Direct Prebiotic Pathway to DNA Nucleosides

Abstract

It is assumed that RNA played a key role in the origin of life, and the transition to more complex but more stable DNA for continuous information storage and replication requires the development of a ribonucleotide reductase to obtain the deoxyribonucleotides from ribonucleotides. This step, as well as an alternative path from abiotic molecules to DNA‐based life is completely unknown. Shown here is the formation of deoxyribonucleosides under relevant prebiotic conditions in water in high regio‐ and stereoselectivity, from all canonical purine and pyrimidine bases, by condensation with acetaldehyde and sugar‐forming precursors. Thus, a continuous path to deoxyribonucleosides, starting from simple, prebiotically available molecules has been discovered. Furthermore, the deoxyapionucleosides (DApiNA) were identified as a potential DNA progenitor. The results suggest that the DNA world evolved much earlier than previously assumed.

Prebiotic Nucleoside Synthesis: The Selectivity of Simplicity

“…[63b] Aselectionfor DNA nucleosides, confirming this consideration, was recently proposed by the Trapp group. [66] The above presentedp rebiotic syntheses of 1 do all have the same disconnection approachi n common: building ag lycosidic bond between 4a and 3 in the last possible step. Eschenmoser describes this disconnection as "the notorious nucleosidation problem".…”

“…The first pathway is proposed by the Sutherland group [99] and is in analogy to the dithioreductiono ft he enzyme ribonucleotide reductase. [101] The second approach by Trapp [66] mimics the reaction catalyzed by the enzyme 2-deoxyribose-5-phosphate aldolase. [101,102] In the first contribution, another variation of the approach [76] to 1 via 22, [99] is presented.…”

Mimochrome, a metalloporphyrin‐based catalytic Swiss knife†

“…Nature has been able to bow kinetics and thermodynamics to make life not only possible but also predominant on Earth. We have learned, through the study of an exponentially growing number of biological structures, that this was accomplished by selecting only few elements [1][2][3][4], few molecules [5][6][7], and even few repetitive folding motifs [8][9][10][11][12][13]. This last aspect may appear surprising at a first glance, but it actually sounds pretty comfortable to chemists, who learned over centuries that the synthesis and/or functionalization of analogues from a starting framework moiety is advantageous and generally affordable, both in terms of synthetic pathway and economic cost.…”

Cysteine Chemistry in Connection with Abiogenesis

“…Despite organic halides (fluorinated, chlorinated, brominated) are present in volcanic emissions, and that a chlorinated aldehyde (2,2,3‐trichloropropanal) has been detected in Archean quartz, halogen derivatives have been poorly noticed as plausible prebiotic molecules. As the α‐chlorination of aldehydes in water is a well‐known process, it is possible that chloroacetaldehyde was produced this way from the plausibly prebiotic acetaldehyde , . Of course, HCl is by far the most abundant Cl source expelled from volcanoes, but molecular chlorine can also be detected in emissions .…”