Up to 75% of the carbon on land is contained in soil organic matter (SOM). SOM can interact with mineral surfaces to prevent or slow SOM decay. Clay minerals are layered aluminosilicates that are less than 2 μm in diameter. Their high surface areas and permanent negative charge on their layers allow them to interact with SOM via several mechanisms including cation exchange. It has been hypothesized that clay minerals had a role in the development of primitive forms of RNA by concentrating and protecting nucleic acids. In this study, the interactions of adenosine, cytidine and guanosine with montmorillonite surfaces were quantified. The amount of nucleoside adsorbed on the clay surface was quantified using UV spectroscopy. To determine the interactions of the nucleoside with clay mineral surface, infrared spectroscopy (IR) and X-ray diffraction (XRD) were used. Nucleosides at various concentrations were mixed with clay mineral solutions and adsorbed at a pH value of 3. After 48 hours, the dried samples were analyzed using IR and XRD. When the nucleosides are interacting with the clay, several IR bands shift. IR bands representing the NH2+stretch in adenosine and guanosine was observed as well as an additional IR band representing the C=O stretch in guanosine. Both bands suggest adenosine and guanosine are interacting with the clay. XRD of cytidine, adenosine and guanosine show d-values indicative of some organic material in the interlayers of montmorillonite. Future experiments will investigate the orientation of the nucleosides when interacting with the clay as well as the effects of pH on the interactions of nucleosides with clay mineral surfaces.

Interactions of nucleosides with montmorillonite

2019 Spring National Meeting

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