Minor groove hydrogen bonds and the replication of unnatural base pairs
Minor groove hydrogen bonds and the replication of unnatural base pairs
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DOI：
10.1021/ja068282b
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发表时间：
2007-05-02
影响因子：
15
通讯作者：
Romesberg, Floyd E.
中科院分区：
文献类型：
--
作者：
Matsuda, Shigeo;Leconte, Aaron M.;Romesberg, Floyd E.
作为扩大遗传字母表的一部分，我们研究了六种不同的含有甲氧基衍生核碱基类似物的非天然核苷酸的DNA合成。采用不同的核碱基取代模式系统地改变了核碱基的电子学、立体结构和氢键势。我们测定了大肠杆菌DNA聚合酶I的Klenow片段在稳态条件下合成和延伸不同非自然碱基对和错配的能力。与过去研究过的其他氢键受体不同，甲氧基不会促进错配，这意味着它们不会被天然核碱基的任何氢键供体识别；然而，它们确实促进了复制。更有效的复制主要是由于引物终止于非自然碱基对的延伸率的增加，有趣的是，这要求甲氧基位于邻位，它位于发育中的小凹槽中，可以与聚合酶形成功能重要的氢键。因此，邻甲氧基对于扩展遗传字母表的努力通常是有用的。
As part of an effort to expand the genetic alphabet, we examined the synthesis of DNA with six different unnatural nucleotides bearing methoxy-derivatized nucleobase analogues. Different nucleobase substitution patterns were used to systematically alter the nucleobase electronics, sterics, and hydrogen-bonding potential. We determined the ability of the Klenow fragment of E. coli DNA polymerase I to synthesize and extend the different unnatural base pairs and mispairs under steady-state conditions. Unlike other hydrogen-bond acceptors examined in the past, the methoxy groups do not facilitate mispairing, implying that they are not recognized by any of the hydrogen-bond donors of the natural nucleobases; however, they do facilitate replication. The more efficient replication results largely from an increase in the rate of extension of primers terminating at the unnatural base pair and, interestingly, requires that the methoxy group be at the ortho position where it is positioned in the developing minor groove and can form a functionally important hydrogen bond with the polymerase. Thus, ortho methoxy groups should be generally useful for the effort to expand the genetic alphabet.