Molecular Engineering of Thiazole Orange Dye: Change of Fluorescent Signaling from Universal to Specific upon Binding with Nucleic Acids in Bioassay.

The universal fluorescent staining property of thiazole orange (TO) dye was adapted in order to be specific for G-quadruplex DNA structures, through the introduction of a styrene-like substituent at the ortho-position of the TO scaffold. This extraordinary outcome was determined from experimental studies and further explored through molecular docking studies. The molecular docking studies help understand how such a small substituent leads to remarkable fluorescent signal discrimination between G-quadruplex DNA and other types of nucleic acids.

A molecular fluorescent dye for specific staining and imaging of RNA in live cells: a novel ligand integration from classical thiazole orange and styryl compounds.

A new RNA-selective fluorescent dye integrated with a thiazole orange and a p-(methylthio)styryl moiety shows better nucleolus RNA staining and imaging performance in live cells than the commercial stains. It also exhibits excellent photostability, cell tolerance, and counterstain compatibility with 4',6-diamidino-2-phenylindole for specific RNA-DNA colocalization in bioassays.

Sensitive and selective detection of uracil-DNA glycosylase activity with a new pyridinium luminescent switch-on molecular probe.

Uracil-deoxyribonucleic acid glycosylase (UDG) is known to function as an important base-excision repair enzyme and eliminate uracil from DNA molecules to maintain genomic integrity. A new small organic molecule (DID-VP) with interesting structural properties was synthesized as a G-quadruplex selective ligand and was demonstrated to be a sensitive luminescent switch-on probe in a convenient luminescent assay specifically for UDG detection in fetal bovine serum samples under rapid and simple conditions. This newly developed analytical method is based on the UDG enzymatic activity to unwind a duplex DNA substrate, and comprises a G-quadruplex-forming sequence (ON1) and uracil-containing DNA strand (ON2) to generate a remarkable fluorescence signal through the specific interaction of DID-VP with ON1.