G-Quadruplex DNA binding by a series of carbocyanine dyes

We have examined a number of carbocyanine dyes for their ability to bind intramolecular G-quadruplex DNA structures (G4′-DNA) using a Taq polymerase stop assay. Of the five dyes examined, only one, N,Nʹ-diethylthiacarbocyanine iodide (DTC), was found to bind to G4′-DNA. DTC was also the only dye found to inhibit human telomerase at 50 μM concentration.