Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
J Am Chem Soc. 2010 May 26;132(20):7194-201. doi: 10.1021/ja101718c.
Hydrogen bond (H-bond) formation in water has been a challenging task because water molecules are constant competitors. In biological systems, however, stable H-bonds are formed by shielding the H-bonding sites from the competing water molecules within hydrophobic pockets. Inspired by the nature's elaborated way, we found that even mononucleotides (G and C) can form the minimal G x C Watson-Crick pair in water by simply providing a synthetic cavity that efficiently shields the Watson-Crick H-bonding sites. The minimal Watson-Crick structure in water was elucidated by NMR study and firmly characterized by crystallographic analysis. The crystal structure also displays that, within the cavity, coencapsulated anions and solvents efficiently mediate the minimal G x C Watson-Crick pair formation. Furthermore, the competition experiments with the other nucleobases clearly revealed the evident selectivity for the G x C base pairing in water. These results show the fact that a H-bonded nucleobase pair was effectively induced and stabilized in the local environment of an artificial hydrophobic cavity.
在水中形成氢键（H-bond）一直是一项具有挑战性的任务，因为水分子是恒定的竞争者。然而，在生物系统中，通过将氢键结合位点屏蔽在疏水口袋内的竞争水分子，可以形成稳定的氢键。受自然界巧妙方式的启发，我们发现，即使是单核苷酸（G 和 C），也可以通过简单地提供一个有效的屏蔽 Watson-Crick 氢键结合位点的合成腔，在水中形成最小的 G x C Watson-Crick 碱基对。通过 NMR 研究阐明了水中最小的 Watson-Crick 结构，并通过晶体学分析进行了坚定的表征。晶体结构还显示，在腔内，共包封的阴离子和溶剂有效地介导了最小的 G x C Watson-Crick 碱基对形成。此外，与其他核苷酸碱基的竞争实验清楚地揭示了在水中对 G x C 碱基配对的明显选择性。这些结果表明，在人工疏水腔的局部环境中，有效地诱导和稳定了氢键键合的核苷酸碱基对。
