CHEMICAL SELF-REPLICATION OF PALINDROMIC DUPLEX DNA
CHEMICAL SELF-REPLICATION OF PALINDROMIC DUPLEX DNA
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DOI：
10.1038/369218a0
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发表时间：
1994-05-19
期刊：
影响因子：
64.8
通讯作者：
NICOLAOU, KC
中科院分区：
文献类型：
--
作者：
LI, T;NICOLAOU, KC
分子复制是生命的一个基本过程，近年来一直是使用简单化学系统进行实验室研究的主题（1-10）。虽然Rebek小组（4，5）的工作集中在生命系统中未知的分子结构上，但基于核苷酸的自我复制和基于模板的自组装系统（6-8）被认为是探索早期地球复制系统进化的潜在模型。以前的复制寡核苷酸是单链的，自我互补的类型：小的寡核苷酸片段在预先存在的模板上组装并连接以形成模板的精确拷贝。然而，由于新形成的链与原始模板的强结合，该过程不能容易地重复。此外，生命系统中的DNA复制是通过互补性而不是自我互补性进行的--每条新组装的链与其模板互补，而不是相同--复制过程以双螺旋开始和结束。在这里，我们报告的回文（对称）双链DNA样寡核苷酸，24单体长，在酶的情况下，通过一个循环，从模板到拷贝的信息转移，并有可能能够扩展到包括非对称序列，选择和突变的自我复制。复制通过一个化学过程进行，包括形成一个中间的三链体结构，并且在错配损害其效率的意义上是序列选择性的。这些结果表明，类似DNA的双螺旋分子可以在没有蛋白质的帮助下复制，这一发现可能与早期地球上复制系统的出现以及DNA扩增新方法的发展有关。
MOLECULAR replication, a fundamental process of life, has in recent years been the subject of laboratory investigations using simple chemical systems(1-10). Whereas the work of Rebek's group(4,5) has focused on molecular architectures not known in living systems, self-replicating and template-based self-assembling systems based on nucleotides(6-8) are regarded as potential models for exploring the evolution of replicating systems on the early Earth. Previous replicating oligonucleotides have been of the single-stranded, self-complementary type: small oligonucleotide fragments are assembled on a pre-existing template and linked to form an exact copy of the template. This process cannot easily be reiterated, however, because of the strong binding of the newly formed strand to the original template. Furthermore, DNA replication in living systems operates by complementarity rather than self-complementarity-each newly assembled strand is complementary to, rather than identical to, its template-and the replication process starts and finishes with double helices. Here we report the self-replication of palindromic (symmetrical) duplex DNA-like oligonucleotides, 24 monomers long, in the absence of enzymes by means of a cycle that transfers information from template to copy and is potentially capable of extension to include non-symmetrical sequences, selection and mutation. Replication proceeds by a chemical process involving the formation of an intermediate triplex structure, and is sequence-selective in the sense that mismatches impair its efficiency. These results indicate that DNA-like double-helical molecules can replicate without assistance from proteins, a finding that may be relevant both to the appearance of replicating systems on the early Earth and to the development of new approaches to DNA amplification.