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

太古代海洋条件下矿物表面氮化合物的固定和演化

• 批准号: 8721219
• 负责人: Gustaf Arrhenius
• 金额: $ 13万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-08-01 至 1991-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8721219&HistoricalAwards=false
• 关键词: Fixation; Evolution; Nitrogen; Compounds; Mineral

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.

本项目涉及对RNA前体地球化学起源可能机制的实验研究。氰化氢的衍生物形成了RNA的碱基，其起源被推断为- 43亿年前。一些研究表明嘌呤和嘧啶的合成途径是可行的，但只有在相对较高的反应物浓度的水溶液中。将这些结果应用于益生元分子进化的一个关键问题是，它们可能存在的稀溶液中的反应物的选择性浓度。必须始终保持高浓度，以允许反应导致氰化物低聚物和有序的杂聚物，这些杂聚物可能是RNA的前身。目前的实验表明，在适当的环境模拟条件下，常见的过渡元素矿物能够进行羧酸盐的光合作用，在大浓度梯度下吸附氰化物，并固定化聚合反应产物。提议的研究涉及通过吸附和插层在表面活性过渡元素矿物中极端稀释氰化物的浓度，随后发生自发或光化学诱导的寡聚化和缩合反应，形成潜在的基因组的矿物-有机杂交前体。