Solution structure of a DNA double helix with consecutive metal-mediated base pairs.
Metal-mediated base pairs represent a powerful tool for the site-specific functionalization of nucleic acids with metal ions. The development of applications of the metal-modified nucleic acids will depend on the availability of structural information on these double helices. We present here the NMR solution structure of a self-complementary DNA oligonucleotide with three consecutive imidazole nucleotides in its centre. In the absence of transition-metal ions, a hairpin structure is adopted with the artificial nucleotides forming the loop. In the presence of Ag(i) ions, a duplex comprising three imidazole-Ag(+)-imidazole base pairs is formed. Direct proof for the formation of metal-mediated base pairs was obtained from ¹J(¹⁵N,¹⁰⁷/¹⁰⁹Ag) couplings upon incorporation of ¹⁵N-labelled imidazole. The duplex adopts a B-type conformation with only minor deviations in the region of the artificial bases. This work represents the first structural characterization of a metal-modified nucleic acid with a continuous stretch of metal-mediated base pairs.
Institute of Inorganic Chemistry, University of Zürich, Winterthurerstr. 190, 8057 Zürich, Switzerland.
Silke
S
Johannsen
Nicole
N
Megger
Dominik
D
Böhme
Roland K O
RK
Sigel
Jens
J
Müller
D020029:Base Pairing / Q000187:drug effects*; D001483:Base Sequence; D004247:DNA / Q000737:chemistry* / Q000235:genetics; D007093:Imidazoles / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000235:genetics; D012834:Silver / Q000494:pharmacology*; D012996:Solutions
D007093:Imidazoles; D009838:Oligodeoxyribonucleotides; D012996:Solutions; D012834:Silver; C029899:imidazole; D004247:DNA