MONTMORILLONITE CATALYSIS OF RNA OLIGOMER FORMATION IN AQUEOUS-SOLUTION - A MODEL FOR THE PREBIOTIC FORMATION OF RNA
MONTMORILLONITE CATALYSIS OF RNA OLIGOMER FORMATION IN AQUEOUS-SOLUTION - A MODEL FOR THE PREBIOTIC FORMATION OF RNA
复制标题
DOI：
10.1021/ja00079a006
复制
发表时间：
1993-12-29
影响因子：
15
通讯作者：
ERTEM, G
中科院分区：
文献类型：
--
作者：
FERRIS, JP;ERTEM, G
腺苷的磷咪唑烷（ImpA）在pH为8的水溶液中，在Na+-蒙脱土的存在下，在室温下反应形成长度达11-mer的腺苷酸低聚物。这些低聚物由磷酸二酯键连接，其中3',5'-键以2:1的比例大于2',5'-键。ImpA, A5'ppA以9:1的比例反应，生成3',5'-与2',5'-连接的磷酸二酯键的比例为3:1的低聚物。这些低聚物中有很大一部分含有A5'ppA基团。与5'-ADP （ppA）或5'-ATP （pppA）相比，a5 '- ppA与ImpA的反应要快得多。与蒙脱土相结合的可交换阳离子对催化剂的催化效果有显著影响，其中Li+、Na+、NH4+和Ca2+的催化效果较好，而Mg2+和Al3+的催化效果几乎为无效。用UO22+-蒙脱土形成长度达四聚体的2′，5′连接低聚物。通过选择性酶解和KOH水解研究对单个低聚物组分进行结构分析，然后对反应产物进行HPLC分析。从低聚物的组成可以得出结论，ImpA加到含有2‘,5’键的3‘端比加到由3’，5'键连接的磷酸二酯键连接的核苷上的速度慢。讨论了矿物催化在原始地球上形成RNA和其他低聚物的潜在重要性。
Oligomers of adenylic acid of up to the 11-mer in length are formed by the reaction of the phosphorimidazolide of adenosine (ImpA) in pH 8 aqueous solution at room temperature in the presence of Na+-montmorillonite. These oligomers are joined by phosphodiester bonds in which the 3',5'-linkage predominates over the 2',5'-linkage by a 2:1 ratio. Reaction of a 9:1 mixture of ImpA, A5'ppA results in the formation of oligomers with a 3:1 ratio of 3',5'- to 2',5'-linked phosphodiester bonds. A high proportion of these oligomers contain the A5'ppA grouping. A5'ppA reacts much more rapidly with ImpA than does 5'-ADP (ppA) or 5'-ATP (pppA). The exchangeable cation associated with the montmorillonite effects the observed catalysis with Li+, Na+, NH4+, and Ca2+ being the more effective while Mg2+ and Al3+ are almost ineffective catalysts. 2',5'-Linked oligomers, up to the tetramer in length, are formed using UO22+-montmorillonite. The structure analysis of individual oligomer fractions was performed by selective enzymatic and KOH hydrolytic studies followed by HPLC analysis of the reaction products. It is concluded from the composition of the oligomers that the rate of addition ImpA to a 3'-terminus containing a 2',5'-linkage is slower than the addition to a nucleoside joined by a 3',5'-linked phosphodiester bond. The potential importance of mineral catalysis of the formation of RNA and other oligomers on primitive Earth is discussed.