An infrared spectroscopy study of the molecular structure changes of DNA after electron and ultraviolet irradiation

Samples of calf thymus DNA and two different leukemic leukocyte DNA's in the solid state have been irradiated (at 300°K) with 800 keV electrons and 4.9 eV (2537Å) ultraviolet rays. The subsequent effects on the DNA's have been studied using infrared spectroscopy as the probe for radiation-produced molecular alterations. The region of the infrared spectrum studied covered the wave number range from 4000 cm^?1 to 300 cm^?1. Our results indicate that under electron and ultraviolet irradiation, the prominent infrared active absorption peaks of all three DNA's are altered. The infrared results of our ultraviolet irradiation of DNA indicate that similar molecular bonds are broken as for the case of DNA irradiated with 800 keV electrons. The results indicate that up to high doses, calf thymus DNA is more sensitive to electron irradiation than the leukemic leukocyte DNA's. The infrared active absorption peaks of the two leukemic leukocyte DNA's respond similarly to electrons. The ultraviolet results indicate some difference between calf thymus DNA and the two leukocyte DNA's in their response to 4.9 eV light.