Changes in UV-Absorbance are Due to Slow and Fast Conformational Rearrangements during DNA-Platination

Kinetics of DNA platination involve at least two conformational rearrangements (1). The fast one is observed by ethidium bromide-dependent fluorescence, and its nature is unknown. The slow one refers to partial melting of DNA and is seen by circular dichroism and Tb3+-dependent fluorescence. We report here that the rearrangements are responsible for UV-hyperchromic effects known to accompany DNA platination (2).