Covalently Mercurated Molecular Beacon for Discriminating the Canonical Nucleobases.

A highly nucleobase discriminating metalated nucleoside analog, 3-fluoro-2-mercuri-6-methylaniline, was incorporated into an oligonucleotide molecular beacon. Fluorescence emission spectra were measured after the addition of four different complementary strands, where the nucleobase opposite of the metalated analog varies. The fluorescence results showed a clear binding selectivity at room temperature, in the order G>T>C>A. The selectivity is based on the different affinities between the metalated nucleoside analog and the canonical nucleobases. The synthesized probe is capable of robust discrimination between the two purine as well as the two pyrimidine bases by fluorescence at room temperature, and more sophisticated temperature analysis allows clear separation of every canonical nucleobase. The probe would, hence, be a suitable method for the detection of single nucleotide polymorphisms.