7-Aminoactinomycin as a fluorescent probe for DNA unwinding and denaturation

A fluorescent analogue of antibiotic actinomycin D, 7-aminoactinomycin D (7AAMD), which is widely used in molecular biology, was shown by steady-state, polarization, and phase fluorescent spectroscopy to bind primarily in the unwound regions of DNA with concomitant increase in its emission intensity. The maximum emission intensity of 7AAMD is observed for denatured DNA. Thus, 7AAMD may serve as a good indicator of DNA unwinding, denaturation, and fragmentation.