The DNA-forming properties of 6-selenoguanine

TitleThe DNA-forming properties of 6-selenoguanine
Publication TypeJournal Article
Year of Publication2014
AuthorsFaustino, Ignacio, Curutchet Carles, F Luque Javier, and Orozco Modesto
JournalPhys. Chem. Chem. Phys.

We present here an exhaustive characterization of the structure and properties of 6-selenoguanine{,} an isoster of guanine{,} and the impact of its introduction in DNA. This study reports the results of state-of-the-art quantum mechanical calculations and atomistic molecular dynamics simulations carried out to shed light on the impact of the replacement of guanine (G) by 6-selenoguanine (SeG) in different forms of DNA. The results point out that the G [rightward arrow] SeG substitution leads to stable DNA duplex{,} antiparallel triplex and G-quadruplex structures{,} though local distortions are also found. These structural changes affect the thermodynamic stability of the mutation leading to a clear destabilization for all studied systems. Interestingly{,} the lowest effect has been found when the mutation was placed in the triplex-forming oligonucleotide strand in a reverse Hoogsteen orientation{,} which favours the antiparallel triplex formation regarding the G-tetraplex formation. Detailed QM studies strongly suggest that SeG impacts the HOMO-LUMO gap and accordingly the transfer properties of DNA{,} opening the way to modulate the conductivity properties of non-natural DNAs.