Clever Guido H, Shionoya Mitsuhiko
Institute for Inorganic Chemistry, Georg-August University Göttingen, Göttingen, Germany.
Met Ions Life Sci. 2012;10:269-94. doi: 10.1007/978-94-007-2172-2_10.
Base-pairing in the naturally occurring DNA and RNA oligonucleotide duplexes is based on π-stacking, hydrogen bonding, and shape complementarity between the nucleobases adenine, thymine, guanine, and cytosine as well as on the hydrophobic-hydrophilic balance in aqueous media. This complex system of multiple supramolecular interactions is the product of a long-term evolutionary process and thus highly optimized to serve its biological functions such as information storage and processing. After the successful implementation of automated DNA synthesis, chemists have begun to introduce artificial modifications inside the core of the DNA double helix in order to study various aspects of base pairing, generate new base pairs orthogonal to the natural ones, and equip the biopolymer with entirely new functions. The idea to replace the hydrogen bonding interactions with metal coordination between ligand-like nucleosides and suitable transition metal ions culminated in the development of a plethora of artificial base-pairing systems termed "metal base-pairs" which were shown to strongly enhance the DNA duplex stability. Furthermore, they show great potential for the use of DNA as a molecular wire in nanoscale electronic architectures. Although single electrons have proven to be transmitted by natural DNA over a distance of several base pairs, the high ohmic resistance of unmodified oligonucleotides was identified as a serious obstacle. By exchanging some or all of the Watson-Crick base pairs in DNA with metal complexes, this problem may be solved. In the future, these research efforts are supposed to lead to DNA-like materials with superior conductivity for nano-electronic applications. Other fields of potential application such as DNA-based supramolecular architecture and catalysis may be strongly influenced by these developments as well. This text is meant to illustrate the basic concepts of metal-base pairing and give an outline over recent developments in this field.
天然存在的DNA和RNA寡核苷酸双链体中的碱基配对基于腺嘌呤、胸腺嘧啶、鸟嘌呤和胞嘧啶之间的π堆积、氢键以及形状互补性，同时也基于水性介质中的疏水-亲水平衡。这种由多种超分子相互作用构成的复杂系统是长期进化过程的产物，因此经过高度优化以实现其生物功能，如信息存储和处理。在自动DNA合成成功实现之后，化学家们开始在DNA双螺旋核心内部引入人工修饰，以便研究碱基配对的各个方面，生成与天然碱基对正交的新碱基对，并为这种生物聚合物赋予全新的功能。用配体样核苷与合适的过渡金属离子之间的金属配位取代氢键相互作用的想法，最终促成了大量被称为“金属碱基对”的人工碱基配对系统的开发，这些系统被证明能显著增强DNA双链体的稳定性。此外，它们在将DNA用作纳米级电子架构中的分子导线方面显示出巨大潜力。尽管已经证明单电子能够通过天然DNA在几个碱基对的距离上进行传输，但未修饰的寡核苷酸的高欧姆电阻被认为是一个严重障碍。通过用金属配合物取代DNA中的一些或所有沃森-克里克碱基对，这个问题可能会得到解决。未来，这些研究工作有望带来具有卓越导电性的类DNA材料，用于纳米电子应用。其他潜在应用领域，如基于DNA的超分子架构和催化，也可能会受到这些进展的强烈影响。本文旨在阐述金属碱基配对的基本概念，并概述该领域的最新进展。
