Optical rotatory dispersion properties of nucleic acid complexes with the oligopeptide antibiotics distamycin A and netropsin.

ORD measurements of nucleic acids in the presence of the oligopeptides netropsin and distamycin A have indicated association of the antibiotics with DNA and strong conformational changes of the DNA structure with specificity to AT-rich helical regions. The RNA conformation is relatively unaffected by these antibiotics. The results are explained in terms of a perturbation of the DNA secondary structure as well as of the chromophore system of the oligopeptides.