Montmorillonite, oligonucleotides, RNA and origin of life
Montmorillonite, oligonucleotides, RNA and origin of life
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DOI：
10.1023/b:orig.0000043130.49790.a7
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发表时间：
2004-12-01
影响因子：
2
通讯作者：
Ertem, G
中科院分区：
文献类型：
--
作者：
Ertem, G
通过滴定法从 Volclay 中制备的钠蒙脱土可促进腺苷 5'-磷咪唑衍生物 ImpA 的自缩合。 AE-HPLC 分析和产物的选择性酶水解表明，该反应中形成的寡聚（A）有 10 个单体单元长，含有 67% 3',5'-磷酸二酯键（Ferris 和 Ertem，1992a）。在相同的反应条件下，胞苷、尿苷和鸟苷的5'-磷咪唑衍生物也会发生自缩合，生成含有多达12-14个寡聚(C)单体单元至6个寡聚(G)单体单元的低聚物。在oligo(C) 和oligo(U) 中，75-80% 的单体通过2',5'-磷酸二酯键连接。通过蒙脱土催化形成的合成寡聚体 (C) 中分离出的六聚体和高级寡聚体含有 3',5'- 和 2',5'- 连接键，可用作从活化单体 2-MeImpG、鸟苷 5'-磷酸-2-甲基咪唑化物进行非酶模板指导合成寡聚 (G) 的催化剂 (Ertem 和 Ferris, 1996)。从合成的oligo(C)中分离出来的仅含有2',5'-连接的五聚体和更高的寡聚体也可用作模板并产生具有2',5'-和3',5'-磷酸二酯键的oligo(G)。使用计算机程序 SIMFIT 对蒙脱土催化寡聚体延伸速率进行的动力学研究表明，oligo(A) 形成的速率常数按 2-mer 的顺序增加
Na-montmorillonite prepared from Volclay by the titration method facilitates the self-condensation of ImpA, the 5'-phosphorimidazolide derivative of adenosine. As was shown by AE-HPLC analysis and selective enzymatic hydrolysis of products, oligo(A)s formed in this reaction are 10 monomer units long and contain 67% 3',5'-phosphodiester bonds (Ferris and Ertem, 1992a). Under the same reaction conditions, 5'-phosphorimidazolide derivatives of cytidine, uridine and guanosine also undergo self-condensation producing oligomers containing up to 12-14 monomer units for oligo(C) s to 6 monomer units for oligo(G) s. In oligo(C) s and oligo(U) s, 75-80% of the monomers are linked by 2',5'-phosphodiester bonds. Hexamer and higher oligomers isolated from synthetic oligo(C) s formed by montmorillonite catalysis, which contain both 3',5'- and 2',5'- linkages, serve as catalysts for the non-enzymatic template directed synthesis of oligo(G) s from activated monomer 2-MeImpG, guanosine 5'-phospho-2-methylimidazolide (Ertem and Ferris, 1996). Pentamer and higher oligomers containing exclusively 2',5'-linkages, which were isolated from the synthetic oligo(C) s, also serve as templates and produce oligo(G) s with both 2',5'- and 3',5'-phosphodiester bonds. Kinetic studies on montmorillonite catalyzed elongation rates of oligomers using the computer program SIMFIT demonstrated that the rate constants for the formation of oligo(A) s increased in the order of 2-mer