A Fluorescent Bisanthracene Macrocycle Discriminates between Matched and Mismatch-Containing DNA

The macrocyclic anthracene derivative that binds to matched and mismatched base pairs in DNA by distinct modes was investigated. The macrocycle was readily synthesized by a [2+2]-type cyclocondensation of anthracene-9,10- dicarboxaldehyde with 2,2'-oxybis(ethylamine), followed by the reduction of the macrocylic and conversion of the amine to a water-soluble hydrochloride salt. The two binding modes could be identified when the titration was performed with a mismatch-containing duplex I-TC. The absorption of the ligand rapidly decreased upon addition of I-TC up to a ligand-to-dna ratio of 4, which corresponds to binding of four ligand molecules to the duplex. The changes of fluorescence properties of macrocycle upon interaction with all 16 base-pair combinations of the duplexes I-YX were determined. It was observed that the probe is able to signal the presence of a single mismatched thymine residue in the duplexes that contain 16 other AT and GC pairs.