Possible conformations of nucleic acid fragments containing the base pair guanine:uracil.

By using classical potential functions, nonbound interaction energy calculations are carried out on the deoxydinucleoside phosphate complexes dUpdA:dUpdG and dUpdU:dGpdA. All dihedral and bond angles, except those of the nitrogen bases, are varied. On the basis of the calculations possible conformations of nucleic acid fragments containing G:U base pair are proposed. Dihedral angles of the conformations are close to those of regular Watson-Crick helices while interaction energies are 3-4 kcal/mole higher than that of A:U containing fragment conformations.