Fourier transform infrared spectroscopy study of drug binding to DNA, 1995

In this study, observations were made on changes that occurred at the DNA phosphate and base vibrational absorption frequencies, from measurements of infrared spectrum of drug-DNA complexes in aqueous solutions. In the complex spectra of the DNA intercalators, ethidium bromide and copper porphyrin, a shift to lower wavenumber occurred at the in-plane C=0/C=N combination vibrational absorption frequency that appears around 1715 cm'1. The DNA asymmetric phosphate stretching vibrational absorption frequency at 1222 cm * was shifted to a higher frequency. The symmetric vibrational frequency at 1087 cm * was slightly shifted to a lower frequency. These shifts were not observed in the complex spectra of the DNA non-intercalator, vanadyl porphyrin. DNA protein bands can be observed in infrared spectroscopy. These bands diminish or disappear when a sample of DNA undergoes protein extraction. So, by comparing the FT-IR spectra of a DNA sample before and after protein extraction one can definitively determine the extent to which protein has been extracted