Insights Into the Origin of Life: Did It Begin from HCN and H₂O?

Abstract

The seminal Urey–Miller experiments showed that molecules crucial to life such as HCN could have formed in the reducing atmosphere of the Hadean Earth and then dissolved in the oceans. Subsequent proponents of the “RNA World” hypothesis have shown aqueous HCN to be the starting point for the formation of the precursors of RNA and proteins. However, the conditions of early Earth suggest that aqueous HCN would have had to react under a significant number of constraints. Therefore, given the limiting conditions, could RNA and protein precursors still have formed from aqueous HCN? If so, what mechanistic routes would have been followed? The current computational study, with the aid of the ab initio nanoreactor (AINR), a powerful new tool in computational chemistry, addresses these crucial questions. Gratifyingly, not only do the results from the AINR approach show that aqueous HCN could indeed have been the source of RNA and protein precursors, but they also indicate that just the interaction of HCN with water would have sufficed to begin a series of reactions leading to the precursors. The current work therefore provides important missing links in the story of prebiotic chemistry and charts the road from aqueous HCN to the precursors of RNA and proteins.

Self‐catalytic mechanism of prebiotic reactions: From formamide to purine bases

“…The highest energy barrier for these reactions is calculated to be 40.3 kcal mol −1 . According to Das et al, [ 98 ] chemical reactions occurring at temperatures of around 100°C have barriers in the region of 40.0 kcal mol −1 . That means that all above presented reactions in formamide should occur.…”

“…Urea has also been detected in mineral‐doped formamide condensation reactions. [ 28 ] As Das and coworkers [ 98 ] noted, chemical reactions having activation barriers to 40.0 kcal mol −1 may occur at temperatures of around 100°C. Moreover, formamide, which plays the role of reactant, reaction media, and catalyst, is liquid in a wide temperature range: 2°C‐210°C.…”

Layered Double Hydroxides in Bioinspired Nanotechnology

“…Recent studies from Das at al. [69] leveraged computational methods to shed light on the role of hydrogen cyanide (HCN) as a source of ribonucleic acid (RNA) and protein precursors. The authors also argued that just the interaction of HCN with water would have sufficed to trigger a series of reactions leading to the life-essential precursors (nucleic acids and proteins), as reported in Figure 1.…”

Viroid-sized rings self-assemble from mononucleotides through wet-dry cycling: implications for the origin of life

“…For instance it has been shown that short oligomers linked by peptide bonds are synthesized from mixtures of amino acids during wet-dry cycling 10-12 . More recently it has been reported that ribonucleotides can be synthesized from simple organic compounds in conditions that incorporate a wet-dry 45 cycle 13,14 .…”