The silicate-mediated formose reaction: bottom-up synthesis of sugar silicates

Abstract

Understanding the mechanism of sugar formation and stabilization is important for constraining theories on the abiotic origin of complex biomolecules. Although previous studies have produced sugars from small molecules through the formose and related reactions, the product mixtures are complex and unstable. We have demonstrated that simple two- and three-carbon molecules (glycolaldehyde and glyceraldehyde), in the presence of aqueous sodium silicate, spontaneously form silicate complexes of four- and six-carbon sugars, respectively. Silicate selects for sugars with a specific stereochemistry and sequesters them from rapid decomposition. Given the abundance of silicate minerals, these observations suggest that formose-like reactions may provide a feasible pathway for the abiotic formation of biologically important sugars, such as ribose.