Highly Stable Double‐Stranded DNA Containing Sequential Silver(I)‐Mediated 7‐Deazaadenine/Thymine Watson–Crick Base Pairs

Abstract

The oligonucleotide d(TX)9 , which consists of an octadecamer sequence with alternating non-canonical 7-deazaadenine (X) and canonical thymine (T) as the nucleobases, was synthesized and shown to hybridize into double-stranded DNA through the formation of hydrogen-bonded Watson-Crick base pairs. dsDNA with metal-mediated base pairs was then obtained by selectively replacing W-C hydrogen bonds by coordination bonds to central silver(I) ions. The oligonucleotide I adopts a duplex structure in the absence of Ag(+) ions, and its stability is significantly enhanced in the presence of Ag(+) ions while its double-helix structure is retained. Temperature-dependent UV spectroscopy, circular dichroism spectroscopy, and ESI mass spectrometry were used to confirm the selective formation of the silver(I)-mediated base pairs. This strategy could become useful for preparing stable metallo-DNA-based nanostructures.

Silver‐Mediated Base Pairs in DNA Incorporating Purines, 7‐Deazapurines, and 8‐Aza‐7‐deazapurines: Impact of Reduced Nucleobase Binding Sites and an Altered Glycosylation Position

“…In more detail, the canonical dA residues were replaced by the pyrazolo[3,4‐ d ]pyrimidine nucleosides 1 (ODN‐ 17 ) and 2 (ODN‐ 18 ) and for comparison with the pyrrolo[2,3‐ d ]pyrimidine nucleoside 3 (ODN‐ 19 ) and the purine nucleoside 4 (ODN‐ 20 ). Regarding nucleoside 3 , silver‐mediated base pair formation was reported for an alternating 18‐mer duplex …”

Silver(I)‐Mediated Base Pairs in DNA Sequences Containing 7‐Deazaguanine/Cytosine: towards DNA with Entirely Metallated Watson–Crick Base Pairs

“…The conversion of native Watson–Crick (W–C) base pairs into W–C metal‐mediated base pairs offers an exciting approach for the development of DNA‐based nanotechnology, since DNA molecules can be rationally organized prior to the addition of metal ions, and the metal ions can be subsequently introduced at each base pair. Noncanonical nucleobases including 1,3‐dideazaadenine, 1‐deazaadenine, or 7‐deazaadenine ( 7C A) have been proven to generate hydrogen‐bonded base pairs that can easily be converted into metal‐mediated base pairs by substitution of one or two hydrogen bonds. Specifically, we have previously demonstrated that, in presence of Ag I ions, 7C A–T base pairs can form a DNA duplex with consecutive W–C Ag I ‐mediated base pairs that preserve the B‐type conformation .…”

“…Noncanonical nucleobases including 1,3‐dideazaadenine, 1‐deazaadenine, or 7‐deazaadenine ( 7C A) have been proven to generate hydrogen‐bonded base pairs that can easily be converted into metal‐mediated base pairs by substitution of one or two hydrogen bonds. Specifically, we have previously demonstrated that, in presence of Ag I ions, 7C A–T base pairs can form a DNA duplex with consecutive W–C Ag I ‐mediated base pairs that preserve the B‐type conformation . Yet, the formation of W–C cytosine/guanine metal‐base pairs is mandatory in order to fully exploit the unique self‐assembly capabilities of DNA .…”

A Dinuclear Mercury(II)‐Mediated Base Pair in DNA

“…[3] With an ever increasing number of proposed or demonstrated applications as metal-ion sensors, [4] in charge transfer, [5] as logic gates, [6] as oligonucleotide sensors, [7] or in the generation of noble-metal nanoclusters, [8] theg eneral interest in metal-mediated base pairs is high. [14] Dinuclear metal-mediated base pairs represent an important class of metal-mediated base pairs.T heir high metal-ion load makes them interesting candidates,f or example,f or the generation of metal nanoclusters.A ll dinuclear metal-mediated base pairs reported to date involve Ag I ions. [14] Dinuclear metal-mediated base pairs represent an important class of metal-mediated base pairs.T heir high metal-ion load makes them interesting candidates,f or example,f or the generation of metal nanoclusters.A ll dinuclear metal-mediated base pairs reported to date involve Ag I ions.…”