Modulation of base selectivity for a base-discriminating fluorescent nucleobase by addition of mercury ion

We altered the fluorescence emission selectivity of a base-discriminating fluorescent base, PyU, from A-selective to T-selective by the addition of mercury ion. The strong fluorescence from a duplex containing the PyU/T base pair was specific to the mercury ion among divalent metal ions, providing a unique method for sensing mercury ions in aqueous solutions.