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Prebiotic chemistry

Chris Mehta, Anthony Perez, Glenn Thompson, Matthew A Pasek
A hypothesis in prebiotic chemistry argues that organics were delivered to the early Earth in abundance by meteoritic sources. This study tests that hypothesis by measuring how the transfer of organic matter to the surface of Earth is affected by energy-dissipation processes such as ablation and airbursts. Exogenous delivery has been relied upon as a source of primordial material, but it must stand to reason that other avenues (i.e., hydrothermal vents, electric discharge) played a bigger role in the formation of life as we know it on Earth if exogenous material was unable to deliver significant quantities of organics...
May 12, 2018: Life
Dougal J Ritson, Claudio Battilocchio, Steven V Ley, John D Sutherland
When considering life's aetiology, the first questions that must be addressed are "how?" and "where?" were ostensibly complex molecules, considered necessary for life's beginning, constructed from simpler, more abundant feedstock molecules on primitive Earth. Previously, we have used multiple clues from the prebiotic synthetic requirements of (proto)biomolecules to pinpoint a set of closely related geochemical scenarios that are suggestive of flow and semi-batch chemistries. We now wish to report a multistep, uninterrupted synthesis of a key heterocycle (2-aminooxazole) en route to activated nucleotides starting from highly plausible, prebiotic feedstock molecules under conditions which mimic this scenario...
May 8, 2018: Nature Communications
Catherine D Neish, Ralph D Lorenz, Elizabeth P Turtle, Jason W Barnes, Melissa G Trainer, Bryan Stiles, Randolph Kirk, Charles A Hibbitts, Michael J Malaska
Saturn's moon Titan has all the ingredients needed to produce "life as we know it." When exposed to liquid water, organic molecules analogous to those found on Titan produce a range of biomolecules such as amino acids. Titan thus provides a natural laboratory for studying the products of prebiotic chemistry. In this work, we examine the ideal locales to search for evidence of, or progression toward, life on Titan. We determine that the best sites to identify biological molecules are deposits of impact melt on the floors of large, fresh impact craters, specifically Sinlap, Selk, and Menrva craters...
May 2, 2018: Astrobiology
Tolga N V Karsili, Mark A Fennimore, Spiridoula Matsika
The elementary synthesis of prebiotic molecules has attracted vast attention in recent years. Due to their rich surface chemistry and lack of suitable atmosphere, comets represent an important host for such synthesis, especially since they are routinely irradiated with short wavelength electromagnetic radiation and energetic cosmological electrons. Using high-level electronic structure theory, we present the details of the reactivity associated with the electron-impact induced prebiotic synthesis of ethylene glycol (a carbohydrate building block) from elementary methanol...
April 25, 2018: Physical Chemistry Chemical Physics: PCCP
Michele Fiore
Nucleic acids, phospholipids and other organic phosphates play central roles in biological pathways. n-Alkyl phosphates and their derivatives have been recognized as amphiphilic molecules for nearly two centuries. In the last 50 years, n-alkyl phosphate derivatives such as di-alkyl phosphates, mono-alkyl phosphatidyl ethanol amines and mono-alkyl phosphocholines have become predominant compounds with applications in different areas, from food chemistry to life science. The aim of this review is to summarize the most relevant progress made in the field of the synthesis of these molecules and to provide a concise perspective on the use of these amphiphiles as possible prebiotic membrane constituents...
April 9, 2018: Organic & Biomolecular Chemistry
Sukrit Ranjan, Zoe R Todd, John D Sutherland, Dimitar D Sasselov
A key challenge in origin-of-life studies is understanding the environmental conditions on early Earth under which abiogenesis occurred. While some constraints do exist (e.g., zircon evidence for surface liquid water), relatively few constraints exist on the abundances of trace chemical species, which are relevant to assessing the plausibility and guiding the development of postulated prebiotic chemical pathways which depend on these species. In this work, we combine literature photochemistry models with simple equilibrium chemistry calculations to place constraints on the plausible range of concentrations of sulfidic anions (HS- , HSO3 - , SO3 2- ) available in surficial aquatic reservoirs on early Earth due to outgassing of SO2 and H2 S and their dissolution into small shallow surface water reservoirs like lakes...
April 8, 2018: Astrobiology
Marilyne Sosson, Clemens Richert
The copying of short DNA or RNA sequences in the absence of enzymes is a fascinating reaction that has been studied in the context of prebiotic chemistry. It involves the incorporation of nucleotides at the terminus of a primer and is directed by base pairing. The reaction occurs in aqueous medium and leads to phosphodiester formation after attack of a nucleophilic group of the primer. Two aspects of this reaction will be discussed in this review. One is the activation of the phosphate that drives what is otherwise an endergonic reaction...
2018: Beilstein Journal of Organic Chemistry
Bruno Mattia Bizzarri, Lorenzo Botta, Maritza Iveth Pérez-Valverde, Raffaele Saladino, Ernesto Di Mauro, Juan Manuel Garcia Ruiz
It has recently been demonstrated that mineral self-assembled structures catalyzing prebiotic chemical reactions may form in natural waters derived from serpentinization, a geological process widespread in the early stages of Earth-like planets. We have synthesized self-assembled membranes by mixing microdrops of metal solutions with alkaline silicate solutions in the presence of formamide (NH2CHO), a single carbon molecule, at 80ºC. We found that these bilayer membranes, made of amorphous silica and metal oxide-hydroxide nanocrystals, catalyze the condensation of formamide, yielding the four nucleobases of RNA, three aminoacids and several carboxylic acids in a single pot experiment...
March 30, 2018: Chemistry: a European Journal
Nikolai E Skoblikow, Andrei A Zimin
The hypothesis of hot volcanic organic stream as the most probable and geologically plausible environment for abiogenic polycondensation is proposed. The primary synthesis of organic compounds is considered as result of an explosive volcanic (perhaps, meteorite-induced) eruption. The eruption was accompanied by a shock wave propagating in the primeval atmosphere and resulting in the formation of hot cloud of simple organic compounds-aldehydes, alcohols, amines, amino alcohols, nitriles, and amino acids-products, which are usually obtained under the artificial conditions in the spark-discharge experiments...
March 28, 2018: Journal of Molecular Evolution
Marie-Christine Bacchus-Montabonel
The formation of the building blocks of life and how they could survive under harsh astrophysical environments remains an open question of prebiotic chemistry. Effectively, ion bombardments or intense UV radiation may drive the destruction of prebiotic compounds. The possible role of sulfur in such processes is addressed here for the first time, by comparing directly proton-induced charge transfer for sulfur containing molecules and that for related COMs. The proton collision on mercaptoacetonitrile HSCH2C[triple bond, length as m-dash]N conformers has thus been investigated theoretically in a wide impact energy range modelling various astrophysical environments and compared to related COMs, namely HCN oligomers, in order to exhibit qualitative tendencies...
March 21, 2018: Physical Chemistry Chemical Physics: PCCP
Raghav R Poudyal, Fatma Pir Cakmak, Christine D Keating, Philip C Bevilacqua
This Perspective focuses on RNA in biological and nonbiological compartments resulting from liquid-liquid phase separation (LLPS), with an emphasis on origins of life. In extant cells, intracellular liquid condensates, many of which are rich in RNAs and intrinsically disordered proteins, provide spatial regulation of biomolecular interactions that can result in altered gene expression. Given the diversity of biogenic and abiogenic molecules that undergo LLPS, such membraneless compartments may have also played key roles in prebiotic chemistries relevant to the origins of life...
March 21, 2018: Biochemistry
Christina Schneider, Sidney Becker, Hidenori Okamura, Antony Crisp, Tynchtyk Amatov, Michael Stadlmeier, Thomas Carell
The RNA-world hypothesis assumes that life on Earth started with small RNA molecules that catalyzed their own formation. Vital to this hypothesis is the need for prebiotic routes towards RNA. Contemporary RNA, however, is not only constructed from the four canonical nucleobases (A, C, G, and U), it also contains many chemically modified (noncanonical) bases. A still open question is whether these noncanonical bases were formed in parallel to the canonical bases (chemical origin) or later, when life demanded higher functional diversity (biological origin)...
May 14, 2018: Angewandte Chemie
Brooke A Anderson, Ramanarayanan Krishnamurthy
Pyrophosphate linkages are important in extant biology and are hypothesized to have played a role in prebiotic chemistry and in the origination of oligonucleotides. Inspired by pyrophosphate as backbones of primordial oligomers, DNA oligomers with varying amounts of pyrophosphate inserts (ppDNA) were synthesized and investigated for their base-pairing properties. As expected, pyrophosphate inserts into the backbone compromised the thermal stability of ppDNA-DNA duplexes. In contrast, the ppDNA-RNA duplex exhibited, remarkably, duplex stability, even with accumulation of pyrophosphate linkages...
May 7, 2018: Chemistry: a European Journal
Avinash Vicholous Dass, Maguy Jaber, André Brack, Frédéric Foucher, Terence P Kee, Thomas Georgelin, Frances Westall
A concise outlook on the potential role of confinement in phosphorylation and phosphate condensation pertaining to prebiotic chemistry is presented. Inorganic confinement is a relatively uncharted domain in studies concerning prebiotic chemistry, and even more so in terms of experimentation. However, molecular crowding within confined dimensions is central to the functioning of contemporary biology. There are numerous advantages to confined environments and an attempt to highlight this fact, within this article, has been undertaken, keeping in context the limitations of aqueous phase chemistry in phosphorylation and, to a certain extent, traditional approaches in prebiotic chemistry...
March 5, 2018: Life
Raffaele Saladino, Lorenzo Botta, Ernesto Di Mauro
Meteorites are consensually considered to be involved in the origin of life on this Planet for several functions and at different levels: (i) as providers of impact energy during their passage through the atmosphere; (ii) as agents of geodynamics, intended both as starters of the Earth's tectonics and as activators of local hydrothermal systems upon their fall; (iii) as sources of organic materials, at varying levels of limited complexity; and (iv) as catalysts. The consensus about the relevance of these functions differs...
February 22, 2018: Life
Sandra L Blair, Nga L Ng, Stephen C Zambrzycki, Anyin Li, Facundo M Fernández
In this communication, we report on the real-time analysis of organic aerosol particles by Vacuum-assisted Plasma Ionization-Mass Spectrometry (Aero-VaPI-MS) using a home-built VaPI ion source coupled to a Synapt G2-S HDMS ion mobility-mass spectrometry (IM-MS) system. Standards of organic molecules of interest in prebiotic chemistry were used to generate aerosols. Monocaprin and decanoic acid aerosol particles were successfully detected in both the positive and negative ion modes, respectively. A complex aerosol mixture of different sizes of polymers of L-malic acid was also examined through ion mobility (IM) separations, resulting in the detection of polymers of up to eight monomeric units...
April 2018: Journal of the American Society for Mass Spectrometry
Saúl A Villafañe-Barajas, João Paulo T Baú, María Colín-García, Alicia Negrón-Mendoza, Alejandro Heredia-Barbero, Teresa Pi-Puig, Dimas A M Zaia
Any proposed model of Earth's primitive environments requires a combination of geochemical variables. Many experiments are prepared in aqueous solutions and in the presence of minerals. However, most sorption experiments are performed in distilled water, and just a few in seawater analogues, mostly inconsistent with a representative primitive ocean model. Therefore, it is necessary to perform experiments that consider the composition and concentration of dissolved salts in the early ocean to understand how these variables could have affected the absorption of organic molecules into minerals...
February 1, 2018: Origins of Life and Evolution of the Biosphere
Surajit Nandi, Debankur Bhattacharyya, Anakuthil Anoop
The HCN oligomerization is considered to be one of the important pathways in the chemical evolution. Nucleobases, aminoacids and many other complex organic molecules can be evolved through this pathway. We report an explorative study based on automated reaction search method that avoid the cognitive bias in searching the chemical reaction space. We have discussed the chemical space of HCN dimer elaborately, and the important trimers and tetramers are discussed briefly. A component wise molecular fingerprint based methodology is proposed for identifying molecular similarity...
January 25, 2018: Chemistry: a European Journal
Clémentine Gibard, Subhendu Bhowmik, Megha Karki, Eun-Kyong Kim, Ramanarayanan Krishnamurthy
Prebiotic phosphorylation of (pre)biological substrates under aqueous conditions is a critical step in the origins of life. Previous investigations have had limited success and/or require unique environments that are incompatible with subsequent generation of the corresponding oligomers or higher-order structures. Here, we demonstrate that diamidophosphate (DAP)-a plausible prebiotic agent produced from trimetaphosphate-efficiently (amido)phosphorylates a wide variety of (pre)biological building blocks (nucleosides/tides, amino acids and lipid precursors) under aqueous (solution/paste) conditions, without the need for a condensing agent...
February 2018: Nature Chemistry
V Riffet, G Frison, G Bouchoux
The two first steps of the Strecker synthesis of glycine, namely (a) addition of ammonia to formaldehyde to give aminomethanol and (b) its dehydration leading to methaneimine, is studied using high level quantum chemistry computations (G3B3). Water solvation is modeled by considering the effect of adding a discrete number of active or passive molecules of water (up to four) and by immersing the identified water-solute complexes in a conductor-like polarizable continuum solvent model. Activation of the reactants by protonation is also examined...
February 15, 2018: Journal of Physical Chemistry. A
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