K. Betz, M. Kimoto, K. Diederichs, I. Hirao, A. Marx, Angew. Chem. Int. Ed. 2017, 56, 12000.
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.
We thank the beamline staff of the Swiss Light Source at the Paul Scherrer Institute for access and help at the beamline. We also thank the Konstanz Research School Chemical Biology (K.B.) and the Japan Science and Technology Agency, Precursory Research for Embryonic Science and Technology (JPMJPR13K9) (M.K.) for financial support. A part of this work was funded by the Institute of Bioengineering and Nanotechnology (Biomedical Research Council, Agency for Science, Technology and Research, Singapore).
This is the peer reviewed version of the following article: K. Betz, M. Kimoto, K. Diederichs, I. Hirao, A. Marx, Angew. Chem. Int. Ed. 2017, 56, 12000.
, which has been published in final form at https://doi.org/10.1002/anie.201704190. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.