title: Silver(I)-mediated Hoogsteen-type base pairs.
abstract: Metal-mediated Hoogsteen-type base pairs are useful for the construction of DNA duplexes containing contiguous stretches of metal ions along the helical axis. To fine-tune the stability of such base pairs and the selectivity toward different metal ions, the availability of a selection of artificial nucleobases is highly desirable. In this study, we follow a theoretical approach utilizing dispersion-corrected density functional methods to evaluate a variety of artificial nucleobases as candidates for metal-mediated Hoogsteen-type base pairs. We focus on silver(I)-mediated Hoogsteen- and reverse Hoogsteen-type base pairs formed between 1-deaza- and 1,3-dideazapurine-derived nucleobases, respectively, and cytosine. Apart from two coordinative bonds, these base pairs are stabilized by a hydrogen bond. We elucidate the impact of different substituents at the C6 position and the presence or absence of an endocyclic N3 nitrogen atom on the overall stability of a base pair and concomitantly on the strength of the hydrogen and coordinative bonds. All artificial base pairs investigated in this study are less stable than the experimentally established benchmark base pair C-Ag(+)-G. The base pair formed from 1,3-dideaza-6-methoxypurine is isoenergetic to the experimentally observed C-Ag(+)-C base pair. This makes 1,3-dideaza-6-methoxypurine a promising candidate for the use as an artificial nucleobase in DNA.
authors.affiliation: University of Muenster, Institute for Inorganic and Analytical Chemistry, Corrensstr. 28/30, 48149 Muenster, Germany.
authors.forename: Dominik A
authors.initials: DA
authors.lastname: Megger
authors.forename: Célia
authors.initials: C
authors.lastname: Fonseca Guerra
authors.forename: F Matthias
authors.initials: FM
authors.lastname: Bickelhaupt
authors.forename: Jens
authors.initials: J
authors.lastname: Müller
mesh_terms: D000465:Algorithms; D020029:Base Pairing; D003198:Computer Simulation; D056831:Coordination Complexes / Q000737:chemistry*; D003596:Cytosine / Q000031:analogs & derivatives / Q000737:chemistry; D006860:Hydrogen Bonding; D008958:Models, Molecular; D011684:Purine Nucleosides / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D056831:Coordination Complexes; D011684:Purine Nucleosides; D012834:Silver; D003596:Cytosine