| | - Stephen Freeland
- Department of Biological Sciences, University of Maryland, Baltimore County, Maryland, USA
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21
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Makarov M, Sanchez Rocha AC, Krystufek R, Cherepashuk I, Dzmitruk V, Charnavets T, Faustino AM, Lebl M, Fujishima K, Fried SD, Hlouchova K. Early Selection of the Amino Acid Alphabet Was Adaptively Shaped by Biophysical Constraints of Foldability. J Am Chem Soc 2023; 145:5320-5329. [PMID: 36826345 PMCID: PMC10017022 DOI: 10.1021/jacs.2c12987] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Indexed: 02/25/2023]
Abstract
Whereas modern proteins rely on a quasi-universal repertoire of 20 canonical amino acids (AAs), numerous lines of evidence suggest that ancient proteins relied on a limited alphabet of 10 "early" AAs and that the 10 "late" AAs were products of biosynthetic pathways. However, many nonproteinogenic AAs were also prebiotically available, which begs two fundamental questions: Why do we have the current modern amino acid alphabet and would proteins be able to fold into globular structures as well if different amino acids comprised the genetic code? Here, we experimentally evaluate the solubility and secondary structure propensities of several prebiotically relevant amino acids in the context of synthetic combinatorial 25-mer peptide libraries. The most prebiotically abundant linear aliphatic and basic residues were incorporated along with or in place of other early amino acids to explore these alternative sequence spaces. The results show that foldability was likely a critical factor in the selection of the canonical alphabet. Unbranched aliphatic amino acids were purged from the proteinogenic alphabet despite their high prebiotic abundance because they generate polypeptides that are oversolubilized and have low packing efficiency. Surprisingly, we find that the inclusion of a short-chain basic amino acid also decreases polypeptides' secondary structure potential, for which we suggest a biophysical model. Our results support the view that, despite lacking basic residues, the early canonical alphabet was remarkably adaptive at supporting protein folding and explain why basic residues were only incorporated at a later stage of protein evolution.
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Affiliation(s)
- Mikhail Makarov
- Department
of Cell Biology, Faculty of Science, Charles
University, BIOCEV, Prague 12843, Czech Republic
| | - Alma C. Sanchez Rocha
- Department
of Cell Biology, Faculty of Science, Charles
University, BIOCEV, Prague 12843, Czech Republic
| | - Robin Krystufek
- Department
of Physical Chemistry, Faculty of Science, Charles University, Prague 12843, Czech Republic
- Institute
of Organic Chemistry and Biochemistry, Czech
Academy of Sciences, Prague 16610, Czech Republic
| | - Ivan Cherepashuk
- Department
of Cell Biology, Faculty of Science, Charles
University, BIOCEV, Prague 12843, Czech Republic
| | - Volha Dzmitruk
- Institute
of Biotechnology of the Czech Academy of Sciences, BIOCEV, Vestec 25250, Czech Republic
| | - Tatsiana Charnavets
- Institute
of Biotechnology of the Czech Academy of Sciences, BIOCEV, Vestec 25250, Czech Republic
| | - Anneliese M. Faustino
- Department
of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Michal Lebl
- Institute
of Organic Chemistry and Biochemistry, Czech
Academy of Sciences, Prague 16610, Czech Republic
| | - Kosuke Fujishima
- Earth-Life
Science Institute, Tokyo Institute of Technology, Tokyo 1528550, Japan
- Graduate
School of Media and Governance, Keio University, Fujisawa 2520882, Japan
| | - Stephen D. Fried
- Department
of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
- T.
C. Jenkins Department of Biophysics, Johns
Hopkins University, Baltimore, Maryland 21218, United States
| | - Klara Hlouchova
- Department
of Cell Biology, Faculty of Science, Charles
University, BIOCEV, Prague 12843, Czech Republic
- Institute
of Organic Chemistry and Biochemistry, Czech
Academy of Sciences, Prague 16610, Czech Republic
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22
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The Structure of Evolutionary Model Space for Proteins across the Tree of Life. BIOLOGY 2023; 12:biology12020282. [PMID: 36829559 PMCID: PMC9952988 DOI: 10.3390/biology12020282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/04/2023] [Accepted: 02/08/2023] [Indexed: 02/12/2023]
Abstract
The factors that determine the relative rates of amino acid substitution during protein evolution are complex and known to vary among taxa. We estimated relative exchangeabilities for pairs of amino acids from clades spread across the tree of life and assessed the historical signal in the distances among these clade-specific models. We separately trained these models on collections of arbitrarily selected protein alignments and on ribosomal protein alignments. In both cases, we found a clear separation between the models trained using multiple sequence alignments from bacterial clades and the models trained on archaeal and eukaryotic data. We assessed the predictive power of our novel clade-specific models of sequence evolution by asking whether fit to the models could be used to identify the source of multiple sequence alignments. Model fit was generally able to correctly classify protein alignments at the level of domain (bacterial versus archaeal), but the accuracy of classification at finer scales was much lower. The only exceptions to this were the relatively high classification accuracy for two archaeal lineages: Halobacteriaceae and Thermoprotei. Genomic GC content had a modest impact on relative exchangeabilities despite having a large impact on amino acid frequencies. Relative exchangeabilities involving aromatic residues exhibited the largest differences among models. There were a small number of exchangeabilities that exhibited large differences in comparisons among major clades and between generalized models and ribosomal protein models. Taken as a whole, these results reveal that a small number of relative exchangeabilities are responsible for much of the structure of the "model space" for protein sequence evolution. The clade-specific models we generated may be useful tools for protein phylogenetics, and the structure of evolutionary model space that they revealed has implications for phylogenomic inference across the tree of life.
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23
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Yarus M. A crescendo of competent coding (c3) contains the Standard Genetic Code. RNA (NEW YORK, N.Y.) 2022; 28:1337-1347. [PMID: 35868841 PMCID: PMC9479743 DOI: 10.1261/rna.079275.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 07/18/2022] [Indexed: 06/15/2023]
Abstract
The Standard Genetic Code (SGC) can arise by fusion of partial codes evolved in different individuals, perhaps for differing prior tasks. Such code fragments can be unified into an SGC after later evolution of accurate third-position Crick wobble. Late wobble advent fills in the coding table, leaving only later development of translational initiation and termination to reach the SGC in separated domains of life. This code fusion mechanism is computationally implemented here. Late Crick wobble after C3 fusion (c3-lCw) is tested for its ability to evolve the SGC. Compared with previously studied isolated coding tables, or with increasing numbers of parallel, but nonfusing codes, c3-lCw reaches the SGC sooner, is successful in a smaller population, and presents accurate and complete codes more frequently. Notably, a long crescendo of SGC-like codes is exposed for selection of superior translation. c3-lCw also effectively suppresses varied disordered assignments, thus converging on a unified code. Such merged codes closely approach the SGC, making its selection plausible. For example: Under routine conditions, ≈1 of 22 c3-lCw environments evolves codes with ≥20 assignments and ≤3 differences from the SGC, notably including codes identical to the Standard Genetic Code.
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Affiliation(s)
- Michael Yarus
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347, USA
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24
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Błażej P, Kowalski DR, Mackiewicz D, Wnetrzak M, Aloqalaa DA, Mackiewicz P. The structure of the genetic code as an optimal graph clustering problem. J Math Biol 2022; 85:9. [PMID: 35838803 DOI: 10.1007/s00285-022-01778-4] [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: 12/22/2017] [Revised: 06/20/2022] [Accepted: 06/24/2022] [Indexed: 11/29/2022]
Abstract
The standard genetic code (SGC) is the set of rules by which genetic information is translated into proteins, from codons, i.e. triplets of nucleotides, to amino acids. The questions about the origin and the main factor responsible for the present structure of the code are still under a hot debate. Various methodologies have been used to study the features of the code and assess the level of its potential optimality. Here, we introduced a new general approach to evaluate the quality of the genetic code structure. This methodology comes from graph theory and allows us to describe new properties of the genetic code in terms of conductance. This parameter measures the robustness of codon groups against the potential changes in translation of the protein-coding sequences generated by single nucleotide substitutions. We described the genetic code as a partition of an undirected and unweighted graph, which makes the model general and universal. Using this approach, we showed that the structure of the genetic code is a solution to the graph clustering problem. We presented and discussed the structure of the codes that are optimal according to the conductance. Despite the fact that the standard genetic code is far from being optimal according to the conductance, its structure is characterised by many codon groups reaching the minimum conductance for their size. The SGC represents most likely a local minimum in terms of errors occurring in protein-coding sequences and their translation.
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Affiliation(s)
- Paweł Błażej
- Department of Genomics, Faculty of Biotechnology, University of Wrocław, ul. Joliot-Curie 14a, Wrocław, Poland.
| | - Dariusz R Kowalski
- School of Computer and Cyber Sciences, Augusta University, Augusta, GA, USA
| | - Dorota Mackiewicz
- Department of Genomics, Faculty of Biotechnology, University of Wrocław, ul. Joliot-Curie 14a, Wrocław, Poland
| | - Małgorzata Wnetrzak
- Department of Genomics, Faculty of Biotechnology, University of Wrocław, ul. Joliot-Curie 14a, Wrocław, Poland
| | | | - Paweł Mackiewicz
- Department of Genomics, Faculty of Biotechnology, University of Wrocław, ul. Joliot-Curie 14a, Wrocław, Poland
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25
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Janzen E, Shen Y, Vázquez-Salazar A, Liu Z, Blanco C, Kenchel J, Chen IA. Emergent properties as by-products of prebiotic evolution of aminoacylation ribozymes. Nat Commun 2022; 13:3631. [PMID: 35752631 PMCID: PMC9233669 DOI: 10.1038/s41467-022-31387-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 06/16/2022] [Indexed: 11/24/2022] Open
Abstract
Systems of catalytic RNAs presumably gave rise to important evolutionary innovations, such as the genetic code. Such systems may exhibit particular tolerance to errors (error minimization) as well as coding specificity. While often assumed to result from natural selection, error minimization may instead be an emergent by-product. In an RNA world, a system of self-aminoacylating ribozymes could enforce the mapping of amino acids to anticodons. We measured the activity of thousands of ribozyme mutants on alternative substrates (activated analogs for tryptophan, phenylalanine, leucine, isoleucine, valine, and methionine). Related ribozymes exhibited shared preferences for substrates, indicating that adoption of additional amino acids by existing ribozymes would itself lead to error minimization. Furthermore, ribozyme activity was positively correlated with specificity, indicating that selection for increased activity would also lead to increased specificity. These results demonstrate that by-products of ribozyme evolution could lead to adaptive value in specificity and error tolerance.
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Affiliation(s)
- Evan Janzen
- Program in Biomolecular Science and Engineering, University of California, Santa Barbara, CA, 93106, USA.,Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, USA
| | - Yuning Shen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, USA.,Department of Chemical and Biomolecular Engineering, Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
| | - Alberto Vázquez-Salazar
- Department of Chemical and Biomolecular Engineering, Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
| | - Ziwei Liu
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK
| | - Celia Blanco
- Department of Chemical and Biomolecular Engineering, Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
| | - Josh Kenchel
- Program in Biomolecular Science and Engineering, University of California, Santa Barbara, CA, 93106, USA.,Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, USA.,Department of Chemical and Biomolecular Engineering, Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
| | - Irene A Chen
- Program in Biomolecular Science and Engineering, University of California, Santa Barbara, CA, 93106, USA. .,Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106, USA. .,Department of Chemical and Biomolecular Engineering, Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA.
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26
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A Closer Look at Non-random Patterns Within Chemistry Space for a Smaller, Earlier Amino Acid Alphabet. J Mol Evol 2022; 90:307-323. [PMID: 35666290 DOI: 10.1007/s00239-022-10061-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 05/11/2022] [Indexed: 10/18/2022]
Abstract
Recent findings, in vitro and in silico, are strengthening the idea of a simpler, earlier stage of genetically encoded proteins which used amino acids produced by prebiotic chemistry. These findings motivate a re-examination of prior work which has identified unusual properties of the set of twenty amino acids found within the full genetic code, while leaving it unclear whether similar patterns also characterize the subset of prebiotically plausible amino acids. We have suggested previously that this ambiguity may result from the low number of amino acids recognized by the definition of prebiotic plausibility used for the analysis. Here, we test this hypothesis using significantly updated data for organic material detected within meteorites, which contain several coded and non-coded amino acids absent from prior studies. In addition to confirming the well-established idea that "late" arriving amino acids expanded the chemistry space encoded by genetic material, we find that a prebiotically plausible subset of coded amino acids generally emulates the patterns found in the full set of 20, namely an exceptionally broad and even distribution of volumes and an exceptionally even distribution of hydrophobicities (quantified as logP) over a narrow range. However, the strength of this pattern varies depending on both the size and composition the library used to create a background (null model) for a random alphabet, and the precise definition of exactly which amino acids were present in a simpler, earlier code. Findings support the idea that a small sample size of amino acids caused previous ambiguous results, and further improvements in meteorite analysis, and/or prebiotic simulations will further clarify the nature and extent of unusual properties. We discuss the case of sulfur-containing amino acids as a specific and clear example and conclude by reviewing the potential impact of better understanding the chemical "logic" of a smaller forerunner to the standard amino acid alphabet.
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27
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Tretyachenko V, Vymětal J, Neuwirthová T, Vondrášek J, Fujishima K, Hlouchová K. Modern and prebiotic amino acids support distinct structural profiles in proteins. Open Biol 2022; 12:220040. [PMID: 35728622 PMCID: PMC9213115 DOI: 10.1098/rsob.220040] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The earliest proteins had to rely on amino acids available on early Earth before the biosynthetic pathways for more complex amino acids evolved. In extant proteins, a significant fraction of the 'late' amino acids (such as Arg, Lys, His, Cys, Trp and Tyr) belong to essential catalytic and structure-stabilizing residues. How (or if) early proteins could sustain an early biosphere has been a major puzzle. Here, we analysed two combinatorial protein libraries representing proxies of the available sequence space at two different evolutionary stages. The first is composed of the entire alphabet of 20 amino acids while the second one consists of only 10 residues (ASDGLIPTEV) representing a consensus view of plausibly available amino acids through prebiotic chemistry. We show that compact conformations resistant to proteolysis are surprisingly similarly abundant in both libraries. In addition, the early alphabet proteins are inherently more soluble and refoldable, independent of the general Hsp70 chaperone activity. By contrast, chaperones significantly increase the otherwise poor solubility of the modern alphabet proteins suggesting their coevolution with the amino acid repertoire. Our work indicates that while both early and modern amino acids are predisposed to supporting protein structure, they do so with different biophysical properties and via different mechanisms.
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Affiliation(s)
- Vyacheslav Tretyachenko
- Department of Cell Biology, Faculty of Science, Charles University, Prague 12843, Czech Republic,Department of Biochemistry, Faculty of Science, Charles University, Prague 12843, Czech Republic
| | - Jiří Vymětal
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague 16610, Czech Republic
| | - Tereza Neuwirthová
- Department of Cell Biology, Faculty of Science, Charles University, Prague 12843, Czech Republic
| | - Jiří Vondrášek
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague 16610, Czech Republic
| | - Kosuke Fujishima
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 1528550, Japan,Graduate School of Media and Governance, Keio University, Fujisawa 2520882 Japan
| | - Klára Hlouchová
- Department of Cell Biology, Faculty of Science, Charles University, Prague 12843, Czech Republic,Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague 16610, Czech Republic
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28
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Jia TZ, Nishikawa S, Fujishima K. Sequencing the Origins of Life. BBA ADVANCES 2022; 2:100049. [PMID: 37082609 PMCID: PMC10074849 DOI: 10.1016/j.bbadva.2022.100049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 02/27/2022] [Accepted: 03/02/2022] [Indexed: 01/10/2023] Open
Abstract
One goal of origins of life research is to understand how primitive informational and catalytic biopolymers emerged and evolved. Recently, a number of sequencing techniques have been applied to analysis of replicating and evolving primitive biopolymer systems, providing a sequence-specific and high-resolution view of primitive chemical processes. Here, we review application of sequencing techniques to analysis of synthetic and primitive nucleic acids and polypeptides. This includes next-generation sequencing of primitive polymerization and evolution processes, followed by discussion of other novel biochemical techniques that could contribute to sequence analysis of primitive biopolymer driven chemical systems. Further application of sequencing to origins of life research, perhaps as a life detection technology, could provide insight into the origin and evolution of informational and catalytic biopolymers on early Earth or elsewhere.
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Affiliation(s)
- Tony Z. Jia
- Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1-IE-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
- Blue Marble Space Institute of Science, 600 1st Ave, Floor 1, Seattle, WA 98104, USA
- Corresponding author
| | - Shota Nishikawa
- Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1-IE-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8501, Japan
| | - Kosuke Fujishima
- Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1-IE-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
- Graduate School of Media and Governance, Keio University, 5322 Endo, Fujisawa-shi, Kanagawa 252-0882, Japan
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29
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Giacobelli VG, Fujishima K, Lepšík M, Tretyachenko V, Kadavá T, Makarov M, Bednárová L, Novák P, Hlouchová K. In vitro evolution reveals non-cationic protein-RNA interaction mediated by metal ions. Mol Biol Evol 2022; 39:6524634. [PMID: 35137196 PMCID: PMC8892947 DOI: 10.1093/molbev/msac032] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
RNA–peptide/protein interactions have been of utmost importance to life since its earliest forms, reaching even before the last universal common ancestor (LUCA). However, the ancient molecular mechanisms behind this key biological interaction remain enigmatic because extant RNA–protein interactions rely heavily on positively charged and aromatic amino acids that were absent (or heavily under-represented) in the early pre-LUCA evolutionary period. Here, an RNA-binding variant of the ribosomal uL11 C-terminal domain was selected from an approximately 1010 library of partially randomized sequences, all composed of ten prebiotically plausible canonical amino acids. The selected variant binds to the cognate RNA with a similar overall affinity although it is less structured in the unbound form than the wild-type protein domain. The variant complex association and dissociation are both slower than for the wild-type, implying different mechanistic processes involved. The profile of the wild-type and mutant complex stabilities along with molecular dynamics simulations uncovers qualitative differences in the interaction modes. In the absence of positively charged and aromatic residues, the mutant uL11 domain uses ion bridging (K+/Mg2+) interactions between the RNA sugar-phosphate backbone and glutamic acid residues as an alternative source of stabilization. This study presents experimental support to provide a new perspective on how early protein–RNA interactions evolved, where the lack of aromatic/basic residues may have been compensated by acidic residues plus metal ions.
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Affiliation(s)
- Valerio G Giacobelli
- Department of Cell Biology, Faculty of Science, Charles University, BIOCEV, Prague, 12800, Czech Republic
| | - Kosuke Fujishima
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo, 1528550, Japan.,Graduate School of Media and Governance, Keio University, Fujisawa, 2520882, Japan
| | - Martin Lepšík
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, 16610, Czech Republic
| | - Vyacheslav Tretyachenko
- Department of Cell Biology, Faculty of Science, Charles University, BIOCEV, Prague, 12800, Czech Republic
| | - Tereza Kadavá
- Department of Biochemistry, Faculty of Science, Charles University, Prague, 12800, Czech Republic
| | - Mikhail Makarov
- Department of Cell Biology, Faculty of Science, Charles University, BIOCEV, Prague, 12800, Czech Republic
| | - Lucie Bednárová
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, 16610, Czech Republic
| | - Petr Novák
- Institute of Microbiology, The Czech Academy of Sciences, Vestec, 25250, Czech Republic
| | - Klára Hlouchová
- Department of Cell Biology, Faculty of Science, Charles University, BIOCEV, Prague, 12800, Czech Republic.,Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, 16610, Czech Republic
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30
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Fried SD, Fujishima K, Makarov M, Cherepashuk I, Hlouchova K. Peptides before and during the nucleotide world: an origins story emphasizing cooperation between proteins and nucleic acids. J R Soc Interface 2022; 19:20210641. [PMID: 35135297 PMCID: PMC8833103 DOI: 10.1098/rsif.2021.0641] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 01/05/2022] [Indexed: 12/14/2022] Open
Abstract
Recent developments in Origins of Life research have focused on substantiating the narrative of an abiotic emergence of nucleic acids from organic molecules of low molecular weight, a paradigm that typically sidelines the roles of peptides. Nevertheless, the simple synthesis of amino acids, the facile nature of their activation and condensation, their ability to recognize metals and cofactors and their remarkable capacity to self-assemble make peptides (and their analogues) favourable candidates for one of the earliest functional polymers. In this mini-review, we explore the ramifications of this hypothesis. Diverse lines of research in molecular biology, bioinformatics, geochemistry, biophysics and astrobiology provide clues about the progression and early evolution of proteins, and lend credence to the idea that early peptides served many central prebiotic roles before they were encodable by a polynucleotide template, in a putative 'peptide-polynucleotide stage'. For example, early peptides and mini-proteins could have served as catalysts, compartments and structural hubs. In sum, we shed light on the role of early peptides and small proteins before and during the nucleotide world, in which nascent life fully grasped the potential of primordial proteins, and which has left an imprint on the idiosyncratic properties of extant proteins.
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Affiliation(s)
- Stephen D. Fried
- Department of Chemistry, Johns Hopkins University, Baltimore, MD 21212, USA
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21212, USA
| | - Kosuke Fujishima
- Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 1528550, Japan
- Graduate School of Media and Governance, Keio University, Fujisawa 2520882, Japan
| | - Mikhail Makarov
- Department of Cell Biology, Faculty of Science, Charles University, BIOCEV, Prague 12800, Czech Republic
| | - Ivan Cherepashuk
- Department of Cell Biology, Faculty of Science, Charles University, BIOCEV, Prague 12800, Czech Republic
| | - Klara Hlouchova
- Department of Cell Biology, Faculty of Science, Charles University, BIOCEV, Prague 12800, Czech Republic
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague 16610, Czech Republic
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31
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Freeland S. Undefining life's biochemistry: implications for abiogenesis. J R Soc Interface 2022; 19:20210814. [PMID: 35193384 PMCID: PMC8867283 DOI: 10.1098/rsif.2021.0814] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 01/19/2022] [Indexed: 12/22/2022] Open
Abstract
In the mid-twentieth century, multiple Nobel Prizes rewarded discoveries of a seemingly universal set of molecules and interactions that collectively defined the chemical basis for life. Twenty-first-century science knows that every detail of this Central Dogma of Molecular Biology can vary through either biological evolution, human engineering (synthetic biology) or both. Clearly the material, molecular basis of replicating, evolving entities can be different. There is far less clarity yet for what constitutes this set of possibilities. One approach to better understand the limits and scope of moving beyond life's central dogma comes from those who study life's origins. RNA, proteins and the genetic code that binds them each look like products of natural selection. This raises the question of what step(s) preceded these particular components? Answers here will clarify whether any discrete point in time or biochemical evolution will objectively merit the label of life's origin, or whether life unfolds seamlessly from the non-living universe.
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Affiliation(s)
- Stephen Freeland
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250, USA
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32
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Rout SK, Rhyner D, Riek R, Greenwald J. Prebiotically Plausible Autocatalytic Peptide Amyloids. Chemistry 2022; 28:e202103841. [PMID: 34812556 PMCID: PMC9299922 DOI: 10.1002/chem.202103841] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Indexed: 12/19/2022]
Abstract
The prebiotic emergence of molecules capable both of self-replication and of storing information was a defining event at the dawn of life. Still, no plausible prebiotic self-replication of biologically relevant molecules has been demonstrated. Building upon the known templating nature of amyloids, we present two systems in which the products of a peptide-bond-forming reaction act as self-replicators to enhance the yield and stereoselectivity of their formation. This first report of an amino acid condensation that can undergo autocatalysis further supports the potential role of amyloids in prebiotic molecular evolution as an environment-responsive and information-coding system capable of self-replication.
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Affiliation(s)
- Saroj K. Rout
- Laboratory of Physical ChemistrySwiss Federal Institute of TechnologyETH HönggerbergVladimir-Prelog-Weg 28093ZürichSwitzerland
| | - David Rhyner
- Laboratory of Physical ChemistrySwiss Federal Institute of TechnologyETH HönggerbergVladimir-Prelog-Weg 28093ZürichSwitzerland
| | - Roland Riek
- Laboratory of Physical ChemistrySwiss Federal Institute of TechnologyETH HönggerbergVladimir-Prelog-Weg 28093ZürichSwitzerland
| | - Jason Greenwald
- Laboratory of Physical ChemistrySwiss Federal Institute of TechnologyETH HönggerbergVladimir-Prelog-Weg 28093ZürichSwitzerland
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33
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From amino acid mixtures to peptides in liquid sulphur dioxide on early Earth. Nat Commun 2021; 12:7182. [PMID: 34893619 PMCID: PMC8664857 DOI: 10.1038/s41467-021-27527-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 11/18/2021] [Indexed: 01/01/2023] Open
Abstract
The formation of peptide bonds is one of the most important biochemical reaction steps. Without the development of structurally and catalytically active polymers, there would be no life on our planet. However, the formation of large, complex oligomer systems is prevented by the high thermodynamic barrier of peptide condensation in aqueous solution. Liquid sulphur dioxide proves to be a superior alternative for copper-catalyzed peptide condensations. Compared to water, amino acids are activated in sulphur dioxide, leading to the incorporation of all 20 proteinogenic amino acids into proteins. Strikingly, even extremely low initial reactant concentrations of only 50 mM are sufficient for extensive peptide formation, yielding up to 2.9% of dialanine in 7 days. The reactions carried out at room temperature and the successful use of the Hadean mineral covellite (CuS) as a catalyst, suggest a volcanic environment for the formation of the peptide world on early Earth. Peptide bond formation is one of the key biochemical reactions needed for the formation of life, but is thermodynamically unfavoured in water. Here, the authors report on the possibility of complex oligomer formation in liquid sulphur dioxide which may have existed on early Earth at the emergence of life.
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34
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Factors in Protobiomonomer Selection for the Origin of the Standard Genetic Code. Acta Biotheor 2021; 69:745-767. [PMID: 34283307 DOI: 10.1007/s10441-021-09420-4] [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: 08/14/2020] [Accepted: 07/01/2021] [Indexed: 10/20/2022]
Abstract
Natural selection of specific protobiomonomers during abiogenic development of the prototype genetic code is hindered by the diversity of structural, spatial, and rotational isomers that have identical elemental composition and molecular mass (M), but can vary significantly in their physicochemical characteristics, such as the melting temperature Tm, the Tm:M ratio, and the solubility in water, due to different positions of atoms in the molecule. These parameters differ between cis- and trans-isomers of dicarboxylic acids, spatial monosaccharide isomers, and structural isomers of α-, β-, and γ-amino acids. The stable planar heterocyclic molecules of the major nucleobases comprise four (C, H, N, O) or three (C, H, N) elements and contain a single -C=C bond and two nitrogen atoms in each heterocycle involved in C-N and C=N bonds. They exist as isomeric resonance hybrids of single and double bonds and as a mixture of tautomer forms due to the presence of -C=O and/or -NH2 side groups. They are thermostable, insoluble in water, and exhibit solid-state stability, which is of central importance for DNA molecules as carriers of genetic information. In M-Tm diagrams, proteinogenic amino acids and the corresponding codons are distributed fairly regularly relative to the distinct clusters of purine and pyrimidine bases, reflecting the correspondence between codons and amino acids that was established in different periods of genetic code development. The body of data on the evolution of the genetic code system indicates that the elemental composition and molecular structure of protobiomonomers, and their M, Tm, photostability, and aqueous solubility determined their selection in the emergence of the standard genetic code.
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35
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The Combinatorial Fusion Cascade to Generate the Standard Genetic Code. Life (Basel) 2021; 11:life11090975. [PMID: 34575125 PMCID: PMC8467831 DOI: 10.3390/life11090975] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 09/14/2021] [Accepted: 09/14/2021] [Indexed: 11/17/2022] Open
Abstract
Combinatorial fusion cascade was proposed as a transition stage between prebiotic chemistry and early forms of life. The combinatorial fusion cascade consists of three stages: eight initial complimentary pairs of amino acids, four protocodes, and the standard genetic code. The initial complimentary pairs and the protocodes are divided into dominant and recessive entities. The transitions between these stages obey the same combinatorial fusion rules for all amino acids. The combinatorial fusion cascade mathematically describes the codon assignments in the standard genetic code. It explains the availability of amino acids with the even and odd numbers of codons, the appearance of stop codons, inclusion of novel canonical amino acids, exceptional high numbers of codons for amino acids arginine, leucine, and serine, and the temporal order of amino acid inclusion into the genetic code. The temporal order of amino acids within the cascade is congruent with the consensus temporal order previously derived from the similarities between the available hypotheses. The control over the combinatorial fusion cascades would open the road for a novel technology to develop artificial microorganisms.
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36
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Abstract
Minimally evolved codes are constructed here; these have randomly chosen standard genetic code (SGC) triplets, completed with completely random triplet assignments. Such "genetic codes" have not evolved, but retain SGC qualities. Retained qualities are basic, part of the underpinning of coding. For example, the sensitivity of coding to arbitrary assignments, which must be < ∼10%, is intrinsic. Such sensitivity comes from the elementary combinatorial properties of coding and constrains any SGC evolution hypothesis. Similarly, assignment of last-evolved functions is difficult because of late kinetic phenomena, likely common across codes. Census of minimally evolved code assignments shows that shape and size of wobble domains controls the code's fit into a coding table, strongly shifting accuracy of codon assignments. Access to the SGC therefore requires a plausible pathway to limited randomness, avoiding difficult completion while fitting a highly ordered, degenerate code into a preset three-dimensional space. Three-dimensional late Crick wobble in a genetic code assembled by lateral transfer between early partial codes satisfies these varied, simultaneous requirements. By allowing parallel evolution of SGC domains, this origin can yield shortened evolution to SGC-level order and allow the code to arise in smaller populations. It effectively yields full codes. Less obviously, it unifies previously studied chemical, biochemical, and wobble order in amino acid assignment, including a stereochemical minority of triplet-amino acid associations. Finally, fusion of intermediates into the final SGC is credible, mirroring broadly accepted later cellular evolution.
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37
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Martínez-Giménez JA, Tabares-Seisdedos R. Possible Ancestral Functions of the Genetic and RNA Operational Precodes and the Origin of the Genetic System. ORIGINS LIFE EVOL B 2021; 51:167-183. [PMID: 34097191 DOI: 10.1007/s11084-021-09610-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 05/17/2021] [Indexed: 11/24/2022]
Abstract
The origin of genetic systems is the central problem in the study of the origin of life for which various explanatory hypotheses have been presented. One model suggests that both ancestral transfer ribonucleic acid (tRNA) molecules and primitive ribosomes were originally involved in RNA replication (Campbell 1991). According to this model the early tRNA molecules catalyzed their own self-loading with a trinucleotide complementary to their anticodon triplet, while the primordial ribosome (protoribosome) catalyzed the transfer of these terminal trinucleotides from one tRNA to another tRNA harboring the growing RNA polymer at the 3´-end.Here we present the notion that the anticodon-codon-like pairs presumably located in the acceptor stem of primordial tRNAs (Rodin et al. 1996) (thus being and remaining, after the code and translation origins, the major contributor to the RNA operational code (Schimmel et al. 1993)) might have originally been used for RNA replication rather than translation; these anticodon and acceptor stem triplets would have been involved in accurately loading the 3'-end of tRNAs with a trinucleotide complementary to their anticodon triplet, thus allowing the accurate repair of tRNAs for their use by the protoribosome during RNA replication.We propose that tRNAs could have catalyzed their own trinucleotide self-loading by forming catalytic tRNA dimers which would have had polymerase activity. Therefore, the loading mechanism and its evolution may have been a basic step in the emergence of new genetic mechanisms such as genetic translation. The evolutionary implications of this proposed loading mechanism are also discussed.
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Affiliation(s)
| | - Rafael Tabares-Seisdedos
- Departamento de Medicina, Facultad de Medicina de Valencia, Universidad de Valencia, Av. Blasco Ibañez 17, 46010, Valencia, Spain.
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38
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Makarov M, Meng J, Tretyachenko V, Srb P, Březinová A, Giacobelli VG, Bednárová L, Vondrášek J, Dunker AK, Hlouchová K. Enzyme catalysis prior to aromatic residues: Reverse engineering of a dephospho-CoA kinase. Protein Sci 2021; 30:1022-1034. [PMID: 33739538 PMCID: PMC8040869 DOI: 10.1002/pro.4068] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 03/12/2021] [Accepted: 03/13/2021] [Indexed: 11/07/2022]
Abstract
The wide variety of protein structures and functions results from the diverse properties of the 20 canonical amino acids. The generally accepted hypothesis is that early protein evolution was associated with enrichment of a primordial alphabet, thereby enabling increased protein catalytic efficiencies and functional diversification. Aromatic amino acids were likely among the last additions to genetic code. The main objective of this study was to test whether enzyme catalysis can occur without the aromatic residues (aromatics) by studying the structure and function of dephospho-CoA kinase (DPCK) following aromatic residue depletion. We designed two variants of a putative DPCK from Aquifex aeolicus by substituting (a) Tyr, Phe and Trp or (b) all aromatics (including His). Their structural characterization indicates that substituting the aromatics does not markedly alter their secondary structures but does significantly loosen their side chain packing and increase their sizes. Both variants still possess ATPase activity, although with 150-300 times lower efficiency in comparison with the wild-type phosphotransferase activity. The transfer of the phosphate group to the dephospho-CoA substrate becomes heavily uncoupled and only the His-containing variant is still able to perform the phosphotransferase reaction. These data support the hypothesis that proteins in the early stages of life could support catalytic activities, albeit with low efficiencies. An observed significant contraction upon ligand binding is likely important for appropriate organization of the active site. Formation of firm hydrophobic cores, which enable the assembly of stably structured active sites, is suggested to provide a selective advantage for adding the aromatic residues.
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Affiliation(s)
- Mikhail Makarov
- Department of Cell Biology, Faculty of ScienceCharles University, BIOCEVPragueCzech Republic
- Department of Biochemistry, Faculty of ScienceCharles UniversityPragueCzech Republic
| | - Jingwei Meng
- Department of Biochemistry and Molecular Biology, Center for Computational Biology and BioinformaticsIndiana University School of MedicineIndianapolisIndianaUSA
| | - Vyacheslav Tretyachenko
- Department of Cell Biology, Faculty of ScienceCharles University, BIOCEVPragueCzech Republic
- Department of Biochemistry, Faculty of ScienceCharles UniversityPragueCzech Republic
| | - Pavel Srb
- Institute of Organic Chemistry and Biochemistry, IOCB Research Centre & Gilead Sciences, Academy of Sciences of the Czech RepublicPragueCzech Republic
| | - Anna Březinová
- Proteomics Core Facility, BIOCEV, Faculty of Science, Charles UniversityPragueCzech Republic
| | | | - Lucie Bednárová
- Institute of Organic Chemistry and Biochemistry, IOCB Research Centre & Gilead Sciences, Academy of Sciences of the Czech RepublicPragueCzech Republic
| | - Jiří Vondrášek
- Institute of Organic Chemistry and Biochemistry, IOCB Research Centre & Gilead Sciences, Academy of Sciences of the Czech RepublicPragueCzech Republic
| | - A. Keith Dunker
- Department of Biochemistry and Molecular Biology, Center for Computational Biology and BioinformaticsIndiana University School of MedicineIndianapolisIndianaUSA
| | - Klára Hlouchová
- Department of Cell Biology, Faculty of ScienceCharles University, BIOCEVPragueCzech Republic
- Institute of Organic Chemistry and Biochemistry, IOCB Research Centre & Gilead Sciences, Academy of Sciences of the Czech RepublicPragueCzech Republic
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39
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Jaramillo-Botero A, Cable ML, Hofmann AE, Malaska M, Hodyss R, Lunine J. Understanding Hypervelocity Sampling of Biosignatures in Space Missions. ASTROBIOLOGY 2021; 21:421-442. [PMID: 33749334 PMCID: PMC7994429 DOI: 10.1089/ast.2020.2301] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 11/09/2020] [Indexed: 05/08/2023]
Abstract
The atomic-scale fragmentation processes involved in molecules undergoing hypervelocity impacts (HVIs; defined as >3 km/s) are challenging to investigate via experiments and still not well understood. This is particularly relevant for the consistency of biosignals from small-molecular-weight neutral organic molecules obtained during solar system robotic missions sampling atmospheres and plumes at hypervelocities. Experimental measurements to replicate HVI effects on neutral molecules are challenging, both in terms of accelerating uncharged species and isolating the multiple transition states over very rapid timescales (<1 ps). Nonequilibrium first-principles-based simulations extend the range of what is possible with experiments. We report on high-fidelity simulations of the fragmentation of small organic biosignature molecules over the range v = 1-12 km/s, and demonstrate that the fragmentation fraction is a sensitive function of velocity, impact angle, molecular structure, impact surface material, and the presence of surrounding ice shells. Furthermore, we generate interpretable fragmentation pathways and spectra for velocity values above the fragmentation thresholds and reveal how organic molecules encased in ice grains, as would likely be the case for those in "ocean worlds," are preserved at even higher velocities than bare molecules. Our results place ideal spacecraft encounter velocities between 3 and 5 km/s for bare amino and fatty acids and within 4-6 km/s for the same species encased in ice grains and predict the onset of organic fragmentation in ice grains at >5 km/s, both consistent with recent experiments exploring HVI effects using impact-induced ionization and analysis via mass spectrometry and from the analysis of Enceladus organics in Cassini Data. From nanometer-sized ice Ih clusters, we establish that HVI energy is dissipated by ice casings through thermal resistance to the impact shock wave and that an upper fragmentation velocity limit exists at which ultimately any organic contents will be cleaved by the surrounding ice-this provides a fundamental path to characterize micrometer-sized ice grains. Altogether, these results provide quantifiable insights to bracket future instrument design and mission parameters.
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Affiliation(s)
- Andres Jaramillo-Botero
- Chemistry and Chemical Engineering Division, California Institute of Technology, Pasadena, California, USA
| | - Morgan L. Cable
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Amy E. Hofmann
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Michael Malaska
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Robert Hodyss
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Jonathan Lunine
- Department of Astronomy and Carl Sagan Institute, Cornell University, Ithaca, New York, USA
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40
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Did Amino Acid Side Chain Reactivity Dictate the Composition and Timing of Aminoacyl-tRNA Synthetase Evolution? Genes (Basel) 2021; 12:genes12030409. [PMID: 33809136 PMCID: PMC8001834 DOI: 10.3390/genes12030409] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/05/2021] [Accepted: 03/10/2021] [Indexed: 12/16/2022] Open
Abstract
The twenty amino acids in the standard genetic code were fixed prior to the last universal common ancestor (LUCA). Factors that guided this selection included establishment of pathways for their metabolic synthesis and the concomitant fixation of substrate specificities in the emerging aminoacyl-tRNA synthetases (aaRSs). In this conceptual paper, we propose that the chemical reactivity of some amino acid side chains (e.g., lysine, cysteine, homocysteine, ornithine, homoserine, and selenocysteine) delayed or prohibited the emergence of the corresponding aaRSs and helped define the amino acids in the standard genetic code. We also consider the possibility that amino acid chemistry delayed the emergence of the glutaminyl- and asparaginyl-tRNA synthetases, neither of which are ubiquitous in extant organisms. We argue that fundamental chemical principles played critical roles in fixation of some aspects of the genetic code pre- and post-LUCA.
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41
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Mayer-Bacon C, Freeland SJ. A broader context for understanding amino acid alphabet optimality. J Theor Biol 2021; 520:110661. [PMID: 33684404 DOI: 10.1016/j.jtbi.2021.110661] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 02/23/2021] [Accepted: 02/25/2021] [Indexed: 12/21/2022]
Abstract
A series of prior publications has reported unusual properties of the set of genetically encoded amino acids shared by all known life. This work uses quantitative measures (descriptors) of size, charge and hydrophobicity to compare the distribution of the genetically encoded amino acids with random samples of plausible alternatives. Results show that the standard "alphabet" of amino acids established by the time of LUCA is distributed with unusual evenness over a broad range for the three, key physicochemical properties. However, different publications have used slightly different assumptions, including variations in the precise descriptors used, the set of plausible alternative molecules considered, and the format in which results have been presented. Here we consolidate these findings into a unified framework in order to clarify unusual features. We find that in general, the remarkable features of the full set of 20 genetically encoded amino acids are robust when compared with random samples drawn from a densely populated picture of plausible, alternative L-α-amino acids. In particular, the genetically encoded set is distributed across an exceptionally broad range of volumes, and distributed exceptionally evenly within a modest range of hydrophobicities. Surprisingly, range and evenness of charge (pKa) is exceptional only for the full amino acid structures, not for their sidechains - a result inconsistent with prior interpretations involving the role that amino acid sidechains play within protein sequences. In stark contrast, these remarkable features are far less clear when the prebiotically plausible subset of genetically encoded amino acids is compared with a much smaller pool of prebiotically plausible alternatives. By considering the nature of the "optimality theory" approach taken to derive these and prior insights, we suggest productive avenues for further research.
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Affiliation(s)
- Christopher Mayer-Bacon
- Department of Biological Sciences, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 25250, USA.
| | - Stephen J Freeland
- Department of Biological Sciences, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 25250, USA
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42
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The origin of the genetic code and origin of ideas. J Theor Biol 2021; 516:110615. [PMID: 33545188 DOI: 10.1016/j.jtbi.2021.110615] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/21/2021] [Accepted: 01/26/2021] [Indexed: 11/22/2022]
Abstract
Inouye et al. (2020) use the observation that Ser is coded in the genetic code by two blocks of codons that differ on more than one base to understand some aspects of the origin of the genetic code organization. I argue instead that this observation per se cannot be used to understand any aspect of the origin of the genetic code, unless it is accompanied by other assumptions concerning in the specific case: (i) the ancestrality of some amino acids, (ii) the hypothesis that the first mRNA to be translated was poly-G, which can be translated into poly-Gly, and (iii) an evolutionary mechanism for the genetic code origin based on the duplication of tRNAs. However, both the tRNA duplication mechanism and the existence of poly-G as the first mRNA to be translated are not corroborated as mechanisms through which the genetic code would have been structured. For example, the origin of the actual mRNA should have been preceded by the evolution of a proto-mRNA which evidently already coded for more than one amino acid. Therefore, when it evolved from proto-mRNA, the mRNA should already have coded for more than one amino acid. In other words, poly-G as mRNA would most likely never have existed because the first mRNAs already had to code for more than one amino acid. On the contrary, all these assumptions would have been operational if the observations of Inouye et al. (2020) had been discussed within the coevolution theory of the origin of the genetic code, which they do not.
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43
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Abstract
Wobble coding is inevitable during evolution of the Standard Genetic Code (SGC). It ultimately splits half of NN U/C/A/G coding boxes with different assignments. Further, it contributes to pervasive SGC order by reinforcing close spacing for identical SGC assignments. But wobble cannot appear too soon, or it will inhibit encoding and more decisively, obstruct evolution of full coding tables. However, these prior results assumed Crick wobble, NN U/C and NN A/G, read by a single adaptor RNA. Superwobble translates NN U/C/A/G codons, using one adaptor RNA with an unmodified 5' anticodon U (appropriate to earliest coding) in modern mitochondria, plastids, and mycoplasma. Assuming the SGC was selected when evolving codes most resembled it, characteristics of the critical selection events can be calculated. For example, continuous superwobble infrequently evolves SGC-like coding tables. So, continuous superwobble is a very improbable origin hypothesis. In contrast, late-arising superwobble shares late Crick wobble's frequent resemblance to SGC order. Thus late superwobble is possible, but yields SGC-like assignments less frequently than late Crick wobble. Ancient coding ambiguity, most simply, arose from Crick wobble alone. This is consistent with SGC assignments to NAN codons.
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Affiliation(s)
- Michael Yarus
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO, 80309-0347, USA.
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44
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Nesterov-Mueller A, Popov R, Seligmann H. Combinatorial Fusion Rules to Describe Codon Assignment in the Standard Genetic Code. Life (Basel) 2020; 11:life11010004. [PMID: 33374866 PMCID: PMC7824455 DOI: 10.3390/life11010004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 12/15/2020] [Accepted: 12/21/2020] [Indexed: 11/16/2022] Open
Abstract
We propose combinatorial fusion rules that describe the codon assignment in the standard genetic code simply and uniformly for all canonical amino acids. These rules become obvious if the origin of the standard genetic code is considered as a result of a fusion of four protocodes: Two dominant AU and GC protocodes and two recessive AU and GC protocodes. The biochemical meaning of the fusion rules consists of retaining the complementarity between cognate codons of the small hydrophobic amino acids and large charged or polar amino acids within the protocodes. The proto tRNAs were assembled in form of two kissing hairpins with 9-base and 10-base loops in the case of dominant protocodes and two 9-base loops in the case of recessive protocodes. The fusion rules reveal the connection between the stop codons, the non-canonical amino acids, pyrrolysine and selenocysteine, and deviations in the translation of mitochondria. Using fusion rules, we predicted the existence of additional amino acids that are essential for the development of the standard genetic code. The validity of the proposed partition of the genetic code into dominant and recessive protocodes is considered referring to state-of-the-art hypotheses. The formation of two aminoacyl-tRNA synthetase classes is compatible with four-protocode partition.
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Affiliation(s)
- Alexander Nesterov-Mueller
- Institute of Microstructure Technology, Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany; (R.P.); (H.S.)
- Correspondence:
| | - Roman Popov
- Institute of Microstructure Technology, Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany; (R.P.); (H.S.)
| | - Hervé Seligmann
- Institute of Microstructure Technology, Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany; (R.P.); (H.S.)
- The National Natural History Collections, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- Laboratory AGEIS EA 7407, Team Tools for e-GnosisMedical & LabcomCNRS/UGA/OrangeLabs Telecoms4Health, Faculty of Medicine, Université Grenoble Alpes, F-38700 La Tronche, France
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45
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Prebiotically-relevant low polyion multivalency can improve functionality of membraneless compartments. Nat Commun 2020; 11:5949. [PMID: 33230101 PMCID: PMC7683531 DOI: 10.1038/s41467-020-19775-w] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/27/2020] [Indexed: 12/02/2022] Open
Abstract
Multivalent polyions can undergo complex coacervation, producing membraneless compartments that accumulate ribozymes and enhance catalysis, and offering a mechanism for functional prebiotic compartmentalization in the origins of life. Here, we evaluate the impact of lower, more prebiotically-relevant, polyion multivalency on the functional performance of coacervates as compartments. Positively and negatively charged homopeptides with 1–100 residues and adenosine mono-, di-, and triphosphate nucleotides are used as model polyions. Polycation/polyanion pairs are tested for coacervation, and resulting membraneless compartments are analyzed for salt resistance, ability to provide a distinct internal microenvironment (apparent local pH, RNA partitioning), and effect on RNA structure formation. We find that coacervates formed by phase separation of the shorter polyions more effectively generated distinct pH microenvironments, accumulated RNA, and preserved duplexes than those formed by longer polyions. Hence, coacervates formed by reduced multivalency polyions are not only viable as functional compartments for prebiotic chemistries, they can outperform higher molecular weight analogues. Short cationic peptides and nucleotides can form complex coacervates, but the influence of reduced multivalency on coacervate functionality was not investigated. Here, the authors report that coacervates formed from short polyions generate distinct pH microenvironments, accumulate RNA and preserve nucleic acid duplexes more efficiently than their longer counterparts.
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46
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Kunnev D. Origin of Life: The Point of No Return. Life (Basel) 2020; 10:life10110269. [PMID: 33153087 PMCID: PMC7693465 DOI: 10.3390/life10110269] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/01/2020] [Accepted: 11/01/2020] [Indexed: 12/13/2022] Open
Abstract
Origin of life research is one of the greatest scientific frontiers of mankind. Many hypotheses have been proposed to explain how life began. Although different hypotheses emphasize different initial phenomena, all of them agree around one important concept: at some point, along with the chain of events toward life, Darwinian evolution emerged. There is no consensus, however, how this occurred. Frequently, the mechanism leading to Darwinian evolution is not addressed and it is assumed that this problem could be solved later, with experimental proof of the hypothesis. Here, the author first defines the minimum components required for Darwinian evolution and then from this standpoint, analyzes some of the hypotheses for the origin of life. Distinctive features of Darwinian evolution and life rooted in the interaction between information and its corresponding structure/function are then reviewed. Due to the obligatory dependency of the information and structure subject to Darwinian evolution, these components must be locked in their origin. One of the most distinctive characteristics of Darwinian evolution in comparison with all other processes is the establishment of a fundamentally new level of matter capable of evolving and adapting. Therefore, the initiation of Darwinian evolution is the "point of no return" after which life begins. In summary: a definition and a mechanism for Darwinian evolution are provided together with a critical analysis of some of the hypotheses for the origin of life.
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Affiliation(s)
- Dimiter Kunnev
- Department of Oral Biology, University at Buffalo, Buffalo, NY 14263, USA
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47
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Velev MV. Entropy and free-energy based interpretation of the laws of supply and demand. ACTA ACUST UNITED AC 2020. [DOI: 10.1007/s43546-020-00009-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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48
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Klenner F, Postberg F, Hillier J, Khawaja N, Cable ML, Abel B, Kempf S, Glein CR, Lunine JI, Hodyss R, Reviol R, Stolz F. Discriminating Abiotic and Biotic Fingerprints of Amino Acids and Fatty Acids in Ice Grains Relevant to Ocean Worlds. ASTROBIOLOGY 2020; 20:1168-1184. [PMID: 32493049 DOI: 10.1089/ast.2019.2188] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Identifying and distinguishing between abiotic and biotic signatures of organic molecules such as amino acids and fatty acids is key to the search for life on extraterrestrial ocean worlds. Impact ionization mass spectrometers can potentially achieve this by sampling water ice grains formed from ocean water and ejected by moons such as Enceladus and Europa, thereby exploring the habitability of their subsurface oceans in spacecraft flybys. Here, we extend previous high-sensitivity laser-based analog experiments of biomolecules in pure water to investigate the mass spectra of amino acids and fatty acids at simulated abiotic and biotic relative abundances. To account for the complex background matrix expected to emerge from a salty Enceladean ocean that has been in extensive chemical exchange with a carbonaceous rocky core, other organic and inorganic constituents are added to the biosignature mixtures. We find that both amino acids and fatty acids produce sodiated molecular peaks in salty solutions. Under the soft ionization conditions expected for low-velocity (2-6 km/s) encounters of an orbiting spacecraft with ice grains, the unfragmented molecular spectral signatures of amino acids and fatty acids accurately reflect the original relative abundances of the parent molecules within the source solution, enabling characteristic abiotic and biotic relative abundance patterns to be identified. No critical interferences with other abiotic organic compounds were observed. Detection limits of the investigated biosignatures under Enceladus-like conditions are salinity dependent (decreasing sensitivity with increasing salinity), at the μM or nM level. The survivability and ionization efficiency of large organic molecules during impact ionization appear to be significantly improved when they are protected by a frozen water matrix. We infer from our experimental results that encounter velocities of 4-6 km/s are most appropriate for impact ionization mass spectrometers to detect and discriminate between abiotic and biotic signatures.
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Affiliation(s)
- Fabian Klenner
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
- Institute of Earth Sciences, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
| | - Frank Postberg
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
- Institute of Earth Sciences, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
| | - Jon Hillier
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
| | - Nozair Khawaja
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
- Institute of Earth Sciences, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
| | - Morgan L Cable
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Bernd Abel
- Leibniz-Institute of Surface Engineering, Leipzig, Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, Universität Leipzig, Leipzig, Germany
| | - Sascha Kempf
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado, USA
| | - Christopher R Glein
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, Texas, USA
| | - Jonathan I Lunine
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
- Department of Astronomy and Carl Sagan Institute, Cornell University, Ithaca, New York, USA
| | - Robert Hodyss
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - René Reviol
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
- Institute of Earth Sciences, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
| | - Ferdinand Stolz
- Leibniz-Institute of Surface Engineering, Leipzig, Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, Universität Leipzig, Leipzig, Germany
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49
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Muchowska KB, Varma SJ, Moran J. Nonenzymatic Metabolic Reactions and Life's Origins. Chem Rev 2020; 120:7708-7744. [PMID: 32687326 DOI: 10.1021/acs.chemrev.0c00191] [Citation(s) in RCA: 141] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Prebiotic chemistry aims to explain how the biochemistry of life as we know it came to be. Most efforts in this area have focused on provisioning compounds of importance to life by multistep synthetic routes that do not resemble biochemistry. However, gaining insight into why core metabolism uses the molecules, reactions, pathways, and overall organization that it does requires us to consider molecules not only as synthetic end goals. Equally important are the dynamic processes that build them up and break them down. This perspective has led many researchers to the hypothesis that the first stage of the origin of life began with the onset of a primitive nonenzymatic version of metabolism, initially catalyzed by naturally occurring minerals and metal ions. This view of life's origins has come to be known as "metabolism first". Continuity with modern metabolism would require a primitive version of metabolism to build and break down ketoacids, sugars, amino acids, and ribonucleotides in much the same way as the pathways that do it today. This review discusses metabolic pathways of relevance to the origin of life in a manner accessible to chemists, and summarizes experiments suggesting several pathways might have their roots in prebiotic chemistry. Finally, key remaining milestones for the protometabolic hypothesis are highlighted.
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Affiliation(s)
| | - Sreejith J Varma
- University of Strasbourg, CNRS, ISIS UMR 7006, 67000 Strasbourg, France
| | - Joseph Moran
- University of Strasbourg, CNRS, ISIS UMR 7006, 67000 Strasbourg, France
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50
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Frenkel-Pinter M, Haynes JW, Mohyeldin AM, C M, Sargon AB, Petrov AS, Krishnamurthy R, Hud NV, Williams LD, Leman LJ. Mutually stabilizing interactions between proto-peptides and RNA. Nat Commun 2020; 11:3137. [PMID: 32561731 PMCID: PMC7305224 DOI: 10.1038/s41467-020-16891-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 05/28/2020] [Indexed: 12/16/2022] Open
Abstract
The close synergy between peptides and nucleic acids in current biology is suggestive of a functional co-evolution between the two polymers. Here we show that cationic proto-peptides (depsipeptides and polyesters), either produced as mixtures from plausibly prebiotic dry-down reactions or synthetically prepared in pure form, can engage in direct interactions with RNA resulting in mutual stabilization. Cationic proto-peptides significantly increase the thermal stability of folded RNA structures. In turn, RNA increases the lifetime of a depsipeptide by >30-fold. Proto-peptides containing the proteinaceous amino acids Lys, Arg, or His adjacent to backbone ester bonds generally promote RNA duplex thermal stability to a greater magnitude than do analogous sequences containing non-proteinaceous residues. Our findings support a model in which tightly-intertwined biological dependencies of RNA and protein reflect a long co-evolutionary history that began with rudimentary, mutually-stabilizing interactions at early stages of polypeptide and nucleic acid co-existence.
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Affiliation(s)
- Moran Frenkel-Pinter
- NSF/NASA Center for Chemical Evolution, Atlanta, GA, USA.,School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA.,NASA Center for the Origins of Life, Georgia Institute of Technology, Atlanta, GA, USA
| | - Jay W Haynes
- NSF/NASA Center for Chemical Evolution, Atlanta, GA, USA.,School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Ahmad M Mohyeldin
- NSF/NASA Center for Chemical Evolution, Atlanta, GA, USA.,School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Martin C
- NSF/NASA Center for Chemical Evolution, Atlanta, GA, USA.,School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Alyssa B Sargon
- NSF/NASA Center for Chemical Evolution, Atlanta, GA, USA.,School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Anton S Petrov
- NSF/NASA Center for Chemical Evolution, Atlanta, GA, USA.,School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA.,NASA Center for the Origins of Life, Georgia Institute of Technology, Atlanta, GA, USA
| | - Ramanarayanan Krishnamurthy
- NSF/NASA Center for Chemical Evolution, Atlanta, GA, USA.,Department of Chemistry, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Nicholas V Hud
- NSF/NASA Center for Chemical Evolution, Atlanta, GA, USA.,School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Loren Dean Williams
- NSF/NASA Center for Chemical Evolution, Atlanta, GA, USA. .,School of Chemistry & Biochemistry, Georgia Institute of Technology, Atlanta, GA, 30332, USA. .,NASA Center for the Origins of Life, Georgia Institute of Technology, Atlanta, GA, USA.
| | - Luke J Leman
- NSF/NASA Center for Chemical Evolution, Atlanta, GA, USA. .,Department of Chemistry, The Scripps Research Institute, La Jolla, CA, 92037, USA.
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