A highly stabilizing silver(I)-mediated base pair in parallel-stranded DNA.

Indranil Sinha, Célia Fonseca Guerra, Jens Müller

Index: Angew. Chem. Int. Ed. Engl. 54(12) , 3603-6, (2015)

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Abstract

The first parallel-stranded DNA duplex with Hoogsteen base pairing that readily incorporates an Ag(+) ion into an internal mispair to form a metal-mediated base pair has been created. Towards this end, the highly stabilizing 6 FP-Ag(+)-6 FP base pair comprising the artificial nucleobase 6-furylpurine (6 FP) was devised. A combination of temperature-dependent UV spectroscopy, CD spectroscopy, and DFT calculations was used to confirm the formation of this base pair. The nucleobase 6 FP is capable of forming metal-mediated base pairs both by the Watson-Crick edge (i.e. in regular antiparallel-stranded DNA) and by the Hoogsteen edge (i.e. in parallel-stranded DNA), depending on the oligonucleotide sequence and the experimental conditions. The 6 FP-Ag(+)-6 FP base pair within parallel-stranded DNA is the most strongly stabilizing Ag(+)-mediated base pair reported to date for any type of nucleic acid, with an increase in melting temperature of almost 15 °C upon the binding of one Ag(+) ion.© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.