Modified 2'-deoxynucleoside triphosphates (dNTPs) bearing [Ru(bpy)(3)](2+) and [Os(bpy)(3)](2+) complexes attached via an acetylene linker to the 5-position of pyrimidines (C and U) or to the 7-position of 7-deazapurines (7-deaza-A and 7-deaza-G) have been prepared in one step by aqueous cross-couplings of halogenated dNTPs with the corresponding terminal acetylenes. Polymerase incorporation by primer extension using Vent (exo-) or Pwo polymerases gave DNA labeled in specific positions with Ru(2+) or Os(2+) complexes. Square-wave voltammetry could be efficiently used to detect these labeled nucleic acids by reversible oxidations of Ru(2+/3+) or Os(2+/3+). The redox potentials of the Ru(2+) complexes (1.1-1.25 V) are very close to that of G oxidation (1.1 V), while the potentials of Os(2+) complexes (0.75 V) are sufficiently different to enable their independent detection. On the other hand, Ru(2+)-labeled DNA can be independently analyzed by luminescence. In combination with previously reported dNTPs bearing ferrocene, aminophenyl, and nitrophenyl tags, the Os-labeled dATP has been successfully used for "multicolor" redox labeling of DNA and for DNA minisequencing.

No abstract

No abstract

The title 5-substituted pyrimidines (U and C) and 7-substituted 7-deazapurines (7-deazaA and 7-deazaG) bearing tetrathiafulvelene (TTF) attached through an acetylene linker have been prepared by Sonogashira cross-coupling of the corresponding 5-or 7-iodo derivatives of nucleosides with 2-ethynyltetrathiafulvalene. Their subsequent triphosphorylation gave the corresponding nucleoside triphosphates (dNTPs). Square-wave voltammetry of the TTF-labelled nucleosides and nucleotides showed two peaks, one at 0.2-0.3 V and the other at around 0.65 V (vs. Ag|AgCl|3 M KCl), which correspond to two reversible one-electron redox pro-