Abstract

The genetic code is considered to use five nucleic bases (adenine, guanine, cytosine, thymine and uracil), which form two pairs for encoding information in DNA and two pairs for encoding information in RNA. Nevertheless, in recent years several artificial base pairs have been developed in attempts to expand the genetic code. Employment of these additional base pairs increases the information capacity and variety of DNA sequences, and provides a platform for the site-specific, enzymatic incorporation of extra functional components into DNA and RNA. As a result, of the development of such expanded systems, many artificial base pairs have been synthesized and tested under various conditions. Following many stages of enhancement, unnatural base pairs have been modified to eliminate their weak points, qualifying them for specific research needs. Moreover, the first attempts to create a semi-synthetic organism containing DNA with unnatural base pairs seem to have been successful. This further extends the possible applications of these kinds of pairs. Herein, we describe the most significant qualities of unnatural base pairs and their actual applications.

中文翻译：

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扩展遗传密码：生物系统中的非自然碱基对

摘要

遗传密码被认为使用了五个核酸碱基（腺嘌呤，鸟嘌呤，胞嘧啶，胸腺嘧啶和尿嘧啶），它们形成了两对用于编码DNA信息和两对用于编码RNA信息。然而，近年来，已经开发了几种人工碱基对，以尝试扩展遗传密码。这些额外碱基对的使用增加了信息容量和DNA序列的多样性，并提供了将额外功能成分以位点特异性，酶促方式掺入DNA和RNA的平台。结果，随着这种扩展系统的发展，已经合成了许多人工碱基对并在各种条件下进行了测试。在增强的许多阶段之后，对非天然碱基对进行了修饰以消除它们的弱点，从而使其有资格满足特定的研究需求。而且，首次尝试创建包含具有非天然碱基对的DNA的半合成生物似乎是成功的。这进一步扩展了此类对的可能应用。在此，我们描述了非自然碱基对的最重要性质及其实际应用。