Department of Chemistry, McGill University, Montreal, QC H3A 0B8, Canada.
Instituto de Química Física 'Rocasolano', CSIC, C/Serrano 119, 28006 Madrid, Spain.
Nucleic Acids Res. 2018 Sep 19;46(16):8038-8056. doi: 10.1093/nar/gky735.
The i-motif represents a paradigmatic example of the wide structural versatility of nucleic acids. In remarkable contrast to duplex DNA, i-motifs are four-stranded DNA structures held together by hemi- protonated and intercalated cytosine base pairs (C:C+). First observed 25 years ago, and considered by many as a mere structural oddity, interest in and discussion on the biological role of i-motifs have grown dramatically in recent years. In this review we focus on structural aspects of i-motif formation, the factors leading to its stabilization and recent studies describing the possible role of i-motifs in fundamental biological processes.
i 型发夹结构是核酸结构多样性的典型范例。与双链 DNA 形成鲜明对比的是，i 型发夹结构是由部分质子化和交错的胞嘧啶碱基对（C:C+）形成的四链 DNA 结构。i 型发夹结构早在 25 年前就被首次观察到，并且被许多人认为只是一种结构上的奇特现象，但近年来，人们对 i 型发夹结构的生物学作用的兴趣和讨论显著增加。在这篇综述中，我们重点介绍 i 型发夹结构的形成的结构方面、导致其稳定的因素以及描述 i 型发夹结构在基本生物学过程中可能发挥的作用的最新研究。
