Prebiotic Mineral Catalysis And Hydrothermal Synthesis Of Some Biologically Important Phosphate Compounds

Biological phosphate esters like sn-glycerol-3-phosphate, glycerol-2-phosphate and phosphoethanolamine were synthesized under prebiotic hydrothermal conditions. Phosphorus was incorporated into the biomolecules, leading to the formation of C-O-P type compounds, hydrothermally. Only perlite-catalyzed reaction at 180℃could result in the formation of sn-glycerol-3-phosphate while glycerol-2-phosphate could obtained at 100℃with or without minerals, and phosphoethanolamine was obtained within a temperature range of 100 to 120℃. The products were detected by paper chromatography and LCMS. Thus phosphorylation of small organic biomolecules was made successful.Moreover, the effects of various potential minerals on the synthesis of glycerol phosphates were also studied. It was proven that the minerals catalyze the prebiotic hydrothermal synthesis of phosphate esters and yields of the products were doubled in the presence of minerals. Hence, it was proved that it is possible to synthesize the biological phosphate esters under simple acidic hydrothermal conditions. Most interestingly, glycerol phosphates could also be synthesized at temperature as high as 200℃. Also, orthophosphate was proven to be one of the ultimate sources of P for the biological world. Also, for the synthesis of glycerol phosphates, condensing agents like cyanamid or urea were not essential and we witnessed that the hydrothermal conditions also favor the formation of C-O-P type biological compounds. Our work leads us to believe that the hydrothermal systems could be the most likely havens for the high energy PO4 esters that could easily be transferred to the developing life.In the other experiment, prebiotic acidic hydrothermal conditions were mimicked and biologically significant phosphate esters such as glucose-1-phosphate, glucose-6-phosphate and glucose-di-phosphate were synthesized under prebiotic hydrothermal conditions, in the presence of a mixture of potential minerals. In the first step acidic prebiotic soup was made. Second step was the hydrothermal synthesis. The synthesis was successfully carried out within a temperature range of 100°C - 160°C. However, the maximum yields were obtained within a temperature window of 100°C-130°C. The yields of glucose monophosphates (total yield of both isomers) and glucose-di-phosphate were 1.4% and 0.05% respectively. The products were firstly analyzed by paper chromatography, and then confirmed by UPLC-MS. Both isomers of glucose phosphate were obtained, with some detectable amount of glucose-di-phosphate. Selected minerals were found to be essential for our synthesis as no products were detected without the minerals.In our experiment, we also witnessed that the reaction mixture within the temperature window of 80°C to 100°C, after the reaction, showed almost no brown tar while the reaction mixture within the temperature window of 120°C to 150°C, after the reaction, showed higher amounts of very dark brown tar while the reaction mixture above 160°C, after the reaction, showed almost black tar and gave off a strong burning smell, implying that almost all the sugar was burnt or decomposed at this temperature.In next step of experiments, a simple phospholipid like phosphatidic acid was synthesized, for the first time, under prebiotic hydrothermal conditions. In the first step ammonium palmitate was synthesized and it was allowed to react with sn-glycerol-3-phoshate, under hydrothermal conditions. Phosphatidic acid was successfully synthesized within a temperature range of 100℃to 140℃, under hydrothermal treatment for 3-4days, in the presence of mineral-clays mixture. The product could not be detected without the mineral-clays mixture. This means that the catalyst mixture is essential for the successful completion of the reaction. The product was identified by MS analysis. Also, the self assembly reaction of the reaction products was also studied and it was found that the reaction products were well capable of forming cell like stable vesicles which could very well engulf the dye. It is worth mentioning here that our group is one of the most initial groups to initiate the prebiotic hydrothermal phosphorylation reactions.In our new set of experiments, we studied behavior of HCHO, under hydrothermal conditions. Many significant parameters such as pH, temperature, pressure, effect of various minerals and clays, time factor etc were also taken into consideration. We attempted to begin the hydrothermal self condensation reactions of HCHO. We carried out the reactions within a temperature range of 100–200℃for a time span of 3-4 days, in the presence of a catalyst mixture (boric acid and Kaolin clay). It was seen that the HCHO under goes self condensation reactions and forms a series of both, acyclic and cyclic compounds. We successfully synthesized 2,4,8,10-tetraoxaspiro [5.5]-undecane under hydrothermal conditions. We were interested to know the effect of temperature on our unique pathway. Hence, we performed the reaction below 100℃. Most interestingly, we found that temperature window of 80℃to 90℃gives a series of small open chained oxygenated products like Carbondioxide, formic acid etc. Also, temperature exceeding 100℃, causes degradation and decomposition of the product, implying that the above described method to synthesize 1 is highly selective in nature and is only feasible at 100℃. We witnessed that boric acid and kaolin mixture was responsible for the stability of the product, as organic product could not be obtained without the presence of the catalyst mixture.