{"title":"On the nature of the triple hydrogen bond in the cytosine-guanine base pair and its role in the tautomerism","authors":"Luca Nanni","doi":"10.1007/s12039-025-02390-x","DOIUrl":null,"url":null,"abstract":"<div><p>This study uses computational methods to explore the triple hydrogen bonding between cytosine and guanine. It specifically focuses on two tautomers: the GC tautomer, which forms during DNA replication, and the tautomer resulting from double proton transfer, denoted as G*C*. The latter tautomer is linked to genetic mutations. The geometric, vibrational, and electronic structures of both tautomers have been calculated using DFT-B3LYP and MP2 levels of theory. The results are then compared to those of the non-interacting bases. The findings indicate that hydrogen bonding is moderately strong for both tautomers, with electrostatic interaction being the primary component. While the variations in the HOMO energy contribute to the stabilization of the triple hydrogen bond in G*C*, the kinetics of the reaction from GC to G*C* is hindered by a relatively high potential barrier. This barrier is mainly caused by a significant increase in nuclear repulsion within G*C*, which is not adequately counterbalanced by the favourable changes in HOMO energies.</p><h3>Graphical Abstract</h3>\n<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":616,"journal":{"name":"Journal of Chemical Sciences","volume":"137 3","pages":""},"PeriodicalIF":2.0000,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Chemical Sciences","FirstCategoryId":"92","ListUrlMain":"https://link.springer.com/article/10.1007/s12039-025-02390-x","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
This study uses computational methods to explore the triple hydrogen bonding between cytosine and guanine. It specifically focuses on two tautomers: the GC tautomer, which forms during DNA replication, and the tautomer resulting from double proton transfer, denoted as G*C*. The latter tautomer is linked to genetic mutations. The geometric, vibrational, and electronic structures of both tautomers have been calculated using DFT-B3LYP and MP2 levels of theory. The results are then compared to those of the non-interacting bases. The findings indicate that hydrogen bonding is moderately strong for both tautomers, with electrostatic interaction being the primary component. While the variations in the HOMO energy contribute to the stabilization of the triple hydrogen bond in G*C*, the kinetics of the reaction from GC to G*C* is hindered by a relatively high potential barrier. This barrier is mainly caused by a significant increase in nuclear repulsion within G*C*, which is not adequately counterbalanced by the favourable changes in HOMO energies.
期刊介绍：
Journal of Chemical Sciences is a monthly journal published by the Indian Academy of Sciences. It formed part of the original Proceedings of the Indian Academy of Sciences – Part A, started by the Nobel Laureate Prof C V Raman in 1934, that was split in 1978 into three separate journals. It was renamed as Journal of Chemical Sciences in 2004. The journal publishes original research articles and rapid communications, covering all areas of chemical sciences. A significant feature of the journal is its special issues, brought out from time to time, devoted to conference symposia/proceedings in frontier areas of the subject, held not only in India but also in other countries.
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