Environmental conditions drive self-organisation of reaction pathways in a prebiotic reaction network

Abstract

The evolution of life from the prebiotic environment required a gradual process of chemical evolution towards greater molecular complexity. Elaborate prebiotically-relevant synthetic routes to the building blocks of life have been established. However, it is still unclear how functional chemical systems evolved with direction using only the interaction between inherent molecular chemical reactivity and the abiotic environment. Here, we demonstrate how complex systems of chemical reactions exhibit well-defined self-organisation in response to varying environmental conditions. This self-organisation allows the compositional complexity of the reaction products to be controlled as a function of factors such as feedstock and catalyst availability. We observe how Breslow’s cycle contributes to the reaction composition by feeding C2 building blocks into the network, alongside reaction pathways dominated by formaldehyde-driven chain growth. The emergence of organised systems of chemical reactions in response to changes in the environment offers a potential mechanism for a chemical evolution process that bridges the gap between prebiotic chemical building blocks and the origin of life.

Trajectory-dependent Compositional Outcomes in a Prebiotic Reaction Network

“…We have recently shown that product compositions of the formose reaction, a model prebiotic reaction system, are the result of inherent interaction between chemical reactivity and the environment. We found that the formose reaction creates compositional patterns in response to varying steady-state environmental conditions 19 . It produces a wide range of carbohydrate molecules (fig.…”

“…It produces a wide range of carbohydrate molecules (fig. S1) from the feedstocks formaldehyde (H2C=O, 1) and an initiator compound, such as dihydroxyacetone (DHA, 3), using metal hydroxides (for example, Ca 2+ and OH -) as catalysts [19][20][21][22][23] . A key characteristic of the formose reaction is that a limited set of reaction classes recursively operate on the feedstocks and their reaction products to create a combinatorial explosion of compounds (fig.…”

“…A key characteristic of the formose reaction is that a limited set of reaction classes recursively operate on the feedstocks and their reaction products to create a combinatorial explosion of compounds (fig. 1a) [17][18][19][20][21][22][23] .…”

“…For each experimental condition, 50 samples were collected from the output of the CSTR (at 40.8 second interval for the noise magnitude variation series and at 30.6 second interval for the frequency variation series). Samples from the reactor outlet were freeze quenched, lyophilized and derivatized [26][27][28] according to our previously reported protocol 19 , and analyzed by gas chromatography-mass spectrometry (GC-MS). Quantification was based on peak integrals of total ion chromatograms and each peak was assigned to a compound via a combination of retention time and mass spectral fragmentation pattern (fig.…”

Autocatalytic reaction cycles for non-enzymatic synthesis of life-sustaining sugars in neutral media

“…A variety of monosaccharides can be generated via aldol reactions in the reaction pathways that branch out from the autocatalytic reaction cycle. Furthermore, various side reactions, such as the crossed Cannizzaro reaction that leads to the decomposition of monosaccharides, also comprise a large part of the entire reaction network 6,12 Fig. 1c).…”