Study of the Hydrogen Bonding in the Adenine—Thymine, Adenine—Cytosine, and Guanine—Thymine Base Pairs

Abstract

The motion of the protons in the hydrogen bonds of the guanine—cytosine base pair has recently been studied by Rein and Harris, using a semiempirical LCAO MO SCF method. These investigations are extended to the adenine—thymine base pair and the ``rare'' base pairs adenine—cytosine and guanine—thymine. The total electronic energy of the ground states of the neutral base pairs and their positive and negative ions has been calculated for about 100 different configurations of the protons in the hydrogen bonds. The potential-energy surfaces obtained are reported together with the equilibrium distributions between different tautomeric forms of the base pairs.