The influence of ribose on borate mineral solubility

Abstract

The prebiotic synthesis of ribose is thought to have played a key role in origin-of-life scenarios based on the RNA world hypothesis. As ribose is readily prone to decomposition, ribose-borate complexes, which are resistant to degradation under alkaline conditions, are often suggested to have protected ribose on early Earth. Prebiotic laboratory experiments exploring ribose-borate complexes, however, generally use high borate concentrations sourced from synthetic reagents that do not reflect the lower solubility of calcium-bearing borate minerals and the limited aqueous borate found in modern geological settings. Here, we describe how the presence of aqueous ribose can significantly increase the solubility of a range of borate-bearing minerals, even the characteristically less soluble calcium-containing borates. Furthermore, it is demonstrated that ribose-borate complexes prevent borate from calcium-induced precipitation, inhibiting its removal from solution and ensuring it remains chemically available for further downstream aqueous reactions. These findings will aid future prebiotic experiments in reflecting more geologically realistic conditions in the context of the RNA world hypothesis and also provide insight into the impact that prebiotic organo-mineralization may have played on geochemical systems on the early Earth.