title: A tridentate "click" nucleoside for metal-mediated base pairing.
abstract: A new silver(I)-mediated base pair comprising an artificial nucleoside with the tridentate ligand 6-(1H-1,2,3-triazol-4-yl)-2,2'-bipyridine and a complementary imidazole nucleoside has been established within a B-DNA double helix. In the absence of any transition metal ion, a DNA duplex containing one such hetero base pair is slightly less stable than a comparable duplex with canonical base pairs. Upon the addition of AgNO3, a silver(I)-mediated base pair with a [3+1] coordination environment is formed, accompanied by an increase in thermal stability of about 5 °C. UV and CD spectroscopic analyses provide clear proof for the coordination of the silver(I) ion to the DNA. In contrast, a DNA duplex comprising a central homo base pair of two 6-(1H-1,2,3-triazol-4-yl)-2,2'-bipyridine entities does not form a stabilizing metal-mediated base pair, as this would require a non-planar [3+3] coordination environment and a concomitant loss of π stacking interactions. The artificial nucleoside carrying the tridentate ligand belongs to a new family of "click" nucleosides, which are conveniently accessible from 2-deoxy-β-d-glycosyl azide via a copper-catalyzed Huisgen 1,3-dipolar cycloaddition with an alkyne-bearing ligand, and significantly extends the applicability of these "click" nucleosides.
authors: Westfälische Wilhelms-Universität Münster, Institut für Anorganische und Analytische Chemie, Corrensstr. 28/30, 48149 Münster, Germany.
authors: Stefanie
authors: S
authors: Litau
authors: Westfälische Wilhelms-Universität Münster, Institut für Anorganische und Analytische Chemie, Corrensstr. 28/30, 48149 Münster, Germany. Electronic address: mueller.j@uni-muenster.de.
authors: Jens
authors: J
authors: Müller
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry*; D020029:Base Pairing; D002384:Catalysis; D002942:Circular Dichroism; D003300:Copper / Q000737:chemistry; D061565:Cycloaddition Reaction; D059371:DNA, B-Form / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry; D008024:Ligands; D008670:Metals / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D009705:Nucleosides / Q000138:chemical synthesis / Q000737:chemistry*; D012834:Silver / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D044366:Transition Temperature
chemical_list: D059371:DNA, B-Form; D007093:Imidazoles; D008024:Ligands; D008670:Metals; D009705:Nucleosides; D012834:Silver; D015082:2,2'-Dipyridyl; D003300:Copper; C029899:imidazole
keywords: DNA; Metal-mediated base pairs; Nucleobases