Abstract EANA2026-46

Adenosine represents a pivotal molecule within the domain of prebiotic chemistry, attributable to its function in metabolism and to the formation of building blocks to DNA and RNA which are essential for life. The molecule consists of an adenine attached to a ribose via a β-N9-glycosidic bond and it is known that is the precursor of AMP, ADP and ATP through phosphorylation processes.1 Mineral surfaces, for instance pyrite (FeS2) plays a relevant role, possess properties that enable the concentration of organic molecules and the catalysis of polymerisation reactions relevant to the origin of life.2 The present study investigates the interaction and reactivity of adenosine molecule on this surface in order to determine the mineral's ability to protect, concentrate or promote biopolymerisation. In addition, the study aims to identify the spectroscopic fingerprint of the functional groups present in the molecule's structure after molecular adsorption.

In order to study this system, experimental studies have been carried out inside the Planetary Atmosphere and Surfaces simulation Chamber (PASC)3 under high-vacuum conditions 1x10-5 mbar at 15 K and at room temperature 298 K, and in a liquid medium. The resulting adsorption products are irradiated with UV light (200-400nm) under the same conditions to study the photochemistry of the system. A powerful multi-technique approach with X-ray photoelectron spectroscopy (XPS), Infrared (IR) and Raman spectroscopies has been used to fully characterise and understand the molecule/mineral interaction. 

Adenosine has been successfully adsorbed on both surfaces, FeS2 and Au. Furthermore, UV exposure has a degradation effect on the formed molecular layers and could also induces photochemical reactions in the studied molecule. UV-induced processes can modify molecular structure through degradation pathways or promote the synthesis of new compounds. Photochemical processes may influence molecular stability and catalytic behaviour, offering plausible pathways for prebiotic chemical evolution. Such processes are of particular astrobiological relevance, not only for understanding the emergence of molecular complexity on the early Earth but also for evaluating the preservation and transformation of organic compounds. These findings emphasize the importance of UV radiation as a key driver of chemical evolution in prebiotic environments.

[1] Camici, M., Garcia-Gil, M., & Tozzi, M. G. (2018). The Inside Story of Adenosine. International Journal of Molecular Sciences, 19(3), 784.

 

[2] Wächtershäuser, G. (1988). Pyrite Formation, the First Energy Source for Life: a Hypothesis. Systematic and Applied Microbiology, 10(3), 207–210.

 

[3]  E. Mateo-Martí , O. Prieto-Ballesteros, J. M. Sobrado, J. Gómez-Elvira and J. A. Martín Gago,  Meassurement and Science Technology, 17, 2274 (2006)