Inhibition of the development of Q-bands on human chromosomes by netropsin

Netropsin, an oligopeptide-type basic antibiotic, having exclusively A-T-specific DNA-binding affinity and situating itself into the minor groove of the double helix, represses the development of Q-bands if human chromosome preparations are treated with it before quinacrine mustard staining. The most probable interpretation of this effect is that netropsin interferes with the intercalation of the dye molecules. It is assumed this phenomenon supports the hypothesis that quinacrine mustard binds preferentially to A-T-rich sequences of DNA in the metaphase chromosomes.