Sabancı University, Faculty of Engineering and Natural Sciences, 34956, Tuzla, Istanbul, Turkey.
Prog Biophys Mol Biol. 2022 Sep;173:4-10. doi: 10.1016/j.pbiomolbio.2022.05.009. Epub 2022 Jun 1.
Spontaneous point mutations are one of the main actors in evolution, and the tautomerization of organic bases in the DNA is hypothesized to be the underlying mechanism of this crucial process. Tautomerization can be induced by proton tunneling, and if it occurs in single-stranded DNA (ssDNA) during the replication process, tautomerized bases might give rise to a mismatch, which will eventually defect the genetic code. In the present work, we report on the tautomerization time in the guanine base of the ssDNA. The model we use includes an intra-base tunneling mechanism such that time tunneling (delay time) is estimated to be around a few pico-seconds. The time delay is found to be biologically relevant which indicates that it is long enough to induce point mutations. Our results close a gap in the literature and sheds light on the importance of point mutations originating from quantum effects in the ssDNA.
自发点突变是进化的主要因素之一，而 DNA 中有机碱基的互变异构被假设为这一关键过程的潜在机制。互变异构可以通过质子隧穿诱导，如果在复制过程中发生在单链 DNA（ssDNA）中，互变异构碱基可能导致错配，最终导致遗传密码缺陷。在本工作中，我们报告了 ssDNA 中鸟嘌呤碱基的互变异构时间。我们使用的模型包括一种碱基内隧穿机制，使得时间隧穿（延迟时间）估计在几个皮秒左右。发现延迟时间与生物学相关，这表明它足够长，可以诱导点突变。我们的结果填补了文献中的空白，并阐明了 ssDNA 中起源于量子效应的点突变的重要性。
