Silver (I) as DNA glue: Ag+- mediated guanine pairing revealed by removing Watson-Crick constraints

Metal ion interactions with DNA have far-reaching implications in biochemistry and DNA nanotechnology. Ag+ is uniquely interesting because it binds exclusively to the bases rather than the backbone of DNA, without the toxicity of Hg2+. In contrast to prior studies of Ag+ incorporation into double-stranded DNA, we remove the constraints of Watson-Crick pairing by focusing on homo-base DNA oligomers of the canonical bases. High resolution electro-spray ionization mass spectrometry reveals an unanticipated Ag+-mediated pairing of guanine homo-base strands, with higher stability than canonical guanine-cytosine pairing. By exploring unrestricted binding geometries, quantum chemical calculations find that Ag+ bridges between non-canonical sites on guanine bases. Circular dichroism spectroscopy shows that the Ag+-mediated structuring of guanine homobase strands persists to at least 90 °C under conditions for which canonical guanine-cytosine duplexes melt below 20 °C. These findings are promising for DNA nanotechnology and metal-ion based biomedical science.

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10.1038/srep10163

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Swasey, S M, Espinosa Leal, L, Lopez Acevedo, O, Pavlovich, J & Gwinn, E G 2015, ' Silver (I) as DNA glue : Ag+- mediated guanine pairing revealed by removing Watson-Crick constraints ', Scientific Reports, vol. 5, 10163, pp. 1-9 . https://doi.org/10.1038/srep10163

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https://urn.fi/URN:NBN:fi:aalto-201805222500

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[article-cris] Perustieteiden korkeakoulu / SCI

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Silver (I) as DNA glue: Ag+- mediated guanine pairing revealed by removing Watson-Crick constraints

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