OLIGOMERIZATION OF (GUANOSINE 5'-PHOSPHOR)-2-METHYLIMIDAZOLIDE ON POLY(C) - AN RNA-POLYMERASE MODEL
OLIGOMERIZATION OF (GUANOSINE 5'-PHOSPHOR)-2-METHYLIMIDAZOLIDE ON POLY(C) - AN RNA-POLYMERASE MODEL
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DOI：
10.1016/0022-2836(82)90169-3
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发表时间：
1982-01-01
影响因子：
5.6
通讯作者：
ORGEL, LE
中科院分区：
文献类型：
--
作者：
INOUE, T;ORGEL, LE
与鸟苷5 "-磷咪唑（ImpG）不同，（鸟苷5"-磷）-2-甲基咪唑（2-MeImpG）在pH值高于7.6时在聚（C）存在下经历有效的、不依赖于缓冲液的、模板导向的寡聚化。该反应以Watson-Crick双螺旋形式发生，主要产生3“-5”-连接的寡聚体，最多可达50-mer，产率高于80%。合成在5 ″ → 5 ″中进行。3“方向，并且在除G以外的核苷酸不显著掺入寡聚体的意义上具有高保真度。在某些条件下，对应于apprx.以比稍长或稍短的低聚物更高的产率获得1和2圈螺旋。在低于pH 7形成的质子化三螺旋结构中，低聚的效率低得多。获得最多约10聚体的低聚物。最丰富的产物在5“末端用GppG焦磷酸基团封端。[The讨论了这些结果与益生元多核苷酸复制研究的相关性。
(Guanosine 5''-phosphor)-2-methylimidazolide (2-MeImpG), unlike guanosine 5''-phosphorimidazolide (ImpG), undergoes an efficient, buffer-independent, template-directed oligomerization in the presence of poly(C) at pH values above 7.6. The reaction occurs in a Watson-Crick double helix and yields predominantly 3''-5''-linked oligomers up to the 50-mer in above 80% yield. Synthesis proceeds in the 5'' .fwdarw. 3'' direction and has high fidelity in the sense that nucleotides other than G are not incorporated significantly into oligomers. Under some conditions, oligomers corresponding to .apprx. 1 and 2 turns of the helix are obtained in higher yield than somewhat longer or somewhat shorter oligomers. In the protonated triple-helical structure formed below pH 7, the efficiency of the oligomerization is much lower. Oligomers up to about the 10-mer are obtained. The most abundant products are capped at the 5'' terminus with a GppG pyrophosphate group. [The relevance of these results to the study of prebiotic polynucleotide replication is discussed.].