Prebiotic chemistry in eutectic solutions at the water–ice matrix

Abstract

A crystalline ice matrix at subzero temperatures can maintain a liquid phase where organic solutes and salts concentrate to form eutectic solutions. This concentration effect converts the confined reactant solutions in the ice matrix, sometimes making condensation and polymerisation reactions occur more favourably. These reactions occur at significantly high rates from a prebiotic chemistry standpoint, and the labile products can be protected from degradation. The experimental study of the synthesis of nitrogen heterocycles at the ice-water system showed the efficiency of this scenario and could explain the origin of nucleobases in the inner Solar System bodies, including meteorites and extra-terrestrial ices, and on the early Earth. The same conditions can also favour the condensation of monomers to form ribonucleic acid and peptides. Together with the synthesis of these monomers, the ice world (i.e., the chemical evolution in the range between the freezing point of water and the limit of stability of liquid brines, 273 to 210 K) is an under-explored experimental model in prebiotic chemistry.

On the Origin of the Canonical Nucleobases: An Assessment of Selection Pressures across Chemical and Early Biological Evolution

“…[19] Many more prebiotic scenarios for the generation of modified bases, either from the native bases or independently, have been explored but are not shown here. [20] …”

“…Greater persistence in this environment would have given the native bases an advantage over others, possibility facilitating their selective incorporation into the first primitive genetic polymers. While much work has been done on the stability of nucleobases under a variety of conditions, [20a,23] Stanley Miller’s comparative studies of the deamination and ring-opening reaction rates are the most relevant to this discussion, as they provide clues to the relative stability of the native heterocycles (see Table 1 for a descending list of half-life values). [20a,24] …”

“…This is supported by an earlier study, where Miller reported that the degradation rate of 2,4-diaminopyrimidine under these conditions is largely attributed to the C4 deamination reaction that generates cytosine. [20a] …”

“…[14b] Previous work from the Miller laboratory successfully illustrated the use of non-pyrimidine or non-purine base heterocycles as pre-RNA world surrogates. [20c] More recently, Hud and coworkers demonstrated that 2-pyrimidinone, a non-native pyrimidine, could undergo effective glycosylation reactions with D-ribose (Figure 8C) to give the zebularine ribonucleoside in high yield. [46] The higher regio- and stereoselective formation of glycosidic bonds between non-native bases and ribose might have played a role in the assembly of the first informational polymers.…”

Prebiotic-chemistry inspired polymer coatings for biomedical and material science applications

“…Hydrolysis experiments of the polymers result in the observation of amino acids with particularly significant amounts of glycine and polycyclic nitrogenous compounds such as purines and imidazole derivatives (Supplementary Figure S1). 9,11,[24][25][26][27][28][29][30] Because of these properties, we investigated the AMN polymer as a candidate for a new generic coating method that may be particularly useful in biomedical applications such as cell culture tools, providing high cell attachment and surface coatings on implantable medical devices providing enhanced tissue integration.…”