Harnessing an emissive guanine surrogate to design small-molecule fluorescent chemosensors of O 6 -methylguanine-DNA-methyltransferase (MGMT).

The fluorescence properties of an emissive guanine surrogate, thienoguanine (thGN, 2-aminothieno[3,4- d ]pyrimidin-4(3 H )-one), were exploited to design two real-time chemosensors of O 6 -methylguanine-DNA-methyltransferase (MGMT), a key DNA repair enzyme involved in the resistance to DNA-alkylating anti-cancer drugs though direct reversal of O 6 -alkylated guanine adducts.