Properties of non‐canonical GC base pairs and their relations with mechanochemical cleavage of DNA are analyzed. A hypothesis of the involvement of the transient GC wobble base pairs both in the mechanisms of the mechanochemical cleavage of DNA and epigenetic mechanisms involving of 5‐methylcytosine, is proposed. The hypothesis explains the increase in the frequency of the breaks of the sugar‐phosphate backbone of DNA after cytosines, the asymmetric character of these breaks, and an increase in break frequency in CpG after cytosine methylation. As an alternative hypothesis, probable implication of GC⁺ Hoogsteen base pairs is considered, which now exemplify the best‐studied non‐canonical GC base pairs in the DNA double helix. Also see the video abstract here https://youtu.be/EUunVWL0ptw.

中文翻译：

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表观遗传修饰的新偏差位点：非规范 GC 碱基对如何有利于 DNA 的机械化学裂解。

分析了非经典 GC 碱基对的特性及其与 DNA 机械化学切割的关系。提出了瞬态 GC 摆动碱基对参与 DNA 机械化学切割机制和涉及 5-甲基胞嘧啶的表观遗传机制的假设。该假设解释了胞嘧啶后 DNA 糖磷酸骨架断裂频率的增加、这些断裂的不对称特征以及胞嘧啶甲基化后 CpG 断裂频率的增加。作为替代假设，考虑了 GC ⁺ Hoogsteen 碱基对的可能含义，这现在是 DNA 双螺旋中研究最充分的非规范 GC 碱基对的例证。另请参阅此处的视频摘要 https://youtu.be/EUunVWL0ptw。