title: The DNA-forming properties of 6-selenoguanine.
abstract: 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 → 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.
authors.affiliation: Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac, 10, Barcelona 08028, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Faustino
authors.forename: Carles
authors.initials: C
authors.lastname: Curutchet
authors.forename: F Javier
authors.initials: FJ
authors.lastname: Luque
authors.forename: Modesto
authors.initials: M
authors.lastname: Orozco
mesh_terms: D004247:DNA / Q000737:chemistry*; D006147:Guanine / Q000031:analogs & derivatives* / Q000737:chemistry; D015394:Molecular Structure; D016566:Organoselenium Compounds / Q000737:chemistry*; D011789:Quantum Theory; D013816:Thermodynamics
chemical_list: D016566:Organoselenium Compounds; C009227:6-selenoguanine; D006147:Guanine; D004247:DNA