[M-IS03] アストロバイオロジー

[MIS03-09] Prebiotic phosphorylation under deep-sea supercritical CO₂-water two-phase environment

*田川 翔大朗¹、播田實 りょう太¹、藤島 皓介^1,2 (1.東京工業大学　地球生命研究所、2.慶應義塾大学大学院　政策・メディア研究科)

キーワード：前生物化学、リン酸化、ヌクレオチド、深海、超臨界二酸化炭素、水熱リアクター

Phosphorylation reaction leading to prebiotic nucleotide synthesis has been so far reported from conditions simulating wet-dry cycle near terrestrial hot springs with atmosphere and water. The advantage of having a two-phase environment is that water can escape from the aqueous phase to the atmosphere, which result in the condensation of various organic molecules. On the other hand, in the deep-sea environment, it is considered that molecules will diffuse and also undergo hydrolysis due to the presence of abundant water. However, natural CO₂ fluid have been discovered near deep-sea hydrothermal vents and the model shows that subsurface pool of liquid and supercritical CO₂ exists. Currently supercritical CO₂ (scCO₂) is mainly used in the industry as a green solvent to dissolve various hydrophobic molecules. Also aqueous phase adjacent to the CO₂ fluid become highly acidic and dissolves various inorganic ions such as phosphates. Thus it led us to further investigate the possibility of nucleotide synthesis via phosphorylation reaction in the water-supercritical CO₂ two phase environment. Here, we used an autoclave to perform nucleoside phosphorylation using different nucleoside (adenosine, uridine, cytidine, or guanosine), phosphate sources (sodium phosphate and hydroxyapatite) and chemicals (urea, formic acid, etc) under various reaction time (24-120 hours) and temperatures (25-140℃). Phosphorylation reaction has been observed from conditions using phosphate and hydroxyapatite source but with the presence of urea and above certain temperature. We look forward to share our latest results and would like to discuss further on how scCO₂/water two-phase system is advantageous for prebiotic organic phosphorylation on Earth’s early ocean.