Searching for Nucleic Acid Alternatives

Eschenmoser, Albert

doi:10.1002/9780470977873.ch1

Cited by 13 publications

(12 citation statements)

References 73 publications

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“…It may be assumed that the phosphate groups on the generated sugars protect them from the base attack required for further product isomerisation. These experiments yielded ribose phosphate as the dominant sugar, supporting the role of glycolaldehyde phosphate as the first nucleotide precursor as proposed by A. Eschenmoser [ 69 , 70 ] in the search for RNA molecular self-constitution [ 71 ]. Since nucleobases do not readily add to ribose, Sutherland has proposed an alternative mechanism via arabinose derivatives; however glycolaldehyde remained the assumed starting material [ 64 ].…”

Section: Discussionsupporting

confidence: 73%

Formaldehyde—A Key Monad of the Biomolecular System

Noe

Freissmuth

Richter

et al. 2013

Life

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Section: Discussionsupporting

confidence: 73%

Formaldehyde—A Key Monad of the Biomolecular System

Noe

Freissmuth

Richter

et al. 2013

Life

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“…As an alternative approach to the abiotic synthesis of functional polymers chemically different from those of contemporary biopolymers has been considered [17][18][19] . It has been long appreciated that model prebiotic systems yield large amounts of intractable tarry polymeric material [20,21].…”

Section: Introductionmentioning

confidence: 99%

Wet-dry Cycling Delays the Gelation of Hyperbranched Polyesters: Implications to the Origin of Life

Mamajanov

2019

Preprint

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In extant biology, biopolymers perform multiple crucial functions. The biopolymers are synthesized by enzyme-controlled biosystems that would not have been available at the earliest stages of chemical evolution and consist of correctly sequenced and/or linked monomers. Some of the abiotic “messy” polymers approximate some functions of biopolymers. Condensation polymers are an attractive search target for abiotic functional polymers since principal polymers of life are produced by condensation and since condensation allows for the accurate construction of high polymers. Herein the formation of hyperbranched polyesters that have been previously used in the construction of enzyme-like catalytic complexes is explored. The experimental setup compares between the branched polyesters prepared under mild continuous heating and the wet-dry cycle conditions. The results reveal that period wetting during which partial hydrolysis of the polyester occurs, helps control the chain growth and retards the gel transition. It is significant to the origin of life studies that environmental, prebiotically plausible conditions could achieve such control without enzymes or a skilled chemist. As expected in marginally controlled systems, the identification of each component of the heterogeneous system has proved challenging, but it is not crucial for drawing the conclusions.

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“…RNA is normally linked by 3′→5′ linkages; however, as has been shown by Szostak and coworkers (Engelhart et al , 2013 ), 2′→5′ linked polymers are also capable of base-pairing and expressing catalytic function. Thus, analogous to the alternative linkages investigated by Eschenmoser ( 2005 ), of the 100 output structural isomers that can only be linked via OH/OH-mediated linkages (such as phosphodiesters), 62 are limited to a single isomeric intermolecular linkage. However, another 27 isomers within the enumerated set, including the natural ribosides, can be intermolecularly coupled via three distinct regiochemistries, with the additional complexity of head-to-tail , head-to-head , and tail-to-tail linkage directionality.…”

Section: Comparison With Rna Monomersmentioning

confidence: 99%

“…Antiviral and antisense research has shown that a wide variety of nonnatural nucleotide analogues have biological activity (Périgaud et al , 1992 ). The recognition and replication features of DNA and RNA are also not unique to those molecules but can also be engendered by a range of related structures (Egholm et al , 1992 ; Eschenmoser and Loewenthal, 1992 ; Schöning et al , 2000 ; Eschenmoser, 2005 ; Zhang et al , 2010 ; Pinheiro et al , 2012 ) ( Fig. 3 ).…”

Section: Introductionmentioning

confidence: 99%

227 Views of RNA: Is RNA Unique in Its Chemical Isomer Space?

2015

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Ribonucleic acid (RNA) is one of the two nucleic acids used by extant biochemistry and plays a central role as the intermediary carrier of genetic information in transcription and translation. If RNA was involved in the origin of life, it should have a facile prebiotic synthesis. A wide variety of such syntheses have been explored. However, to date no one-pot reaction has been shown capable of yielding RNA monomers from likely prebiotically abundant starting materials, though this does not rule out the possibility that simpler, more easily prebiotically accessible nucleic acids may have preceded RNA. Given structural constraints, such as the ability to form complementary base pairs and a linear covalent polymer, a variety of structural isomers of RNA could potentially function as genetic platforms. By using structure-generation software, all the potential structural isomers of the ribosides (BC5H9O4, where B is nucleobase), as well as a set of simpler minimal analogues derived from them, that can potentially serve as monomeric building blocks of nucleic acid–like molecules are enumerated. Molecules are selected based on their likely stability under biochemically relevant conditions (e.g., moderate pH and temperature) and the presence of at least two functional groups allowing the monomers to be incorporated into linear polymers. The resulting structures are then evaluated by using molecular descriptors typically applied in quantitative structure–property relationship (QSPR) studies and predicted physicochemical properties. Several databases have been queried to determine whether any of the computed isomers had been synthesized previously. Very few of the molecules that emerge from this structure set have been previously described. We conclude that ribonucleosides may have competed with a multitude of alternative structures whose potential proto-biochemical roles and abiotic syntheses remain to be explored. Key Words: Evolution—Chemical evolution—Exobiology—Prebiotic chemistry—RNA world. Astrobiology 15, 538–558.

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Searching for Nucleic Acid Alternatives

Cited by 13 publications

References 73 publications

Formaldehyde—A Key Monad of the Biomolecular System

Formaldehyde—A Key Monad of the Biomolecular System

Wet-dry Cycling Delays the Gelation of Hyperbranched Polyesters: Implications to the Origin of Life

227 Views of RNA: Is RNA Unique in Its Chemical Isomer Space?

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