Photoreactivity of 5-iodouracil-containing telomeric DNA

The photoreaction of 5-iodouracil-('U)-containing telomeric oligonucleotides in parallel or antiparallel structures, generated in the presence of K' or Na' ions, was investigated. It was found that the photoreactivity of telomeric DNA depends on the differences in the quadruplex conformations in the presence of K' or Na' ions.