New evolutionary insights into the non‐enzymatic origin of RNA oligomers

Abstract

We outline novel findings on the non-enzymatic polymerization of nucleotides under plausible prebiotic conditions and on the spontaneous onset of informational complexity in the founding molecule, RNA. We argue that the unique ability of 3', 5' cyclic guanosine monophosphate to form stacked architectures and polymerize in a self-sustained manner suggests that this molecule may serve as the 'seed of life' from which all self-replicating oligonucleotides can be derived via a logically complete sequence of simple events. WIREs RNA 2017, 8:e1400. doi: 10.1002/wrna.1400 For further resources related to this article, please visit the WIREs website.

Primitive RNA-catalysis with guanine-rich oligonucleotide sequences – the case of a (GGC)3nonamer

“…While modern RNA-catalysis utilizes mechanisms that are optimized in order to be less sequence specific, in the prebiotic world the situation was most likely different. Our studies on the polymerization efficiency of cyclic nucleotide precursors show that 3',5' cyclic GMP has a better polymerization potential than other 3',5' cyclic nucleotides (Costanzo et al 2009;Costanzo et al 2012;Šponer et al 2015;Šponer et al 2017). For example, drying of 3',5' cyclic GMP at slightly elevated temperatures commonly leads to formation of oligoG sequences with length of ca.…”

Stability of 2′,3′ and 3′,5′ cyclic nucleotides in formamide and in water: a theoretical insight into the factors controlling the accumulation of nucleic acid building blocks in a prebiotic pool

“…20,23 A plausible geological context for our formamide-model described herein and in Ref. 23 is a pool on top of a stable, geologically active region, which undergoes rapid cooling upon heavy raining.…”

“…These are the two solvents most frequently considered in recent origin of life studies. [17][18][19][20][21][22] We will show that while aqueous solutions and lower temperatures could favor accumulation of 2',3' cyclic nucleotides over that of the 3',5' cyclic form, at higher temperatures and in formamide solvent 3',5' cyclic nucleotides are the thermodynamically preferred species. Thus, after a temperature drop, 23 initial cycles of polymerization leading to the first RNA molecules could indeed occur in a 3',5'-cyclic-nucleotide rich environment.…”

“…20,23 The simple formamide-based origin scenario we outlined in Ref. 23 suggests a non-equilibrium solution for the origin of life where different chemical steps take place consecutively under different conditions (see Figure 6).…”

Nonenzymatic Oligomerization of 3′,5′‐Cyclic CMP Induced by Proton and UV Irradiation Hints at a Nonfastidious Origin of RNA

“…The self-oligomerization of 3',5'-cCMP is am ore problematic process than oligomerization of 3',5'-cGMP,d ue to the weaker stacking self-association of the former.H owever,t hese difficulties do not hamper the spontaneous emergence of the first RNAs, because different nucleotidesd on ot need to oligomerize with the same efficiency.I narecent study [44] we have suggested that short oligoGs equences could play ak ey role in orchestrating nonenzymatic RNA synthesis, acting as the "seeds" of the process. Thus, even dimerizationo rt rimerizationo f cCMPs could greatly facilitatet he generation of the first mixed-sequence RNA chains.…”