Fixation and Evolution of Nitrogen Compounds on Mineral Surfaces Under Archaean Ocean Conditions

该项目涉及可能机制的实验研究 RNA前体的地球化学起源。 的衍生物 氰化氢形成RNA的碱基，其来源是 推算到-43亿年。 一些调查显示， 显示了嘌呤和嘧啶合成的途径， 可行的，但只有在相对较高的反应物浓度， 水溶液中 将这些结果应用于 前生物分子进化涉及选择性浓缩 反应物可能来自稀溶液中 存在过 必须始终保持高浓度 为了使反应产生氰化物低聚物， 有序的杂聚物， 对于RNA。 目前的实验表明， 元素矿物在适当的环境模拟下 条件是能够光合作用的羧酸盐，吸附 氰化物对大浓度梯度，和 聚合反应产物的固定化。 拟议 研究涉及氰化物的浓度从极端稀释， 表面活性过渡元素吸附和嵌入 矿物质，其次是自发或光化学诱导 低聚和缩合反应，以形成潜在的 基因组的无机-有机混合前体。

This project involves experimental studies of possible mechanisms for the geochemical origin of RNA precursors. Derivatives of hydrogen cyanide form the bases of RNA, whose origin is extrapolated to -4.3 billion years. Several investigations have shown pathways for purine and pyrimidine synthesis, which are viable, but only at relatively high reactant concentration in aqueous solution. A crucial problem in applying these results to prebiotic molecular evolution concerns the selective concentration of the reactants from the dilute solution in which they probably existed. High concentrations must have been consistly maintained in order to permit reactions leading to cyanide oligomers and to the ordered heteropolymers that would have served as forerunners for RNA. Current experiments indicate that common transition element minerals under appropriate environmental modeling conditions are capable of photosynthesis of carboxylates, sorption of cyanide against large concentration gradients, and immobilization of the polymeric reaction products. The proposed studies involve concentration of cyanide from extreme dilution by sorption and intercalation in surface active transition element minerals, followed by spontaneous or photochemically induced oligomerization and condensation reactions to form potential mineral-organic hybrid precursors of the genome.