Fatty acid-assisted nonenzymatic synthesis reactions of ribonucleotides

Abstract

The vital role of RNA in present day cells and its ability to act as both informational and catalytic entity supports the “RNA World” hypothesis. As chemical polymerization of ribonucleotides is an uphill process, various methods have been used to establish the independent origin of RNA. One such study has demonstrated the polymerization of nucleotides under alternating dehydration and rehydration (DH-RH) conditions in the presence of lipids. The collective effect of temperature and organizing effect brought about by the lipids is thought to overcome the energetic barrier. However, the presence of complex lipids on early Earth is debatable. One solution to surpass this shortcoming is to use simpler prebiotically relevant amphiphiles. In the current project we have analyzed the role of fatty acids in promoting nonenzymatic polymerization of RNA monomers. In addition to DH-RH reactions, polymerization in eutectic phases and clay-catalyzed polymerization was also studied. Overall, the presence of fatty acids did not particularly improve polymerization efficiency in the various scenarios tested. However, in the eutectic phase and DH-RH reactions, the fatty acids had a protective role in reactions that involved adenosine ribonucleotides. However, this was not seen with other ribonucleotides. This study does not corroborate previous findings in which the authors had used phospholipids in their oligomerization reactions. This indicates that the chemical identity of the lipid involved in such nonenzymatic reactions will determine their potential for catalyzing oligomerization of ribonucleotides into RNA-like polymers.