Three sets of 7-deazaadenine and cytosine nucleosides and nucleoside triphosphates bearing either unsubstituted ferrocene, octamethylferrocene and ferrocenecarboxamide linked through an alkyne tether to position 7 or 5, respectively, were designed and synthesized. The modified dNFcX TPs were good substrates for KOD XL DNA polymerase in primer extension and were used for enzymatic synthesis of redox-labelled DNA probes. Square-wave voltammetry showed that the octamethylferrocene oxidation potential was shifted to lower values, whilst the ferrocenecarboxamide was shifted to higher potentials, as compared to ferrocene. Tailed PEX products containing different ratios of Fc-labelled A (dAFc ) and FcPa-labelled C (dCFcPa ) were synthesized and hybridized with capture oligonucleotides immobilized on gold electrodes to study the electrochemistry of the redox-labelled DNA. Clearly distinguishable, fully orthogonal and ratiometric peaks were observed for the dAFc and dCFcPa bases in DNA, demonstrating their potential for use in redox coding of nucleobases and for the direct electrochemical measurement of the relative ratio of nucleobases in an unknown sequence of DNA.

• Keywords
• DNA, electrochemistry, ferrocenes, nucleobases, redox labelling,
• MeSH
• Staining and Labeling methods   MeSH
• Cytidine Triphosphate chemistry   MeSH
• DNA Probes chemical synthesis   chemistry   MeSH
• DNA-Directed DNA Polymerase metabolism   MeSH
• DNA chemistry   metabolism   MeSH
• Electrochemical Techniques MeSH
• Metallocenes chemistry   MeSH
• Nucleotides chemistry   MeSH
• Oxidation-Reduction MeSH
• Substrate Specificity MeSH
• Ferrous Compounds chemistry   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Cytidine Triphosphate MeSH
• DNA Probes MeSH
• DNA-Directed DNA Polymerase MeSH
• DNA MeSH
• ferrocene MeSH Browser
• Metallocenes MeSH
• Nucleotides MeSH
• Ferrous Compounds MeSH