Stable Copper(I)‐Mediated Base Pairing in DNA

Abstract

A GNA (glycol nucleic acid) functionalized nucleoside analogue containing the artificial nucleobase 1H-imidazo[4,5-f][1,10]phenanthroline (P) was used to form a copper(I)-mediated base pair within a DNA duplex. The geometrical constraints imposed by the artificial nucleobase play a pivotal role in this unprecedented stabilization of copper(I) in aqueous medium via metal-mediated base pairing. The formation of the copper(I)-mediated base pair was investigated by temperature-dependent UV spectroscopy and CD spectroscopy. The metal-mediated base pair stabilizes the DNA oligonucleotide duplex by 23 °C. A redox chemistry approach confirmed that this base pair formation was due to the incorporation of copper(I) into the duplex. This first report of a copper(I)-mediated base pair adds metal-based diversity to the field and consequently opens up the range of possible applications of metal-modified nucleic acids.

Metal‐Modified Nucleic Acids: Metal‐Mediated Base Pairs, Triples, and Tetrads

“…[27] In contrast to those intercalators,the Im Phen-Ag I -Im Phen pair is covalently linked to the duplex. As the same characteristic CD-spectroscopic features have also been observed for the Im Phen-Cu I -Im Phen and Im Phen-Zn II -Im Phen pairs, [28] the enantiospecific formation of non-planar metalmediated base pairs comprising two bidentate ligands appears to be ageneral phenomenon in metal-mediated base pairing.…”

“…By incorporating pyridine nucleosides Pyr into the center of the triplex d(T 10 PyrT 10 )·d(A 10 PyrA 10 )*d(T 10 PyrT 10 ), as table triple helix was obtained. As its thermal stability was significantly increased in the presence of Ag I ions, [26,28] b) Im Phen-Hg II -T; [29] c) Im Phen-Ag I -C; [29] d) eA-Ag I 2 -eA; [32] e) eA-Hg II 2 -T; [33] f) COO Im-Cu II -COO Im; [34] g) OH U-M-OH U(M= for example, Gd III ,Z n II ); [35] h) C Hg -T; [36] i) Phe Py Pd -T. [37] R, R' = DNA backbone.…”

Stable Hg(II)-mediated base pairs with a phenanthroline-derived nucleobase surrogate in antiparallel-stranded DNA

“…292 nm (Δλ = + 8 nm). Such an effect had previously been seen for the Ag(I)-, Cu(I)-, and Zn(II)-mediated homo base pairs of P and had been assigned to the enantiospecific formation of a chiral tetrahedrally distorted metal complex [51][52][53]. In addition, the molar ellipticity of the two positive Cotton effects increases significantly.…”

“…1b). The ligand prefers to engage in a tetrahedral coordination geometry when forming [2 + 2] coordination complexes with Ag(I) [51], Cu(I) [52], and Zn(II) [53]. On the other hand, in the presence of a complementary monodentate nucleobase, it is also compatible with a [2 + 1] coordination pattern when a d 10 -configured metal ion is applied [47][48][49][50].…”

Concomitant Site‐Specific Incorporation of Silver(I) and Mercury(II) Ions into a DNA Duplex

“…[7] Most recently,t he first Cu Imediated base pair stable in aqueouss olutionw as reported. [8] Based on such metal-containing nucleic acids, several promising applications have been proposeda nd investigated, including charge transfer throughD NA, [9] DNA-templated metal nanoparticle generation, [10] DNA-based hybrid catalysis, [11] metal-ion sensors, [12] recognition of oligonucleotide sequences, [13] metal-responsive materials, [6a, 7b, 14] and expansion of the geneticf our letter code, [4i] to name just af ew.…”