Structural Basis for Expansion of the Genetic Alphabet with an Artificial Nucleobase Pair
Structural Basis for Expansion of the Genetic Alphabet with an Artificial Nucleobase Pair
复制标题
DOI：
10.1002/anie.201704190
复制
发表时间：
2017-09-18
影响因子：
16.6
通讯作者：
Marx, Andreas
中科院分区：
文献类型：
--
作者：
Betz, Karin;Kimoto, Michiko;Marx, Andreas
没有通过氢键配对能力的疏水性人工核碱基对是扩展遗传字母表的有希望的候选者。最成功的核碱基替代物彼此之间以及它们的天然对应物之间几乎没有相似性。因此，令人困惑的是，这些非天然分子是如何被DNA聚合酶加工的，而DNA聚合酶已经进化到可以有效地与天然结构单元一起工作。在这里，我们报告的结构洞察插入的一个最有前途的疏水性非天然碱基对，dDs-dPx对，到DNA链的DNA聚合酶。我们解决了KlenTaq DNA聚合酶的晶体结构与修饰的模板/引物双链体结合到非天然的三磷酸。三元复合物表明，人工对采用平面结构，就像一个天然的核碱基对，并确定功能，可能暗示的机制占较低的掺入效率时观察到的处理非天然底物。
Hydrophobic artificial nucleobase pairs without the ability to pair through hydrogen bonds are promising candidates to expand the genetic alphabet. The most successful nucleobase surrogates show little similarity to each other and their natural counterparts. It is thus puzzling how these unnatural molecules are processed by DNA polymerases that have evolved to efficiently work with the natural building blocks. Here, we report structural insight into the insertion of one of the most promising hydrophobic unnatural base pairs, the dDs-dPx pair, into a DNA strand by a DNA polymerase. We solved a crystal structure of KlenTaq DNA polymerase with a modified template/primer duplex bound to the unnatural triphosphate. The ternary complex shows that the artificial pair adopts a planar structure just like a natural nucleobase pair, and identifies features that might hint at the mechanisms accounting for the lower incorporation efficiency observed when processing the unnatural substrates.