An analysis of the different behavior of DNA and RNA through the study of the mutual relationship between stacking and hydrogen bonding

The mutual relationship between stacking and hydrogen bonding and the possible influence of stacking in the different behavior of DNA and RNA base pairs have been studied through complete DFT optimization of different structures of A-U and A-T dimers (i.e., A-U/U-A and A-T/T-A), using some functionals developed by the group of Truhlar. The results obtained in this work clearly show that stacking and hydrogen bonding are deeply connected. The different behavior of DNA and RNA when replacing uracil by thymine can be interpreted through the formation of a stabilizing CH/π interaction between the methyl group of thymine and the five-member ring of adenine. © 2009 American Chemical Society.