Calculations of the circular dichroism of double‐helical nucleic acids. I. Effects involving π → π* transitions

The circular dichroism of double‐helical nucleic acids was calculated as a function of geometry using the theory of Tinoco and Johnson. This theory does not include contributions of near ultraviolet transitions that are not π → π* in nature. The calculated circular dichroism shows a strong dependence on the distance of base pairs from the helix axis and the tilt of the base pair. Smaller dependences are predicted for the propeller‐like twist of a base pair and for variation of the angular increment per base pair. Moderately good agreement between calculated and many experimentally observed spectra could be generated.