Direct Assessment of Interresidue Forces in Watson−Crick Base Pairs Using Theoretical Compliance Constants

This communication presents quantum mechanical calculations of interresidue potential constants for the Watson-Crick base pairs adenine-thymine (AT) and guanine-cytosine (GC), permitting a unique quantification of hydrogen bond strengths. Due to the calculated compliance constants, large differences between individual H bonds were found, while a repulsive character of the C-H...O bond in AT can be excluded.